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Majumder S, Deganutti G, Pipitò L, Chaudhuri D, Datta J, Giri K. Computational Insights into the Conformational Dynamics of HIV-1 Vpr in a Lipid Bilayer for Ion Channel Modeling. J Chem Inf Model 2024; 64:3360-3374. [PMID: 38597744 DOI: 10.1021/acs.jcim.3c01859] [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: 04/11/2024]
Abstract
HIV-1 Vpr is a multifunctional accessory protein consisting of 96 amino acids that play a critical role in viral pathogenesis. Among its diverse range of activities, Vpr can create a cation-selective ion channel within the plasma membrane. However, the oligomeric state of this channel has not yet been elucidated. In this study, we investigated the conformational dynamics of Vpr helices to model the ion channel topology. First, we employed a series of multiscale simulations to investigate the specific structure of monomeric Vpr in a membrane model. During the lipid bilayer self-assembly coarse grain simulation, the C-terminal helix (residues 56-77) effectively formed the transmembrane region, while the N-terminal helix exhibited an amphipathic nature by associating horizontally with a single leaflet. All-atom molecular dynamics (MD) simulations of full-length Vpr inside a phospholipid bilayer show that the C-terminal helix remains very stable inside the bilayer core in a vertical orientation. Subsequently, using the predicted C-terminal helix orientation and conformation, various oligomeric states (ranging from tetramer to heptamer) possibly forming the Vpr ion channel were built and further evaluated. Among these models, the pentameric form exhibited consistent stability in MD simulations and displayed a compatible conformation for a water-assisted ion transport mechanism. This study provides structural insights into the ion channel activity of the Vpr protein and the foundation for developing therapeutics against HIV-1 Vpr-related conditions.
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Affiliation(s)
- Satyabrata Majumder
- Department of Life Sciences, Presidency University, 86/1 College Street, Kolkata 700073, India
| | - Giuseppe Deganutti
- Centre for Health and Life Sciences, Coventry University, Coventry CV1 5FB, U.K
| | - Ludovico Pipitò
- Centre for Health and Life Sciences, Coventry University, Coventry CV1 5FB, U.K
| | - Dwaipayan Chaudhuri
- Department of Life Sciences, Presidency University, 86/1 College Street, Kolkata 700073, India
| | - Joyeeta Datta
- Department of Life Sciences, Presidency University, 86/1 College Street, Kolkata 700073, India
| | - Kalyan Giri
- Department of Life Sciences, Presidency University, 86/1 College Street, Kolkata 700073, India
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2
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Jones MS, Shmilovich K, Ferguson AL. DiAMoNDBack: Diffusion-Denoising Autoregressive Model for Non-Deterministic Backmapping of Cα Protein Traces. J Chem Theory Comput 2023; 19:7908-7923. [PMID: 37906711 DOI: 10.1021/acs.jctc.3c00840] [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: 11/02/2023]
Abstract
Coarse-grained molecular models of proteins permit access to length and time scales unattainable by all-atom models and the simulation of processes that occur on long time scales, such as aggregation and folding. The reduced resolution realizes computational accelerations, but an atomistic representation can be vital for a complete understanding of mechanistic details. Backmapping is the process of restoring all-atom resolution to coarse-grained molecular models. In this work, we report DiAMoNDBack (Diffusion-denoising Autoregressive Model for Non-Deterministic Backmapping) as an autoregressive denoising diffusion probability model to restore all-atom details to coarse-grained protein representations retaining only Cα coordinates. The autoregressive generation process proceeds from the protein N-terminus to C-terminus in a residue-by-residue fashion conditioned on the Cα trace and previously backmapped backbone and side-chain atoms within the local neighborhood. The local and autoregressive nature of our model makes it transferable between proteins. The stochastic nature of the denoising diffusion process means that the model generates a realistic ensemble of backbone and side-chain all-atom configurations consistent with the coarse-grained Cα trace. We train DiAMoNDBack over 65k+ structures from the Protein Data Bank (PDB) and validate it in applications to a hold-out PDB test set, intrinsically disordered protein structures from the Protein Ensemble Database (PED), molecular dynamics simulations of fast-folding mini-proteins from DE Shaw Research, and coarse-grained simulation data. We achieve state-of-the-art reconstruction performance in terms of correct bond formation, avoidance of side-chain clashes, and the diversity of the generated side-chain configurational states. We make the DiAMoNDBack model publicly available as a free and open-source Python package.
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Affiliation(s)
- Michael S Jones
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Kirill Shmilovich
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Andrew L Ferguson
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
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3
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Cooper BF, Clark R, Kudhail A, Bhabha G, Ekiert DC, Khalid S, Isom GL. Phospholipid transport to the bacterial outer membrane through an envelope-spanning bridge. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.05.561070. [PMID: 37873249 PMCID: PMC10592960 DOI: 10.1101/2023.10.05.561070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
The outer membrane of Gram-negative bacteria provides a formidable barrier, essential for both pathogenesis and antimicrobial resistance. Biogenesis of the outer membrane requires the transport of phospholipids across the cell envelope. Recently, YhdP was implicated as a major protagonist in the transport of phospholipids from the inner membrane to the outer membrane however the molecular mechanism of YhdP mediated transport remains elusive. Here, utilising AlphaFold, we observe YhdP to form an elongated assembly of 60 β strands that curve to form a continuous hydrophobic groove. This architecture is consistent with our negative stain electron microscopy data which reveals YhdP to be approximately 250 Å in length and thus sufficient to span the bacterial cell envelope. Furthermore, molecular dynamics simulations and in vivo bacterial growth assays indicate essential helical regions at the N- and C-termini of YhdP, that may embed into the inner and outer membranes respectively, reinforcing its envelope spanning nature. Our in vivo crosslinking data reveal phosphate-containing substrates captured along the length of the YhdP groove, providing direct evidence that YhdP transports phospholipids. This finding is congruent with our molecular dynamics simulations which demonstrate the propensity for inner membrane lipids to spontaneously enter the groove of YhdP. Collectively, our results support a model in which YhdP bridges the cell envelope, providing a hydrophobic environment for the transport of phospholipids to the outer membrane.
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Affiliation(s)
- Benjamin F. Cooper
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Robert Clark
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Anju Kudhail
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Gira Bhabha
- Department of Cell Biology, New York University School of Medicine, New York, NY, 10016
| | - Damian C. Ekiert
- Department of Cell Biology, New York University School of Medicine, New York, NY, 10016
- Department of Microbiology, New York University School of Medicine, New York, NY, 10016
| | - Syma Khalid
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Georgia L. Isom
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
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4
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Wei X, Yang Q, Yang Z, Huang T, Yang H, Wang L, Pan L, Ding J. Discovery of novel TRPV1 modulators through machine learning-based molecular docking and molecular similarity searching. Chem Biol Drug Des 2023; 102:409-423. [PMID: 37489095 DOI: 10.1111/cbdd.14270] [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: 04/11/2023] [Revised: 05/04/2023] [Accepted: 05/09/2023] [Indexed: 07/26/2023]
Abstract
The transient receptor potential vanilloid 1 (TRPV1) channel belongs to the transient receptor potential channel superfamily and participates in many physiological processes. TRPV1 modulators (both agonists and antagonists) can effectively inhibit pain caused by various factors and have curative effects in various diseases, such as itch, cancer, and cardiovascular diseases. Therefore, the development of TRPV1 channel modulators is of great importance. In this study, the structure-based virtual screening and ligand-based virtual screening methods were used to screen compound databases respectively. In the structure-based virtual screening route, a full-length human TRPV1 protein was first constructed, three molecular docking methods with different precisions were performed based on the hTRPV1 structure, and a machine learning-based rescoring model by the XGBoost algorithm was constructed to enrich active compounds. In the ligand-based virtual screening route, the ROCS program was used for 3D shape similarity searching and the EON program was used for electrostatic similarity searching. Final 77 compounds were selected from two routes for in vitro assays. The results showed that 8 of them were identified as active compounds, including three hits with IC50 values close to capsazepine. In addition, one hit is a partial agonist with both agonistic and antagonistic activity. The mechanisms of some active compounds were investigated by molecular dynamics simulation, which explained their agonism or antagonism.
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Affiliation(s)
- Xinmiao Wei
- State Key Laboratory of NBC Protection for Civilian, Beijing, China
| | - Qifan Yang
- State Key Laboratory of NBC Protection for Civilian, Beijing, China
| | - Zhijiang Yang
- State Key Laboratory of NBC Protection for Civilian, Beijing, China
| | - Tengxin Huang
- State Key Laboratory of NBC Protection for Civilian, Beijing, China
- School of Physics and Electronic Engineering, Sichuan University of Science & Engineering, Zigong, China
| | - Hang Yang
- State Key Laboratory of NBC Protection for Civilian, Beijing, China
- School of Physics and Electronic Engineering, Sichuan University of Science & Engineering, Zigong, China
| | - Liangliang Wang
- State Key Laboratory of NBC Protection for Civilian, Beijing, China
| | - Li Pan
- State Key Laboratory of NBC Protection for Civilian, Beijing, China
| | - Junjie Ding
- State Key Laboratory of NBC Protection for Civilian, Beijing, China
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Das T, Mukhopadhyay C. Comparison and Possible Binding Orientations of SARS-CoV-2 Spike N-Terminal Domain for Gangliosides GM3 and GM1. J Phys Chem B 2023; 127:6940-6948. [PMID: 37523476 DOI: 10.1021/acs.jpcb.3c02286] [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: 08/02/2023]
Abstract
SARS-CoV-2 spike glycoprotein is anchored by gangliosides. The sialic acid in the ganglioside headgroup is responsible for virus attachment and entry into host cells. We used coarse-grained (CG) molecular dynamics simulations to expand on our previous study of GM1 interaction with two different orientations of the SARS-CoV-2 S1 subunit N-terminal domain (NTD) and to confirm the role of sialic acid receptors in driving the viral receptor; GM3 was used as another ganglioside on the membrane. Because of the smaller headgroup, sialic acid is crucial in GM3 interactions, whereas GM1 interacts with NTD via both the sialic acid and external galactose. In line with our previous findings for NTD orientations in GM1 binding, we identified two orientations, "compact" and "distributed", comprising sugar receptor-interacting residues in GM3-embedded lipid bilayers. Gangliosides in closer proximity to the compact NTD orientation might cause relatively greater restrictions to penetrate the bilayer. However, the attachment of a distributed NTD orientation with more negative interaction energies appears to facilitate GM1/GM3 to move quickly across the membrane. Our findings likely shed some light on the orientations that the NTD receptor acquires during the early phases of interaction with GM1 and GM3 in a membrane environment.
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Affiliation(s)
- Tanushree Das
- Department of Chemistry, University of Calcutta, 92, A.P.C. Road, Kolkata 700009, India
| | - Chaitali Mukhopadhyay
- Department of Chemistry, University of Calcutta, 92, A.P.C. Road, Kolkata 700009, India
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Ledum M, Sen S, Li X, Carrer M, Feng Y, Cascella M, Bore SL. HylleraasMD: A Domain Decomposition-Based Hybrid Particle-Field Software for Multiscale Simulations of Soft Matter. J Chem Theory Comput 2023; 19:2939-2952. [PMID: 37130290 DOI: 10.1021/acs.jctc.3c00134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We present HylleraasMD (HyMD), a comprehensive implementation of the recently proposed Hamiltonian formulation of hybrid particle-field molecular dynamics. The methodology is based on a tunable, grid-independent length-scale of coarse graining, obtained by filtering particle densities in reciprocal space. This enables systematic convergence of energies and forces by grid refinement, also eliminating nonphysical force aliasing. Separating the time integration of fast modes associated with internal molecular motion from slow modes associated with their density fields, we enable the first time-reversible, energy-conserving hybrid particle-field simulations. HyMD comprises the optional use of explicit electrostatics, which, in this formalism, corresponds to the long-range potential in particle-mesh Ewald. We demonstrate the ability of HyMD to perform simulations in the microcanonical and canonical ensembles with a series of test cases, comprising lipid bilayers and vesicles, surfactant micelles, and polypeptide chains, comparing our results to established literature. An on-the-fly increase of the characteristic coarse-grain length significantly speeds up dynamics, accelerating self-diffusion and leading to expedited aggregation. Exploiting this acceleration, we find that the time scales involved in the self-assembly of polymeric structures can lie in the tens to hundreds of picoseconds instead of the multimicrosecond regime observed with comparable coarse-grained models.
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Affiliation(s)
- Morten Ledum
- Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, PO Box 1033 Blindern, 0315 Oslo, Norway
| | - Samiran Sen
- Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, PO Box 1033 Blindern, 0315 Oslo, Norway
| | - Xinmeng Li
- Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, PO Box 1033 Blindern, 0315 Oslo, Norway
| | - Manuel Carrer
- Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, PO Box 1033 Blindern, 0315 Oslo, Norway
| | - Yu Feng
- Berkeley Center for Cosmological Physics and Department of Physics, University of California, Berkeley, California 94720, United States
| | - Michele Cascella
- Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, PO Box 1033 Blindern, 0315 Oslo, Norway
| | - Sigbjørn Løland Bore
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States
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7
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Go YJ, Kalathingal M, Rhee YM. Elucidating activation and deactivation dynamics of VEGFR-2 transmembrane domain with coarse-grained molecular dynamics simulations. PLoS One 2023; 18:e0281781. [PMID: 36795710 PMCID: PMC9934429 DOI: 10.1371/journal.pone.0281781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 02/01/2023] [Indexed: 02/17/2023] Open
Abstract
The vascular endothelial growth factor receptor 2 (VEGFR-2) is a member of receptor tyrosine kinases (RTKs) and is a dimeric membrane protein that functions as a primary regulator of angiogenesis. As is usual with RTKs, spatial alignment of its transmembrane domain (TMD) is essential toward VEGFR-2 activation. Experimentally, the helix rotations within TMD around their own helical axes are known to participate importantly toward the activation process in VEGFR-2, but the detailed dynamics of the interconversion between the active and inactive TMD forms have not been clearly elucidated at the molecular level. Here, we attempt to elucidate the process by using coarse grained (CG) molecular dynamics (MD) simulations. We observe that inactive dimeric TMD in separation is structurally stable over tens of microseconds, suggesting that TMD itself is passive and does not allow spontaneous signaling of VEGFR-2. By starting from the active conformation, we reveal the mechanism of TMD inactivation through analyzing the CG MD trajectories. We observe that interconversions between a left-handed overlay and a right-handed one are essential for the process of going from an active TMD structure to the inactive form. In addition, our simulations find that the helices can rotate properly when the overlaying structure of the helices interconverts and when the crossing angle of the two helices changes by larger than ~40 degrees. As the activation right after the ligand attachment on VEGFR-2 will take place in the reverse manner of this inactivation process, these structural aspects will also appear importantly for the activation process. The rather large change in helix configuration for activation also explains why VEGFR-2 rarely self-activate and how the activating ligand structurally drive the whole VEGFR-2. This mechanism of TMD activation / inactivation within VEGFR-2 may help in further understanding the overall activation processes of other RTKs.
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Affiliation(s)
- Yeon Ju Go
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Mahroof Kalathingal
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Young Min Rhee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
- * E-mail:
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8
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Dessaux D, Mathé J, Ramirez R, Basdevant N. Current Rectification and Ionic Selectivity of α-Hemolysin: Coarse-Grained Molecular Dynamics Simulations. J Phys Chem B 2022; 126:4189-4199. [PMID: 35657610 DOI: 10.1021/acs.jpcb.2c01028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In order to understand the physical processes of nanopore experiments at the molecular level, microscopic information from molecular dynamics is greatly needed. Coarse-grained models are a good alternative to classical all-atom models since they allow longer and faster simulations. We performed coarse-grained molecular dynamics of the ionic transport through the α-hemolysin protein nanopore, inserted into a lipid bilayer surrounded by solvent and ions. For this purpose, we used the MARTINI coarse-grained force field and its polarizable water solvent (PW). Moreover, the electric potential difference applied experimentally was mimicked by the application of an electric field to the system. We present, in this study, the results of 1.5 μs long-molecular dynamics simulations of 12 different systems for which different charged amino acids were neutralized, each of them in the presence of nine different electric fields ranging between ±0.04 V/nm (a total of around 100 simulations). We were able to observe several specific features of this pore, current asymmetry and anion selectivity, in agreement with previous studies and experiments, and we identified the charged amino acids responsible for these current behaviors, therefore validating our coarse-grain approach to study ionic transport through nanopores. We also propose a microscopic explanation of these ionic current features using ionic density maps.
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Affiliation(s)
- Delphine Dessaux
- Université Paris-Saclay, Univ Evry, CNRS, LAMBE UMR8587, Évry-Courcouronnes 91025, France
| | - Jérôme Mathé
- Université Paris-Saclay, Univ Evry, CNRS, LAMBE UMR8587, Évry-Courcouronnes 91025, France
| | - Rosa Ramirez
- Université Paris-Saclay, Univ Evry, CNRS, LAMBE UMR8587, Évry-Courcouronnes 91025, France
| | - Nathalie Basdevant
- Université Paris-Saclay, Univ Evry, CNRS, LAMBE UMR8587, Évry-Courcouronnes 91025, France
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Wang L, Zhang J, Wang D, Song C. Membrane contact probability: An essential and predictive character for the structural and functional studies of membrane proteins. PLoS Comput Biol 2022; 18:e1009972. [PMID: 35353812 PMCID: PMC9000120 DOI: 10.1371/journal.pcbi.1009972] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/11/2022] [Accepted: 02/25/2022] [Indexed: 11/20/2022] Open
Abstract
One of the unique traits of membrane proteins is that a significant fraction of their hydrophobic amino acids is exposed to the hydrophobic core of lipid bilayers rather than being embedded in the protein interior, which is often not explicitly considered in the protein structure and function predictions. Here, we propose a characteristic and predictive quantity, the membrane contact probability (MCP), to describe the likelihood of the amino acids of a given sequence being in direct contact with the acyl chains of lipid molecules. We show that MCP is complementary to solvent accessibility in characterizing the outer surface of membrane proteins, and it can be predicted for any given sequence with a machine learning-based method by utilizing a training dataset extracted from MemProtMD, a database generated from molecular dynamics simulations for the membrane proteins with a known structure. As the first of many potential applications, we demonstrate that MCP can be used to systematically improve the prediction precision of the protein contact maps and structures. The distribution of residues on protein surfaces is largely determined by the surrounding environment. For soluble proteins, most of the residues on the outer surface are hydrophilic, and people use the quantity “solvent accessibility” to describe and predict these surface residues. In contrast, for membrane proteins that are embedded in a lipid bilayer, many of their surface residues are hydrophobic and membrane-contacting, but there is yet a widely-accepted quantity for the description or prediction of this characteristic property. Here, we propose a new quantity termed “membrane contact probability (MCP)”, which can be used to describe and predict the membrane-contacting surface residues of proteins. We also propose a machine learning-based method to predict MCP from protein sequences, utilizing the dataset generated by physics-based computer simulations. We demonstrate that a quantity such as MCP is helpful for protein structure prediction, and we believe that it will find broad applications in the structure and function studies of membrane proteins.
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Affiliation(s)
- Lei Wang
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary studies, Peking University, Beijing, China
| | - Jiangguo Zhang
- School of Life Sciences, Peking University, Beijing, China
| | - Dali Wang
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary studies, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Chen Song
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary studies, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- * E-mail:
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10
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Islam S, Mukhopadhyay C. Aggregation of Lysozyme in the Presence of a Mixed Bilayer of POPC and POPG. ACS OMEGA 2021; 6:17861-17869. [PMID: 34308021 PMCID: PMC8295997 DOI: 10.1021/acsomega.1c01145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 06/30/2021] [Indexed: 05/04/2023]
Abstract
Understanding the molecular mechanisms by which amyloidogenic proteins interact with membranes is a challenging task. Amyloid accumulates from many human diseases have been observed to contain membrane lipids. In this work, coarse-grained molecular dynamics simulations have been used to inspect hen egg white lysozyme (HEWL) aggregation and membrane association in the presence of a pure POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) bilayer and a POPC and POPG (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylglycerol) mixed bilayer. It was observed that, in both cases, two HEWLs formed aggregates. In the presence of a mixed bilayer, after aggregation, the aggregated system started to interact with the membrane. It has been found that one of the lysozymes which came closer to the mixed bilayer unfolded more. The process of the initial insertion of an aggregated system in the mixed bilayer has been analyzed. The structural rearrangements of the protein and lipids were analyzed as well along the course of the simulation. Although with a pure POPC bilayer, aggregation was observed, the aggregated system moved away from the membrane. We believe that our study will provide considerable insights into lysozyme aggregation in the presence of a membrane environment.
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Affiliation(s)
- Shahee Islam
- Department of Chemistry, University
of Calcutta, 92, A. P. C. Road, Kolkata 700009, India
| | - Chaitali Mukhopadhyay
- Department of Chemistry, University
of Calcutta, 92, A. P. C. Road, Kolkata 700009, India
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11
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Broadening the Scope of Polyoxometalates as Artificial Proteases in Surfactant Solutions: Hydrolysis of Ovalbumin by Zr(IV)-Substituted Keggin Complex. INORGANICS 2021. [DOI: 10.3390/inorganics9040022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Development of catalysts for the selective hydrolysis of proteins is challenging, yet important for many applications in biotechnology and proteomics. The hydrolysis of hydrophobic proteins is particularly challenging, as due to their poor solubility, the use of surfactants is often required. In this study, the proteolytic potential of catalyst systems based on the Zr(IV)-substituted Keggin polyoxometalate (Et2NH2)10[Zr(PW11O39)2] (Zr-K 1:2) and three different surfactants (ionic SDS (sodium dodecyl sulfate); zwitterionic Zw3-12 (n-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate); and CHAPS (3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate)), which differ in structure and polarity, has been investigated. Hydrolysis of ovalbumin (OVA) was examined in the presence of Zr-K 1:2 and surfactants by sodium dodecyl sulfate poly(acrylamide) gel electrophoresis (SDS-PAGE), which showed the appearance of new polypeptide fragments at lower molecular weight, indicating that selective hydrolysis of OVA took place for all three catalyst systems. The same fragmentation pattern was observed, showing that the selectivity was not affected by surfactants. However, the surfactants influenced the performance of the catalyst. Hence, the interactions of OVA with surfactants and Zr-K 1:2 were investigated using different techniques such as tryptophan fluorescence, Circular Dichroism, and Dynamic Light Scattering. The speciation of the catalyst in surfactant solutions was also followed by 31P Nuclear Magnetic Resonance spectroscopy providing insight into its stability under reaction conditions.
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12
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Souza LM, Souza FR, Reynaud F, Pimentel AS. Tuning the hydrophobicity of a coarse grained model of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine using the experimental octanol-water partition coefficient. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.114132] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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13
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Yong L, Huang M, Wei Y, Xu J, Yi Z. Investigating the interaction between three perfluorinated carboxylic acids and the G protein-coupled estrogen receptor: spectroscopic analyses and computational simulations. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2020; 12:3944-3953. [PMID: 32743632 DOI: 10.1039/d0ay01052a] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In this paper, perfluorinated compounds (PFCs), such as perfluorobutyric acid (PFBA), perfluorooctanoic acid (PFOA) and perfluorododecanoic acid (PFDoA), were selected as typical representatives of perfluorinated carboxylic acids (PFCAs) to study the effects of PFCAs on the G protein-coupled estrogen receptor (GPER). The interaction mechanism of the three types of PFCAs with the GPER was investigated using steady-state fluorescence spectroscopy, ultraviolet-visible spectroscopy, three-dimensional fluorescence spectroscopy, and Fourier transform infrared spectroscopy combined with molecular docking and molecular dynamics simulations. Among these techniques, steady-state fluorescence and ultraviolet-visible spectroscopic analyses showed that PFBA, PFOA and PFDoA quenched the endogenous GPER fluorescence by combined dynamic and static quenching and non-radiative energy transfer. The binding constants (Ka) of PFCAs on the GPER were all larger than 105 L mol-1, indicating that their affinity for the GPER was strong. Fourier transform infrared spectroscopy and three-dimensional fluorescence showed that the secondary structure of the GPER changed after binding to PFCAs. Thermodynamic analysis showed ΔG < 0, which indicated that the interaction between the GPER and PFCAs was spontaneous. For the binding of PFBA and PFOA to the GPER, ΔH > 0 and ΔS > 0, indicating that the interaction was mainly driven by hydrophobic forces; for the binding of PFDoA to the GPER, ΔH < 0 and ΔS < 0, suggesting that van der Waals force and hydrogen bonding were the main interaction forces. Molecular dynamics simulations suggested that the stability of the GPER-PFCA complexes was higher than that of the free GPER, and also that the structure and hydrophobicity of the GPER changed after binding to PFCAs. Molecular docking analysis showed that all three PFCAs could form hydrogen bonds with the GPER, which improved the stability of the complex.
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Affiliation(s)
- Li Yong
- Guangxi Colleges and Universities Key Laboratory of Food Safety and Detection, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, China.
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14
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Jing H, Wang Y, Desai PR, Ramamurthi KS, Das S. Formation and Properties of a Self-Assembled Nanoparticle-Supported Lipid Bilayer Probed through Molecular Dynamics Simulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:5524-5533. [PMID: 32362127 PMCID: PMC7494177 DOI: 10.1021/acs.langmuir.0c00593] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We have carried out coarse-grained molecular dynamics (MD) simulations to study the self-assembly procedure of a system of randomly placed lipid molecules, water beads, and a nanoparticle (NP). The self-assembly results in the formation of the nanoparticle-supported lipid bilayer (NPSLBL), with the self-assembly mechanism being driven by events such as the formation of small lipid clusters, merging of the lipid clusters in the vicinity of the NP to form NP-embedded vesicle with a pore, and collapsing of that pore to eventually form the equilibrated NPSLBL system overcoming a large free-energy barrier. Subsequently, we quantify the properties and the configurations of this NPSLBL system. We reveal that unlike our proposition of an equal number of lipid molecules occupying the inner and outer leaflets in a recent report studying the properties of a preassembled lipid bilayer, the equilibrated self-assembled NPSLBL system demonstrates a much larger number of lipid molecules occupying the outer leaflet as compared to the inner leaflet. Second, the thickness of the water layer entrapped between the NP and the inner leaflet shows similar values as predicted by experiments and our previous study. Finally, we reveal that, similar to our previous study, the diffusivity of the lipid molecules in the outer leaflet is larger than that in the inner leaflet but, due to higher temperature employed during our simulations, are even larger than that predicted by our previous study.
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Affiliation(s)
- Haoyuan Jing
- Department of Mechanical Engineering, University of Maryland, 4298 Campus Drive, College Park, MD 20742
| | - Yanbin Wang
- Department of Mechanical Engineering, University of Maryland, 4298 Campus Drive, College Park, MD 20742
| | - Parth Rakesh Desai
- Department of Mechanical Engineering, University of Maryland, 4298 Campus Drive, College Park, MD 20742
| | - Kumaran S. Ramamurthi
- Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Siddhartha Das
- Department of Mechanical Engineering, University of Maryland, 4298 Campus Drive, College Park, MD 20742
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15
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Wang Q, Corey RA, Hedger G, Aryal P, Grieben M, Nasrallah C, Baronina A, Pike ACW, Shi J, Carpenter EP, Sansom MSP. Lipid Interactions of a Ciliary Membrane TRP Channel: Simulation and Structural Studies of Polycystin-2. Structure 2019; 28:169-184.e5. [PMID: 31806353 PMCID: PMC7001106 DOI: 10.1016/j.str.2019.11.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/04/2019] [Accepted: 11/08/2019] [Indexed: 01/08/2023]
Abstract
Polycystin-2 (PC2) is a transient receptor potential (TRP) channel present in ciliary membranes of the kidney. PC2 shares a transmembrane fold with other TRP channels, in addition to an extracellular domain found in TRPP and TRPML channels. Using molecular dynamics (MD) simulations and cryoelectron microscopy we identify and characterize PIP2 and cholesterol interactions with PC2. PC2 is revealed to have a PIP binding site close to the equivalent vanilloid/lipid binding site in the TRPV1 channel. A 3.0-Å structure reveals a binding site for cholesterol on PC2. Cholesterol interactions with the channel at this site are characterized by MD simulations. The two classes of lipid binding sites are compared with sites observed in other TRPs and in Kv channels. These findings suggest PC2, in common with other ion channels, may be modulated by both PIPs and cholesterol, and position PC2 within an emerging model of the roles of lipids in the regulation and organization of ciliary membranes. Lipid interactions of PC2 channels have been explored by MD simulation and cryo-EM PIP2 binds to a site corresponding to the vanilloid/lipid binding site of TRPV1 Cholesterol binds between the S3 and S4 helices and S6 of the adjacent subunit PC2, in common with other channels, may be modulated by PIPs and cholesterol
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Affiliation(s)
- Qinrui Wang
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK; Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Robin A Corey
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - George Hedger
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Prafulla Aryal
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Mariana Grieben
- Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Chady Nasrallah
- Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Agnese Baronina
- Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Ashley C W Pike
- Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Jiye Shi
- UCB Pharma, 208 Bath Road, Slough SL1 3WE, UK
| | - Elisabeth P Carpenter
- Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK.
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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16
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Ionic transport through a protein nanopore: a Coarse-Grained Molecular Dynamics Study. Sci Rep 2019; 9:15740. [PMID: 31673049 PMCID: PMC6823379 DOI: 10.1038/s41598-019-51942-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 07/17/2019] [Indexed: 11/09/2022] Open
Abstract
The MARTINI coarse-grained (CG) force field is used to test the ability of CG models to simulate ionic transport through protein nanopores. The ionic conductivity of CG ions in solution was computed and compared with experimental results. Next, we studied the electrostatic behavior of a solvated CG lipid bilayer in salt solution under an external electric field. We showed this approach correctly describes the experimental conditions under a potential bias. Finally, we performed CG molecular dynamics simulations of the ionic transport through a protein nanopore (α-hemolysin) inserted in a lipid bilayer, under different electric fields, for 2-3 microseconds. The resulting I - V curve is qualitatively consistent with experiments, although the computed current is one order of magnitude smaller. Current saturation was observed for potential biases over ±350 mV. We also discuss the time to reach a stationary regime and the role of the protein flexibility in our CG simulations.
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17
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Ryazantsev MN, Nikolaev DM, Struts AV, Brown MF. Quantum Mechanical and Molecular Mechanics Modeling of Membrane-Embedded Rhodopsins. J Membr Biol 2019; 252:425-449. [PMID: 31570961 DOI: 10.1007/s00232-019-00095-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 09/10/2019] [Indexed: 12/20/2022]
Abstract
Computational chemistry provides versatile methods for studying the properties and functioning of biological systems at different levels of precision and at different time scales. The aim of this article is to review the computational methodologies that are applicable to rhodopsins as archetypes for photoactive membrane proteins that are of great importance both in nature and in modern technologies. For each class of computational techniques, from methods that use quantum mechanics for simulating rhodopsin photophysics to less-accurate coarse-grained methodologies used for long-scale protein dynamics, we consider possible applications and the main directions for improvement.
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Affiliation(s)
- Mikhail N Ryazantsev
- Institute of Chemistry, Saint Petersburg State University, 26 Universitetskii pr, Saint Petersburg, Russia, 198504
| | - Dmitrii M Nikolaev
- Saint-Petersburg Academic University - Nanotechnology Research and Education Centre RAS, Saint Petersburg, Russia, 194021
| | - Andrey V Struts
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721, USA.,Laboratory of Biomolecular NMR, Saint Petersburg State University, Saint Petersburg, Russia, 199034
| | - Michael F Brown
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721, USA. .,Department of Physics, University of Arizona, Tucson, AZ, 85721, USA.
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18
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Conrard L, Tyteca D. Regulation of Membrane Calcium Transport Proteins by the Surrounding Lipid Environment. Biomolecules 2019; 9:E513. [PMID: 31547139 PMCID: PMC6843150 DOI: 10.3390/biom9100513] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/09/2019] [Accepted: 09/10/2019] [Indexed: 12/11/2022] Open
Abstract
Calcium ions (Ca2+) are major messengers in cell signaling, impacting nearly every aspect of cellular life. Those signals are generated within a wide spatial and temporal range through a large variety of Ca2+ channels, pumps, and exchangers. More and more evidences suggest that Ca2+ exchanges are regulated by their surrounding lipid environment. In this review, we point out the technical challenges that are currently being overcome and those that still need to be defeated to analyze the Ca2+ transport protein-lipid interactions. We then provide evidences for the modulation of Ca2+ transport proteins by lipids, including cholesterol, acidic phospholipids, sphingolipids, and their metabolites. We also integrate documented mechanisms involved in the regulation of Ca2+ transport proteins by the lipid environment. Those include: (i) Direct interaction inside the protein with non-annular lipids; (ii) close interaction with the first shell of annular lipids; (iii) regulation of membrane biophysical properties (e.g., membrane lipid packing, thickness, and curvature) directly around the protein through annular lipids; and (iv) gathering and downstream signaling of several proteins inside lipid domains. We finally discuss recent reports supporting the related alteration of Ca2+ and lipids in different pathophysiological events and the possibility to target lipids in Ca2+-related diseases.
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Affiliation(s)
- Louise Conrard
- CELL Unit, de Duve Institute and Université catholique de Louvain, UCL B1.75.05, avenue Hippocrate, 75, B-1200 Brussels, Belgium
| | - Donatienne Tyteca
- CELL Unit, de Duve Institute and Université catholique de Louvain, UCL B1.75.05, avenue Hippocrate, 75, B-1200 Brussels, Belgium.
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19
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Lancet D, Zidovetzki R, Markovitch O. Systems protobiology: origin of life in lipid catalytic networks. J R Soc Interface 2019; 15:rsif.2018.0159. [PMID: 30045888 PMCID: PMC6073634 DOI: 10.1098/rsif.2018.0159] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 06/29/2018] [Indexed: 12/17/2022] Open
Abstract
Life is that which replicates and evolves, but there is no consensus on how life emerged. We advocate a systems protobiology view, whereby the first replicators were assemblies of spontaneously accreting, heterogeneous and mostly non-canonical amphiphiles. This view is substantiated by rigorous chemical kinetics simulations of the graded autocatalysis replication domain (GARD) model, based on the notion that the replication or reproduction of compositional information predated that of sequence information. GARD reveals the emergence of privileged non-equilibrium assemblies (composomes), which portray catalysis-based homeostatic (concentration-preserving) growth. Such a process, along with occasional assembly fission, embodies cell-like reproduction. GARD pre-RNA evolution is evidenced in the selection of different composomes within a sparse fitness landscape, in response to environmental chemical changes. These observations refute claims that GARD assemblies (or other mutually catalytic networks in the metabolism first scenario) cannot evolve. Composomes represent both a genotype and a selectable phenotype, anteceding present-day biology in which the two are mostly separated. Detailed GARD analyses show attractor-like transitions from random assemblies to self-organized composomes, with negative entropy change, thus establishing composomes as dissipative systems—hallmarks of life. We show a preliminary new version of our model, metabolic GARD (M-GARD), in which lipid covalent modifications are orchestrated by non-enzymatic lipid catalysts, themselves compositionally reproduced. M-GARD fills the gap of the lack of true metabolism in basic GARD, and is rewardingly supported by a published experimental instance of a lipid-based mutually catalytic network. Anticipating near-future far-reaching progress of molecular dynamics, M-GARD is slated to quantitatively depict elaborate protocells, with orchestrated reproduction of both lipid bilayer and lumenal content. Finally, a GARD analysis in a whole-planet context offers the potential for estimating the probability of life's emergence. The invigorated GARD scrutiny presented in this review enhances the validity of autocatalytic sets as a bona fide early evolution scenario and provides essential infrastructure for a paradigm shift towards a systems protobiology view of life's origin.
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Affiliation(s)
- Doron Lancet
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Raphael Zidovetzki
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA 92521, USA
| | - Omer Markovitch
- Origins Center, Center for Systems Chemistry, Stratingh Institute for Chemistry, University of Groningen, Groningen, the Netherlands.,Blue Marble Space Institute of Science, Seattle, WA, USA
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20
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Untangling Direct and Domain-Mediated Interactions Between Nicotinic Acetylcholine Receptors in DHA-Rich Membranes. J Membr Biol 2019; 252:385-396. [PMID: 31321460 DOI: 10.1007/s00232-019-00079-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 07/04/2019] [Indexed: 02/01/2023]
Abstract
At the neuromuscular junction (NMJ), the nicotinic acetylcholine receptor (nAChR) self-associates to give rise to rapid muscle movement. While lipid domains have maintained nAChR aggregates in vitro, their specific roles in nAChR clustering are currently unknown. In the present study, we carried out coarse-grained molecular dynamics simulations (CG-MD) of 1-4 nAChR molecules in two membrane environments: one mixture containing domain-forming, homoacidic lipids, and a second mixture consisting of heteroacidic lipids. Spontaneous dimerization of nAChRs was up to ten times more likely in domain-forming membranes; however, the effect was not significant in four-protein systems, suggesting that lipid domains are less critical to nAChR oligomerization when protein concentration is higher. With regard to lipid preferences, nAChRs consistently partitioned into liquid-disordered domains occupied by the omega-3 ([Formula: see text]-3) fatty acid, docosahexaenoic acid (DHA); enrichment of DHA boundary lipids increased with protein concentration, particularly in homoacidic membranes. This result suggests dimer formation blocks access of saturated chains and cholesterol, but not polyunsaturated chains, to boundary lipid sites.
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21
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Iyer BR, Mahalakshmi R. Hydrophobic Characteristic Is Energetically Preferred for Cysteine in a Model Membrane Protein. Biophys J 2019; 117:25-35. [PMID: 31221440 PMCID: PMC6626846 DOI: 10.1016/j.bpj.2019.05.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 05/17/2019] [Accepted: 05/22/2019] [Indexed: 11/17/2022] Open
Abstract
The naturally occurring amino acid cysteine has often been implicated with a crucial role in maintaining protein structure and stability. An intriguing duality in the intrinsic hydrophobicity of the cysteine side chain is that it exhibits both polar as well as hydrophobic characteristics. Here, we have utilized a cysteine-scanning mutational strategy on the transmembrane β-barrel PagP to examine the membrane depth-dependent energetic contribution of the free cysteine side chain (thiolate) versus the parent residue at an experimental pH of 9.5 in phosphatidylcholine vesicles. We find that introduction of cysteine causes destabilization at several of the 26 lipid-facing sites of PagP that we mutated in this study. The destabilization is minimal (0.5-1.5 kcal/mol) when the mutation is toward the bilayer midplane, whereas it is higher in magnitude (3.0-5.0 kcal/mol) near the bilayer interface. These observations suggest that cysteine forms more favorable interactions with the hydrophobic lipid core as compared to the amphiphilic water-lipid interface. The destabilizing effect is more pronounced when cysteine replaces the interfacial aromatics, which are known to participate in tertiary interaction networks in transmembrane β-barrels. Our observations from experiments involving the introduction of cysteine at the bilayer midplane further strengthen previous views that the free cysteine side chain does possess strongly apolar characteristics. Additionally, the free energy changes observed upon cysteine incorporation show a depth-dependent correlation with the estimated energetic cost of partitioning derived from reported hydrophobicity scales. Our results and observations from the thermodynamic analysis of the PagP barrel may explain why cysteine, despite possessing a polar sulfhydryl group, tends to behave as a hydrophobic (rather than polar) residue in folded protein structures.
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Affiliation(s)
- Bharat Ramasubramanian Iyer
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh, India
| | - Radhakrishnan Mahalakshmi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh, India.
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22
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Minh Hung H, Dieu Hang T, Nguyen MT. Structural Investigation of Human Prolactin Receptor Transmembrane Domain Homodimerization in a Membrane Environment through Multiscale Simulations. J Phys Chem B 2019; 123:4858-4866. [PMID: 31099581 DOI: 10.1021/acs.jpcb.9b01986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
It is well established that prolactin (PRL) and its receptor (PRLR) are associated with hundreds of biological functions. They have been postulated to be linked to breast and prostate cancers, and PRLR signaling has attracted considerable medical and pharmaceutical interest in the development of compounds targeting PRLR. Dimerization of the receptor through its transmembrane (TM) domain is a key step for understanding its signaling and related issues. Our multiscale simulation results revealed that its TM domain can form dimers in a membrane environment with distinct states stabilized by different residue motifs. On the basis of the simulated data, an activation mechanism of PRL with the importance of two symmetrical tryptophan residues was proposed in detail to determine the conformational change of its receptor, which is essential for signal transduction. The better knowledge of PRLR structure and its protein-protein interaction can considerably contribute to a further understanding of PRLR signaling action and thereby help to develop some new PRLR signaling-based strategies for PRL-related diseases.
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Affiliation(s)
- Huynh Minh Hung
- Department of Chemistry , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium.,Department of Chemistry , Quy Nhon University , Quy Nhon 590000 , Vietnam
| | - Tran Dieu Hang
- Department of Chemistry , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium.,Department of Chemistry , Quy Nhon University , Quy Nhon 590000 , Vietnam
| | - Minh Tho Nguyen
- Computational Chemistry Research Group , Ton Duc Thang University , Ho Chi Minh City 700000 Vietnam.,Faculty of Applied Sciences , Ton Duc Thang University , Ho Chi Minh City 700000 Vietnam
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23
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Marrink SJ, Corradi V, Souza PC, Ingólfsson HI, Tieleman DP, Sansom MS. Computational Modeling of Realistic Cell Membranes. Chem Rev 2019; 119:6184-6226. [PMID: 30623647 PMCID: PMC6509646 DOI: 10.1021/acs.chemrev.8b00460] [Citation(s) in RCA: 410] [Impact Index Per Article: 82.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Indexed: 12/15/2022]
Abstract
Cell membranes contain a large variety of lipid types and are crowded with proteins, endowing them with the plasticity needed to fulfill their key roles in cell functioning. The compositional complexity of cellular membranes gives rise to a heterogeneous lateral organization, which is still poorly understood. Computational models, in particular molecular dynamics simulations and related techniques, have provided important insight into the organizational principles of cell membranes over the past decades. Now, we are witnessing a transition from simulations of simpler membrane models to multicomponent systems, culminating in realistic models of an increasing variety of cell types and organelles. Here, we review the state of the art in the field of realistic membrane simulations and discuss the current limitations and challenges ahead.
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Affiliation(s)
- Siewert J. Marrink
- Groningen
Biomolecular Sciences and Biotechnology Institute & Zernike Institute
for Advanced Materials, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Valentina Corradi
- Centre
for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Paulo C.T. Souza
- Groningen
Biomolecular Sciences and Biotechnology Institute & Zernike Institute
for Advanced Materials, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Helgi I. Ingólfsson
- Biosciences
and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, United States
| | - D. Peter Tieleman
- Centre
for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Mark S.P. Sansom
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, U.K.
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24
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Shearer J, Jefferies D, Khalid S. Outer Membrane Proteins OmpA, FhuA, OmpF, EstA, BtuB, and OmpX Have Unique Lipopolysaccharide Fingerprints. J Chem Theory Comput 2019; 15:2608-2619. [PMID: 30848905 DOI: 10.1021/acs.jctc.8b01059] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The outer membrane of Gram-negative bacteria has a highly complex asymmetrical architecture, containing a mixture of phospholipids in the inner leaflet and almost exclusively lipopolysaccharide (LPS) molecules in the outer leaflet. In E. coli, the outer membrane contains a wide range of proteins with a β barrel architecture, that vary in size from the smallest having eight strands to larger barrels composed of 22 strands. Here we report coarse-grained molecular dynamics simulations of six proteins from the E. coli outer membrane OmpA, OmpX, BtuB, FhuA, OmpF, and EstA in a range of membrane environments, which are representative of the in vivo conditions for different strains of E. coli. We show that each protein has a unique pattern of interaction with the surrounding membrane, which is influenced by the composition of the protein, the level of LPS in the outer leaflet, and the differing mobilities of the lipids in the two leaflets of the membrane. Overall we present analyses from over 200 μs of simulation for each protein.
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Affiliation(s)
- Jonathan Shearer
- School of Chemistry , University of Southampton, Highfield , Southampton , SO17 1BJ United Kingdom
| | - Damien Jefferies
- School of Chemistry , University of Southampton, Highfield , Southampton , SO17 1BJ United Kingdom
| | - Syma Khalid
- School of Chemistry , University of Southampton, Highfield , Southampton , SO17 1BJ United Kingdom
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25
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Hedger G, Koldsø H, Chavent M, Siebold C, Rohatgi R, Sansom MSP. Cholesterol Interaction Sites on the Transmembrane Domain of the Hedgehog Signal Transducer and Class F G Protein-Coupled Receptor Smoothened. Structure 2019; 27:549-559.e2. [PMID: 30595453 PMCID: PMC6408332 DOI: 10.1016/j.str.2018.11.003] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/28/2018] [Accepted: 11/02/2018] [Indexed: 12/12/2022]
Abstract
Transduction of Hedgehog signals across the plasma membrane is facilitated by the class F G-protein-coupled-receptor (GPCR) Smoothened (SMO). Recent studies suggest that SMO is modulated via interactions of its transmembrane (TM) domain with cholesterol. We apply molecular dynamics simulations of SMO embedded in cholesterol containing lipid bilayers, revealing a direct interaction of cholesterol with the TM domain at regions distinct from those observed in class A GPCRs. In particular the extracellular tips of helices TM2 and TM3 form a well-defined cholesterol interaction site. Potential of mean force calculations yield a free energy landscape for cholesterol binding. Alongside analysis of equilibrium cholesterol occupancy, this reveals the existence of a dynamic "greasy patch" interaction with the TM domain of SMO, which may be compared with previously identified lipid interaction sites on other membrane proteins. These predictions provide molecular-level insights into cholesterol interactions with a class F GPCR, suggesting potential druggable sites.
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Affiliation(s)
- George Hedger
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Heidi Koldsø
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Matthieu Chavent
- Institut de Pharmacologie et de Biologie Structurale IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Christian Siebold
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Rajat Rohatgi
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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26
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Irvine WA, Flanagan JU, Allison JR. Computational Prediction of Amino Acids Governing Protein-Membrane Interaction for the PIP3 Cell Signaling System. Structure 2019; 27:371-380.e3. [DOI: 10.1016/j.str.2018.10.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 08/13/2018] [Accepted: 10/18/2018] [Indexed: 10/27/2022]
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27
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Evangelista Falcon W, Ellingson SR, Smith JC, Baudry J. Ensemble Docking in Drug Discovery: How Many Protein Configurations from Molecular Dynamics Simulations are Needed To Reproduce Known Ligand Binding? J Phys Chem B 2019; 123:5189-5195. [DOI: 10.1021/acs.jpcb.8b11491] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Wilfredo Evangelista Falcon
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, United States
- UT/ORNL Center for Molecular Biophysics, Oak Ridge, Tennessee 37830, United States
- College of Medicine, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Sally R. Ellingson
- UT/ORNL Center for Molecular Biophysics, Oak Ridge, Tennessee 37830, United States
| | - Jeremy C. Smith
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, United States
- UT/ORNL Center for Molecular Biophysics, Oak Ridge, Tennessee 37830, United States
| | - Jerome Baudry
- Department of Biological Sciences, The University of Alabama in Huntsville, Huntsville, Alabama 35899, United States
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28
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Sharp L, Salari R, Brannigan G. Boundary lipids of the nicotinic acetylcholine receptor: Spontaneous partitioning via coarse-grained molecular dynamics simulation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:887-896. [PMID: 30664881 DOI: 10.1016/j.bbamem.2019.01.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 01/10/2019] [Accepted: 01/11/2019] [Indexed: 12/20/2022]
Abstract
Reconstituted nicotinic acetylcholine receptors (nAChRs) exhibit significant gain-of-function upon addition of cholesterol to reconstitution mixtures, and cholesterol affects the organization of nAChRs within domain-forming membranes, but whether nAChR partitions to cholesterol-rich liquid-ordered ("raft" or lo) domains or cholesterol-poor liquid-disordered (ldo) domains is unknown. We use coarse-grained molecular dynamics simulations to observe spontaneous interactions of cholesterol, saturated lipids, and polyunsaturated (PUFA) lipids with nAChRs. In binary Dipalmitoylphosphatidylcholine:Cholesterol (DPPC:CHOL) mixtures, both CHOL and DPPC acyl chains were observed spontaneously entering deep "non-annular" cavities in the nAChR TMD, particularly at the subunit interface and the β subunit center, facilitated by the low amino acid density in the cryo-EM structure of nAChR in a native membrane. Cholesterol was highly enriched in the annulus around the TMD, but this effect extended over (at most) 5-10 Å. In domain-forming ternary mixtures containing PUFAs, the presence of a single receptor did not significantly affect the likelihood of domain formation. nAChR partitioned to any cholesterol-poor ldo domain that was present, regardless of whether the ldo or lo domain lipids had PC or PE headgroups. Enrichment of PUFAs among boundary lipids was positively correlated with their propensity for demixing from cholesterol-rich phases. Long n-3 chains (tested here with Docosahexaenoic Acid, DHA) were highly enriched in annular and non-annular embedded sites, partially displacing cholesterol and completely displacing DPPC, and occupying sites even deeper within the bundle. Shorter n-6 chains were far less effective at displacing cholesterol from non-annular sites.
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Affiliation(s)
- Liam Sharp
- Center for Computational and Integrative Biology, Rutgers University-Camden, Camden, NJ, United States of America
| | - Reza Salari
- Center for Computational and Integrative Biology, Rutgers University-Camden, Camden, NJ, United States of America
| | - Grace Brannigan
- Center for Computational and Integrative Biology, Rutgers University-Camden, Camden, NJ, United States of America; Department of Physics, Rutgers University-Camden, Camden, NJ, United States of America.
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29
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Newport TD, Sansom MS, Stansfeld PJ. The MemProtMD database: a resource for membrane-embedded protein structures and their lipid interactions. Nucleic Acids Res 2019; 47:D390-D397. [PMID: 30418645 PMCID: PMC6324062 DOI: 10.1093/nar/gky1047] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 10/05/2018] [Accepted: 10/16/2018] [Indexed: 12/19/2022] Open
Abstract
Integral membrane proteins fulfil important roles in many crucial biological processes, including cell signalling, molecular transport and bioenergetic processes. Advancements in experimental techniques are revealing high resolution structures for an increasing number of membrane proteins. Yet, these structures are rarely resolved in complex with membrane lipids. In 2015, the MemProtMD pipeline was developed to allow the automated lipid bilayer assembly around new membrane protein structures, released from the Protein Data Bank (PDB). To make these data available to the scientific community, a web database (http://memprotmd.bioch.ox.ac.uk) has been developed. Simulations and the results of subsequent analysis can be viewed using a web browser, including interactive 3D visualizations of the assembled bilayer and 2D visualizations of lipid contact data and membrane protein topology. In addition, ensemble analyses are performed to detail conserved lipid interaction information across proteins, families and for the entire database of 3506 PDB entries. Proteins may be searched using keywords, PDB or Uniprot identifier, or browsed using classification systems, such as Pfam, Gene Ontology annotation, mpstruc or the Transporter Classification Database. All files required to run further molecular simulations of proteins in the database are provided.
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Affiliation(s)
- Thomas D Newport
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Phillip J Stansfeld
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
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30
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Huber RG, Carpenter TS, Dube N, Holdbrook DA, Ingólfsson HI, Irvine WA, Marzinek JK, Samsudin F, Allison JR, Khalid S, Bond PJ. Multiscale Modeling and Simulation Approaches to Lipid-Protein Interactions. Methods Mol Biol 2019; 2003:1-30. [PMID: 31218611 DOI: 10.1007/978-1-4939-9512-7_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Lipid membranes play a crucial role in living systems by compartmentalizing biological processes and forming a barrier between these processes and the environment. Naturally, a large apparatus of biomolecules is responsible for construction, maintenance, transport, and degradation of these lipid barriers. Additional classes of biomolecules are tasked with transport of specific substances or transduction of signals from the environment across lipid membranes. In this article, we intend to describe a set of techniques that enable one to build accurate models of lipid systems and their associated proteins, and to simulate their dynamics over a variety of time and length scales. We discuss the methods and challenges that allow us to derive structural, mechanistic, and thermodynamic information from these models. We also show how these models have recently been applied in research to study some of the most complex lipid-protein systems to date, including bacterial and viral envelopes, neuronal membranes, and mammalian signaling systems.
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Affiliation(s)
- Roland G Huber
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Timothy S Carpenter
- Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Namita Dube
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Daniel A Holdbrook
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Helgi I Ingólfsson
- Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - William A Irvine
- Centre for Theoretical Chemistry and Physics, Institute of Natural and Mathematical Sciences, Massey University, Auckland, New Zealand
| | - Jan K Marzinek
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | | | - Jane R Allison
- School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
- Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand
| | - Syma Khalid
- School of Chemistry, University of Southampton, Southampton, UK
| | - Peter J Bond
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore.
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31
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Goossens K, De Winter H. Molecular Dynamics Simulations of Membrane Proteins: An Overview. J Chem Inf Model 2018; 58:2193-2202. [PMID: 30336018 DOI: 10.1021/acs.jcim.8b00639] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Simulations of membrane proteins have been rising in popularity in the past decade. Advancements in technology and force fields made it possible to simulate behavior of membrane proteins. Membrane protein simulations can now be used as supporting evidence for experimental findings, for elucidating protein mechanisms, and validating protein crystal structures. Unrelated to experimental data, these simulations can also serve to investigate larger scale processes like protein sorting, protein-membrane interactions, and more. In this review, the history as well as the state-of-the-art methodologies in membrane protein simulations will be summarized. An emphasis will be put on how to set up the system and on the current models for the different components of the simulation system. An overview of the available tools for membrane protein simulation will be given, and current limitations and prospects will also be discussed.
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Affiliation(s)
- Kenneth Goossens
- Department of Pharmaceutical Sciences, Laboratory of Medicinal Chemistry , University of Antwerp , Universiteitsplein 1 , 2610 Wilrijk , Belgium
| | - Hans De Winter
- Department of Pharmaceutical Sciences, Laboratory of Medicinal Chemistry , University of Antwerp , Universiteitsplein 1 , 2610 Wilrijk , Belgium
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32
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Coarse-grained dynamics of supramolecules: Conformational changes in outer shells of Dengue viruses. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 143:20-37. [PMID: 30273615 DOI: 10.1016/j.pbiomolbio.2018.09.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 09/22/2018] [Accepted: 09/24/2018] [Indexed: 01/12/2023]
Abstract
While structural data on viruses are more and more common, information on their dynamics is much harder to obtain as those viruses form very large molecular complexes. In this paper, we propose a new method for computing the coarse-grained normal modes of such supra-molecules, NormalGo. A new formalism is developed to represent the Hessian of a quadratic potential using tensor products. This formalism is applied to the Tirion elastic potential, as well as to a Gō like potential. When combined with a fast method for computing a select set of eigenpairs of the Hessian, this new formalism enables the computation of thousands of normal modes of a full viral shell with more than one hundred thousand atoms in less than 2 h on a standard desktop computer. We then compare the two coarse-grained potentials. We show that, despite significant differences in their formulations, the Tirion and the Gō like potentials capture very similar dynamics characteristics of the molecule under study. However, we find that the Gō like potential should be preferred as it leads to less local deformations in the structure of the molecule during normal mode dynamics. Finally, we use NormalGo to characterize the structural transitions that occur when FAB fragments bind to the icosahedral outer shell of serotype 3 of the Dengue virus. We have identified residues at the surface of the outer shell that are important for the transition between the FAB-free and FAB-bound conformations, and therefore potentially useful for the design of antibodies to Dengue viruses.
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33
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Darvill N, Dubois DJ, Rouse SL, Hammoudi PM, Blake T, Benjamin S, Liu B, Soldati-Favre D, Matthews S. Structural Basis of Phosphatidic Acid Sensing by APH in Apicomplexan Parasites. Structure 2018; 26:1059-1071.e6. [PMID: 29910186 PMCID: PMC6084407 DOI: 10.1016/j.str.2018.05.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 03/26/2018] [Accepted: 05/08/2018] [Indexed: 10/29/2022]
Abstract
Plasmodium falciparum and Toxoplasma gondii are obligate intracellular parasites that belong to the phylum of Apicomplexa and cause major human diseases. Their access to an intracellular lifestyle is reliant on the coordinated release of proteins from the specialized apical organelles called micronemes and rhoptries. A specific phosphatidic acid effector, the acylated pleckstrin homology domain-containing protein (APH) plays a central role in microneme exocytosis and thus is essential for motility, cell entry, and egress. TgAPH is acylated on the surface of the micronemes and recruited to phosphatidic acid (PA)-enriched membranes. Here, we dissect the atomic details of APH PA-sensing hub and its functional interaction with phospholipid membranes. We unravel the key determinant of PA recognition for the first time and show that APH inserts into and clusters multiple phosphate head-groups at the bilayer binding surface.
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Affiliation(s)
- Nick Darvill
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - David J Dubois
- Department of Microbiology & Molecular Medicine, Faculty of Medicine, University of Geneva, 1 Rue Michel-Servet, 1211 Geneva, Switzerland
| | - Sarah L Rouse
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Pierre-Mehdi Hammoudi
- Department of Microbiology & Molecular Medicine, Faculty of Medicine, University of Geneva, 1 Rue Michel-Servet, 1211 Geneva, Switzerland
| | - Tom Blake
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Stefi Benjamin
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Bing Liu
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK; BioBank, First Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Dominique Soldati-Favre
- Department of Microbiology & Molecular Medicine, Faculty of Medicine, University of Geneva, 1 Rue Michel-Servet, 1211 Geneva, Switzerland.
| | - Steve Matthews
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK; BioBank, First Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
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34
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Chipot C, Dehez F, Schnell JR, Zitzmann N, Pebay-Peyroula E, Catoire LJ, Miroux B, Kunji ERS, Veglia G, Cross TA, Schanda P. Perturbations of Native Membrane Protein Structure in Alkyl Phosphocholine Detergents: A Critical Assessment of NMR and Biophysical Studies. Chem Rev 2018; 118:3559-3607. [PMID: 29488756 PMCID: PMC5896743 DOI: 10.1021/acs.chemrev.7b00570] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Indexed: 12/25/2022]
Abstract
Membrane proteins perform a host of vital cellular functions. Deciphering the molecular mechanisms whereby they fulfill these functions requires detailed biophysical and structural investigations. Detergents have proven pivotal to extract the protein from its native surroundings. Yet, they provide a milieu that departs significantly from that of the biological membrane, to the extent that the structure, the dynamics, and the interactions of membrane proteins in detergents may considerably vary, as compared to the native environment. Understanding the impact of detergents on membrane proteins is, therefore, crucial to assess the biological relevance of results obtained in detergents. Here, we review the strengths and weaknesses of alkyl phosphocholines (or foscholines), the most widely used detergent in solution-NMR studies of membrane proteins. While this class of detergents is often successful for membrane protein solubilization, a growing list of examples points to destabilizing and denaturing properties, in particular for α-helical membrane proteins. Our comprehensive analysis stresses the importance of stringent controls when working with this class of detergents and when analyzing the structure and dynamics of membrane proteins in alkyl phosphocholine detergents.
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Affiliation(s)
- Christophe Chipot
- SRSMC, UMR 7019 Université de Lorraine CNRS, Vandoeuvre-les-Nancy F-54500, France
- Laboratoire
International Associé CNRS and University of Illinois at Urbana−Champaign, Vandoeuvre-les-Nancy F-54506, France
- Department
of Physics, University of Illinois at Urbana−Champaign, 1110 West Green Street, Urbana, Illinois 61801, United States
| | - François Dehez
- SRSMC, UMR 7019 Université de Lorraine CNRS, Vandoeuvre-les-Nancy F-54500, France
- Laboratoire
International Associé CNRS and University of Illinois at Urbana−Champaign, Vandoeuvre-les-Nancy F-54506, France
| | - Jason R. Schnell
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Nicole Zitzmann
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | | | - Laurent J. Catoire
- Laboratory
of Biology and Physico-Chemistry of Membrane Proteins, Institut de Biologie Physico-Chimique (IBPC), UMR
7099 CNRS, Paris 75005, France
- University
Paris Diderot, Paris 75005, France
- PSL
Research University, Paris 75005, France
| | - Bruno Miroux
- Laboratory
of Biology and Physico-Chemistry of Membrane Proteins, Institut de Biologie Physico-Chimique (IBPC), UMR
7099 CNRS, Paris 75005, France
- University
Paris Diderot, Paris 75005, France
- PSL
Research University, Paris 75005, France
| | - Edmund R. S. Kunji
- Medical
Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Gianluigi Veglia
- Department
of Biochemistry, Molecular Biology, and Biophysics, and Department
of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Timothy A. Cross
- National
High Magnetic Field Laboratory, Florida
State University, Tallahassee, Florida 32310, United States
| | - Paul Schanda
- Université
Grenoble Alpes, CEA, CNRS, IBS, Grenoble F-38000, France
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35
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Miller H, Zhou Z, Shepherd J, Wollman AJM, Leake MC. Single-molecule techniques in biophysics: a review of the progress in methods and applications. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:024601. [PMID: 28869217 DOI: 10.1088/1361-6633/aa8a02] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Single-molecule biophysics has transformed our understanding of biology, but also of the physics of life. More exotic than simple soft matter, biomatter lives far from thermal equilibrium, covering multiple lengths from the nanoscale of single molecules to up to several orders of magnitude higher in cells, tissues and organisms. Biomolecules are often characterized by underlying instability: multiple metastable free energy states exist, separated by levels of just a few multiples of the thermal energy scale k B T, where k B is the Boltzmann constant and T absolute temperature, implying complex inter-conversion kinetics in the relatively hot, wet environment of active biological matter. A key benefit of single-molecule biophysics techniques is their ability to probe heterogeneity of free energy states across a molecular population, too challenging in general for conventional ensemble average approaches. Parallel developments in experimental and computational techniques have catalysed the birth of multiplexed, correlative techniques to tackle previously intractable biological questions. Experimentally, progress has been driven by improvements in sensitivity and speed of detectors, and the stability and efficiency of light sources, probes and microfluidics. We discuss the motivation and requirements for these recent experiments, including the underpinning mathematics. These methods are broadly divided into tools which detect molecules and those which manipulate them. For the former we discuss the progress of super-resolution microscopy, transformative for addressing many longstanding questions in the life sciences, and for the latter we include progress in 'force spectroscopy' techniques that mechanically perturb molecules. We also consider in silico progress of single-molecule computational physics, and how simulation and experimentation may be drawn together to give a more complete understanding. Increasingly, combinatorial techniques are now used, including correlative atomic force microscopy and fluorescence imaging, to probe questions closer to native physiological behaviour. We identify the trade-offs, limitations and applications of these techniques, and discuss exciting new directions.
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Affiliation(s)
- Helen Miller
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, United Kingdom
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36
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Shimizu K, Cao W, Saad G, Shoji M, Terada T. Comparative analysis of membrane protein structure databases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1077-1091. [PMID: 29331638 DOI: 10.1016/j.bbamem.2018.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 12/28/2017] [Accepted: 01/04/2018] [Indexed: 12/11/2022]
Abstract
BACKGROUND Membrane proteins play important roles in cell survival and cell communication, as they function as transporters, receptors, anchors and enzymes. They are also potential targets for drugs that block receptors or inhibit enzymes related to diseases. Although the number of known structures of membrane proteins is still small relative to the size of the proteome as a whole, many new membrane protein structures have been determined recently. SCOPE OF THE ARTICLE We compared and analyzed the widely used membrane protein databases, mpstruc, Orientations of Proteins in Membranes (OPM), and PDBTM, as well as the extended dataset of mpstruc based on sequence similarity, the PDB structures whose classification field indicates that they are "membrane proteins" and the proteins with Structural Classification of Proteins (SCOP) class-f domains. We evaluated the relationships between these databases or datasets based on the overlap in their contents and the degree of consistency in the structural, topological, and functional classifications and in the transmembrane domain assignment. MAJOR CONCLUSIONS The membrane databases differ from each other in their coverage, and in the criteria that they use for annotation and classification. To ensure the efficient use of these databases, it is important to understand their differences and similarities. The establishment of more detailed and consistent annotations for the sequence, structure, membrane association, and function of membrane proteins is still required. GENERAL SIGNIFICANCE Considering the recent growth of experimentally determined structures, a broad survey and cumulative analysis of the sum of knowledge as presented in the membrane protein structure databases can be helpful to elucidate structures and functions of membrane proteins. We also aim to provide a framework for future research and classification of membrane proteins.
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Affiliation(s)
- Kentaro Shimizu
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
| | - Wei Cao
- Faculty of Information Networking for Innovation and Design, Toyo University, Tokyo, Japan.
| | - Gull Saad
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
| | - Michiru Shoji
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
| | - Tohru Terada
- Agricultural Bioinformatics Research Unit, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
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37
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Biswal D, Kusalik PG. Molecular simulations of self-assembly processes in metal-organic frameworks: Model dependence. J Chem Phys 2017; 147:044702. [PMID: 28764378 DOI: 10.1063/1.4994700] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Molecular simulation is a powerful tool for investigating microscopic behavior in various chemical systems, where the use of suitable models is critical to successfully reproduce the structural and dynamic properties of the real systems of interest. In this context, molecular dynamics simulation studies of self-assembly processes in metal-organic frameworks (MOFs), a well-known class of porous materials with interesting chemical and physical properties, are relatively challenging, where a reasonably accurate representation of metal-ligand interactions is anticipated to play an important role. In the current study, we both investigate the performance of some existing models and introduce and test new models to help explore the self-assembly in an archetypal Zn-carboxylate MOF system. To this end, the behavior of six different Zn-ion models, three solvent models, and two ligand models was examined and validated against key experimental structural parameters. To explore longer time scale ordering events during MOF self-assembly via explicit solvent simulations, it is necessary to identify a suitable combination of simplified model components representing metal ions, organic ligands, and solvent molecules. It was observed that an extended cationic dummy atom (ECDA) Zn-ion model combined with an all-atom carboxylate ligand model and a simple dipolar solvent model can reproduce characteristic experimental structures for the archetypal MOF system. The successful use of these models in extensive sets of molecular simulations, which provide key insights into the self-assembly mechanism of this archetypal MOF system occurring during the early stages of this process, has been very recently reported.
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Affiliation(s)
- Debasmita Biswal
- Department of Chemistry, University of Calgary, 2500 University Dr. NW, Calgary, Alberta T2N 1N4, Canada
| | - Peter G Kusalik
- Department of Chemistry, University of Calgary, 2500 University Dr. NW, Calgary, Alberta T2N 1N4, Canada
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38
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Nawae W, Hannongbua S, Ruengjitchatchawalya M. Molecular dynamics exploration of poration and leaking caused by Kalata B1 in HIV-infected cell membrane compared to host and HIV membranes. Sci Rep 2017; 7:3638. [PMID: 28620219 PMCID: PMC5472625 DOI: 10.1038/s41598-017-03745-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 05/05/2017] [Indexed: 12/21/2022] Open
Abstract
The membrane disruption activities of kalata B1 (kB1) were investigated using molecular dynamics simulations with membrane models. The models were constructed to mimic the lipid microdomain formation in membranes of HIV particle, HIV-infected cell, and host cell. The differences in the lipid ratios of these membranes caused the formation of liquid ordered (lo) domains of different sizes, which affected the binding and activity of kB1. Stronger kB1 disruptive activity was observed for the membrane with small sized lo domain. Our results show that kB1 causes membrane leaking without bilayer penetration. The membrane poration mechanism involved in the disorganization of the lo domain and in cholesterol inter-leaflet translocation is described. This study enhances our understanding of the membrane activity of kB1, which may be useful for designing novel and potentially therapeutic peptides based on the kB1 framework.
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Affiliation(s)
- Wanapinun Nawae
- Pilot Plant Development and Training Institution, King Mongkut's University of Technology Thonburi (Bang Khun Thian Campus), 49 Soi Thian Thale 25, Bang Khun Thian Chai Thale Rd., Tha Kham, Bang Khun Thian, Bangkok, 10150, Thailand
| | - Supa Hannongbua
- Department of Chemistry, Kasetsart University, 50 Phaholyothin Rd., Ladyao, Chatuchak, Bangkok, Thailand, 10900
| | - Marasri Ruengjitchatchawalya
- Biotechnology Program, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi (Bang KhunThian Campus), 49 Soi Thian Thale 25, Bang Khun Thian Chai Thale Rd., Tha Kham, Bang Khun Thian, Bangkok, 10150, Thailand.
- Bioinformatics and Systems Biology Program, King Mongkut's University of Technology Thonburi (Bang Khun Thian Campus), 49 Soi Thian Thale 25, Bang Khun Thian Chai Thale Rd., Tha Kham, Bang Khun Thian, Bangkok, 10150, Thailand.
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39
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Wei P, Sun FD, Zuo LM, Qu J, Chen P, Xu LD, Luo SZ. Critical residues and motifs for homodimerization of the first transmembrane domain of the plasma membrane glycoprotein CD36. J Biol Chem 2017; 292:8683-8693. [PMID: 28336533 DOI: 10.1074/jbc.m117.779595] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 03/09/2017] [Indexed: 12/19/2022] Open
Abstract
The plasma transmembrane (TM) glycoprotein CD36 is critically involved in many essential signaling processes, especially the binding/uptake of long-chain fatty acids and oxidized low-density lipoproteins. The association of CD36 potentially activates cytosolic protein tyrosine kinases that are thought to associate with the C-terminal cytoplasmic tail of CD36. To understand the mechanisms by which CD36 mediates ligand binding and signal transduction, we have characterized the homo-oligomeric interaction of CD36 TM domains in membrane environments and with molecular dynamics (MD) simulations. Analysis of pyrene- and coumarin-labeled TM1 peptides in SDS by FRET confirmed the homodimerization of the CD36 TM1 peptide. Homodimerization assays of CD36 TM domains with the TOXCAT technique showed that its first TM (TM1) domain, but not the second TM (TM2) domain, could homodimerize in a cell membrane. Small-residue, site-specific mutation scanning revealed that the CD36 TM1 dimerization is mediated by the conserved small residues Gly12, Gly16, Ala20, and Gly23 Furthermore, molecular dynamics (MD) simulation studies demonstrated that CD36 TM1 exhibited a switching dimerization with two right-handed packing modes driven by the 12GXXXGXXXA20 and 20AXXG23 motifs, and the mutational effect of G16I and G23I revealed these representative conformations of CD36 TM1. This packing switch pattern of CD36 TM1 homodimer was further examined and confirmed by FRET analysis of monobromobimane (mBBr)-labeled CD36 TM1 peptides. Overall, this work provides a structural basis for understanding the role of TM association in regulating signal transduction via CD36.
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Affiliation(s)
- Peng Wei
- From the Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China.,the School of Basic Medical Science, Beijing University of Chinese Medicine, Beijing 100029, China, and
| | - Fu-de Sun
- From the Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Li-Min Zuo
- the Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, Beijing 100050, China
| | - Jing Qu
- From the Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Peng Chen
- From the Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Li-da Xu
- From the Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Shi-Zhong Luo
- From the Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China,
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40
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Fowler PW, Sansom MSP, Reithmeier RAF. Effect of the Southeast Asian Ovalocytosis Deletion on the Conformational Dynamics of Signal-Anchor Transmembrane Segment 1 of Red Cell Anion Exchanger 1 (AE1, Band 3, or SLC4A1). Biochemistry 2017; 56:712-722. [PMID: 28068080 PMCID: PMC5299548 DOI: 10.1021/acs.biochem.6b00966] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The first transmembrane (TM1) helix in the red cell anion exchanger (AE1, Band 3, or SLC4A1) acts as an internal signal anchor that binds the signal recognition particle and directs the nascent polypeptide chain to the endoplasmic reticulum (ER) membrane where it moves from the translocon laterally into the lipid bilayer. The sequence N-terminal to TM1 forms an amphipathic helix that lies at the membrane interface and is connected to TM1 by a bend at Pro403. Southeast Asian ovalocytosis (SAO) is a red cell abnormality caused by a nine-amino acid deletion (Ala400-Ala408) at the N-terminus of TM1. Here we demonstrate, by extensive (∼4.5 μs) molecular dynamics simulations of TM1 in a model 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine membrane, that the isolated TM1 peptide is highly dynamic and samples the structure of TM1 seen in the crystal structure of the membrane domain of AE1. The SAO deletion not only removes the proline-induced bend but also causes a "pulling in" of the part of the amphipathic helix into the hydrophobic phase of the bilayer, as well as the C-terminal of the peptide. The dynamics of the SAO peptide very infrequently resembles the structure of TM1 in AE1, demonstrating the disruptive effect the SAO deletion has on AE1 folding. These results provide a precise molecular view of the disposition and dynamics of wild-type and SAO TM1 in a lipid bilayer, an important early biosynthetic intermediate in the insertion of AE1 into the ER membrane, and extend earlier results of cell-free translation experiments.
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Affiliation(s)
- Philip W Fowler
- Department of Biochemistry, University of Oxford , South Parks Road, Oxford OX1 3QU, U.K
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford , South Parks Road, Oxford OX1 3QU, U.K
| | - Reinhart A F Reithmeier
- Department of Biochemistry, University of Toronto , 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
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41
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Pizzirusso A, De Nicola A, Sevink GJA, Correa A, Cascella M, Kawakatsu T, Rocco M, Zhao Y, Celino M, Milano G. Biomembrane solubilization mechanism by Triton X-100: a computational study of the three stage model. Phys Chem Chem Phys 2017; 19:29780-29794. [DOI: 10.1039/c7cp03871b] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The solubilization mechanism of lipid membranes in the presence of Triton X-100 (TX-100) is investigated at molecular resolution using hybrid particle field–self consistence field simulations.
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Affiliation(s)
| | - Antonio De Nicola
- Dipartimento di Chimica e Biologia
- Università di Salerno
- Fisciano
- Italy
| | - G. J. Agur Sevink
- Leiden Institute of Chemistry
- Leiden University
- 2300 RA Leiden
- The Netherlands
| | - Andrea Correa
- Department of Chemical Science
- Federico II University of Naples
- 80126 Napoli
- Italy
| | - Michele Cascella
- Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences
- University of Oslo
- 0371 Oslo
- Norway
| | | | - Mattia Rocco
- Biopolimeri e Proteomica
- Ospedale Policlinico San Martino
- Genova
- Italy
| | - Ying Zhao
- Institute of Nano-Photonics
- School of Physics and Materials Engineering
- Dalian Minzu University
- Dalian 116600
- China
| | | | - Giuseppe Milano
- Dipartimento di Chimica e Biologia
- Università di Salerno
- Fisciano
- Italy
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42
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Periole X. Interplay of G Protein-Coupled Receptors with the Membrane: Insights from Supra-Atomic Coarse Grain Molecular Dynamics Simulations. Chem Rev 2016; 117:156-185. [PMID: 28073248 DOI: 10.1021/acs.chemrev.6b00344] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
G protein-coupled receptors (GPCRs) are central to many fundamental cellular signaling pathways. They transduce signals from the outside to the inside of cells in physiological processes ranging from vision to immune response. It is extremely challenging to look at them individually using conventional experimental techniques. Recently, a pseudo atomistic molecular model has emerged as a valuable tool to access information on GPCRs, more specifically on their interactions with their environment in their native cell membrane and the consequences on their supramolecular organization. This approach uses the Martini coarse grain (CG) model to describe the receptors, lipids, and solvent in molecular dynamics (MD) simulations and in enough detail to allow conserving the chemical specificity of the different molecules. The elimination of unnecessary degrees of freedom has opened up large-scale simulations of the lipid-mediated supramolecular organization of GPCRs. Here, after introducing the Martini CGMD method, we review these studies carried out on various members of the GPCR family, including rhodopsin (visual receptor), opioid receptors, adrenergic receptors, adenosine receptors, dopamine receptor, and sphingosine 1-phosphate receptor. These studies have brought to light an interesting set of novel biophysical principles. The insights range from revealing localized and heterogeneous deformations of the membrane bilayer at the surface of the protein, specific interactions of lipid molecules with individual GPCRs, to the effect of the membrane matrix on global GPCR self-assembly. The review ends with an overview of the lessons learned from the use of the CGMD method, the biophysical-chemical findings on lipid-protein interplay.
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Affiliation(s)
- Xavier Periole
- Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen , Nijenborgh 7, 9747AG Groningen, The Netherlands
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43
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Hedger G, Rouse SL, Domański J, Chavent M, Koldsø H, Sansom MSP. Lipid-Loving ANTs: Molecular Simulations of Cardiolipin Interactions and the Organization of the Adenine Nucleotide Translocase in Model Mitochondrial Membranes. Biochemistry 2016; 55:6238-6249. [PMID: 27786441 PMCID: PMC5120876 DOI: 10.1021/acs.biochem.6b00751] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
![]()
The exchange of ADP
and ATP across the inner mitochondrial membrane
is a fundamental cellular process. This exchange is facilitated by
the adenine nucleotide translocase, the structure and function of
which are critically dependent on the signature phospholipid of mitochondria,
cardiolipin (CL). Here we employ multiscale molecular dynamics simulations
to investigate CL interactions within a membrane environment. Using
simulations at both coarse-grained and atomistic resolutions, we identify
three CL binding sites on the translocase, in agreement with those
seen in crystal structures and inferred from nuclear magnetic resonance
measurements. Characterization of the free energy landscape for lateral
lipid interaction via potential of mean force calculations demonstrates
the strength of interaction compared to those of binding sites on
other mitochondrial membrane proteins, as well as their selectivity
for CL over other phospholipids. Extending the analysis to other members
of the family, yeast Aac2p and mouse uncoupling protein 2, suggests
a degree of conservation. Simulation of large patches of a model mitochondrial
membrane containing multiple copies of the translocase shows that
CL interactions persist in the presence of protein–protein
interactions and suggests CL may mediate interactions between translocases.
This study provides a key example of how computational microscopy
may be used to shed light on regulatory lipid–protein interactions.
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Affiliation(s)
- George Hedger
- Department of Biochemistry, University of Oxford , South Parks Road, Oxford OX1 3QU, U.K
| | - Sarah L Rouse
- Department of Biochemistry, University of Oxford , South Parks Road, Oxford OX1 3QU, U.K.,Department of Life Sciences, Imperial College London , London SW7 2AZ, U.K
| | - Jan Domański
- Department of Biochemistry, University of Oxford , South Parks Road, Oxford OX1 3QU, U.K
| | - Matthieu Chavent
- Department of Biochemistry, University of Oxford , South Parks Road, Oxford OX1 3QU, U.K
| | - Heidi Koldsø
- Department of Biochemistry, University of Oxford , South Parks Road, Oxford OX1 3QU, U.K.,D. E. Shaw Research , 120 West 45th Street, 39th Floor, New York, New York 10036, United States
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford , South Parks Road, Oxford OX1 3QU, U.K
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44
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Fowler PW, Hélie J, Duncan A, Chavent M, Koldsø H, Sansom MSP. Membrane stiffness is modified by integral membrane proteins. SOFT MATTER 2016; 12:7792-7803. [PMID: 27722554 PMCID: PMC5314686 DOI: 10.1039/c6sm01186a] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 08/25/2016] [Indexed: 05/12/2023]
Abstract
The ease with which a cell membrane can bend and deform is important for a wide range of biological functions. Peripheral proteins that induce curvature in membranes (e.g. BAR domains) have been studied for a number of years. Little is known, however, about the effect of integral membrane proteins on the stiffness of a membrane (characterised by the bending rigidity, Kc). We demonstrate by computer simulation that adding integral membrane proteins at physiological densities alters the stiffness of the membrane. First we establish that the coarse-grained MARTINI forcefield is able to accurately reproduce the bending rigidity of a small patch of 1500 phosphatidyl choline lipids by comparing the calculated value to both experiment and an atomistic simulation of the same system. This enables us to simulate the dynamics of large (ca. 50 000 lipids) patches of membrane using the MARTINI coarse-grained description. We find that altering the lipid composition changes the bending rigidity. Adding integral membrane proteins to lipid bilayers also changes the bending rigidity, whilst adding a simple peripheral membrane protein has no effect. Our results suggest that integral membrane proteins can have different effects, and in the case of the bacterial outer membrane protein, BtuB, the greater the density of protein, the larger the reduction in stiffness.
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Affiliation(s)
- Philip W Fowler
- Department of Biochemistry, University of Oxford, South Parks Rd, Oxford, OX1 3QU, UK.
| | - Jean Hélie
- Department of Biochemistry, University of Oxford, South Parks Rd, Oxford, OX1 3QU, UK.
| | - Anna Duncan
- Department of Biochemistry, University of Oxford, South Parks Rd, Oxford, OX1 3QU, UK.
| | - Matthieu Chavent
- Department of Biochemistry, University of Oxford, South Parks Rd, Oxford, OX1 3QU, UK.
| | - Heidi Koldsø
- Department of Biochemistry, University of Oxford, South Parks Rd, Oxford, OX1 3QU, UK.
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Rd, Oxford, OX1 3QU, UK.
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45
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Hung HM, Hang TD, Nguyen MT. Multiscale simulations on conformational dynamics and membrane interactions of the non-structural 2 (NS2) transmembrane domain. Biochem Biophys Res Commun 2016; 478:193-198. [DOI: 10.1016/j.bbrc.2016.07.069] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Accepted: 07/16/2016] [Indexed: 01/08/2023]
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46
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Byrne EF, Sircar R, Miller PS, Hedger G, Luchetti G, Nachtergaele S, Tully MD, Mydock-McGrane L, Covey DF, Rambo RP, Sansom MSP, Newstead S, Rohatgi R, Siebold C. Structural basis of Smoothened regulation by its extracellular domains. Nature 2016; 535:517-522. [PMID: 27437577 PMCID: PMC4970916 DOI: 10.1038/nature18934] [Citation(s) in RCA: 254] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 06/15/2016] [Indexed: 01/04/2023]
Abstract
Developmental signals of the Hedgehog (Hh) and Wnt families are transduced across the membrane by Frizzledclass G-protein-coupled receptors (GPCRs) composed of both a heptahelical transmembrane domain (TMD) and an extracellular cysteine-rich domain (CRD). How the large extracellular domains of GPCRs regulate signalling by the TMD is unknown. We present crystal structures of the Hh signal transducer and oncoprotein Smoothened, a GPCR that contains two distinct ligand-binding sites: one in its TMD and one in the CRD. The CRD is stacked a top the TMD, separated by an intervening wedge-like linker domain. Structure-guided mutations show that the interface between the CRD, linker domain and TMD stabilizes the inactive state of Smoothened. Unexpectedly, we find a cholesterol molecule bound to Smoothened in the CRD binding site. Mutations predicted to prevent cholesterol binding impair the ability of Smoothened to transmit native Hh signals. Binding of a clinically used antagonist, vismodegib, to the TMD induces a conformational change that is propagated to the CRD, resulting in loss of cholesterol from the CRD-linker domain-TMD interface. Our results clarify the structural mechanism by which the activity of a GPCR is controlled by ligand-regulated interactions between its extracellular and transmembrane domains.
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Affiliation(s)
- Eamon F.X. Byrne
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Ria Sircar
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, California, United States of America
| | - Paul S. Miller
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - George Hedger
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Giovanni Luchetti
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, California, United States of America
| | - Sigrid Nachtergaele
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, California, United States of America
| | - Mark D. Tully
- Diamond Light Source Ltd, Harwell Science &Innovation Campus, Didcot, UK
| | - Laurel Mydock-McGrane
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Douglas F. Covey
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Robert P. Rambo
- Diamond Light Source Ltd, Harwell Science &Innovation Campus, Didcot, UK
| | | | - Simon Newstead
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Rajat Rohatgi
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, California, United States of America
| | - Christian Siebold
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
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47
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Kalli AC, Rog T, Vattulainen I, Campbell ID, Sansom MSP. The Integrin Receptor in Biologically Relevant Bilayers: Insights from Molecular Dynamics Simulations. J Membr Biol 2016; 250:337-351. [PMID: 27465729 PMCID: PMC5579164 DOI: 10.1007/s00232-016-9908-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/25/2016] [Indexed: 11/27/2022]
Abstract
Integrins are heterodimeric (αβ) cell surface receptors that are potential therapeutic targets for a number of diseases. Despite the existence of structural data for all parts of integrins, the structure of the complete integrin receptor is still not available. We have used available structural data to construct a model of the complete integrin receptor in complex with talin F2-F3 domain. It has been shown that the interactions of integrins with their lipid environment are crucial for their function but details of the integrin/lipid interactions remain elusive. In this study an integrin/talin complex was inserted in biologically relevant bilayers that resemble the cell plasma membrane containing zwitterionic and charged phospholipids, cholesterol and sphingolipids to study the dynamics of the integrin receptor and its effect on bilayer structure and dynamics. The results of this study demonstrate the dynamic nature of the integrin receptor and suggest that the presence of the integrin receptor alters the lipid organization between the two leaflets of the bilayer. In particular, our results suggest elevated density of cholesterol and of phosphatidylserine lipids around the integrin/talin complex and a slowing down of lipids in an annulus of ~30 Å around the protein due to interactions between the lipids and the integrin/talin F2-F3 complex. This may in part regulate the interactions of integrins with other related proteins or integrin clustering thus facilitating signal transduction across cell membranes.
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Affiliation(s)
- Antreas C Kalli
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Tomasz Rog
- Department of Physics, Tampere University of Technology, P.O. Box 692, 33101, Tampere, Finland
| | - Ilpo Vattulainen
- Department of Physics, Tampere University of Technology, P.O. Box 692, 33101, Tampere, Finland
- MEMPHYS - Center for Biomembrane Physics, University of Southern Denmark, 5230, Odense M, Denmark
| | - Iain D Campbell
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
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48
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Hedger G, Shorthouse D, Koldsø H, Sansom MSP. Free Energy Landscape of Lipid Interactions with Regulatory Binding Sites on the Transmembrane Domain of the EGF Receptor. J Phys Chem B 2016; 120:8154-63. [PMID: 27109430 PMCID: PMC5002933 DOI: 10.1021/acs.jpcb.6b01387] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
![]()
Lipid molecules can
bind to specific sites on integral membrane
proteins, modulating their structure and function. We have undertaken
coarse-grained simulations to calculate free energy profiles for glycolipids
and phospholipids interacting with modulatory sites on the transmembrane
helix dimer of the EGF receptor within a lipid bilayer environment.
We identify lipid interaction sites at each end of the transmembrane
domain and compute interaction free energy profiles for lipids with
these sites. Interaction free energies ranged from ca. −40
to −4 kJ/mol for different lipid species. Those lipids (glycolipid
GM3 and phosphoinositide PIP2) known to modulate EGFR function
exhibit the strongest binding to interaction sites on the EGFR, and
we are able to reproduce the preference for interaction with GM3 over
other glycolipids suggested by experiment. Mutation of amino acid
residues essential for EGFR function reduce the binding free energy
of these key lipid species. The residues interacting with the lipids
in the simulations are in agreement with those suggested by experimental
(mutational) studies. This approach provides a generalizable tool
for characterizing the interactions of lipids that bind to specific
sites on integral membrane proteins.
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Affiliation(s)
- George Hedger
- Department of Biochemistry, University of Oxford , South Parks Road, Oxford OX1 3QU, United Kingdom
| | - David Shorthouse
- Department of Biochemistry, University of Oxford , South Parks Road, Oxford OX1 3QU, United Kingdom.,MRC Cancer Unit, University of Cambridge , MRC Research Centre, Box 197, Cambridge CB2 0X1, United Kingdom
| | - Heidi Koldsø
- Department of Biochemistry, University of Oxford , South Parks Road, Oxford OX1 3QU, United Kingdom.,D. E. Shaw Research , 120 West 45th Street, 39th floor, New York, New York 10036, United States
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford , South Parks Road, Oxford OX1 3QU, United Kingdom
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49
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Skjevik ÅA, Madej BD, Dickson CJ, Lin C, Teigen K, Walker RC, Gould IR. Simulation of lipid bilayer self-assembly using all-atom lipid force fields. Phys Chem Chem Phys 2016; 18:10573-84. [PMID: 27034995 DOI: 10.1039/c5cp07379k] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In this manuscript we expand significantly on our earlier communication by investigating the bilayer self-assembly of eight different types of phospholipids in unbiased molecular dynamics (MD) simulations using three widely used all-atom lipid force fields. Irrespective of the underlying force field, the lipids are shown to spontaneously form stable lamellar bilayer structures within 1 microsecond, the majority of which display properties in satisfactory agreement with the experimental data. The lipids self-assemble via the same general mechanism, though at formation rates that differ both between lipid types, force fields and even repeats on the same lipid/force field combination. In addition to zwitterionic phosphatidylcholine (PC) and phosphatidylethanolamine (PE) lipids, anionic phosphatidylserine (PS) and phosphatidylglycerol (PG) lipids are represented. To our knowledge this is the first time bilayer self-assembly of phospholipids with negatively charged head groups is demonstrated in all-atom MD simulations.
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Affiliation(s)
- Åge A Skjevik
- San Diego Supercomputer Center, University of California San Diego, 9500 Gilman Drive MC0505, La Jolla, California 92093-0505, USA.
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50
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Jeřábek P, Florián J, Martínek V. Membrane-Anchored Cytochrome P450 1A2–Cytochrome b5 Complex Features an X-Shaped Contact between Antiparallel Transmembrane Helices. Chem Res Toxicol 2016; 29:626-36. [DOI: 10.1021/acs.chemrestox.5b00349] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Petr Jeřábek
- Department
of Biochemistry, Faculty of Science, Charles University in Prague, Albertov 2030, 128 43 Prague 2, Czech Republic
| | - Jan Florián
- Department
of Chemistry and Biochemistry, Loyola University Chicago, 1032 West Sheridan
Road, Chicago, Illinois 60660, United States
| | - Václav Martínek
- Department
of Biochemistry, Faculty of Science, Charles University in Prague, Albertov 2030, 128 43 Prague 2, Czech Republic
- Department of Teaching and Didactics of Chemistry, Faculty of Science, Charles University in Prague, Albertov 3, 128 43 Prague 2, Czech Republic
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