1
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Roth P, Jeckelmann JM, Fender I, Ucurum Z, Lemmin T, Fotiadis D. Structure and mechanism of a phosphotransferase system glucose transporter. Nat Commun 2024; 15:7992. [PMID: 39266522 PMCID: PMC11393339 DOI: 10.1038/s41467-024-52100-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 08/26/2024] [Indexed: 09/14/2024] Open
Abstract
Glucose is the primary source of energy for many organisms and is efficiently taken up by bacteria through a dedicated transport system that exhibits high specificity. In Escherichia coli, the glucose-specific transporter IICBGlc serves as the major glucose transporter and functions as a component of the phosphoenolpyruvate-dependent phosphotransferase system. Here, we report cryo-electron microscopy (cryo-EM) structures of the glucose-bound IICBGlc protein. The dimeric transporter embedded in lipid nanodiscs was captured in the occluded, inward- and occluded, outward-facing conformations. Together with biochemical and biophysical analyses, and molecular dynamics (MD) simulations, we provide insights into the molecular basis and dynamics for substrate recognition and binding, including the gates regulating the binding sites and their accessibility. By combination of these findings, we present a mechanism for glucose transport across the plasma membrane. Overall, this work provides molecular insights into the structure, dynamics, and mechanism of the IICBGlc transporter in a native-like lipid environment.
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Affiliation(s)
- Patrick Roth
- Institute of Biochemistry and Molecular Medicine, Medical Faculty, University of Bern, Bern, Switzerland
| | - Jean-Marc Jeckelmann
- Institute of Biochemistry and Molecular Medicine, Medical Faculty, University of Bern, Bern, Switzerland
| | - Inken Fender
- Institute of Biochemistry and Molecular Medicine, Medical Faculty, University of Bern, Bern, Switzerland
| | - Zöhre Ucurum
- Institute of Biochemistry and Molecular Medicine, Medical Faculty, University of Bern, Bern, Switzerland
| | - Thomas Lemmin
- Institute of Biochemistry and Molecular Medicine, Medical Faculty, University of Bern, Bern, Switzerland
| | - Dimitrios Fotiadis
- Institute of Biochemistry and Molecular Medicine, Medical Faculty, University of Bern, Bern, Switzerland.
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2
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Cottom CO, Stephenson R, Ricci D, Yang L, Gumbart JC, Noinaj N. Structural characterization of the POTRA domains from A. baumannii reveals new conformations in BamA. Structure 2024:S0969-2126(24)00330-7. [PMID: 39293443 DOI: 10.1016/j.str.2024.08.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 07/17/2024] [Accepted: 08/22/2024] [Indexed: 09/20/2024]
Abstract
Recent studies have demonstrated BamA, the central component of the β-barrel assembly machinery (BAM), as an important therapeutic target to combat infections caused by Acinetobacter baumannii and other Gram-negative pathogens. Homology modeling indicates BamA in A. baumannii consists of five polypeptide transport-associated (POTRA) domains and a β-barrel membrane domain. We characterized the POTRA domains of BamA from A. baumannii in solution using size-exclusion chromatography small angle X-ray scattering (SEC-SAXS) analysis and determined crystal structures in two conformational states that are drastically different than those previously observed in BamA from other bacteria, indicating that the POTRA domains are even more conformationally dynamic than has been observed previously. Molecular dynamics simulations of the POTRA domains from A. baumannii and Escherichia coli allowed us to identify key structural features that contribute to the observed novel states. Together, these studies expand on our current understanding of the conformational plasticity within BamA across differing bacterial species.
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Affiliation(s)
| | - Robert Stephenson
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Dante Ricci
- Achaogen, Inc., South San Francisco, CA, USA
| | - Lixinhao Yang
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA
| | - James C Gumbart
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA; School of Physics, Georgia Institute of Technology, Atlanta, GA, USA
| | - Nicholas Noinaj
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA; Markey Center for Structural Biology, Purdue University, West Lafayette, IN, USA; Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, USA.
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3
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Isu UH, Polasa A, Moradi M. Differential Behavior of Conformational Dynamics in Active and Inactive States of Cannabinoid Receptor 1. J Phys Chem B 2024; 128:8437-8447. [PMID: 39169808 PMCID: PMC11382280 DOI: 10.1021/acs.jpcb.4c02828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2024]
Abstract
Cannabinoid receptor 1 (CB1) is a G protein-coupled receptor that regulates critical physiological processes including pain, appetite, and cognition. Understanding the conformational dynamics of CB1 associated with transitions between inactive and active signaling states is imperative for developing targeted modulators. Using microsecond-level all-atom molecular dynamics simulations, we identified marked differences in the conformational ensembles of inactive and active CB1 in apo. The inactive state exhibited substantially increased structural heterogeneity and plasticity compared to the more rigidified active state in the absence of stabilizing ligands. Transmembrane helices TM3 and TM7 were identified as distinguishing factors modulating the state-dependent dynamics. TM7 displayed amplified fluctuations selectively in the inactive state simulations attributed to disruption of conserved electrostatic contacts anchoring it to surrounding helices in the active state. Additionally, we identified significant reorganizations in key salt bridge and hydrogen bond networks contributing to the CB1 activation/inactivation. For instance, D213-Y224 hydrogen bond and D184-K192 salt bridge showed marked rearrangements between the states. Collectively, these findings reveal the specialized role of TM7 in directing state-dependent CB1 dynamics through electrostatic switch mechanisms. By elucidating the intrinsic enhanced flexibility of inactive CB1, this study provides valuable insights into the conformational landscape enabling functional transitions. Our perspective advances understanding of CB1 activation mechanisms and offers opportunities for structure-based drug discovery targeting the state-specific conformational dynamics of this receptor.
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Affiliation(s)
- Ugochi H Isu
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Adithya Polasa
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Mahmoud Moradi
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, United States
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4
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Satalkar V, Degaga GD, Li W, Pang YT, McShan AC, Gumbart JC, Mitchell JC, Torres MP. Generative β-hairpin design using a residue-based physicochemical property landscape. Biophys J 2024; 123:2790-2806. [PMID: 38297834 PMCID: PMC11393682 DOI: 10.1016/j.bpj.2024.01.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/20/2023] [Accepted: 01/25/2024] [Indexed: 02/02/2024] Open
Abstract
De novo peptide design is a new frontier that has broad application potential in the biological and biomedical fields. Most existing models for de novo peptide design are largely based on sequence homology that can be restricted based on evolutionarily derived protein sequences and lack the physicochemical context essential in protein folding. Generative machine learning for de novo peptide design is a promising way to synthesize theoretical data that are based on, but unique from, the observable universe. In this study, we created and tested a custom peptide generative adversarial network intended to design peptide sequences that can fold into the β-hairpin secondary structure. This deep neural network model is designed to establish a preliminary foundation of the generative approach based on physicochemical and conformational properties of 20 canonical amino acids, for example, hydrophobicity and residue volume, using extant structure-specific sequence data from the PDB. The beta generative adversarial network model robustly distinguishes secondary structures of β hairpin from α helix and intrinsically disordered peptides with an accuracy of up to 96% and generates artificial β-hairpin peptide sequences with minimum sequence identities around 31% and 50% when compared against the current NCBI PDB and nonredundant databases, respectively. These results highlight the potential of generative models specifically anchored by physicochemical and conformational property features of amino acids to expand the sequence-to-structure landscape of proteins beyond evolutionary limits.
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Affiliation(s)
- Vardhan Satalkar
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia
| | - Gemechis D Degaga
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Wei Li
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia
| | - Yui Tik Pang
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia
| | - Andrew C McShan
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia; School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia
| | - Julie C Mitchell
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee.
| | - Matthew P Torres
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia; School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia.
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5
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Li Y, Liu Y, Yang B, Li G, Chu H. Polarizable atomic multipole-based force field for cholesterol. J Biomol Struct Dyn 2024; 42:7747-7757. [PMID: 37565356 DOI: 10.1080/07391102.2023.2245045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 07/21/2023] [Indexed: 08/12/2023]
Abstract
Cholesterol is one of the essential component of lipid in membrane. We present a polarizable atomic multipole force field (FF) for the molecular dynamic simulation of cholesterol. The FF building process follows the computational framework as the atomic multipole optimized energetics for biomolecular applications (AMOEBA) model. In this framework, the electronics parameters, including atomic monopole moments, dipole moments, and quadrupole moments calculated from ab initio calculations in the gas phase, are applied to represent the charge distribution. Furthermore, the many-body polarization is modeled by following the same pattern of distributed atomic polarizabilities. Then, the bilayers composed of two typical phospholipid molecules, 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), in a range of different cholesterol concentrations are built and implemented by molecular dynamics (MD) simulations based on the proposed polarizable FF. The simulation results are statistically analyzed to validate the feasibility of the proposed FF. The structural properties of the bilayers are calculated to compare with the related experimental values. The MD values show the same trend of experimental values changes.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Yan Li
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, Liaoning, China
| | - Ye Liu
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, Liaoning, China
| | - Boya Yang
- Dalian Municipal Central Hospital, Liaoning, China
| | - Guohui Li
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, Liaoning, China
| | - Huiying Chu
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, Liaoning, China
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6
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Babii S, Li W, Yang L, Grzegorzewicz AE, Jackson M, Gumbart JC, Zgurskaya HI. Allosteric coupling of substrate binding and proton translocation in MmpL3 transporter from Mycobacterium tuberculosis. mBio 2024:e0218324. [PMID: 39212407 DOI: 10.1128/mbio.02183-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2024] [Accepted: 08/01/2024] [Indexed: 09/04/2024] Open
Abstract
Infections caused by Mycobacterium spp. are very challenging to treat, and multidrug-resistant strains rapidly spread in human populations. Major contributing factors include the unique physiological features of these bacteria, drug efflux, and the low permeability barrier of their outer membrane. Here, we focus on MmpL3 from Mycobacterium tuberculosis, an essential inner membrane transporter of the resistance-nodulation-division superfamily required for the translocation of mycolic acids in the form of trehalose monomycolates (TMM) from the cytoplasm or plasma membrane to the periplasm or outer membrane. The MmpL3-dependent transport of TMM is essential for the growth of M. tuberculosis in vitro, inside macrophages, and in M. tuberculosis-infected mice. MmpL3 is also a validated target for several recently identified anti-mycobacterial agents. In this study, we reconstituted the lipid transport activity of the purified MmpL3 using a two-lipid vesicle system and established the ability of MmpL3 to actively extract phospholipids from the outer leaflet of a lipid bilayer. In contrast, we found that MmpL3 lacks the ability to translocate the same phospholipid substrate across the plasma membrane indicating that it is not an energy-dependent flippase. The lipid extraction activity was modulated by substitutions in critical charged and polar residues of the periplasmic substrate-binding pocket of MmpL3, coupled to the proton transfer activity of MmpL3 and inhibited by a small molecule inhibitor SQ109. Based on the results, we propose a mechanism of allosteric coupling wherein substrate translocation by MmpL3 is coupled to the energy provided by the downhill transfer of protons. The reconstituted activities will facilitate understanding the mechanism of MmpL3-dependent transport of lipids and the discovery of new therapeutic options for Mycobacterium spp. infections.IMPORTANCEMmpL3 from Mycobacterium tuberculosis is an essential transporter involved in the assembly of the mycobacterial outer membrane. It is also an important target in undergoing efforts to discover new anti-tuberculosis drugs effective against multidrug-resistant strains spreading in human populations. The recent breakthrough structural studies uncovered features of MmpL3 that suggested a possible lipid transport mechanism. In this study, we reconstituted and characterized the lipid transport activity of MmpL3 and demonstrated that this activity is blocked by MmpL3 inhibitors and substrate mimics. We further uncovered the mechanism of how the binding of a substrate in the periplasmic domain is communicated to the transmembrane proton relay of MmpL3. The uncovered mechanism and the developed assays provide new opportunities for mechanistic analyses of MmpL3 function and its inhibition.
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Affiliation(s)
- Svitlana Babii
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
| | - Wei Li
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Lixinhao Yang
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Anna E Grzegorzewicz
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - James C Gumbart
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Helen I Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
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7
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Ngo VA. Insight into molecular basis and dynamics of full-length CRaf kinase in cellular signaling mechanisms. Biophys J 2024; 123:2623-2637. [PMID: 38946141 PMCID: PMC11365224 DOI: 10.1016/j.bpj.2024.06.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 05/15/2024] [Accepted: 06/28/2024] [Indexed: 07/02/2024] Open
Abstract
Raf kinases play key roles in signal transduction in cells for regulating proliferation, differentiation, and survival. Despite decades of research into functions and dynamics of Raf kinases with respect to other cytosolic proteins, understanding Raf kinases is limited by the lack of their full-length structures at the atomic resolution. Here, we present the first model of the full-length CRaf kinase obtained from artificial intelligence/machine learning algorithms with a converging ensemble of structures simulated by large-scale temperature replica exchange simulations. Our model is validated by comparing simulated structures with the latest cryo-EM structure detailing close contacts among three key domains and regions of the CRaf. Our simulations identify potentially new epitopes of intramolecule interactions within the CRaf and reveal a dynamical nature of CRaf kinases, in which the three domains can move back and forth relative to each other for regulatory dynamics. The dynamic conformations are then used in a docking algorithm to shed insight into the paradoxical effect caused by vemurafenib in comparison with a paradox breaker PLX7904. We propose a model of Raf-heterodimer/KRas-dimer as a signalosome based on the dynamics of the full-length CRaf.
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Affiliation(s)
- Van A Ngo
- Advanced Computing for Life Sciences and Engineering, Science Engagement Section, Computing and Computational Sciences, National Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee.
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8
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Lincoff J, Helsell CVM, Marcoline FV, Natale AM, Grabe M. Membrane curvature sensing and symmetry breaking of the M2 proton channel from Influenza A. eLife 2024; 13:e81571. [PMID: 39150863 PMCID: PMC11383528 DOI: 10.7554/elife.81571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 08/07/2024] [Indexed: 08/18/2024] Open
Abstract
The M2 proton channel aids in the exit of mature influenza viral particles from the host plasma membrane through its ability to stabilize regions of high negative Gaussian curvature (NGC) that occur at the neck of budding virions. The channels are homo-tetramers that contain a cytoplasm-facing amphipathic helix (AH) that is necessary and sufficient for NGC generation; however, constructs containing the transmembrane spanning helix, which facilitates tetramerization, exhibit enhanced curvature generation. Here, we used all-atom molecular dynamics (MD) simulations to explore the conformational dynamics of M2 channels in lipid bilayers revealing that the AH is dynamic, quickly breaking the fourfold symmetry observed in most structures. Next, we carried out MD simulations with the protein restrained in four- and twofold symmetric conformations to determine the impact on the membrane shape. While each pattern was distinct, all configurations induced pronounced curvature in the outer leaflet, while conversely, the inner leaflets showed minimal curvature and significant lipid tilt around the AHs. The MD-generated profiles at the protein-membrane interface were then extracted and used as boundary conditions in a continuum elastic membrane model to calculate the membrane-bending energy of each conformation embedded in different membrane surfaces characteristic of a budding virus. The calculations show that all three M2 conformations are stabilized in inward-budding, concave spherical caps and destabilized in outward-budding, convex spherical caps, the latter reminiscent of a budding virus. One of the C2-broken symmetry conformations is stabilized by 4 kT in NGC surfaces with the minimum energy conformation occurring at a curvature corresponding to 33 nm radii. In total, our work provides atomistic insight into the curvature sensing capabilities of M2 channels and how enrichment in the nascent viral particle depends on protein shape and membrane geometry.
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Affiliation(s)
- James Lincoff
- Cardiovascular Research Institute, Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States
| | - Cole V M Helsell
- Cardiovascular Research Institute, Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States
- Graduate Group in Biophysics, University of California, San Francisco, San Francisco, United States
| | - Frank V Marcoline
- Cardiovascular Research Institute, Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States
| | - Andrew M Natale
- Cardiovascular Research Institute, Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States
- Graduate Group in Biophysics, University of California, San Francisco, San Francisco, United States
| | - Michael Grabe
- Cardiovascular Research Institute, Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States
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9
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Talandashti R, Moqadam M, Reuter N. Model Mechanism for Lipid Uptake by the Human STARD2/PC-TP Phosphatidylcholine Transfer Protein. J Phys Chem Lett 2024; 15:8287-8295. [PMID: 39143857 PMCID: PMC11331517 DOI: 10.1021/acs.jpclett.4c01743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2024] [Revised: 07/11/2024] [Accepted: 07/16/2024] [Indexed: 08/16/2024]
Abstract
The human StAR-related lipid transfer domain protein 2 (STARD2), also known as phosphatidylcholine (PC) transfer protein, is a single-domain lipid transfer protein thought to transfer PC lipids between intracellular membranes. We performed extensive μs-long molecular dynamics simulations of STARD2 of its apo and holo forms in the presence or absence of complex lipid bilayers. The simulations in water reveal ligand-dependent conformational changes. In the 2 μs-long simulations of apo STARD2 in the presence of a lipid bilayer, we observed spontaneous reproducible PC lipid uptake into the protein hydrophobic cavity. We propose that the lipid extraction mechanism involves one to two metastable states stabilized by choline-tyrosine or choline-tryptophane cation-π interactions. Using free energy perturbation, we evaluate that PC-tyrosine cation-π interactions contribute 1.8 and 2.5 kcal/mol to the affinity of a PC-STARD2 metastable state, thus potentially providing a significant decrease of the energy barrier required for lipid desorption.
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Affiliation(s)
- Reza Talandashti
- Department
of Chemistry, University of Bergen, Bergen 5020, Norway
- Computational
Biology Unit, Department of Informatics, University of Bergen, Bergen 5020, Norway
| | - Mahmoud Moqadam
- Department
of Chemistry, University of Bergen, Bergen 5020, Norway
- Computational
Biology Unit, Department of Informatics, University of Bergen, Bergen 5020, Norway
| | - Nathalie Reuter
- Department
of Chemistry, University of Bergen, Bergen 5020, Norway
- Computational
Biology Unit, Department of Informatics, University of Bergen, Bergen 5020, Norway
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10
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Hirschi S, Lemmin T, Ayoub N, Kalbermatter D, Pellegata D, Ucurum Z, Gertsch J, Fotiadis D. Structural insights into the mechanism and dynamics of proteorhodopsin biogenesis and retinal scavenging. Nat Commun 2024; 15:6950. [PMID: 39138159 PMCID: PMC11322631 DOI: 10.1038/s41467-024-50960-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 07/25/2024] [Indexed: 08/15/2024] Open
Abstract
Microbial ion-pumping rhodopsins (MRs) are extensively studied retinal-binding membrane proteins. However, their biogenesis, including oligomerisation and retinal incorporation, remains poorly understood. The bacterial green-light absorbing proton pump proteorhodopsin (GPR) has emerged as a model protein for MRs and is used here to address these open questions using cryo-electron microscopy (cryo-EM) and molecular dynamics (MD) simulations. Specifically, conflicting studies regarding GPR stoichiometry reported pentamer and hexamer mixtures without providing possible assembly mechanisms. We report the pentameric and hexameric cryo-EM structures of a GPR mutant, uncovering the role of the unprocessed N-terminal signal peptide in the assembly of hexameric GPR. Furthermore, certain proteorhodopsin-expressing bacteria lack retinal biosynthesis pathways, suggesting that they scavenge the cofactor from their environment. We shed light on this hypothesis by solving the cryo-EM structure of retinal-free proteoopsin, which together with mass spectrometry and MD simulations suggests that decanoate serves as a temporary placeholder for retinal in the chromophore binding pocket. Further MD simulations elucidate possible pathways for the exchange of decanoate and retinal, offering a mechanism for retinal scavenging. Collectively, our findings provide insights into the biogenesis of MRs, including their oligomeric assembly, variations in protomer stoichiometry and retinal incorporation through a potential cofactor scavenging mechanism.
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Affiliation(s)
- Stephan Hirschi
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland.
- Department of Biochemistry, University of Oxford, OX1 3QU, Oxford, UK.
| | - Thomas Lemmin
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland.
| | - Nooraldeen Ayoub
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland
| | - David Kalbermatter
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland
| | - Daniele Pellegata
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland
| | - Zöhre Ucurum
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland
| | - Jürg Gertsch
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland
| | - Dimitrios Fotiadis
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland.
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11
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López-Sánchez U, Munro LJ, Ladefoged LK, Pedersen AJ, Brun CC, Lyngby SM, Baud D, Juillan-Binard C, Pedersen MG, Lummis SCR, Bang-Andersen B, Schiøtt B, Chipot C, Schoehn G, Neyton J, Dehez F, Nury H, Kristensen AS. Structural determinants for activity of the antidepressant vortioxetine at human and rodent 5-HT 3 receptors. Nat Struct Mol Biol 2024; 31:1232-1242. [PMID: 38698207 DOI: 10.1038/s41594-024-01282-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 03/19/2024] [Indexed: 05/05/2024]
Abstract
Vortioxetine (VTX) is a recently approved antidepressant that targets a variety of serotonin receptors. Here, we investigate the drug's molecular mechanism of operation at the serotonin 5-HT3 receptor (5-HT3R), which features two properties: VTX acts differently on rodent and human 5-HT3R, and VTX appears to suppress any subsequent response to agonists. Using a combination of cryo-EM, electrophysiology, voltage-clamp fluorometry and molecular dynamics, we show that VTX stabilizes a resting inhibited state of the mouse 5-HT3R and an agonist-bound-like state of human 5-HT3R, in line with the functional profile of the drug. We report four human 5-HT3R structures and show that the human receptor transmembrane domain is intrinsically fragile. We also explain the lack of recovery after VTX administration via a membrane partition mechanism.
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Affiliation(s)
- Uriel López-Sánchez
- University Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
- Program in Cellular and Molecular Medicine, Boston Children's Hospital and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Lachlan Jake Munro
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | | | - Anders Juel Pedersen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Christian Colding Brun
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Signe Meisner Lyngby
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Delphine Baud
- University Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
| | | | | | - Sarah C R Lummis
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | | | - Birgit Schiøtt
- Department of Chemistry, Aarhus University, Aarhus, Denmark
| | - Christophe Chipot
- Université de Lorraine, CNRS, LPCT, Nancy, France
- Laboratoire International Associé CNRS and University of Illinois at Urbana-Champaign, Vandoeuvre-les-Nancy, France
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Guy Schoehn
- University Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
| | - Jacques Neyton
- University Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
| | - Francois Dehez
- Université de Lorraine, CNRS, LPCT, Nancy, France
- Laboratoire International Associé CNRS and University of Illinois at Urbana-Champaign, Vandoeuvre-les-Nancy, France
| | - Hugues Nury
- University Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France.
| | - Anders S Kristensen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
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12
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Barrionuevo EM, Peralta E, Manzur De Nardi A, Monat J, Fallico MJ, Llanos MA, Gavernet L, Mustafá ER, Martin P, Talevi A. In Silico Screening Identification of Fatty Acids and Fatty Acid Derivatives with Antiseizure Activity: In Vitro and In Vivo Validation. Pharmaceutics 2024; 16:996. [PMID: 39204342 PMCID: PMC11357650 DOI: 10.3390/pharmaceutics16080996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2024] [Revised: 07/19/2024] [Accepted: 07/24/2024] [Indexed: 09/04/2024] Open
Abstract
High fat diets have been used as complementary treatments for seizure disorders for more than a century. Moreover, many fatty acids and derivatives, including the broad-spectrum antiseizure medication valproic acid, have been explored and used as pharmacological agents to treat epilepsy. In this work, we have explored the anticonvulsant potential of a large library of fatty acids and fatty acid derivatives, the LIPID MAPS Structure Database, using structure-based virtual screening to assess their ability to block the voltage-gated sodium channel 1.2 (NaV1.2), a validated target for antiseizure medications. Four of the resulting in silico hits were submitted for experimental confirmation using in vitro patch clamp experiments, and their protective role was evaluated in an acute mice seizure model, the Maximal Electroshock seizure model. These four compounds were found to protect mice against seizures. Two of them exhibited blocking effects on NaV1.2, CaV2.2, and CaV3.1.
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Affiliation(s)
- Emilia Mercedes Barrionuevo
- Laboratory of Bioactive Compound Research and Development (LIDeB), Faculty of Exact Sciences, National University of La Plata (UNLP), Blvd. 120 1489, La Plata 1900, Argentina
- Argentinean National Council of Scientific and Technical Research (CONICET), CCT La Plata, La Plata 1900, Argentina
| | - Estefanía Peralta
- Laboratory of Bioactive Compound Research and Development (LIDeB), Faculty of Exact Sciences, National University of La Plata (UNLP), Blvd. 120 1489, La Plata 1900, Argentina
- Argentinean National Council of Scientific and Technical Research (CONICET), CCT La Plata, La Plata 1900, Argentina
| | - Agustín Manzur De Nardi
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), Universidad Nacional de La Plata–CICPBA–CONICET, Boulevard 120 no. 1489, La Plata 1900, Argentina
| | - Juliana Monat
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), Universidad Nacional de La Plata–CICPBA–CONICET, Boulevard 120 no. 1489, La Plata 1900, Argentina
| | - Maximiliano José Fallico
- Laboratory of Bioactive Compound Research and Development (LIDeB), Faculty of Exact Sciences, National University of La Plata (UNLP), Blvd. 120 1489, La Plata 1900, Argentina
- Argentinean National Council of Scientific and Technical Research (CONICET), CCT La Plata, La Plata 1900, Argentina
| | - Manuel Augusto Llanos
- Laboratory of Bioactive Compound Research and Development (LIDeB), Faculty of Exact Sciences, National University of La Plata (UNLP), Blvd. 120 1489, La Plata 1900, Argentina
- Argentinean National Council of Scientific and Technical Research (CONICET), CCT La Plata, La Plata 1900, Argentina
| | - Luciana Gavernet
- Laboratory of Bioactive Compound Research and Development (LIDeB), Faculty of Exact Sciences, National University of La Plata (UNLP), Blvd. 120 1489, La Plata 1900, Argentina
- Argentinean National Council of Scientific and Technical Research (CONICET), CCT La Plata, La Plata 1900, Argentina
| | - Emilio Román Mustafá
- Electrophysiology Laboratory of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET), Scientific Research Commission of the Province of Buenos Aires (CIC-PBA) and National University of La Plata (UNLP)], La Plata 1900, Argentina
| | - Pedro Martin
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), Universidad Nacional de La Plata–CICPBA–CONICET, Boulevard 120 no. 1489, La Plata 1900, Argentina
| | - Alan Talevi
- Laboratory of Bioactive Compound Research and Development (LIDeB), Faculty of Exact Sciences, National University of La Plata (UNLP), Blvd. 120 1489, La Plata 1900, Argentina
- Argentinean National Council of Scientific and Technical Research (CONICET), CCT La Plata, La Plata 1900, Argentina
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13
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Chen SY, Fiedler MK, Gronauer TF, Omelko O, von Wrisberg MK, Wang T, Schneider S, Sieber SA, Zacharias M. Unraveling the mechanism of small molecule induced activation of Staphylococcus aureus signal peptidase IB. Commun Biol 2024; 7:895. [PMID: 39043865 PMCID: PMC11266668 DOI: 10.1038/s42003-024-06575-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 07/11/2024] [Indexed: 07/25/2024] Open
Abstract
Staphylococcus aureus signal peptidase IB (SpsB) is an essential enzyme for protein secretion. While inhibition of its activity by small molecules is a well-precedented mechanism to kill bacteria, the mode of activation is however less understood. We here investigate the activation mechanism of a recently introduced activator, the antibiotic compound PK150, and demonstrate by combined experimental and Molecular Dynamics (MD) simulation studies a unique principle of enzyme stimulation. Mass spectrometric studies with an affinity-based probe of PK150 unravel the binding site of PK150 in SpsB which is used as a starting point for MD simulations. Our model shows the localization of the molecule in an allosteric pocket next to the active site which shields the catalytic dyad from excess water that destabilizes the catalytic geometry. This mechanism is validated by the placement of mutations aligning the binding pocket of PK150. While the mutants retain turnover of the SpsB substrate, no stimulation of activity is observed upon PK150 addition. Overall, our study elucidates a previously little investigated mechanism of enzyme activation and serves as a starting point for the development of future enzyme activators.
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Affiliation(s)
- Shu-Yu Chen
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, Zurich, 8093, Switzerland
- TUM School of Natural Sciences, Department Biosciences, Theoretical Biophysics (T38), Center for Functional Protein Assemblies (CPA), Technical University Munich (TUM), Ernst-Otto-Fischer Str. 8, Garching, 85748, Germany
| | - Michaela K Fiedler
- TUM School of Natural Sciences, Department Biosciences, Chair of Organic Chemistry II, Center for Functional Protein Assemblies (CPA), Technical University Munich (TUM), Ernst-Otto-Fischer Str. 8, Garching, 85748, Germany
| | - Thomas F Gronauer
- TUM School of Natural Sciences, Department Biosciences, Chair of Organic Chemistry II, Center for Functional Protein Assemblies (CPA), Technical University Munich (TUM), Ernst-Otto-Fischer Str. 8, Garching, 85748, Germany
| | - Olesia Omelko
- TUM School of Natural Sciences, Department Biosciences, Chair of Organic Chemistry II, Center for Functional Protein Assemblies (CPA), Technical University Munich (TUM), Ernst-Otto-Fischer Str. 8, Garching, 85748, Germany
| | - Marie-Kristin von Wrisberg
- Department of Chemistry, Ludwig-Maximilians University Munich (LMU), Butenandtstr. 5-13, Munich, 81377, Germany
| | - Tao Wang
- TUM School of Natural Sciences, Department Biosciences, Chair of Organic Chemistry II, Center for Functional Protein Assemblies (CPA), Technical University Munich (TUM), Ernst-Otto-Fischer Str. 8, Garching, 85748, Germany
| | - Sabine Schneider
- Department of Chemistry, Ludwig-Maximilians University Munich (LMU), Butenandtstr. 5-13, Munich, 81377, Germany
| | - Stephan A Sieber
- TUM School of Natural Sciences, Department Biosciences, Chair of Organic Chemistry II, Center for Functional Protein Assemblies (CPA), Technical University Munich (TUM), Ernst-Otto-Fischer Str. 8, Garching, 85748, Germany.
| | - Martin Zacharias
- TUM School of Natural Sciences, Department Biosciences, Theoretical Biophysics (T38), Center for Functional Protein Assemblies (CPA), Technical University Munich (TUM), Ernst-Otto-Fischer Str. 8, Garching, 85748, Germany.
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14
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Kariyawasam NL, Wereszczynski J. The Influence of Ionic Environment on Nucleosome-Mica Interactions Revealed via Molecular Dynamics Simulations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.25.600666. [PMID: 38979319 PMCID: PMC11230366 DOI: 10.1101/2024.06.25.600666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Mica serves as a crucial substrate in Atomic Force Microscopy (AFM) studies for visualizing and characterizing nucleosomes. Nucleosomes interact with the negatively charged mica surface via adsorbed cations. However, the specific influences of monovalent and divalent cations on nucleosome adsorption to the mica surface remain unclear. In this study, we investigated the binding of nucleosomes to the mica surface in the presence of monovalent potassium ions and divalent magnesium ions using molecular dynamics simulations. We also explored the impact of pre-treated mica surfaces on nucleosome binding and structure. Our findings reveal that nucleosome-mica interactions vary depending on the cations present, resulting in distinct effects on nucleosome structure. Notably, nucleosomes bind effectively to a mica surface in the presence of potassium ions with minimal structural perturbations.
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Affiliation(s)
- Nilusha L Kariyawasam
- Department of Physics, Illinois Institute of Technology, Chicago, USA
- Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, Chicago, USA
| | - Jeff Wereszczynski
- Departments of Physics and Biology, Illinois Institute of Technology, Chicago, USA
- Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, Chicago, USA
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15
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Lihan M, Tajkhorshid E. Improved Highly Mobile Membrane Mimetic Model for Investigating Protein-Cholesterol Interactions. J Chem Inf Model 2024; 64:4822-4834. [PMID: 38844760 DOI: 10.1021/acs.jcim.4c00619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/25/2024]
Abstract
Cholesterol (CHL) plays an integral role in modulating the function and activity of various mammalian membrane proteins. Due to the slow dynamics of lipids, conventional computational studies of protein-CHL interactions rely on either long-time scale atomistic simulations or coarse-grained approximations to sample the process. A highly mobile membrane mimetic (HMMM) has been developed to enhance lipid diffusion and thus used to facilitate the investigation of lipid interactions with peripheral membrane proteins and, with customized in silico solvents to replace phospholipid tails, with integral membrane proteins. Here, we report an updated HMMM model that is able to include CHL, a nonphospholipid component of the membrane, henceforth called HMMM-CHL. To this end, we had to optimize the effect of the customized solvents on CHL behavior in the membrane. Furthermore, the new solvent is compatible with simulations using force-based switching protocols. In the HMMM-CHL, both improved CHL dynamics and accelerated lipid diffusion are integrated. To test the updated model, we have applied it to the characterization of protein-CHL interactions in two membrane protein systems, the human β2-adrenergic receptor (β2AR) and the mitochondrial voltage-dependent anion channel 1 (VDAC-1). Our HMMM-CHL simulations successfully identified CHL binding sites and captured detailed CHL interactions in excellent consistency with experimental data as well as other simulation results, indicating the utility of the improved model in applications where an enhanced sampling of protein-CHL interactions is desired.
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Affiliation(s)
- Muyun Lihan
- Center for Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
- NIH Center for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Emad Tajkhorshid
- Center for Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
- NIH Center for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
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16
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Wang D, Zhang Z, Baudys J, Haynes C, Osman SH, Zhou B, Barr JR, Gumbart JC. Enhanced Surface Accessibility of SARS-CoV-2 Omicron Spike Protein Due to an Altered Glycosylation Profile. ACS Infect Dis 2024; 10:2032-2046. [PMID: 38728322 PMCID: PMC11184558 DOI: 10.1021/acsinfecdis.4c00015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 04/27/2024] [Accepted: 04/30/2024] [Indexed: 05/12/2024]
Abstract
SARS-CoV-2 spike (S) proteins undergo extensive glycosylation, aiding in proper folding, enhancing stability, and evading host immune surveillance. In this study, we used mass spectrometric analysis to elucidate the N-glycosylation characteristics and disulfide bonding of recombinant spike proteins derived from the SARS-CoV-2 Omicron variant (B.1.1.529) in comparison with the D614G spike variant. Furthermore, we conducted microsecond-long molecular dynamics simulations on spike proteins to resolve how the different N-glycans impact spike conformational sampling in the two variants. Our findings reveal that the Omicron spike protein maintains an overall resemblance to the D614G spike variant in terms of site-specific glycan processing and disulfide bond formation. Nonetheless, alterations in glycans were observed at certain N-glycosylation sites. These changes, in synergy with mutations within the Omicron spike protein, result in increased surface accessibility of the macromolecule, including the ectodomain, receptor-binding domain, and N-terminal domain. Additionally, mutagenesis and pull-down assays reveal the role of glycosylation of a specific sequon (N149); furthermore, the correlation of MD simulation and HDX-MS identified several high-dynamic areas of the spike proteins. These insights contribute to our understanding of the interplay between structure and function, thereby advancing effective vaccination and therapeutic strategies.
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Affiliation(s)
- Dongxia Wang
- National
Center for Environmental Health, Division of Laboratory Sciences, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia 30322 United States
| | - Zijian Zhang
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332 United States
| | - Jakub Baudys
- National
Center for Environmental Health, Division of Laboratory Sciences, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia 30322 United States
| | - Christopher Haynes
- National
Center for Environmental Health, Division of Laboratory Sciences, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia 30322 United States
| | - Sarah H. Osman
- National
Center for Environmental Health, Division of Laboratory Sciences, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia 30322 United States
| | - Bin Zhou
- National
Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia 30322 United States
| | - John R. Barr
- National
Center for Environmental Health, Division of Laboratory Sciences, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia 30322 United States
| | - James C. Gumbart
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332 United States
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17
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Bošković F, Maffeo C, Patiño-Guillén G, Tivony R, Aksimentiev A, Keyser UF. Nanopore Translocation Reveals Electrophoretic Force on Noncanonical RNA:DNA Double Helix. ACS NANO 2024; 18:15013-15024. [PMID: 38822455 PMCID: PMC11171748 DOI: 10.1021/acsnano.4c01466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 05/13/2024] [Accepted: 05/22/2024] [Indexed: 06/03/2024]
Abstract
Electrophoretic transport plays a pivotal role in advancing sensing technologies. So far, systematic studies have focused on the translocation of canonical B-form or A-form nucleic acids, while direct RNA analysis is emerging as the new frontier for nanopore sensing and sequencing. Here, we compare the less-explored dynamics of noncanonical RNA:DNA hybrids in electrophoretic transport to the well-researched transport of B-form DNA. Using DNA/RNA nanotechnology and solid-state nanopores, the translocation of RNA:DNA (RD) and DNA:DNA (DD) duplexes was examined. Notably, RD duplexes were found to translocate through nanopores faster than DD duplexes, despite containing the same number of base pairs. Our experiments reveal that RD duplexes present a noncanonical helix, with distinct transport properties from B-form DD molecules. We find that RD and DD molecules, with the same contour length, move with comparable velocity through nanopores. We examined the physical characteristics of both duplex forms using atomic force microscopy, atomistic molecular dynamics simulations, agarose gel electrophoresis, and dynamic light scattering measurements. With the help of coarse-grained and molecular dynamics simulations, we find the effective force per unit length applied by the electric field to a fragment of RD or DD duplex in nanopores with various geometries or shapes to be approximately the same. Our results shed light on the significance of helical form in nucleic acid translocation, with implications for RNA sensing, sequencing, and the molecular understanding of electrophoretic transport.
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Affiliation(s)
- Filip Bošković
- Cavendish
Laboratory, University of Cambridge, Cambridge CB3 0HE, U.K.
| | - Christopher Maffeo
- Department
of Physics, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Beckman
Institute for Advanced Science and Technology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | | | - Ran Tivony
- Cavendish
Laboratory, University of Cambridge, Cambridge CB3 0HE, U.K.
| | - Aleksei Aksimentiev
- Department
of Physics, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Beckman
Institute for Advanced Science and Technology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Department
of Bioengineering, University of Illinois
at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Ulrich F. Keyser
- Cavendish
Laboratory, University of Cambridge, Cambridge CB3 0HE, U.K.
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18
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Lewis BR, Uddin MR, Kuo KM, Shah LMN, Harris NJ, Booth PJ, Hammerschmid D, Gumbart JC, Zgurskaya HI, Reading E. Mg 2+-dependent mechanism of environmental versatility in a multidrug efflux pump. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.10.597921. [PMID: 38915626 PMCID: PMC11195059 DOI: 10.1101/2024.06.10.597921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Tripartite resistance nodulation and cell division multidrug efflux pumps span the periplasm and are a major driver of multidrug resistance among Gram-negative bacteria. The periplasm provides a distinct environment between the inner and outer membranes of Gram-negative bacteria. Cations, such as Mg2+, become concentrated within the periplasm and, in contrast to the cytoplasm, its pH is sensitive to conditions outside the cell. Here, we reveal an interplay between Mg2+ and pH in modulating the dynamics of the periplasmic adaptor protein, AcrA, and its function within the prototypical AcrAB-TolC multidrug efflux pump from Escherichia coli. In the absence of Mg2+, AcrA becomes increasingly plastic within acidic conditions, but when Mg2+ is bound this is ameliorated, resulting in domain specific organisation in neutral to weakly acidic regimes. We establish a unique histidine residue directs these structural dynamics and is essential for sustaining pump efflux activity across acidic, neutral, and alkaline conditions. Overall, we propose Mg2+ conserves the structural mobility of AcrA to ensure optimal AcrAB-TolC function within rapid changing environments commonly faced by the periplasm during bacterial infection and colonization. This work highlights that Mg2+ is an important mechanistic component in this pump class and possibly across other periplasmic lipoproteins.
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Affiliation(s)
- Benjamin Russell Lewis
- Department of Chemistry, Britannia House, 7 Trinity Street, King’s College London, London, SE1 1DB, UK
| | - Muhammad R. Uddin
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, USA
| | - Katie M. Kuo
- School of Physics, Georgia Institute of Technology, 837 State Street NW, Atlanta, Georgia 30332, USA
| | - Laila M. N. Shah
- Department of Chemistry, Britannia House, 7 Trinity Street, King’s College London, London, SE1 1DB, UK
| | - Nicola J. Harris
- Department of Chemistry, Britannia House, 7 Trinity Street, King’s College London, London, SE1 1DB, UK
| | - Paula J. Booth
- Department of Chemistry, Britannia House, 7 Trinity Street, King’s College London, London, SE1 1DB, UK
| | - Dietmar Hammerschmid
- Department of Chemistry, Britannia House, 7 Trinity Street, King’s College London, London, SE1 1DB, UK
- School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - James C. Gumbart
- School of Physics, Georgia Institute of Technology, 837 State Street NW, Atlanta, Georgia 30332, USA
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, Georgia 30332, USA
| | - Helen I. Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, USA
| | - Eamonn Reading
- Department of Chemistry, Britannia House, 7 Trinity Street, King’s College London, London, SE1 1DB, UK
- School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, UK
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19
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Ryoo D, Hwang H, Gumbart JC. Thicket and Mesh: How the Outer Membrane Can Resist Tension Imposed by the Cell Wall. J Phys Chem B 2024; 128:5371-5377. [PMID: 38787347 PMCID: PMC11163421 DOI: 10.1021/acs.jpcb.3c08510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 05/07/2024] [Accepted: 05/09/2024] [Indexed: 05/25/2024]
Abstract
The cell envelope of Gram-negative bacteria is composed of an outer membrane (OM) and an inner membrane (IM) and a peptidoglycan cell wall (CW) between them. Combined with Braun's lipoprotein (Lpp), which connects the OM and the CW, and numerous membrane proteins that exist in both OM and IM, the cell envelope creates a mechanically stable environment that resists various physical and chemical perturbations to the cell, including turgor pressure caused by the solute concentration difference between the cytoplasm of the cell and the extracellular environment. Previous computational studies have explored how individual components (OM, IM, and CW) can resist turgor pressure although combinations of them have been less well studied. To that end, we constructed multiple OM-CW systems, including the Lpp connections with the CW under increasing degrees of strain. The results show that the OM can effectively resist the tension imposed by the CW, shrinking by only 3-5% in area even when the CW is stretched to 2.5× its relaxed area. The area expansion modulus of the system increases with increasing CW strain, although the OM remains a significant contributor to the envelope's mechanical stability. Additionally, we find that when the protein TolC is embedded in the OM, its stiffness increases.
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Affiliation(s)
- David Ryoo
- Interdisciplinary
Bioengineering Graduate Program, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
| | - Hyea Hwang
- School
of Materials Science and Engineering, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
| | - James C. Gumbart
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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20
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Bošković F, Maffeo C, Patiño-Guillén G, Tivony R, Aksimentiev A, Keyser UF. Nanopore translocation reveals electrophoretic force on non-canonical RNA:DNA double helix. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.09.12.557357. [PMID: 37745457 PMCID: PMC10515835 DOI: 10.1101/2023.09.12.557357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Electrophoretic transport plays a pivotal role in advancing sensing technologies. So far, systematic studies have focused on translocation of canonical B-form or A-form nucleic acids, while direct RNA analysis is emerging as the new frontier for nanopore sensing and sequencing. Here, we compare the less-explored dynamics of non-canonical RNA:DNA hybrids in electrophoretic transport with the well-researched transport of B-form DNA. Using DNA/RNA nanotechnology and solid-state nanopores, the translocation of RNA:DNA (RD) and DNA:DNA (DD) duplexes was examined. Notably, RD duplexes were found to translocate through nanopores faster than DD duplexes, despite containing the same number of base pairs. Our experiments reveal that RD duplexes present a non-canonical helix with distinct transport properties from B-form DD molecules. We find RD and DD molecules with the same contour length move with comparable velocity through nanopores. We examined the physical characteristics of both duplex forms using atomic force microscopy, atomistic molecular dynamics simulations, agarose gel electrophoresis, and dynamic light scattering measurements. With the help of coarse-grained and molecular dynamics simulations, we find the effective force per unit length applied by the electric field to a fragment of RD or DD duplex in nanopores with various geometries or shapes to be approximately the same within experimental errors. Our results shed light on the significance of helical form in nucleic acid translocation, with implications for RNA sensing, sequencing, and molecular understanding of electrophoretic transport.
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21
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Isu UH, Polasa A, Moradi M. Differential Behavior of Conformational Dynamics in Active and Inactive States of Cannabinoid Receptor 1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.17.589939. [PMID: 38659869 PMCID: PMC11042334 DOI: 10.1101/2024.04.17.589939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
The cannabinoid receptor CB1 is a G protein-coupled receptor that regulates critical physiological processes including pain, appetite, and cognition. Understanding the conformational dynamics of CB1 associated with transitions between inactive and active signaling states is imperative for developing targeted modulators. Using microsecond-level all-atom molecular dynamics simulations, we identified marked differences in the conformational ensembles of inactive and active CB1 states in apo conditions. The inactive state exhibited substantially increased structural heterogeneity and plasticity compared to the more rigidified active state in the absence of stabilizing ligands. Transmembrane helices TM3 and TM7 were identified as distinguishing factors modulating the state-dependent dynamics. TM7 displayed amplified fluctuations selectively in the inactive state simulations attributed to disruption of conserved electrostatic contacts anchoring it to surrounding helices in the active state. Additionally, we identified significant reorganization of key salt bridge and hydrogen bond networks known to control CB1 activation between states. For instance, a conserved D213-Y224 hydrogen bond and D184-K192 salt bridge interactions showed marked rearrangements between the states. Collectively, these findings reveal the specialized role of TM7 in directing state-dependent CB1 dynamics through electrostatic switch mechanisms. By elucidating the intrinsic enhanced flexibility of inactive CB1, this study provides valuable insights into the conformational landscape enabling functional transitions. Our perspective advances understanding of CB1 activation mechanisms and offers opportunities for structure-based drug discovery targeting the state-specific conformational dynamics of this receptor.
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22
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Lucker J, Kio M, Klauda JB. Expanding the CHARMM36 United Atom Chain Model for the Inclusion of Sphingolipids. J Phys Chem B 2024. [PMID: 38688001 DOI: 10.1021/acs.jpcb.4c01404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
The inclusion of accurate yet computationally inexpensive lipid force fields (FF) is pertinent for the study of lipids and lipid-containing systems using molecular dynamics (MD). Within the past decade, the implementation and further expansion of a united atom (UA) FF for lipids have been developed in the CHARMM family of FFs. The most recent version of the UA presented more accurate descriptions of lipid properties for several phospholipids with saturated and monounsaturated chains, termed C36UAr. However, the original C36UAr model lacks parameters for an important class of lipids, such as sphingolipids. The focus of this article is to broaden the scope of the C36UAr chain model to incorporate these lipids. In this study, two common sphingolipids, N-palmitoyl sphingomyelin and N-stearoyl sphingomyelin are converted to a UA-chain representation and simulated to investigate the accuracy and speed over the all-atom FF model for sphingolipids. Improvements were found among multiple parameters, for example, in the surface area per lipid (SA/lip) and hydrogen order parameters, over the all-atom simulations of these sphingomyelins in C36, while as much as halving the simulation time for simulations of the same setup otherwise. Thus, the accuracy and efficiency found in this study are consistent with those found in the C36UAr model for phospholipids and expand the application of C36UAr to a wider array of membrane models to better match that in vivo.
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Affiliation(s)
- Joshua Lucker
- Institute for Physical Science and Technology, Biophysics Program, University of Maryland, College Park, Maryland 20742, United States
| | - Michael Kio
- Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Jeffery B Klauda
- Institute for Physical Science and Technology, Biophysics Program, University of Maryland, College Park, Maryland 20742, United States
- Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742, United States
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23
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Wu K, Itskanov S, Lynch DL, Chen Y, Turner A, Gumbart JC, Park E. Substrate recognition mechanism of the endoplasmic reticulum-associated ubiquitin ligase Doa10. Nat Commun 2024; 15:2182. [PMID: 38467638 PMCID: PMC10928120 DOI: 10.1038/s41467-024-46409-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Accepted: 02/14/2024] [Indexed: 03/13/2024] Open
Abstract
Doa10 (MARCHF6 in metazoans) is a large polytopic membrane-embedded E3 ubiquitin ligase in the endoplasmic reticulum (ER) that plays an important role in quality control of cytosolic and ER proteins. Although Doa10 is highly conserved across eukaryotes, it is not understood how Doa10 recognizes its substrates. Here, we define the substrate recognition mechanism of Doa10 by structural and functional analyses on Saccharomyces cerevisiae Doa10 and its model substrates. Cryo-EM analysis shows that Doa10 has unusual architecture with a large lipid-filled central cavity, and its conserved middle domain forms an additional water-filled lateral tunnel open to the cytosol. Our biochemical data and molecular dynamics simulations suggest that the entrance of the substrate's degron peptide into the lateral tunnel is required for efficient polyubiquitination. The N- and C-terminal membrane domains of Doa10 seem to form fence-like features to restrict polyubiquitination to those proteins that can access the central cavity and lateral tunnel. Our study reveals how extended hydrophobic sequences at the termini of substrate proteins are recognized by Doa10 as a signal for quality control.
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Affiliation(s)
- Kevin Wu
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
| | - Samuel Itskanov
- Biophysics Graduate Program, University of California, Berkeley, CA, 94720, USA
| | - Diane L Lynch
- School of Physics and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Yuanyuan Chen
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
| | - Aasha Turner
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
| | - James C Gumbart
- School of Physics and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Eunyong Park
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA.
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA.
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24
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Shi X, Pumm AK, Maffeo C, Kohler F, Feigl E, Zhao W, Verschueren D, Golestanian R, Aksimentiev A, Dietz H, Dekker C. A DNA turbine powered by a transmembrane potential across a nanopore. NATURE NANOTECHNOLOGY 2024; 19:338-344. [PMID: 37884658 PMCID: PMC10950783 DOI: 10.1038/s41565-023-01527-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 09/12/2023] [Indexed: 10/28/2023]
Abstract
Rotary motors play key roles in energy transduction, from macroscale windmills to nanoscale turbines such as ATP synthase in cells. Despite our abilities to construct engines at many scales, developing functional synthetic turbines at the nanoscale has remained challenging. Here, we experimentally demonstrate rationally designed nanoscale DNA origami turbines with three chiral blades. These DNA nanoturbines are 24-27 nm in height and diameter and can utilize transmembrane electrochemical potentials across nanopores to drive DNA bundles into sustained unidirectional rotations of up to 10 revolutions s-1. The rotation direction is set by the designed chirality of the turbine. All-atom molecular dynamics simulations show how hydrodynamic flows drive this turbine. At high salt concentrations, the rotation direction of turbines with the same chirality is reversed, which is explained by a change in the anisotropy of the electrophoretic mobility. Our artificial turbines operate autonomously in physiological conditions, converting energy from naturally abundant electrochemical potentials into mechanical work. The results open new possibilities for engineering active robotics at the nanoscale.
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Affiliation(s)
- Xin Shi
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, The Netherlands
- Department of Chemistry, KU Leuven, Leuven, Belgium
| | - Anna-Katharina Pumm
- Department of Bioscience, School of Natural Sciences, Technical University of Munich, Garching, Germany
- Munich Institute of Biomedical Engineering, Technical University of Munich, Garching, Germany
| | - Christopher Maffeo
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Fabian Kohler
- Department of Bioscience, School of Natural Sciences, Technical University of Munich, Garching, Germany
| | - Elija Feigl
- Department of Bioscience, School of Natural Sciences, Technical University of Munich, Garching, Germany
| | - Wenxuan Zhao
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, The Netherlands
| | - Daniel Verschueren
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, The Netherlands
- The SW7 Group, London, UK
| | - Ramin Golestanian
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
- Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford, UK
| | - Aleksei Aksimentiev
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
| | - Hendrik Dietz
- Department of Bioscience, School of Natural Sciences, Technical University of Munich, Garching, Germany.
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, The Netherlands.
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25
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Dehghani-Ghahnaviyeh S, Soylu C, Furet P, Velez-Vega C. Dissecting the Interaction Fingerprints and Binding Affinity of BYL719 Analogs Targeting PI3Kα. J Phys Chem B 2024; 128:1819-1829. [PMID: 38373112 DOI: 10.1021/acs.jpcb.3c06766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
Phosphatidylinositol-3-kinase Alpha (PI3Kα) is a lipid kinase which regulates signaling pathways involved in cell proliferation. Dysregulation of these pathways promotes several human cancers, pushing for the development of anticancer drugs to target PI3Kα. One such medicinal chemistry campaign at Novartis led to the discovery of BYL719 (Piqray, Alpelicib), a PI3Kα inhibitor approved by the FDA in 2019 for treatment of HR+/HER2-advanced breast cancer with a PIK3CA mutation. Structure-based drug design played a key role in compound design and optimization throughout the discovery process. However, further characterization of potency drivers via structural dynamics and energetic analyses can be advantageous for ensuing PI3Kα programs. Here, our goal is to employ various in-silico techniques, including molecular simulations and machine learning, to characterize 14 ligands from the BYL719 analogs and predict their binding affinities. The structural insights from molecular simulations suggest that although the ligand-hinge interaction is the primary driver of ligand stability at the pocket, the R group positioning at C2 or C6 of pyridine/pyrimidine also plays a major role. Binding affinities predicted via thermodynamic integration (TI) are in good agreement with previously reported IC50s. Yet, computationally demanding techniques such as TI might not always be the most efficient approach for affinity prediction, as in our case study, fast high-throughput techniques were capable of classifying compounds as active or inactive, and one docking approach showed accuracy comparable to TI.
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Affiliation(s)
- Sepehr Dehghani-Ghahnaviyeh
- Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Cihan Soylu
- Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Pascal Furet
- Novartis Institutes for BioMedical Research, CH4002 Basel, Switzerland
| | - Camilo Velez-Vega
- Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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26
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Wu K, Itskanov S, Lynch DL, Chen Y, Turner A, Gumbart JC, Park E. Substrate recognition mechanism of the endoplasmic reticulum-associated ubiquitin ligase Doa10. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.09.574907. [PMID: 38260251 PMCID: PMC10802466 DOI: 10.1101/2024.01.09.574907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Doa10 (MARCH6 in metazoans) is a large polytopic membrane-embedded E3 ubiquitin ligase in the endoplasmic reticulum (ER) that plays an important role in quality control of cytosolic and ER proteins. Although Doa10 is highly conserved across eukaryotes, it is not understood how Doa10 recognizes its substrates. Here, we defined the substrate recognition mechanism of Doa10 by structural and functional analyses on Saccharomyces cerevisiae Doa10 and its well-defined degron Deg1. Cryo-EM analysis shows that Doa10 has unusual architecture with a large lipid-filled central cavity, and its conserved middle domain forms an additional water-filled lateral tunnel open to the cytosol. Our biochemical data and molecular dynamics simulations suggest that the entrance of the substrate's degron peptide into the lateral tunnel is required for efficient polyubiquitination. The N- and C-terminal membrane domains of Doa10 seem to form fence-like features to restrict polyubiquitination to those proteins that can access the central cavity and lateral tunnel.
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Affiliation(s)
- Kevin Wu
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
| | - Samuel Itskanov
- Biophysics Graduate Program, University of California, Berkeley, CA 94720, USA
| | - Diane L. Lynch
- School of Physics and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Yuanyuan Chen
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
| | - Aasha Turner
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - James C. Gumbart
- School of Physics and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Eunyong Park
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
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27
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Blazhynska M, Gumbart JC, Chen H, Tajkhorshid E, Roux B, Chipot C. A Rigorous Framework for Calculating Protein-Protein Binding Affinities in Membranes. J Chem Theory Comput 2023; 19:9077-9092. [PMID: 38091976 PMCID: PMC11145395 DOI: 10.1021/acs.jctc.3c00941] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
Calculating the binding free energy of integral transmembrane (TM) proteins is crucial for understanding the mechanisms by which they recognize one another and reversibly associate. The glycophorin A (GpA) homodimer, composed of two α-helical segments, has long served as a model system for studying TM protein reversible association. The present work establishes a methodological framework for calculating the binding affinity of the GpA homodimer in the heterogeneous environment of a membrane. Our investigation carefully considered a variety of protocols, including the appropriate choice of the force field, rigorous standardization reflecting the experimental conditions, sampling algorithm, anisotropic environment, and collective variables, to accurately describe GpA dimerization via molecular dynamics-based approaches. Specifically, two strategies were explored: (i) an unrestrained potential mean force (PMF) calculation, which merely enhances sampling along the separation of the two binding partners without any restraint, and (ii) a so-called "geometrical route", whereby the α-helices are progressively separated with imposed restraints on their orientational, positional, and conformational degrees of freedom to accelerate convergence. Our simulations reveal that the simplified, unrestrained PMF approach is inadequate for the description of GpA dimerization. Instead, the geometrical route, tailored specifically to GpA in a membrane environment, yields excellent agreement with experimental data within a reasonable computational time. A dimerization free energy of -10.7 kcal/mol is obtained, in fairly good agreement with available experimental data. The geometrical route further helps elucidate how environmental forces drive association before helical interactions stabilize it. Our simulations also brought to light a distinct, long-lived spatial arrangement that potentially serves as an intermediate state during dimer formation. The methodological advances in the generalized geometrical route provide a powerful tool for accurate and efficient binding-affinity calculations of intricate TM protein complexes in inhomogeneous environments.
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Affiliation(s)
- Marharyta Blazhynska
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign, Unité Mixte de Recherche n°7019, Université de Lorraine, B.P. 70239, Vandœuvre-lès-Nancy cedex 54506, France
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, Georgia 30332, United States
| | - Haochuan Chen
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign, Unité Mixte de Recherche n°7019, Université de Lorraine, B.P. 70239, Vandœuvre-lès-Nancy cedex 54506, France
| | - Emad Tajkhorshid
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 N. Mathews Avenue, Urbana, Illinois 61801, United States
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Benoît Roux
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 E. 57th Street W225, Chicago, Illinois 60637, United States
- Department of Chemistry, The University of Chicago, 5735 S. Ellis Avenue, Chicago, Illinois 60637, United States
| | - Christophe Chipot
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign, Unité Mixte de Recherche n°7019, Université de Lorraine, B.P. 70239, Vandœuvre-lès-Nancy cedex 54506, France
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 N. Mathews Avenue, Urbana, Illinois 61801, United States
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 E. 57th Street W225, Chicago, Illinois 60637, United States
- Department of Chemistry, The University of Hawai'i at Ma̅noa, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
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28
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Morales-Salazar I, Garduño-Albino CE, Montes-Enríquez FP, Nava-Tapia DA, Navarro-Tito N, Herrera-Zúñiga LD, González-Zamora E, Islas-Jácome A. Synthesis of Pyrrolo[3,4- b]pyridin-5-ones via Ugi-Zhu Reaction and In Vitro-In Silico Studies against Breast Carcinoma. Pharmaceuticals (Basel) 2023; 16:1562. [PMID: 38004428 PMCID: PMC10674953 DOI: 10.3390/ph16111562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 10/31/2023] [Accepted: 11/02/2023] [Indexed: 11/26/2023] Open
Abstract
An Ugi-Zhu three-component reaction (UZ-3CR) coupled in a one-pot manner to a cascade process (N-acylation/aza Diels-Alder cycloaddition/decarboxylation/dehydration) was performed to synthesize a series of pyrrolo[3,4-b]pyridin-5-ones in 20% to 92% overall yields using ytterbium triflate as a catalyst, toluene as a solvent, and microwaves as a heat source. The synthesized molecules were evaluated in vitro against breast cancer cell lines MDA-MB-231 and MCF-7, finding that compound 1f, at a concentration of 6.25 μM, exhibited a potential cytotoxic effect. Then, to understand the interactions between synthesized compounds and the main proteins related to the cancer cell lines, docking studies were performed on the serine/threonine kinase 1 (AKT1) and Orexetine type 2 receptor (Ox2R), finding moderate to strong binding energies, which matched accurately with the in vitro results. Additionally, molecular dynamics were performed between proteins related to the studied cell lines and the three best ligands.
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Affiliation(s)
- Ivette Morales-Salazar
- Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, Ciudad de México 09340, Mexico; (I.M.-S.); (C.E.G.-A.); (F.P.M.-E.); (E.G.-Z.)
| | - Carlos E. Garduño-Albino
- Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, Ciudad de México 09340, Mexico; (I.M.-S.); (C.E.G.-A.); (F.P.M.-E.); (E.G.-Z.)
| | - Flora P. Montes-Enríquez
- Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, Ciudad de México 09340, Mexico; (I.M.-S.); (C.E.G.-A.); (F.P.M.-E.); (E.G.-Z.)
| | - Dania A. Nava-Tapia
- Laboratorio de Biología Celular del Cáncer, Universidad Autónoma de Guerrero, Chilpancingo de los Bravo 39086, Mexico;
| | - Napoleón Navarro-Tito
- Laboratorio de Biología Celular del Cáncer, Universidad Autónoma de Guerrero, Chilpancingo de los Bravo 39086, Mexico;
| | - Leonardo David Herrera-Zúñiga
- Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, Ciudad de México 09340, Mexico; (I.M.-S.); (C.E.G.-A.); (F.P.M.-E.); (E.G.-Z.)
| | - Eduardo González-Zamora
- Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, Ciudad de México 09340, Mexico; (I.M.-S.); (C.E.G.-A.); (F.P.M.-E.); (E.G.-Z.)
| | - Alejandro Islas-Jácome
- Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, Ciudad de México 09340, Mexico; (I.M.-S.); (C.E.G.-A.); (F.P.M.-E.); (E.G.-Z.)
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29
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Jiang S, Steup LC, Kippnich C, Lazaridi S, Malengo G, Lemmin T, Yuan J. The inhibitory mechanism of a small protein reveals its role in antimicrobial peptide sensing. Proc Natl Acad Sci U S A 2023; 120:e2309607120. [PMID: 37792514 PMCID: PMC10576120 DOI: 10.1073/pnas.2309607120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 09/06/2023] [Indexed: 10/06/2023] Open
Abstract
A large number of small membrane proteins have been uncovered in bacteria, but their mechanism of action has remained mostly elusive. Here, we investigate the mechanism of a physiologically important small protein, MgrB, which represses the activity of the sensor kinase PhoQ and is widely distributed among enterobacteria. The PhoQ/PhoP two-component system is a master regulator of the bacterial virulence program and interacts with MgrB to modulate bacterial virulence, fitness, and drug resistance. A combination of cross-linking approaches with functional assays and protein dynamic simulations revealed structural rearrangements due to interactions between MgrB and PhoQ near the membrane/periplasm interface and along the transmembrane helices. These interactions induce the movement of the PhoQ catalytic domain and the repression of its activity. Without MgrB, PhoQ appears to be much less sensitive to antimicrobial peptides, including the commonly used C18G. In the presence of MgrB, C18G promotes MgrB to dissociate from PhoQ, thus activating PhoQ via derepression. Our findings reveal the inhibitory mechanism of the small protein MgrB and uncover its importance in antimicrobial peptide sensing.
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Affiliation(s)
- Shan Jiang
- Max Planck Institute for Terrestrial Microbiology, 35043Marburg, Germany
- Center for Synthetic Microbiology, 35043Marburg, Germany
| | - Lydia C. Steup
- Max Planck Institute for Terrestrial Microbiology, 35043Marburg, Germany
- Center for Synthetic Microbiology, 35043Marburg, Germany
| | - Charlotte Kippnich
- Max Planck Institute for Terrestrial Microbiology, 35043Marburg, Germany
- Center for Synthetic Microbiology, 35043Marburg, Germany
| | - Symela Lazaridi
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, 3012Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012Bern, Switzerland
| | - Gabriele Malengo
- Max Planck Institute for Terrestrial Microbiology, 35043Marburg, Germany
- Center for Synthetic Microbiology, 35043Marburg, Germany
| | - Thomas Lemmin
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, 3012Bern, Switzerland
| | - Jing Yuan
- Max Planck Institute for Terrestrial Microbiology, 35043Marburg, Germany
- Center for Synthetic Microbiology, 35043Marburg, Germany
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30
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Krishnan S, Aksimentiev A, Lindsay S, Matyushov D. Long-Range Conductivity in Proteins Mediated by Aromatic Residues. ACS PHYSICAL CHEMISTRY AU 2023; 3:444-455. [PMID: 37780537 PMCID: PMC10540285 DOI: 10.1021/acsphyschemau.3c00017] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 09/30/2023]
Abstract
Single-molecule measurements show that many proteins, lacking any redox cofactors, nonetheless exhibit electrical conductance on the order of a nanosiemen over 10 nm distances, implying that electrons can transit an entire protein in less than a nanosecond when subject to a potential difference of less than 1 V. This is puzzling because, for fast transport (i.e., a free energy barrier of zero), the hopping rate is determined by the reorganization energy of approximately 0.8 eV, and this sets the time scale of a single hop to at least 1 μs. Furthermore, the Fermi energies of typical metal electrodes are far removed from the energies required for sequential oxidation and reduction of the aromatic residues of the protein, which should further reduce the hopping current. Here, we combine all-atom molecular dynamics (MD) simulations of non-redox-active proteins (consensus tetratricopeptide repeats) with an electron transfer theory to demonstrate a molecular mechanism that can account for the unexpectedly fast electron transport. According to our MD simulations, the reorganization energy produced by the energy shift on charging (the Stokes shift) is close to the conventional value of 0.8 eV. However, the non-ergodic sampling of molecular configurations by the protein results in reaction-reorganization energies, extracted directly from the distribution of the electrostatic energy fluctuations, that are only ∼0.2 eV, which is small enough to enable long-range conductivity, without invoking quantum coherent transport. Using the MD values of the reorganization energies, we calculate a current decay with distance that is in agreement with experiment.
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Affiliation(s)
- Siddharth Krishnan
- Department
of Physics and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Aleksei Aksimentiev
- Department
of Physics and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Stuart Lindsay
- Department
of Physics, Arizona State University, Tempe, Arizona 85281, United States
- School
of Molecular Sciences, Arizona State University, Tempe, Arizona 85281, United States
- Biodesign
Institute, Arizona State University, Tempe, Arizona 85281, United States
| | - Dmitry Matyushov
- Department
of Physics, Arizona State University, Tempe, Arizona 85281, United States
- School
of Molecular Sciences, Arizona State University, Tempe, Arizona 85281, United States
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31
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Sim SI, Chen Y, Lynch DL, Gumbart JC, Park E. Structural basis of mitochondrial protein import by the TIM23 complex. Nature 2023; 621:620-626. [PMID: 37344598 DOI: 10.1038/s41586-023-06239-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 05/19/2023] [Indexed: 06/23/2023]
Abstract
Mitochondria import nearly all of their approximately 1,000-2,000 constituent proteins from the cytosol across their double-membrane envelope1-5. Genetic and biochemical studies have shown that the conserved protein translocase, termed the TIM23 complex, mediates import of presequence-containing proteins (preproteins) into the mitochondrial matrix and inner membrane. Among about ten different subunits of the TIM23 complex, the essential multipass membrane protein Tim23, together with the evolutionarily related protein Tim17, has long been postulated to form a protein-conducting channel6-11. However, the mechanism by which these subunits form a translocation path in the membrane and enable the import process remains unclear due to a lack of structural information. Here we determined the cryo-electron microscopy structure of the core TIM23 complex (heterotrimeric Tim17-Tim23-Tim44) from Saccharomyces cerevisiae. Contrary to the prevailing model, Tim23 and Tim17 themselves do not form a water-filled channel, but instead have separate, lipid-exposed concave cavities that face in opposite directions. Our structural and biochemical analyses show that the cavity of Tim17, but not Tim23, forms the protein translocation path, whereas Tim23 probably has a structural role. The results further suggest that, during translocation of substrate polypeptides, the nonessential subunit Mgr2 seals the lateral opening of the Tim17 cavity to facilitate the translocation process. We propose a new model for the TIM23-mediated protein import and sorting mechanism, a central pathway in mitochondrial biogenesis.
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Affiliation(s)
- Sue Im Sim
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Yuanyuan Chen
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
| | - Diane L Lynch
- School of Physics, Georgia Institute of Technology, Atlanta, GA, USA
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, GA, USA
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA
| | - Eunyong Park
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA.
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32
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Kuo K, Liu J, Pavlova A, Gumbart JC. Drug Binding to BamA Targets Its Lateral Gate. J Phys Chem B 2023; 127:7509-7517. [PMID: 37587651 PMCID: PMC10476194 DOI: 10.1021/acs.jpcb.3c04501] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 07/30/2023] [Indexed: 08/18/2023]
Abstract
BamA, the core component of the β-barrel assembly machinery (BAM) complex, is an outer-membrane protein (OMP) in Gram-negative bacteria. Its function is to insert and fold substrate OMPs into the outer membrane (OM). Evidence suggests that BamA follows the asymmetric hybrid-barrel model where the first and last strands of BamA separate, a process known as lateral gate opening, to allow nascent substrate OMP β-strands to sequentially insert and fold through β-augmentation. Recently, multiple lead compounds that interfere with BamA's function have been identified. We modeled and then docked one of these compounds into either the extracellular loops of BamA or the open lateral gate. With the compound docked in the loops, we found that the lateral gate remains closed during 5 μs molecular dynamics simulations. The same compound when docked in the open lateral gate stays bound to the β16 strand of BamA during the simulation, which would prevent substrate OMP folding. In addition, we simulated mutants of BamA that are resistant to one or more of the identified lead compounds. In these simulations, we observed a differing degree and/or frequency of opening of BamA's lateral gate compared to BamA-apo, suggesting that the mutations grant resistance by altering the dynamics at the gate. We conclude that the compounds act by inhibiting BamA lateral gate opening and/or binding of substrate, thus preventing subsequent OMP folding and insertion.
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Affiliation(s)
- Katie
M. Kuo
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
| | - Jinchan Liu
- Department
of Molecular Biophysics and Biochemistry (MB&B), Yale University, New Haven, Connecticut 06510, United States
| | - Anna Pavlova
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - James C. Gumbart
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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33
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Li Y, Acharya A, Yang L, Liu J, Tajkhorshid E, Zgurskaya HI, Jackson M, Gumbart JC. Insights into substrate transport and water permeation in the mycobacterial transporter MmpL3. Biophys J 2023; 122:2342-2352. [PMID: 36926696 PMCID: PMC10257117 DOI: 10.1016/j.bpj.2023.03.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 02/04/2023] [Accepted: 03/10/2023] [Indexed: 03/17/2023] Open
Abstract
Mycobacteria, such as Mycobacterium tuberculosis, are characterized by a uniquely thick and waxy cell envelope that consists of two membranes, with a variety of mycolates comprising their outer membrane (OM). The protein Mycobacterial membrane protein Large 3 (MmpL3) is responsible for the transport of a primary OM component, trehalose monomycolate (TMM), from the inner (cytoplasmic) membrane (IM) to the periplasmic space, a process driven by the proton gradient. Although multiple structures of MmpL3 with bound substrates have been solved, the exact pathway(s) for TMM or proton transport remains elusive. Here, employing molecular dynamics simulations we investigate putative pathways for either transport species. We hypothesized that MmpL3 will cycle through similar conformational states as the related transporter AcrB, which we used as targets for modeling the conformation of MmpL3. A continuous water pathway through the transmembrane region was found in one of these states, illustrating a putative pathway for protons. Additional equilibrium simulations revealed that TMM can diffuse from the membrane into a binding pocket in MmpL3 spontaneously. We also found that acetylation of TMM, which is required for transport, makes it more stable within MmpL3's periplasmic cavity compared with the unacetylated form.
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Affiliation(s)
- Yupeng Li
- Theoretical and Computational Biophysics Group, NIH Resource for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois; Center for Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, Illinois
| | - Atanu Acharya
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia
| | - Lixinhao Yang
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia
| | - Jinchan Liu
- Department of Molecular Biophysics and Biochemistry (MB&B), Yale University, New Haven, Connecticut
| | - Emad Tajkhorshid
- Theoretical and Computational Biophysics Group, NIH Resource for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois; Center for Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, Illinois; Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Helen I Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia; School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia.
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Sterlini B, Franchi F, Morinelli L, Corradi B, Parodi C, Albini M, Bianchi A, Marte A, Baldelli P, Alberini G, Maragliano L, Valente P, Benfenati F, Corradi A. Missense mutations in the membrane domain of PRRT2 affect its interaction with Nav1.2 voltage-gated sodium channels. Neurobiol Dis 2023:106177. [PMID: 37271286 DOI: 10.1016/j.nbd.2023.106177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/16/2023] [Accepted: 05/27/2023] [Indexed: 06/06/2023] Open
Abstract
PRRT2 is a neuronal protein that controls neuronal excitability and network stability by modulating voltage-gated Na+ channel (Nav). PRRT2 pathogenic variants cause pleiotropic syndromes including epilepsy, paroxysmal kinesigenic dyskinesia and episodic ataxia attributable to loss-of-function pathogenetic mechanism. Based on the evidence that the transmembrane domain of PRRT2 interacts with Nav1.2/1.6, we focused on eight missense mutations located within the domain that show expression and membrane localization similar to the wild-type protein. Molecular dynamics simulations showed that the mutants do not alter the structural stability of the PRRT2 membrane domain and preserve its conformation. Using affinity assays, we found that the A320V and V286M mutants displayed respectively decreased and increased binding to Nav1.2. Accordingly, surface biotinylation showed an increased Nav1.2 surface exposure induced by the A320V mutant. Electrophysiological analysis confirmed the lack of modulation of Nav1.2 biophysical properties by the A320V mutant with a loss-of-function phenotype, while the V286M mutant displayed a gain-of-function with respect to wild-type PRRT2 with a more pronounced left-shift of the inactivation kinetics and delayed recovery from inactivation. The data confirm the key role played by the PRRT2-Nav interaction in the pathogenesis of the PRRT2-linked disorders and suggest an involvement of the A320 and V286 residues in the interaction site. Given the similar clinical phenotype caused by the two mutations, we speculate that circuit instability and paroxysmal manifestations may arise when PRRT2 function is outside the physiological range.
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Affiliation(s)
- Bruno Sterlini
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy; Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova 16132, Italy
| | - Francesca Franchi
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova 16132, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, Genova 16132, Italy
| | - Lisastella Morinelli
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy; Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova 16132, Italy
| | - Beatrice Corradi
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy; Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova 16132, Italy
| | - Chiara Parodi
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy
| | - Martina Albini
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy
| | - Alessandra Bianchi
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy
| | - Antonella Marte
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy
| | - Pietro Baldelli
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, Genova 16132, Italy
| | - Giulio Alberini
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova 16132, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, Genova 16132, Italy
| | - Luca Maragliano
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova 16132, Italy; Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Pierluigi Valente
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy; Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova 16132, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova 16132, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, Genova 16132, Italy.
| | - Anna Corradi
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, Genova 16132, Italy.
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Blazhynska M, Goulard Coderc de Lacam E, Chen H, Chipot C. Improving Speed and Affordability without Compromising Accuracy: Standard Binding Free-Energy Calculations Using an Enhanced Sampling Algorithm, Multiple-Time Stepping, and Hydrogen Mass Repartitioning. J Chem Theory Comput 2023. [PMID: 37196198 DOI: 10.1021/acs.jctc.3c00141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Accurate evaluation of protein-ligand binding free energies in silico is of paramount importance for understanding the mechanisms of biological regulation and providing a theoretical basis for drug design and discovery. Based on a series of atomistic molecular dynamics simulations in an explicit solvent, using well-tempered metadynamics extended adaptive biasing force (WTM-eABF) as an enhanced sampling algorithm, the so-called "geometrical route" offers a rigorous theoretical framework for binding affinity calculations that match experimental values. However, although robust, this strategy remains expensive, requiring substantial computational time to achieve convergence of the simulations. Improving the efficiency of the geometrical route, while preserving its reliability through improved ergodic sampling, is, therefore, highly desirable. In this contribution, having identified the computational bottleneck of the geometrical route, to accelerate the calculations we combine (i) a longer time step for the integration of the equations of motion with hydrogen-mass repartitioning (HMR), and (ii) multiple time-stepping (MTS) for collective-variable and biasing-force evaluation. Altogether, we performed 50 independent WTM-eABF simulations in triplicate for the "physical" separation of the Abl kinase-SH3 domain:p41 complex, following different HMR and MTS schemes, while tuning, in distinct protocols, the parameters of the enhanced-sampling algorithm. To demonstrate the consistency and reliability of the results obtained with the best-performing setups, we carried out quintuple simulations. Furthermore, we demonstrated the transferability of our method to other complexes by triplicating a 200 ns separation simulation of nine chosen protocols for the MDM2-p53:NVP-CGM097 complex. [Holzer et al. J. Med. Chem. 2015, 58, 6348-6358.] Our results, based on an aggregate simulation time of 14.4 μs, allowed an optimal set of parameters to be identified, able to accelerate convergence by a factor of three without any noticeable loss of accuracy.
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Affiliation(s)
- Marharyta Blazhynska
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign, Unité Mixte de Recherche n°7019, Université de Lorraine, B.P. 70239, 54506 Vandœuvre-lès-Nancy cedex, France
| | - Emma Goulard Coderc de Lacam
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign, Unité Mixte de Recherche n°7019, Université de Lorraine, B.P. 70239, 54506 Vandœuvre-lès-Nancy cedex, France
| | - Haochuan Chen
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign, Unité Mixte de Recherche n°7019, Université de Lorraine, B.P. 70239, 54506 Vandœuvre-lès-Nancy cedex, France
| | - Christophe Chipot
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign, Unité Mixte de Recherche n°7019, Université de Lorraine, B.P. 70239, 54506 Vandœuvre-lès-Nancy cedex, France
- Theoretical and Computational Biophysics Group, Beckman Institute, and Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 E. 57th Street W225, Chicago, Illinois 60637, United States
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Alberini G, Alexis Paz S, Corradi B, Abrams CF, Benfenati F, Maragliano L. Molecular Dynamics Simulations of Ion Permeation in Human Voltage-Gated Sodium Channels. J Chem Theory Comput 2023; 19:2953-2972. [PMID: 37116214 DOI: 10.1021/acs.jctc.2c00990] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
The recent determination of cryo-EM structures of voltage-gated sodium (Nav) channels has revealed many details of these proteins. However, knowledge of ionic permeation through the Nav pore remains limited. In this work, we performed atomistic molecular dynamics (MD) simulations to study the structural features of various neuronal Nav channels based on homology modeling of the cryo-EM structure of the human Nav1.4 channel and, in addition, on the recently resolved configuration for Nav1.2. In particular, single Na+ permeation events during standard MD runs suggest that the ion resides in the inner part of the Nav selectivity filter (SF). On-the-fly free energy parametrization (OTFP) temperature-accelerated molecular dynamics (TAMD) was also used to calculate two-dimensional free energy surfaces (FESs) related to single/double Na+ translocation through the SF of the homology-based Nav1.2 model and the cryo-EM Nav1.2 structure, with different realizations of the DEKA filter domain. These additional simulations revealed distinct mechanisms for single and double Na+ permeation through the wild-type SF, which has a charged lysine in the DEKA ring. Moreover, the configurations of the ions in the SF corresponding to the metastable states of the FESs are specific for each SF motif. Overall, the description of these mechanisms gives us new insights into ion conduction in human Nav cryo-EM-based and cryo-EM configurations that could advance understanding of these systems and how they differ from potassium and bacterial Nav channels.
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Affiliation(s)
- Giulio Alberini
- Center for Synaptic Neuroscience and Technology (NSYN@UniGe), Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy
- IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Sergio Alexis Paz
- Departamento de Química Teórica y Computacional, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Fisicoquímica de Córdoba (INFIQC), X5000HUA Córdoba, Argentina
| | - Beatrice Corradi
- Center for Synaptic Neuroscience and Technology (NSYN@UniGe), Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy
- Department of Experimental Medicine, Università degli Studi di Genova, Viale Benedetto XV 3, 16132 Genova, Italy
| | - Cameron F Abrams
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Fabio Benfenati
- Center for Synaptic Neuroscience and Technology (NSYN@UniGe), Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy
- IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Luca Maragliano
- Center for Synaptic Neuroscience and Technology (NSYN@UniGe), Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Via Brecce Bianche, 60131 Ancona, Italy
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37
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Franchi F, Marte A, Corradi B, Sterlini B, Alberini G, Romei A, De Fusco A, Vogel A, Maragliano L, Baldelli P, Corradi A, Valente P, Benfenati F. The intramembrane COOH-terminal domain of PRRT2 regulates voltage-dependent Na + channels. J Biol Chem 2023; 299:104632. [PMID: 36958475 PMCID: PMC10164911 DOI: 10.1016/j.jbc.2023.104632] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 03/14/2023] [Accepted: 03/16/2023] [Indexed: 03/25/2023] Open
Abstract
Proline-rich transmembrane protein 2 (PRRT2) is the single causative gene for pleiotropic paroxysmal syndromes including epilepsy, kinesigenic dyskinesia, episodic ataxia and migraine. PRRT2 is a neuron-specific type-2 membrane protein with a COOH-terminal intramembrane domain and a long proline-rich NH2-terminal cytoplasmic region. A large array of experimental data indicates that PRRT2 is a neuron stability gene that negatively controls intrinsic excitability by regulating surface membrane localization and biophysical properties of voltage-dependent Na+ channels Nav1.2 and Nav1.6, but not Nav1.1. To further investigate the regulatory role of PRRT2, we studied the structural features of this membrane protein with molecular dynamics simulations, and its structure-function relationships with Nav1.2 channels by biochemical and electrophysiological techniques. We found that the intramembrane COOH-terminal region maintains a stable conformation over time, with the first transmembrane domain forming a helix-loop-helix motif within the bilayer. The unstructured NH2-terminal cytoplasmic region bound to the Nav1.2 better than the isolated COOH-terminal intramembrane domain, mimicking full-length PRRT2, while the COOH-terminal intramembrane domain was able to modulate Na+ current and channel biophysical properties, still maintaining the striking specificity for Nav1.2 vs Nav1.1. channels. The results identify PRRT2 as a dual-domain protein in which the NH2-terminal cytoplasmic region acts as a binding antenna for Na+ channels, while the COOH-terminal membrane domain regulates channel exposure on the membrane and its biophysical properties.
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Affiliation(s)
- Francesca Franchi
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy; Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy
| | - Antonella Marte
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Beatrice Corradi
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy; Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy
| | - Bruno Sterlini
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy
| | - Giulio Alberini
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Alessandra Romei
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Antonio De Fusco
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Alexander Vogel
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Luca Maragliano
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy; Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Pietro Baldelli
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Anna Corradi
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Pierluigi Valente
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy;.
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Fábián B, Thallmair S, Hummer G. Optimal Bond Constraint Topology for Molecular Dynamics Simulations of Cholesterol. J Chem Theory Comput 2023; 19:1592-1601. [PMID: 36800179 PMCID: PMC10018735 DOI: 10.1021/acs.jctc.2c01032] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Indexed: 02/18/2023]
Abstract
We recently observed artificial temperature gradients in molecular dynamics (MD) simulations of phase-separating ternary lipid mixtures using the Martini 2 force field. We traced this artifact to insufficiently converged bond length constraints with typical time steps and default settings for the linear constraint solver (LINCS). Here, we systematically optimize the constraint scaffold of cholesterol. With massive virtual sites in an equimomental arrangement, we accelerate bond constraint convergence while preserving the original cholesterol force field and dynamics. The optimized model does not induce nonphysical temperature gradients even at relaxed LINCS settings and is at least as fast as the original model at the strict LINCS settings required for proper thermal sampling. We provide a python script to diagnose possible problems with constraint convergence for other molecules and force fields. Equimomental constraint topology optimization can also be used to boost constraint convergence in atomistic MD simulations of molecular systems.
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Affiliation(s)
- Balázs Fábián
- Department
of Theoretical Biophysics, Max Planck Institute
of Biophysics, Max-von-Laue Straße 3, 60438 Frankfurt am Main, Germany
| | - Sebastian Thallmair
- Frankfurt
Institute for Advanced Studies, Ruth-Moufang-Straße 1, 60438 Frankfurt am Main, Germany
| | - Gerhard Hummer
- Department
of Theoretical Biophysics, Max Planck Institute
of Biophysics, Max-von-Laue Straße 3, 60438 Frankfurt am Main, Germany
- Institute
of Biophysics, Goethe University Frankfurt, 60438 Frankfurt
am Main, Germany
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39
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Sahil M, Sarkar S, Mondal J. Long-time-step molecular dynamics can retard simulation of protein-ligand recognition process. Biophys J 2023; 122:802-816. [PMID: 36726313 PMCID: PMC10027446 DOI: 10.1016/j.bpj.2023.01.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 10/31/2022] [Accepted: 01/25/2023] [Indexed: 02/03/2023] Open
Abstract
Molecular dynamics (MD) simulation of biologically relevant processes at realistic time scale and atomistic precision is generally limited by prohibitively large computational cost, due to its restriction of using an ultrashort integration time step (1-2 fs). A popular numerical recipe to reduce the associated computational burden is adopting schemes that would allow relatively longer-time-step for MD propagation. Here, we explore the perceived potential of one of the most frequently used long-time-step protocols, namely the hydrogen mass repartitioning (HMR) approach, in alleviating the computational overhead associated with simulation of the kinetic process of protein-ligand recognition events. By repartitioning the mass of heavier atoms to their linked hydrogen atoms, HMR leverages around twofold longer time step than regular simulation, holding promise of significant performance boost. However, our probe into direct simulation of the protein-ligand recognition event, one of the computationally most challenging processes, shows that long-time-step HMR MD simulations do not necessarily translate to a computationally affordable solution. Our investigations spanning cumulative 176 μs in three independent proteins (T4 lysozyme, sensor domain of MopR, and galectin-3) show that long-time-step HMR-based MD simulations can catch the ligand in its act of recognizing the native cavity. But, as a major caveat, the ligand is found to require significantly longer time to identify buried native protein cavity in an HMR MD simulation than regular simulation, thereby defeating the purpose of its usage for performance upgrade. A molecular analysis shows that the longer time required by a ligand to recognize the protein in HMR is rooted in faster diffusion of the ligand, which reduces the survival probability of decisive on-pathway metastable intermediates, thereby slowing down the eventual recognition process at the native cavity. Together, the investigation stresses careful assessment of pitfalls of long-time-step algorithms before attempting to utilize them for higher performance for biomolecular recognition simulations.
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Affiliation(s)
- Mohammad Sahil
- Tata Institute of Fundamental Research, Hyderabad 500046, India
| | - Susmita Sarkar
- Tata Institute of Fundamental Research, Hyderabad 500046, India
| | - Jagannath Mondal
- Tata Institute of Fundamental Research, Hyderabad 500046, India.
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40
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Brickel S, Demkiv AO, Crean RM, Pinto GP, Kamerlin SCL. Q-RepEx: A Python pipeline to increase the sampling of empirical valence bond simulations. J Mol Graph Model 2023; 119:108402. [PMID: 36610324 DOI: 10.1016/j.jmgm.2022.108402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/17/2022] [Accepted: 12/26/2022] [Indexed: 12/31/2022]
Abstract
The exploration of chemical systems occurs on complex energy landscapes. Comprehensively sampling rugged energy landscapes with many local minima is a common problem for molecular dynamics simulations. These multiple local minima trap the dynamic system, preventing efficient sampling. This is a particular challenge for large biochemical systems with many degrees of freedom. Replica exchange molecular dynamics (REMD) is an approach that accelerates the exploration of the conformational space of a system, and thus can be used to enhance the sampling of complex biomolecular processes. In parallel, the empirical valence bond (EVB) approach is a powerful approach for modeling chemical reactivity in biomolecular systems. Here, we present an open-source Python-based tool that interfaces with the Q simulation package, and increases the sampling efficiency of the EVB free energy perturbation/umbrella sampling approach by means of REMD. This approach, Q-RepEx, both decreases the computational cost of the associated REMD-EVB simulations, and opens the door to more efficient studies of biochemical reactivity in systems with significant conformational fluctuations along the chemical reaction coordinate.
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Affiliation(s)
- Sebastian Brickel
- Department of Chemistry - BMC, Uppsala University, BMC Box 576, S-751 23, Uppsala, Sweden
| | - Andrey O Demkiv
- Department of Chemistry - BMC, Uppsala University, BMC Box 576, S-751 23, Uppsala, Sweden
| | - Rory M Crean
- Department of Chemistry - BMC, Uppsala University, BMC Box 576, S-751 23, Uppsala, Sweden
| | - Gaspar P Pinto
- Department of Chemistry - BMC, Uppsala University, BMC Box 576, S-751 23, Uppsala, Sweden
| | - Shina Caroline Lynn Kamerlin
- Department of Chemistry - BMC, Uppsala University, BMC Box 576, S-751 23, Uppsala, Sweden; School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, GA, 30332-0400, USA.
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Structure and supramolecular organization of the canine distemper virus attachment glycoprotein. Proc Natl Acad Sci U S A 2023; 120:e2208866120. [PMID: 36716368 PMCID: PMC9963377 DOI: 10.1073/pnas.2208866120] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Canine distemper virus (CDV) is an enveloped RNA morbillivirus that triggers respiratory, enteric, and high incidence of severe neurological disorders. CDV induces devastating outbreaks in wild and endangered animals as well as in domestic dogs in countries associated with suboptimal vaccination programs. The receptor-binding tetrameric attachment (H)-protein is part of the morbilliviral cell entry machinery. Here, we present the cryo-electron microscopy (cryo-EM) structure and supramolecular organization of the tetrameric CDV H-protein ectodomain. The structure reveals that the morbilliviral H-protein is composed of three main domains: stalk, neck, and heads. The most unexpected feature was the inherent asymmetric architecture of the CDV H-tetramer being shaped by the neck, which folds into an almost 90° bent conformation with respect to the stalk. Consequently, two non-contacting receptor-binding H-head dimers, which are also tilted toward each other, are located on one side of an intertwined four helical bundle stalk domain. Positioning of the four protomer polypeptide chains within the neck domain is guided by a glycine residue (G158), which forms a hinge point exclusively in two protomer polypeptide chains. Molecular dynamics simulations validated the stability of the asymmetric structure under near physiological conditions and molecular docking showed that two receptor-binding sites are fully accessible. Thus, this spatial organization of the CDV H-tetramer would allow for concomitant protein interactions with the stalk and head domains without steric clashes. In summary, the structure of the CDV H-protein ectodomain provides new insights into the morbilliviral cell entry system and offers a blueprint for next-generation structure-based antiviral drug discovery.
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Takeda H, Busto JV, Lindau C, Tsutsumi A, Tomii K, Imai K, Yamamori Y, Hirokawa T, Motono C, Ganesan I, Wenz LS, Becker T, Kikkawa M, Pfanner N, Wiedemann N, Endo T. A multipoint guidance mechanism for β-barrel folding on the SAM complex. Nat Struct Mol Biol 2023; 30:176-187. [PMID: 36604501 DOI: 10.1038/s41594-022-00897-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 11/11/2022] [Indexed: 01/07/2023]
Abstract
Mitochondrial β-barrel proteins are essential for the transport of metabolites, ions and proteins. The sorting and assembly machinery (SAM) mediates their folding and membrane insertion. We report the cryo-electron microscopy structure of the yeast SAM complex carrying an early eukaryotic β-barrel folding intermediate. The lateral gate of Sam50 is wide open and pairs with the last β-strand (β-signal) of the substrate-the 19-β-stranded Tom40 precursor-to form a hybrid barrel in the membrane plane. The Tom40 barrel grows and curves, guided by an extended bridge with Sam50. Tom40's first β-segment (β1) penetrates into the nascent barrel, interacting with its inner wall. The Tom40 amino-terminal segment then displaces β1 to promote its pairing with Tom40's last β-strand to complete barrel formation with the assistance of Sam37's dynamic α-protrusion. Our study thus reveals a multipoint guidance mechanism for mitochondrial β-barrel folding.
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Affiliation(s)
- Hironori Takeda
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan.,Nara Institute of Science and Technology, Ikoma, Japan
| | - Jon V Busto
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Caroline Lindau
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Akihisa Tsutsumi
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kentaro Tomii
- Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan
| | - Kenichiro Imai
- Cellular and Molecular Biotechnology Research Institute, AIST, Tokyo, Japan
| | - Yu Yamamori
- Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan
| | - Takatsugu Hirokawa
- Cellular and Molecular Biotechnology Research Institute, AIST, Tokyo, Japan.,Division of Biomedical Science, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.,Transborder Medical Research Center, University of Tsukuba, Tsukuba, Japan
| | - Chie Motono
- Cellular and Molecular Biotechnology Research Institute, AIST, Tokyo, Japan.,Computational Bio Big-Data Open Innovation Laboratory, AIST, Waseda University, Tokyo, Japan
| | - Iniyan Ganesan
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Lena-Sophie Wenz
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Sanofi-Aventis Deutschland GmbH, Frankfurt, Germany
| | - Thomas Becker
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Masahide Kikkawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Nikolaus Pfanner
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany. .,CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany. .,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
| | - Nils Wiedemann
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany. .,CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany. .,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
| | - Toshiya Endo
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan. .,Institute for Protein Dynamics, Kyoto Sangyo University, Kyoto, Japan.
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43
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Duan J, Xu P, Zhang H, Luan X, Yang J, He X, Mao C, Shen DD, Ji Y, Cheng X, Jiang H, Jiang Y, Zhang S, Zhang Y, Xu HE. Mechanism of hormone and allosteric agonist mediated activation of follicle stimulating hormone receptor. Nat Commun 2023; 14:519. [PMID: 36720854 PMCID: PMC9889800 DOI: 10.1038/s41467-023-36170-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 01/18/2023] [Indexed: 02/02/2023] Open
Abstract
Follicle stimulating hormone (FSH) is an essential glycoprotein hormone for human reproduction, which functions are mediated by a G protein-coupled receptor, FSHR. Aberrant FSH-FSHR signaling causes infertility and ovarian hyperstimulation syndrome. Here we report cryo-EM structures of FSHR in both inactive and active states, with the active structure bound to FSH and an allosteric agonist compound 21 f. The structures of FSHR are similar to other glycoprotein hormone receptors, highlighting a conserved activation mechanism of hormone-induced receptor activation. Compound 21 f formed extensive interactions with the TMD to directly activate FSHR. Importantly, the unique residue H6157.42 in FSHR plays an essential role in determining FSHR selectivity for various allosteric agonists. Together, our structures provide a molecular basis of FSH and small allosteric agonist-mediated FSHR activation, which could inspire the design of FSHR-targeted drugs for the treatment of infertility and controlled ovarian stimulation for in vitro fertilization.
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Affiliation(s)
- Jia Duan
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203, Shanghai, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Peiyu Xu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203, Shanghai, China
| | - Huibing Zhang
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, Zhejiang, China.,MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Zhejiang Provincial Key Laboratory of Immunity and Inflammatory diseases, Hangzhou, Zhejiang, China
| | - Xiaodong Luan
- Department of Cardiology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China.,Medical Research Center, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China.,School of medicine, Tsinghua university, Beijing, China.,Tsinghua-Peking Center for life science, Tsinghua university, Beijing, China
| | - Jiaqi Yang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203, Shanghai, China
| | - Xinheng He
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203, Shanghai, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Chunyou Mao
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, Zhejiang, China.,MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Zhejiang Provincial Key Laboratory of Immunity and Inflammatory diseases, Hangzhou, Zhejiang, China
| | - Dan-Dan Shen
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, Zhejiang, China.,MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Zhejiang Provincial Key Laboratory of Immunity and Inflammatory diseases, Hangzhou, Zhejiang, China
| | - Yujie Ji
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203, Shanghai, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Xi Cheng
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203, Shanghai, China
| | - Hualiang Jiang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203, Shanghai, China.,University of Chinese Academy of Sciences, 100049, Beijing, China.,Lingang Laboratory, 200031, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, 201210, Shanghai, China
| | - Yi Jiang
- Lingang Laboratory, 200031, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, 201210, Shanghai, China
| | - Shuyang Zhang
- Department of Cardiology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China. .,Medical Research Center, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China. .,School of medicine, Tsinghua university, Beijing, China. .,Tsinghua-Peking Center for life science, Tsinghua university, Beijing, China.
| | - Yan Zhang
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China. .,Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, Zhejiang, China. .,MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China. .,Zhejiang Provincial Key Laboratory of Immunity and Inflammatory diseases, Hangzhou, Zhejiang, China.
| | - H Eric Xu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203, Shanghai, China. .,University of Chinese Academy of Sciences, 100049, Beijing, China. .,School of Life Science and Technology, ShanghaiTech University, 201210, Shanghai, China.
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44
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Mottin M, de Paula Sousa BK, de Moraes Roso Mesquita NC, de Oliveira KIZ, Noske GD, Sartori GR, de Oliveira Albuquerque A, Urbina F, Puhl AC, Moreira-Filho JT, Souza GE, Guido RV, Muratov E, Neves BJ, da Silva JHM, Clark AE, Siqueira-Neto JL, Perryman AL, Oliva G, Ekins S, Andrade CH. Discovery of New Zika Protease and Polymerase Inhibitors through the Open Science Collaboration Project OpenZika. J Chem Inf Model 2022; 62:6825-6843. [PMID: 36239304 PMCID: PMC9923514 DOI: 10.1021/acs.jcim.2c00596] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The Zika virus (ZIKV) is a neurotropic arbovirus considered a global threat to public health. Although there have been several efforts in drug discovery projects for ZIKV in recent years, there are still no antiviral drugs approved to date. Here, we describe the results of a global collaborative crowdsourced open science project, the OpenZika project, from IBM's World Community Grid (WCG), which integrates different computational and experimental strategies for advancing a drug candidate for ZIKV. Initially, molecular docking protocols were developed to identify potential inhibitors of ZIKV NS5 RNA-dependent RNA polymerase (NS5 RdRp), NS3 protease (NS2B-NS3pro), and NS3 helicase (NS3hel). Then, a machine learning (ML) model was built to distinguish active vs inactive compounds for the cytoprotective effect against ZIKV infection. We performed three independent target-based virtual screening campaigns (NS5 RdRp, NS2B-NS3pro, and NS3hel), followed by predictions by the ML model and other filters, and prioritized a total of 61 compounds for further testing in enzymatic and phenotypic assays. This yielded five non-nucleoside compounds which showed inhibitory activity against ZIKV NS5 RdRp in enzymatic assays (IC50 range from 0.61 to 17 μM). Two compounds thermally destabilized NS3hel and showed binding affinity in the micromolar range (Kd range from 9 to 35 μM). Moreover, the compounds LabMol-301 inhibited both NS5 RdRp and NS2B-NS3pro (IC50 of 0.8 and 7.4 μM, respectively) and LabMol-212 thermally destabilized the ZIKV NS3hel (Kd of 35 μM). Both also protected cells from death induced by ZIKV infection in in vitro cell-based assays. However, while eight compounds (including LabMol-301 and LabMol-212) showed a cytoprotective effect and prevented ZIKV-induced cell death, agreeing with our ML model for prediction of this cytoprotective effect, no compound showed a direct antiviral effect against ZIKV. Thus, the new scaffolds discovered here are promising hits for future structural optimization and for advancing the discovery of further drug candidates for ZIKV. Furthermore, this work has demonstrated the importance of the integration of computational and experimental approaches, as well as the potential of large-scale collaborative networks to advance drug discovery projects for neglected diseases and emerging viruses, despite the lack of available direct antiviral activity and cytoprotective effect data, that reflects on the assertiveness of the computational predictions. The importance of these efforts rests with the need to be prepared for future viral epidemic and pandemic outbreaks.
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Affiliation(s)
- Melina Mottin
- Laboratory of Molecular Modeling and Drug Design (LabMol), Faculdade de Farmácia, Universidade Federal de Goiás, Goiânia, GO, 74605-170, Brazil
- Pathogen-Host Interface Laboratory, Department of Cell Biology, University of Brasilia, Brasilia, 70910-900, Brazil
| | - Bruna Katiele de Paula Sousa
- Laboratory of Molecular Modeling and Drug Design (LabMol), Faculdade de Farmácia, Universidade Federal de Goiás, Goiânia, GO, 74605-170, Brazil
| | | | | | - Gabriela Dias Noske
- São Carlos Institute of Physics, University of São Paulo, Avenida João Dagnone, 1100, São Carlos, São Paulo, 13563-120, Brazil
| | | | | | - Fabio Urbina
- Collaborations Pharmaceuticals, Inc., Raleigh, NC, 27606, USA
| | - Ana C. Puhl
- Collaborations Pharmaceuticals, Inc., Raleigh, NC, 27606, USA
| | - José Teófilo Moreira-Filho
- Laboratory of Molecular Modeling and Drug Design (LabMol), Faculdade de Farmácia, Universidade Federal de Goiás, Goiânia, GO, 74605-170, Brazil
| | - Guilherme E. Souza
- São Carlos Institute of Physics, University of São Paulo, Avenida João Dagnone, 1100, São Carlos, São Paulo, 13563-120, Brazil
| | - Rafael V.C. Guido
- São Carlos Institute of Physics, University of São Paulo, Avenida João Dagnone, 1100, São Carlos, São Paulo, 13563-120, Brazil
| | - Eugene Muratov
- University of North Carolina - University of North Carolina at Chapel Hill, 27599, USA
- Universidade Federal de Paraíba, Joao Pessoa, PB, 58051-900, Brazil
| | - Bruno Junior Neves
- Laboratory of Molecular Modeling and Drug Design (LabMol), Faculdade de Farmácia, Universidade Federal de Goiás, Goiânia, GO, 74605-170, Brazil
| | | | - Alex E. Clark
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, 92093, USA
| | - Jair L. Siqueira-Neto
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, 92093, USA
| | - Alexander L. Perryman
- Department of Pharmacology, Physiology and Neuroscience, Rutgers University–New Jersey Medical School, Newark, NJ 07103, United States
- Repare Therapeutics, 7210 Rue Frederick-Banting, Suite 100, Montreal, QC, H4S 2A1, Canada
| | - Glaucius Oliva
- São Carlos Institute of Physics, University of São Paulo, Avenida João Dagnone, 1100, São Carlos, São Paulo, 13563-120, Brazil
| | - Sean Ekins
- Collaborations Pharmaceuticals, Inc., Raleigh, NC, 27606, USA
| | - Carolina Horta Andrade
- Laboratory of Molecular Modeling and Drug Design (LabMol), Faculdade de Farmácia, Universidade Federal de Goiás, Goiânia, GO, 74605-170, Brazil
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45
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Dutta P, Roy P, Sengupta N. Effects of External Perturbations on Protein Systems: A Microscopic View. ACS OMEGA 2022; 7:44556-44572. [PMID: 36530249 PMCID: PMC9753117 DOI: 10.1021/acsomega.2c06199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 11/14/2022] [Indexed: 06/17/2023]
Abstract
Protein folding can be viewed as the origami engineering of biology resulting from the long process of evolution. Even decades after its recognition, research efforts worldwide focus on demystifying molecular factors that underlie protein structure-function relationships; this is particularly relevant in the era of proteopathic disease. A complex co-occurrence of different physicochemical factors such as temperature, pressure, solvent, cosolvent, macromolecular crowding, confinement, and mutations that represent realistic biological environments are known to modulate the folding process and protein stability in unique ways. In the current review, we have contextually summarized the substantial efforts in unveiling individual effects of these perturbative factors, with major attention toward bottom-up approaches. Moreover, we briefly present some of the biotechnological applications of the insights derived from these studies over various applications including pharmaceuticals, biofuels, cryopreservation, and novel materials. Finally, we conclude by summarizing the challenges in studying the combined effects of multifactorial perturbations in protein folding and refer to complementary advances in experiment and computational techniques that lend insights to the emergent challenges.
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Affiliation(s)
- Pallab Dutta
- Department
of Biological Sciences, Indian Institute
of Science Education and Research (IISER) Kolkata, Mohanpur741246, India
| | - Priti Roy
- Department
of Biological Sciences, Indian Institute
of Science Education and Research (IISER) Kolkata, Mohanpur741246, India
- Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma74078, United States
| | - Neelanjana Sengupta
- Department
of Biological Sciences, Indian Institute
of Science Education and Research (IISER) Kolkata, Mohanpur741246, India
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46
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Harris JA, Liu R, Martins de Oliveira V, Vázquez-Montelongo EA, Henderson JA, Shen J. GPU-Accelerated All-Atom Particle-Mesh Ewald Continuous Constant pH Molecular Dynamics in Amber. J Chem Theory Comput 2022; 18:7510-7527. [PMID: 36377980 PMCID: PMC10130738 DOI: 10.1021/acs.jctc.2c00586] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Constant pH molecular dynamics (MD) simulations sample protonation states on the fly according to the conformational environment and user specified pH conditions; however, the current accuracy is limited due to the use of implicit-solvent models or a hybrid solvent scheme. Here, we report the first GPU-accelerated implementation, parametrization, and validation of the all-atom continuous constant pH MD (CpHMD) method with particle-mesh Ewald (PME) electrostatics in the Amber22 pmemd.cuda engine. The titration parameters for Asp, Glu, His, Cys, and Lys were derived for the CHARMM c22 and Amber ff14sb and ff19sb force fields. We then evaluated the PME-CpHMD method using the asynchronous pH replica-exchange titration simulations with the c22 force field for six benchmark proteins, including BBL, hen egg white lysozyme (HEWL), staphylococcal nuclease (SNase), thioredoxin, ribonuclease A (RNaseA), and human muscle creatine kinase (HMCK). The root-mean-square deviation from the experimental pKa's of Asp, Glu, His, and Cys is 0.76 pH units, and the Pearson's correlation coefficient for the pKa shifts with respect to model values is 0.80. We demonstrated that a finite-size correction or much enlarged simulation box size can remove a systematic error of the calculated pKa's and improve agreement with experiment. Importantly, the simulations captured the relevant biology in several challenging cases, e.g., the titration order of the catalytic dyad Glu35/Asp52 in HEWL and the coupled residues Asp19/Asp21 in SNase, the large pKa upshift of the deeply buried catalytic Asp26 in thioredoxin, and the large pKa downshift of the deeply buried catalytic Cys283 in HMCK. We anticipate that PME-CpHMD will offer proper pH control to improve the accuracies of MD simulations and enable mechanistic studies of proton-coupled dynamical processes that are ubiquitous in biology but remain poorly understood due to the lack of experimental tools and limitation of current MD simulations.
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Affiliation(s)
- Julie A Harris
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland21201, United States
| | - Ruibin Liu
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland21201, United States
| | - Vinicius Martins de Oliveira
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland21201, United States.,Lilly Biotechnology Center, San Diego, California92121, United States
| | | | - Jack A Henderson
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland21201, United States
| | - Jana Shen
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland21201, United States
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47
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Pang YT, Acharya A, Lynch DL, Pavlova A, Gumbart JC. SARS-CoV-2 spike opening dynamics and energetics reveal the individual roles of glycans and their collective impact. Commun Biol 2022; 5:1170. [PMID: 36329138 PMCID: PMC9631587 DOI: 10.1038/s42003-022-04138-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 10/20/2022] [Indexed: 11/06/2022] Open
Abstract
The trimeric spike (S) glycoprotein, which protrudes from the SARS-CoV-2 viral envelope, binds to human ACE2, initiated by at least one protomer's receptor binding domain (RBD) switching from a "down" (closed) to an "up" (open) state. Here, we used large-scale molecular dynamics simulations and two-dimensional replica exchange umbrella sampling calculations with more than a thousand windows and an aggregate total of 160 μs of simulation to investigate this transition with and without glycans. We find that the glycosylated spike has a higher barrier to opening and also energetically favors the down state over the up state. Analysis of the S-protein opening pathway reveals that glycans at N165 and N122 interfere with hydrogen bonds between the RBD and the N-terminal domain in the up state, while glycans at N165 and N343 can stabilize both the down and up states. Finally, we estimate how epitope exposure for several known antibodies changes along the opening path. We find that the BD-368-2 antibody's epitope is continuously exposed, explaining its high efficacy.
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Affiliation(s)
- Yui Tik Pang
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Atanu Acharya
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA.,BioInspired Syracuse and Department of Chemistry, Syracuse University, Syracuse, NY, 13244, USA
| | - Diane L Lynch
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Anna Pavlova
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
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48
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Structure of the human heterodimeric transporter 4F2hc-LAT2 in complex with Anticalin, an alternative binding protein for applications in single-particle cryo-EM. Sci Rep 2022; 12:18269. [PMID: 36310334 PMCID: PMC9618567 DOI: 10.1038/s41598-022-23270-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 10/27/2022] [Indexed: 12/31/2022] Open
Abstract
Cryo-EM structure determination of relatively small and flexible membrane proteins at high resolution is challenging. Increasing the size and structural features by binding of high affinity proteins to the biomolecular target allows for better particle alignment and may result in structural models of higher resolution and quality. Anticalins are alternative binding proteins to antibodies, which are based on the lipocalin scaffold and show potential for theranostic applications. The human heterodimeric amino acid transporter 4F2hc-LAT2 is a membrane protein complex that mediates transport of certain amino acids and derivatives thereof across the plasma membrane. Here, we present and discuss the cryo-EM structure of human 4F2hc-LAT2 in complex with the anticalin D11vs at 3.2 Å resolution. Relative high local map resolution (2.8-3.0 Å) in the LAT2 substrate binding site together with molecular dynamics simulations indicated the presence of fixed water molecules potentially involved in shaping and stabilizing this region. Finally, the presented work expands the application portfolio of anticalins and widens the toolset of binding proteins to promote high-resolution structure solution by single-particle cryo-EM.
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49
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Sung MW, Driggers CM, Mostofian B, Russo JD, Patton BL, Zuckerman DM, Shyng SL. Ligand-mediated Structural Dynamics of a Mammalian Pancreatic K ATP Channel. J Mol Biol 2022; 434:167789. [PMID: 35964676 PMCID: PMC9618280 DOI: 10.1016/j.jmb.2022.167789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/22/2022] [Accepted: 08/09/2022] [Indexed: 11/16/2022]
Abstract
Regulation of pancreatic KATP channels involves orchestrated interactions of their subunits, Kir6.2 and SUR1, and ligands. Previously we reported KATP channel cryo-EM structures in the presence and absence of pharmacological inhibitors and ATP, focusing on the mechanisms by which inhibitors act as pharmacological chaperones of KATP channels (Martin et al., 2019). Here we analyzed the same cryo-EM datasets with a focus on channel conformational dynamics to elucidate structural correlates pertinent to ligand interactions and channel gating. We found pharmacological inhibitors and ATP enrich a channel conformation in which the Kir6.2 cytoplasmic domain is closely associated with the transmembrane domain, while depleting one where the Kir6.2 cytoplasmic domain is extended away into the cytoplasm. This conformational change remodels a network of intra- and inter-subunit interactions as well as the ATP and PIP2 binding pockets. The structures resolved key contacts between the distal N-terminus of Kir6.2 and SUR1's ABC module involving residues implicated in channel function and showed a SUR1 residue, K134, participates in PIP2 binding. Molecular dynamics simulations revealed two Kir6.2 residues, K39 and R54, that mediate both ATP and PIP2 binding, suggesting a mechanism for competitive gating by ATP and PIP2.
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Affiliation(s)
- Min Woo Sung
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR, USA. https://twitter.com/MinWooSung5
| | - Camden M Driggers
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Barmak Mostofian
- Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, Portland, OR, USA
| | - John D Russo
- Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Bruce L Patton
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Daniel M Zuckerman
- Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, Portland, OR, USA.
| | - Show-Ling Shyng
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR, USA.
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Stampelou M, Suchankova A, Tzortzini E, Dhingra L, Barkan K, Lougiakis N, Marakos P, Pouli N, Ladds G, Kolocouris A. Dual A1/A3 Adenosine Receptor Antagonists: Binding Kinetics and Structure-Activity Relationship Studies Using Mutagenesis and Alchemical Binding Free Energy Calculations. J Med Chem 2022; 65:13305-13327. [PMID: 36173355 DOI: 10.1021/acs.jmedchem.2c01123] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Drugs targeting adenosine receptors (AR) can provide treatment for diseases. We report the identification of 7-(phenylamino)-pyrazolo[3,4-c]pyridines L2-L10, A15, and A17 as low-micromolar to low-nanomolar A1R/A3R dual antagonists, with 3-phenyl-5-cyano-7-(trimethoxyphenylamino)-pyrazolo[3,4-c]pyridine (A17) displaying the highest affinity at both receptors with a long residence time of binding, as determined using a NanoBRET-based assay. Two binding orientations of A17 produce stable complexes inside the orthosteric binding area of A1R in molecular dynamics (MD) simulations, and we selected the most plausible orientation based on the agreement with alanine mutagenesis supported by affinity experiments. Interestingly, for drug design purposes, the mutation of L2506.51 to alanine increased the binding affinity of A17 at A1R. We explored the structure-activity relationships against A1R using alchemical binding free energy calculations with the thermodynamic integration coupled with the MD simulation (TI/MD) method, applied on the whole G-protein-coupled receptor-membrane system, which showed a good agreement (r = 0.73) between calculated and experimental relative binding free energies.
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Affiliation(s)
- Margarita Stampelou
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis-Zografou, 15771 Athens, Greece
| | - Anna Suchankova
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K
| | - Efpraxia Tzortzini
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis-Zografou, 15771 Athens, Greece
| | - Lakshiv Dhingra
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K
| | - Kerry Barkan
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K
| | - Nikolaos Lougiakis
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis-Zografou, 15771 Athens, Greece
| | - Panagiotis Marakos
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis-Zografou, 15771 Athens, Greece
| | - Nicole Pouli
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis-Zografou, 15771 Athens, Greece
| | - Graham Ladds
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K
| | - Antonios Kolocouris
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis-Zografou, 15771 Athens, Greece
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