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Saini S, Pareekh S, Kumar Y. Investigating the structural impact of Omicron RBD mutation on antibody escape and receptor management. J Biomol Struct Dyn 2024; 42:4668-4678. [PMID: 37334729 DOI: 10.1080/07391102.2023.2222174] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 06/01/2023] [Indexed: 06/20/2023]
Abstract
The SARS-CoV-2 Variant B.1.1.5291 evolved rapidly in late November 2021 from the existing mutants sparking fear worldwide owing to its infamous immune escape from a varied class of neutralising antibodies. To assess the structural behaviour of Omicron-Receptor Binding Domain (RBD) upon interacting with cross-reactive CR3022 antibody, we investigated the computational approach of structural engagement in B.1.1529 RBD and wild-type RBD with CR3022 antibody. The current study investigates the interacting interface between the RBDs and CR3022 to decipher the key residues accompanying the potential mutational landscape of SARS-CoV-2 variants. We conducted in-silico docking followed by molecular dynamics simulation analysis to examine the dynamic behaviour of protein-protein interactions. Furthermore, the study unleashed possible interactions post energy decomposition analysis via MM-GBSA. Conclusively, the mutational landscape of RBD eases in designing and discovering the effective neutralisation accompanied by development of a universal vaccine.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Samvedna Saini
- Department of Biological Sciences and Engineering (BSE), Netaji Subhas University of Technology (NSUT), New Delhi, India
| | - Savita Pareekh
- High Performance Computing (HPC) & AI Innovation Lab, Dell EMC, Bengaluru, India
| | - Yatender Kumar
- Department of Biological Sciences and Engineering (BSE), Netaji Subhas University of Technology (NSUT), New Delhi, India
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2
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Yang H, Zhou D, Zhou Z, Duan M, Yu H. Mechanistic Insight into the Mechanical Unfolding of the Integral Membrane Diacylglycerol Kinase. JACS AU 2024; 4:1422-1435. [PMID: 38665647 PMCID: PMC11040704 DOI: 10.1021/jacsau.3c00829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 02/29/2024] [Accepted: 03/01/2024] [Indexed: 04/28/2024]
Abstract
The essential forces stabilizing membrane proteins and governing their folding and unfolding are difficult to decipher. Single-molecule atomic force spectroscopy mechanically unfolds individual membrane proteins and quantifies their dynamics and energetics. However, it remains challenging to structurally assign unfolding intermediates precisely and to deduce dominant interactions between specific residues that facilitate either the localized stabilization of these intermediates or the global assembly of membrane proteins. Here, we performed force spectroscopy experiments and multiscale molecular dynamics simulations to study the unfolding pathway of diacylglycerol kinase (DGK), a small trimeric multispan transmembrane enzyme. The remarkable agreement between experiments and simulations allowed precise structural assignment and interaction analysis of unfolding intermediates, bypassing existing limitations on structural mapping, and thus provided mechanistic explanations for the formation of these states. DGK unfolding was found to proceed with structural segments varying in size that do not correlate with its secondary structure. We identified intermolecular side-chain packing interactions as one of the major contributions to the stability of unfolding intermediates. Mutagenesis creating packing defects induced a dramatic decrease in the mechano-stability of corresponding intermediates and also in the thermo-stability of DGK trimer, in good agreement with predictions from simulations. Hence, the molecular determinants of the mechano- and thermo-stability of a membrane protein can be identified at residue resolution. The accurate structural assignment established and microscopic mechanism revealed in this work may substantially expand the scope of single-molecule studies of membrane proteins.
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Affiliation(s)
- Huiying Yang
- School
of Physics, Huazhong University of Science
and Technology, Wuhan 430074, China
| | - Daihong Zhou
- School
of Physics, Huazhong University of Science
and Technology, Wuhan 430074, China
| | - Zhangyi Zhou
- School
of Physics, Huazhong University of Science
and Technology, Wuhan 430074, China
| | - Mojie Duan
- Innovation
Academy for Precision Measurement Science and Technology, Chinese
Academy of Sciences, Wuhan 430071, China
| | - Hao Yu
- School
of Physics, Huazhong University of Science
and Technology, Wuhan 430074, China
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3
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Saini S, Kumar Y. Structural and functional analysis of engineered antibodies for cancer immunotherapy: insights into protein compactness and solvent accessibility. J Biomol Struct Dyn 2024:1-14. [PMID: 38173178 DOI: 10.1080/07391102.2023.2300129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 12/22/2023] [Indexed: 01/05/2024]
Abstract
Antibodies are crucial tools in various biomedical applications, including immunotherapy. In this study, we focused on designing and engineering antibodies to enhance their structural dynamics and functional properties. By employing advanced computational techniques and experimental validation, we gained crucial insights into the impact of specific mutations on the engineered antibodies. This study investigates the design and engineering of antibodies to improve their structural dynamics and functional properties. Structural attributes, such as protein compactness and solvent accessibility, were assessed, revealing interesting trends in anti-CD3 and anti-HER2 antibodies. Mutations in CD3 antibodies resulted in a more stable conformation, while mutant HER2 antibodies exhibited altered interaction with the target. Analysis of secondary structure assignments demonstrated significant changes in the folding and stability of the mutant antibodies compared to the wild-type counterparts. The conformational landscape of the engineered antibodies was explored, providing insights into folding pathways and binding mechanisms. Overall, the current study highlights the significance of antibody design and engineering in modulating structural dynamics and functional properties. The findings contribute to developing improved immunotherapeutic strategies by optimising antibody-based therapeutics for targeted diseases with enhanced efficacy and precision.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Samvedna Saini
- Department of Biological Sciences and Engineering (BSE), Netaji Subhas University of Technology (NSUT), New Delhi, India
| | - Yatender Kumar
- Department of Biological Sciences and Engineering (BSE), Netaji Subhas University of Technology (NSUT), New Delhi, India
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4
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Rollins ZA, Faller R, George SC. A dynamic biomimetic model of the membrane-bound CD4-CD3-TCR complex during pMHC disengagement. Biophys J 2023; 122:3133-3145. [PMID: 37381600 PMCID: PMC10432225 DOI: 10.1016/j.bpj.2023.06.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/19/2023] [Accepted: 06/23/2023] [Indexed: 06/30/2023] Open
Abstract
The coordinated (dis)engagement of the membrane-bound T cell receptor (TCR)-CD3-CD4 complex from the peptide-major histocompatibility complex (pMHC) is fundamental to TCR signal transduction and T cell effector function. As such, an atomic-scale understanding would not only enhance our basic understanding of the adaptive immune response but would also accelerate the rational design of TCRs for immunotherapy. In this study, we explore the impact of the CD4 coreceptor on the TCR-pMHC (dis)engagement by constructing a molecular-level biomimetic model of the CD3-TCR-pMHC and CD4-CD3-TCR-pMHC complexes within a lipid bilayer. After allowing the system complexes to equilibrate (engage), we use steered molecular dynamics to dissociate (disengage) the pMHC. We find that 1) the CD4 confines the pMHC closer to the T cell by 1.8 nm at equilibrium; 2) CD4 confinement shifts the TCR along the MHC binding groove engaging a different set of amino acids and enhancing the TCR-pMHC bond lifetime; 3) the CD4 translocates under load increasing the interaction strength between the CD4-pMHC, CD4-TCR, and CD4-CD3; and 4) upon dissociation, the CD3-TCR complex undergoes structural oscillation and increased energetic fluctuation between the CD3-TCR and CD3-lipids. These atomic-level simulations provide mechanistic insight on how the CD4 coreceptor impacts TCR-pMHC (dis)engagement. More specifically, our results provide further support (enhanced bond lifetime) for a force-dependent kinetic proofreading model and identify an alternate set of amino acids in the TCR that dominate the TCR-pMHC interaction and could thus impact the design of TCRs for immunotherapy.
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Affiliation(s)
- Zachary A Rollins
- Department of Chemical Engineering, University of California, Davis, Davis, California
| | - Roland Faller
- Department of Chemical Engineering, University of California, Davis, Davis, California
| | - Steven C George
- Department of Biomedical Engineering, University of California, Davis, Davis, California.
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5
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Singh R, Kundu P, Mishra VK, Singh BK, Bhattacharyya S, Das AK. Crystal structure of FadA2 thiolase from Mycobacterium tuberculosis and prediction of its substrate specificity and membrane-anchoring properties. FEBS J 2023; 290:3997-4022. [PMID: 37026388 DOI: 10.1111/febs.16792] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 03/17/2023] [Accepted: 04/05/2023] [Indexed: 04/08/2023]
Abstract
Tuberculosis (TB) is one of the leading causes of human death caused by Mycobacterium tuberculosis (Mtb). Mtb can enter into a long-lasting persistence where it can utilize fatty acids as the carbon source. Hence, fatty acid metabolism pathway enzymes are considered promising and pertinent mycobacterial drug targets. FadA2 (thiolase) is one of the enzymes involved in Mtb's fatty acid metabolism pathway. FadA2 deletion construct (ΔL136-S150) was designed to produce soluble protein. The crystal structure of FadA2 (ΔL136-S150) at 2.9 Å resolution was solved and analysed for membrane-anchoring region. The four catalytic residues of FadA2 are Cys99, His341, His390 and Cys427, and they belong to four loops with characteristic sequence motifs, i.e., CxT, HEAF, GHP and CxA. FadA2 is the only thiolase of Mtb which belongs to the CHH category containing the HEAF motif. Analysing the substrate-binding channel, it has been suggested that FadA2 is involved in the β-oxidation pathway, i.e., the degradative pathway, as the long-chain fatty acid can be accommodated in the channel. The catalysed reaction is favoured by the presence of two oxyanion holes, i.e., OAH1 and OAH2. OAH1 formation is unique in FadA2, formed by the NE2 of His390 present in the GHP motif and NE2 of His341 present in the HEAF motif, whereas OAH2 formation is similar to CNH category thiolase. Sequence and structural comparison with the human trifunctional enzyme (HsTFE-β) suggests the membrane-anchoring region in FadA2. Molecular dynamics simulations of FadA2 with a membrane containing POPE lipid were conducted to understand the role of a long insertion sequence of FadA2 in membrane anchoring.
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Affiliation(s)
- Rashika Singh
- Department of Biotechnology, Indian Institute of Technology Kharagpur, India
| | - Prasun Kundu
- Department of Biotechnology, Indian Institute of Technology Kharagpur, India
| | | | - Bina Kumari Singh
- School of Bioscience, Indian Institute of Technology Kharagpur, India
| | - Sudipta Bhattacharyya
- Department of Bioscience & Bioengineering, Indian Institute of Technology Jodhpur, India
| | - Amit Kumar Das
- Department of Biotechnology, Indian Institute of Technology Kharagpur, India
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6
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Ibrahim MAA, Abdeljawaad KAA, Abdelrahman AHM, Sidhom PA, Tawfeek AM, Mekhemer GAH, Abd El-Rahman MK, Dabbish E, Shoeib T. In-Silico Mining of the Toxins Database (T3DB) towards Hunting Prospective Candidates as ABCB1 Inhibitors: Integrated Molecular Docking and Lipid Bilayer-Enhanced Molecular Dynamics Study. Pharmaceuticals (Basel) 2023; 16:1019. [PMID: 37513931 PMCID: PMC10384459 DOI: 10.3390/ph16071019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 07/11/2023] [Accepted: 07/14/2023] [Indexed: 07/30/2023] Open
Abstract
Multidrug resistance (MDR) is one of the most problematic issues in chemotherapeutic carcinoma therapy. The ABCB1 transporter, a drug efflux pump overexpressed in cancer cells, has been thoroughly investigated for its association with MDR. Thus, discovering ABCB1 inhibitors can reverse the MDR in cancer cells. In the current work, a molecular docking technique was utilized for hunting the most prospective ABCB1 inhibitors from the Toxin and Toxin-Target Database (T3DB). Based on the docking computations, the most promising T3DB compounds complexed with the ABCB1 transporter were subjected to molecular dynamics (MD) simulations over 100 ns. Utilizing the MM-GBSA approach, the corresponding binding affinities were computed. Compared to ZQU (calc. -49.8 kcal/mol), Emamectin B1a (T3D1043), Emamectin B1b (T3D1044), Vincristine (T3D4016), Vinblastine (T3D4017), and Vindesine (T3D2479) complexed with ABCB1 transporter demonstrated outstanding binding affinities with ΔGbinding values of -93.0, -92.6, -93.8, -92.2, and -90.8 kcal/mol, respectively. The structural and energetic investigations confirmed the constancy of the identified T3DB compounds complexed with the ABCB1 transporter during the 100 ns MD course. To mimic the physiological conditions, MD simulations were conducted for those identified inhibitors complexed with ABCB1 transporter in the presence of a POPC membrane. These findings revealed that Emamectin B1a, Emamectin B1b, Vincristine, Vinblastine, and Vindesine are promising ABCB1 inhibitors that can reverse the MDR. Therefore, subjecting those compounds to further in-vitro and in-vivo investigations is worthwhile.
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Affiliation(s)
- Mahmoud A A Ibrahim
- Computational Chemistry Laboratory, Chemistry Department, Faculty of Science, Minia University, Minia 61519, Egypt
- School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4000, South Africa
| | - Khlood A A Abdeljawaad
- Computational Chemistry Laboratory, Chemistry Department, Faculty of Science, Minia University, Minia 61519, Egypt
| | - Alaa H M Abdelrahman
- Computational Chemistry Laboratory, Chemistry Department, Faculty of Science, Minia University, Minia 61519, Egypt
| | - Peter A Sidhom
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Tanta University, Tanta 31527, Egypt
| | - Ahmed M Tawfeek
- Chemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Gamal A H Mekhemer
- Computational Chemistry Laboratory, Chemistry Department, Faculty of Science, Minia University, Minia 61519, Egypt
| | - Mohamed K Abd El-Rahman
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA
| | - Eslam Dabbish
- Department of Chemistry, The American University in Cairo, New Cairo 11835, Egypt
| | - Tamer Shoeib
- Department of Chemistry, The American University in Cairo, New Cairo 11835, Egypt
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7
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Cao S, Shi C, Wang B, Xiu P, Wang Y, Liu Y, Wang G. Evolutionary shifts in pheromone receptors contribute to speciation in four Helicoverpa species. Cell Mol Life Sci 2023; 80:199. [PMID: 37421463 PMCID: PMC11072504 DOI: 10.1007/s00018-023-04837-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 05/22/2023] [Accepted: 06/13/2023] [Indexed: 07/10/2023]
Abstract
Male moths utilize their pheromone communication systems to distinguish potential mates from other sympatric species, which contributes to maintaining reproductive isolation and even drives speciation. The molecular mechanisms underlying the evolution of pheromone communication systems are usually studied between closely-related moth species for their similar but divergent traits associated with pheromone production, detection, and/or processing. In this study, we first identified the functional differentiation in two orthologous pheromone receptors, OR14b, and OR16, in four Helicoverpa species, Helicoverpa armigera, H. assulta, H. zea, and H. gelotopoeon. To understand the substrate response specificity of these two PRs, we performed all-atom molecular dynamics simulations of OR14b and OR16 based on AlphaFold2 structural prediction, and molecular docking, allowing us to predict a few key amino acids involved in substrate binding. These candidate residues were further tested and validated by site-directed mutagenesis and functional analysis. These results together identified two hydrophobic amino acids at positions 164 and 232 are the determinants of the response specificity of HarmOR14b and HzeaOR14b to Z9-14:Ald and Z9-16:Ald by directly interacting with the substrates. Interestingly, in OR16 orthologs, we found that position 66 alone determines the specific binding of Z11-16:OH, likely via allosteric interactions. Overall, we have developed an effective integrated method to identify the critical residues for substrate selectivity of ORs and elucidated the molecular mechanism of the diversification of pheromone recognition systems.
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Affiliation(s)
- Song Cao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
| | - Chen Shi
- Department of Engineering Mechanics, Zhejiang University, Hangzhou, 310027, China
| | - Bing Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Peng Xiu
- Department of Engineering Mechanics, Zhejiang University, Hangzhou, 310027, China
| | - Yong Wang
- College of Life Sciences, Zhejiang University, Hangzhou, 310058, China.
- The Provincial International Science and Technology Cooperation Base On Engineering Biology, International Campus of Zhejiang University, Haining, 314499, China.
| | - Yang Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
| | - Guirong Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China.
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8
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Tzortzini E, Kolocouris A. Molecular Biophysics of Class A G Protein Coupled Receptors-Lipids Interactome at a Glance-Highlights from the A 2A Adenosine Receptor. Biomolecules 2023; 13:957. [PMID: 37371538 DOI: 10.3390/biom13060957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 05/25/2023] [Accepted: 05/28/2023] [Indexed: 06/29/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are embedded in phospholipid membrane bilayers with cholesterol representing 34% of the total lipid content in mammalian plasma membranes. Membrane lipids interact with GPCRs structures and modulate their function and drug-stimulated signaling through conformational selection. It has been shown that anionic phospholipids form strong interactions between positively charged residues in the G protein and the TM5-TM6-TM 7 cytoplasmic interface of class A GPCRs stabilizing the signaling GPCR-G complex. Cholesterol with a high content in plasma membranes can be identified in more specific sites in the transmembrane region of GPCRs, such as the Cholesterol Consensus Motif (CCM) and Cholesterol Recognition Amino Acid Consensus (CRAC) motifs and other receptor dependent and receptor state dependent sites. Experimental biophysical methods, atomistic (AA) MD simulations and coarse-grained (CG) molecular dynamics simulations have been applied to investigate these interactions. We emphasized here the impact of phosphatidyl inositol-4,5-bisphosphate (PtdIns(4,5)P2 or PIP2), a minor phospholipid component and of cholesterol on the function-related conformational equilibria of the human A2A adenosine receptor (A2AR), a representative receptor in class A GPCR. Several GPCRs of class A interacted with PIP2 and cholesterol and in many cases the mechanism of the modulation of their function remains unknown. This review provides a helpful comprehensive overview for biophysics that enter the field of GPCRs-lipid systems.
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Affiliation(s)
- Efpraxia Tzortzini
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, 15771 Athens, Greece
| | - Antonios Kolocouris
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, 15771 Athens, Greece
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9
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Smith A, Runde S, Chew AK, Kelkar AS, Maheshwari U, Van Lehn RC, Zavala VM. Topological Analysis of Molecular Dynamics Simulations using the Euler Characteristic. J Chem Theory Comput 2023; 19:1553-1567. [PMID: 36812112 DOI: 10.1021/acs.jctc.2c00766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Molecular dynamics (MD) simulations are used in diverse scientific and engineering fields such as drug discovery, materials design, separations, biological systems, and reaction engineering. These simulations generate highly complex data sets that capture the 3D spatial positions, dynamics, and interactions of thousands of molecules. Analyzing MD data sets is key for understanding and predicting emergent phenomena and in identifying key drivers and tuning design knobs of such phenomena. In this work, we show that the Euler characteristic (EC) provides an effective topological descriptor that facilitates MD analysis. The EC is a versatile, low-dimensional, and easy-to-interpret descriptor that can be used to reduce, analyze, and quantify complex data objects that are represented as graphs/networks, manifolds/functions, and point clouds. Specifically, we show that the EC is an informative descriptor that can be used for machine learning and data analysis tasks such as classification, visualization, and regression. We demonstrate the benefits of the proposed approach through case studies that aim to understand and predict the hydrophobicity of self-assembled monolayers and the reactivity of complex solvent environments.
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Affiliation(s)
- Alexander Smith
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Spencer Runde
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Alex K Chew
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Atharva S Kelkar
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Utkarsh Maheshwari
- Department of Electrical and Computer Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Reid C Van Lehn
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Victor M Zavala
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States
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10
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Start Me Up: How Can Surrounding Gangliosides Affect Sodium-Potassium ATPase Activity and Steer towards Pathological Ion Imbalance in Neurons? Biomedicines 2022; 10:biomedicines10071518. [PMID: 35884824 PMCID: PMC9313118 DOI: 10.3390/biomedicines10071518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/21/2022] [Accepted: 06/24/2022] [Indexed: 12/04/2022] Open
Abstract
Gangliosides, amphiphilic glycosphingolipids, tend to associate laterally with other membrane constituents and undergo extensive interactions with membrane proteins in cis or trans configurations. Studies of human diseases resulting from mutations in the ganglioside biosynthesis pathway and research on transgenic mice with the same mutations implicate gangliosides in the pathogenesis of epilepsy. Gangliosides are reported to affect the activity of the Na+/K+-ATPase, the ubiquitously expressed plasma membrane pump responsible for the stabilization of the resting membrane potential by hyperpolarization, firing up the action potential and ion homeostasis. Impaired Na+/K+-ATPase activity has also been hypothesized to cause seizures by several mechanisms. In this review we present different epileptic phenotypes that are caused by impaired activity of Na+/K+-ATPase or changed membrane ganglioside composition. We further discuss how gangliosides may influence Na+/K+-ATPase activity by acting as lipid sorting machinery providing the optimal stage for Na+/K+-ATPase function. By establishing a distinct lipid environment, together with other membrane lipids, gangliosides possibly modulate Na+/K+-ATPase activity and aid in “starting up” and “turning off” this vital pump. Therefore, structural changes of neuronal membranes caused by altered ganglioside composition can be a contributing factor leading to aberrant Na+/K+-ATPase activity and ion imbalance priming neurons for pathological firing.
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11
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Williams SI, Yu X, Ni T, Gilbert RJ, Stansfeld PJ. Structural, functional and computational studies of membrane recognition by Plasmodium Perforin-Like Proteins 1 and 2. J Mol Biol 2022; 434:167642. [DOI: 10.1016/j.jmb.2022.167642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/06/2022] [Accepted: 05/13/2022] [Indexed: 11/25/2022]
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12
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Buyan A, Corry B. Initiating Coarse-Grained MD Simulations for Membrane-Bound Proteins. Methods Mol Biol 2022; 2402:131-141. [PMID: 34854041 DOI: 10.1007/978-1-0716-1843-1_11] [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] [Indexed: 06/13/2023]
Abstract
Molecular dynamics (MD) simulations have become a widely used tool in the scientific community for understanding molecular scale phenomena that are challenging to address with wet-lab techniques. Coarse-grained simulations, in which multiple atoms are combined into single beads, allow for larger systems and longer time scales to be explored than atomistic techniques. Here, we describe the procedures and equipment required to set up coarse-grained simulations of membrane-bound proteins in a lipid bilayer that can mimic many membrane environments.
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Affiliation(s)
- Amanda Buyan
- Research School of Biology, Australian National University, Canberra, ACT, Australia.
| | - Ben Corry
- Research School of Biology, Australian National University, Canberra, ACT, Australia
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13
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Ilangumaran Ponmalar I, Sarangi NK, Basu JK, Ayappa KG. Pore Forming Protein Induced Biomembrane Reorganization and Dynamics: A Focused Review. Front Mol Biosci 2021; 8:737561. [PMID: 34568431 PMCID: PMC8459938 DOI: 10.3389/fmolb.2021.737561] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 07/30/2021] [Indexed: 11/13/2022] Open
Abstract
Pore forming proteins are a broad class of pathogenic proteins secreted by organisms as virulence factors due to their ability to form pores on the target cell membrane. Bacterial pore forming toxins (PFTs) belong to a subclass of pore forming proteins widely implicated in bacterial infections. Although the action of PFTs on target cells have been widely investigated, the underlying membrane response of lipids during membrane binding and pore formation has received less attention. With the advent of superresolution microscopy as well as the ability to carry out molecular dynamics (MD) simulations of the large protein membrane assemblies, novel microscopic insights on the pore forming mechanism have emerged over the last decade. In this review, we focus primarily on results collated in our laboratory which probe dynamic lipid reorganization induced in the plasma membrane during various stages of pore formation by two archetypal bacterial PFTs, cytolysin A (ClyA), an α-toxin and listeriolysin O (LLO), a β-toxin. The extent of lipid perturbation is dependent on both the secondary structure of the membrane inserted motifs of pore complex as well as the topological variations of the pore complex. Using confocal and superresolution stimulated emission depletion (STED) fluorescence correlation spectroscopy (FCS) and MD simulations, lipid diffusion, cholesterol reorganization and deviations from Brownian diffusion are correlated with the oligomeric state of the membrane bound protein as well as the underlying membrane composition. Deviations from free diffusion are typically observed at length scales below ∼130 nm to reveal the presence of local dynamical heterogeneities that emerge at the nanoscale-driven in part by preferential protein binding to cholesterol and domains present in the lipid membrane. Interrogating the lipid dynamics at the nanoscale allows us further differentiate between binding and pore formation of β- and α-PFTs to specific domains in the membrane. The molecular insights gained from the intricate coupling that occurs between proteins and membrane lipids and receptors during pore formation are expected to improve our understanding of the virulent action of PFTs.
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Affiliation(s)
| | - Nirod K. Sarangi
- School of Chemical Science, Dublin City University, Dublin, Ireland
| | - Jaydeep K. Basu
- Department of Physics, Indian Institute of Science, Bangalore, India
| | - K. Ganapathy Ayappa
- Center for BioSystems Science and Engineering, Indian Institute of Science, Bangalore, India
- Department of Chemical Engineering, Indian Institute of Science, Bengaluru, India
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14
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Geiger J, Sexton R, Al-Sahouri Z, Lee MY, Chun E, Harikumar KG, Miller LJ, Beckstein O, Liu W. Evidence that specific interactions play a role in the cholesterol sensitivity of G protein-coupled receptors. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2021; 1863:183557. [PMID: 33444621 PMCID: PMC8656464 DOI: 10.1016/j.bbamem.2021.183557] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 12/15/2020] [Accepted: 12/30/2020] [Indexed: 10/22/2022]
Abstract
G protein-coupled receptors (GPCRs) are known to be modulated by membrane cholesterol levels, but whether or not the effects are caused by specific receptor-cholesterol interactions or cholesterol's general effects on the membrane is not well-understood. We performed coarse-grained molecular dynamics (CGMD) simulations coupled with structural bioinformatics approaches on the β2-adrenergic receptor (β2AR) and the cholecystokinin (CCK) receptor subfamily. The β2AR has been shown to be sensitive to membrane cholesterol and cholesterol molecules have been clearly resolved in numerous β2AR crystal structures. The two CCK receptors are highly homologous and preserve similar cholesterol recognition motifs but despite their homology, CCK1R shows functional sensitivity to membrane cholesterol while CCK2R does not. Our results offer new insights into how cholesterol modulates GPCR function by showing cholesterol interactions with β2AR that agree with previously published data; additionally, we observe differential and specific cholesterol binding in the CCK receptor subfamily while revealing a previously unreported Cholesterol Recognition Amino-acid Consensus (CRAC) sequence that is also conserved across 38% of class A GPCRs. A thermal denaturation assay (LCP-Tm) shows that mutation of a conserved CRAC sequence on TM7 of the β2AR affects cholesterol stabilization of the receptor in a lipid bilayer. The results of this study provide a better understanding of receptor-cholesterol interactions that can contribute to novel and improved therapeutics for a variety of diseases.
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Affiliation(s)
- James Geiger
- Center for Applied Structural Discovery at the Biodesign Institute, Arizona State University, Tempe, AZ, United States of America
| | - Rick Sexton
- Department of Physics and Center for Biological Physics, Arizona State University, Tempe, AZ, United States of America
| | - Zina Al-Sahouri
- Center for Applied Structural Discovery at the Biodesign Institute, Arizona State University, Tempe, AZ, United States of America
| | - Ming-Yue Lee
- Center for Applied Structural Discovery at the Biodesign Institute, Arizona State University, Tempe, AZ, United States of America
| | - Eugene Chun
- Center for Applied Structural Discovery at the Biodesign Institute, Arizona State University, Tempe, AZ, United States of America
| | - Kaleeckal G Harikumar
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ, United States of America
| | - Laurence J Miller
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ, United States of America
| | - Oliver Beckstein
- Department of Physics and Center for Biological Physics, Arizona State University, Tempe, AZ, United States of America.
| | - Wei Liu
- Center for Applied Structural Discovery at the Biodesign Institute, Arizona State University, Tempe, AZ, United States of America.
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15
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Ligand-Induced Conformational Dynamics of A Tyramine Receptor from Sitophilus oryzae. Sci Rep 2019; 9:16275. [PMID: 31700013 PMCID: PMC6838067 DOI: 10.1038/s41598-019-52478-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 10/18/2019] [Indexed: 12/20/2022] Open
Abstract
Tyramine receptor (TyrR) is a biogenic amine G protein-coupled receptor (GPCR) associated with many important physiological functions in insect locomotion, reproduction, and pheromone response. Binding of specific ligands to the TyrR triggers conformational changes, relays the signal to G proteins, and initiates an appropriate cellular response. Here, we monitor the binding effect of agonist compounds, tyramine and amitraz, to a Sitophilus oryzae tyramine receptor (SoTyrR) homology model and their elicited conformational changes. All-atom molecular dynamics (MD) simulations of SoTyrR-ligand complexes have shown varying dynamic behavior, especially at the intracellular loop 3 (IL3) region. Moreover, in contrast to SoTyrR-tyramine, SoTyrR-amitraz and non-liganded SoTyrR shows greater flexibility at IL3 residues and were found to be coupled to the most dominant motion in the receptor. Our results suggest that the conformational changes induced by amitraz are different from the natural ligand tyramine, albeit being both agonists of SoTyrR. This is the first attempt to understand the biophysical implication of amitraz and tyramine binding to the intracellular domains of TyrR. Our data may provide insights into the early effects of ligand binding to the activation process of SoTyrR.
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16
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Zou Y, Ewalt J, Ng HL. Recent Insights from Molecular Dynamics Simulations for G Protein-Coupled Receptor Drug Discovery. Int J Mol Sci 2019; 20:E4237. [PMID: 31470676 PMCID: PMC6747122 DOI: 10.3390/ijms20174237] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 08/26/2019] [Accepted: 08/27/2019] [Indexed: 02/06/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are critical drug targets. GPCRs convey signals from the extracellular to the intracellular environment through G proteins. Some ligands that bind to GPCRs activate different downstream signaling pathways. G protein activation, or -arrestin biased signaling, involves ligands binding to receptors and stabilizing conformations that trigger a specific pathway. -arrestin biased signaling has become a hot target for structure-based drug discovery. However, challenges include that there are few crystal structures available in the Protein Data Bank and that GPCRs are highly dynamic. Hence, molecular dynamics (MD) simulations are especially valuable for obtaining detailed mechanistic information, including identification of allosteric sites and understanding modulators' interactions with receptors and ligands. Here, we highlight recent MD simulation studies and enhanced sampling methods used to study biased G protein-coupled receptor signaling and their conformational dynamics as well as applications to drug discovery.
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Affiliation(s)
- Ye Zou
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506, USA
| | - John Ewalt
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506, USA
| | - Ho-Leung Ng
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506, USA.
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17
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Schott-Verdugo S, Gohlke H. PACKMOL-Memgen: A Simple-To-Use, Generalized Workflow for Membrane-Protein-Lipid-Bilayer System Building. J Chem Inf Model 2019; 59:2522-2528. [PMID: 31120747 DOI: 10.1021/acs.jcim.9b00269] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present PACKMOL-Memgen, a simple-to-use, generalized workflow for automated building of membrane-protein-lipid-bilayer systems based on open-source tools including Packmol, memembed, pdbremix, and AmberTools. Compared with web-interface-based related tools, PACKMOL-Memgen allows setup of multiple configurations of a system in a user-friendly and efficient manner within minutes. The generated systems are well-packed and thus well-suited as starting configurations in MD simulations under periodic boundary conditions, requiring only moderate equilibration times. PACKMOL-Memgen is distributed with AmberTools and runs on most computing platforms, and its output can also be used for CHARMM or adapted to other molecular-simulation packages.
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Affiliation(s)
- Stephan Schott-Verdugo
- Institute for Pharmaceutical and Medicinal Chemistry , Heinrich Heine University Düsseldorf , 40225 Düsseldorf , Germany.,Centro de Bioinformática y Simulación Molecular (CBSM), Faculty of Engineering , Universidad de Talca , 1 Poniente 1141 , Casilla 721 , Talca , Chile
| | - Holger Gohlke
- Institute for Pharmaceutical and Medicinal Chemistry , Heinrich Heine University Düsseldorf , 40225 Düsseldorf , Germany.,John von Neumann Institute for Computing (NIC), Jülich Supercomputing Centre (JSC) & Institute for Complex Systems-Structural Biochemistry (ICS 6) , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany
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18
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Bhaskara RM, Grumati P, Garcia-Pardo J, Kalayil S, Covarrubias-Pinto A, Chen W, Kudryashev M, Dikic I, Hummer G. Curvature induction and membrane remodeling by FAM134B reticulon homology domain assist selective ER-phagy. Nat Commun 2019; 10:2370. [PMID: 31147549 PMCID: PMC6542808 DOI: 10.1038/s41467-019-10345-3] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 04/25/2019] [Indexed: 02/06/2023] Open
Abstract
FAM134B/RETREG1 is a selective ER-phagy receptor that regulates the size and shape of the endoplasmic reticulum. The structure of its reticulon-homology domain (RHD), an element shared with other ER-shaping proteins, and the mechanism of membrane shaping remain poorly understood. Using molecular modeling and molecular dynamics (MD) simulations, we assemble a structural model for the RHD of FAM134B. Through MD simulations of FAM134B in flat and curved membranes, we relate the dynamic RHD structure with its two wedge-shaped transmembrane helical hairpins and two amphipathic helices to FAM134B functions in membrane-curvature induction and curvature-mediated protein sorting. FAM134B clustering, as expected to occur in autophagic puncta, amplifies the membrane-shaping effects. Electron microscopy of in vitro liposome remodeling experiments support the membrane remodeling functions of the different RHD structural elements. Disruption of the RHD structure affects selective autophagy flux and leads to disease states. FAM134B/RETREG1 is a selective ER-phagy receptor that regulates the size and shape of the endoplasmic reticulum. Here authors use molecular modeling and molecular dynamics simulations to assemble a structural model for the reticulon-homology domain of FAM134B.
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Affiliation(s)
- Ramachandra M Bhaskara
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue Straße 3, 60438, Frankfurt am Main, Germany
| | - Paolo Grumati
- Institute of Biochemistry II, School of Medicine, Goethe University Frankfurt, Theoder-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Javier Garcia-Pardo
- Buchmann Institute of Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue Straße 15, 60438, Frankfurt am Main, Germany.,Fraunhofer Institute for Molecular Biology and Applied Ecology, Division for Translational Medicine and Pharmacology, Theodor-Stern-Kai 7, 60596, Frankfurt am Main, Germany
| | - Sissy Kalayil
- Buchmann Institute of Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue Straße 15, 60438, Frankfurt am Main, Germany
| | - Adriana Covarrubias-Pinto
- Institute of Biochemistry II, School of Medicine, Goethe University Frankfurt, Theoder-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Wenbo Chen
- Buchmann Institute of Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue Straße 15, 60438, Frankfurt am Main, Germany.,Max Planck Institute of Biophysics, Max-von-Laue Straße 3, 60438, Frankfurt am Main, Germany
| | - Mikhail Kudryashev
- Buchmann Institute of Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue Straße 15, 60438, Frankfurt am Main, Germany.,Max Planck Institute of Biophysics, Max-von-Laue Straße 3, 60438, Frankfurt am Main, Germany
| | - Ivan Dikic
- Institute of Biochemistry II, School of Medicine, Goethe University Frankfurt, Theoder-Stern-Kai 7, 60590, Frankfurt am Main, Germany. .,Buchmann Institute of Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue Straße 15, 60438, Frankfurt am Main, Germany.
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue Straße 3, 60438, Frankfurt am Main, Germany. .,Institute for Biophysics, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany.
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19
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Enkavi G, Javanainen M, Kulig W, Róg T, Vattulainen I. Multiscale Simulations of Biological Membranes: The Challenge To Understand Biological Phenomena in a Living Substance. Chem Rev 2019; 119:5607-5774. [PMID: 30859819 PMCID: PMC6727218 DOI: 10.1021/acs.chemrev.8b00538] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Indexed: 12/23/2022]
Abstract
Biological membranes are tricky to investigate. They are complex in terms of molecular composition and structure, functional over a wide range of time scales, and characterized by nonequilibrium conditions. Because of all of these features, simulations are a great technique to study biomembrane behavior. A significant part of the functional processes in biological membranes takes place at the molecular level; thus computer simulations are the method of choice to explore how their properties emerge from specific molecular features and how the interplay among the numerous molecules gives rise to function over spatial and time scales larger than the molecular ones. In this review, we focus on this broad theme. We discuss the current state-of-the-art of biomembrane simulations that, until now, have largely focused on a rather narrow picture of the complexity of the membranes. Given this, we also discuss the challenges that we should unravel in the foreseeable future. Numerous features such as the actin-cytoskeleton network, the glycocalyx network, and nonequilibrium transport under ATP-driven conditions have so far received very little attention; however, the potential of simulations to solve them would be exceptionally high. A major milestone for this research would be that one day we could say that computer simulations genuinely research biological membranes, not just lipid bilayers.
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Affiliation(s)
- Giray Enkavi
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Matti Javanainen
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy
of Sciences, Flemingovo naḿesti 542/2, 16610 Prague, Czech Republic
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
| | - Waldemar Kulig
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Tomasz Róg
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
| | - Ilpo Vattulainen
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
- MEMPHYS-Center
for Biomembrane Physics
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20
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Visualizing Biological Membrane Organization and Dynamics. J Mol Biol 2019; 431:1889-1919. [DOI: 10.1016/j.jmb.2019.02.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 02/02/2019] [Accepted: 02/13/2019] [Indexed: 11/22/2022]
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21
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Single-Molecule Imaging and Computational Microscopy Approaches Clarify the Mechanism of the Dimerization and Membrane Interactions of Green Fluorescent Protein. Int J Mol Sci 2019; 20:ijms20061410. [PMID: 30897814 PMCID: PMC6471090 DOI: 10.3390/ijms20061410] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 03/15/2019] [Accepted: 03/19/2019] [Indexed: 02/01/2023] Open
Abstract
Green fluorescent protein (GFP) is widely used as a biomarker in living systems; however, GFP and its variants are prone to forming low-affinity dimers under physiological conditions. This undesirable tendency is exacerbated when fluorescent proteins (FP) are confined to membranes, fused to naturally-oligomeric proteins, or expressed at high levels in cells. Oligomerization of FPs introduces artifacts into the measurement of subunit stoichiometry, as well as interactions between proteins fused to FPs. Introduction of a single mutation, A206K, has been shown to disrupt hydrophobic interactions in the region responsible for GFP dimerization, thereby contributing to its monomerization. Nevertheless, a detailed understanding of how this single amino acid-dependent inhibition of dimerization in GFP occurs at the atomic level is still lacking. Single-molecule experiments combined with computational microscopy (atomistic molecular dynamics) revealed that the amino group of A206 contributes to GFP dimer formation via a multivalent electrostatic interaction. We further showed that myristoyl modification is an efficient mechanism to promote membrane attachment of GFP. Molecular dynamics-based site-directed mutagenesis has been used to identify the key functional residues in FPs. The data presented here have been utilized as a monomeric control in downstream single-molecule studies, facilitating more accurate stoichiometry quantification of functional protein complexes in living cells.
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22
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Van Liefferinge F, Krammer EM, Sengupta D, Prévost M. Lipid composition and salt concentration as regulatory factors of the anion selectivity of VDAC studied by coarse-grained molecular dynamics simulations. Chem Phys Lipids 2018; 220:66-76. [PMID: 30448398 DOI: 10.1016/j.chemphyslip.2018.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 11/08/2018] [Accepted: 11/12/2018] [Indexed: 12/27/2022]
Abstract
The voltage-dependent anion channel (VDAC) is a mitochondrial outer membrane protein whose fundamental function is to facilitate and regulate the flow of metabolites between the cytosol and the mitochondrial intermembrane space. Using coarse-grained molecular dynamics simulations, we investigated the dependence of VDAC selectivity towards small inorganic anions on two factors: the ionic strength and the lipid composition. In agreement with experimental data we found that VDAC becomes less anion selective with increasing salt concentration due to the screening of a few basic residues that point into the pore lumen. The molecular dynamics simulations provide insight into the regulation mechanism of VDAC selectivity by the composition in the lipid membrane and suggest that the ion distribution is differently modulated by POPE compared to the POPC bilayer. This occurs through the more persistent interactions of acidic residues located at both rims of the β-barrel with head groups of POPE which in turn impact the electrostatic potential and thereby the selectivity of the pore. This mechanism occurs not only in POPE single component membranes but also in a mixed POPE/POPC bilayer by an enrichment of POPE over POPC lipids on the surface of VDAC. Thus we show here that computationally-inexpensive coarse-grained simulations are able to capture, in a semi-quantitative way, essential features of VDAC anion selectivity and could pave the way toward a molecular level understanding of metabolite transport in natural membranes.
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Affiliation(s)
- F Van Liefferinge
- Structure et Fonction des Membranes Biologiques, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - E-M Krammer
- Structure et Fonction des Membranes Biologiques, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - D Sengupta
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India
| | - M Prévost
- Structure et Fonction des Membranes Biologiques, Université Libre de Bruxelles (ULB), Brussels, Belgium.
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23
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Cryo-EM reveals two distinct serotonin-bound conformations of full-length 5-HT 3A receptor. Nature 2018; 563:270-274. [PMID: 30401837 PMCID: PMC6237196 DOI: 10.1038/s41586-018-0660-7] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 08/30/2018] [Indexed: 12/19/2022]
Abstract
Serotonin receptor (5-HT3AR)1, a cationic pentameric ligand-gated ion channel (pLGIC), is the clinical target for management of nausea and vomiting associated with radiation and chemotherapies2. Upon binding, serotonin induces a global conformational change encompassing the ligand-binding extracellular domain (ECD), the transmembrane domain (TMD), and the intracellular domain (ICD), the molecular details of which are unclear. Here, we present two serotonin-bound structures of the full-length 5-HT3AR in distinct conformations at 3.32 Å and 3.89 Å resolutions that reveal the mechanism underlying channel activation. When compared to Apo-5-HT3AR, serotonin-bound states underwent a large twisting motion in the ECD and TMD leading to the opening of a 165 Å long permeation pathway. Notably, this motion results in creation of lateral portals for ion permeation at the interface of the TMD and ICD. Combined with molecular dynamics simulations, these structures provide novel insights into conformational coupling across domains and functional modulation.
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24
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Molecular mechanism of substrate selectivity of the arginine-agmatine Antiporter AdiC. Sci Rep 2018; 8:15607. [PMID: 30353119 PMCID: PMC6199258 DOI: 10.1038/s41598-018-33963-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 10/08/2018] [Indexed: 12/02/2022] Open
Abstract
The arginine-agmatine antiporter (AdiC) is a component of an acid resistance system developed by enteric bacteria to resist gastric acidity. In order to avoid neutral proton antiport, the monovalent form of arginine, about as abundant as its divalent form under acidic conditions, should be selectively bound by AdiC for transport into the cytosol. In this study, we shed light on the mechanism through which AdiC distinguishes Arg+ from Arg2+ of arginine by investigating the binding of both forms in addition to that of divalent agmatine, using a combination of molecular dynamics simulations with molecular and quantum mechanics calculations. We show that AdiC indeed preferentially binds Arg+. The weaker binding of divalent compounds results mostly from their greater tendency to remain hydrated than Arg+. Our data suggests that the binding of Arg+ promotes the deprotonation of Glu208, a gating residue, which in turn reinforces its interactions with AdiC, leading to longer residence times of Arg+ in the binding site. Although the total electric charge of the ligand appears to be the determinant factor in the discrimination process, two local interactions formed with Trp293, another gating residue of the binding site, also contribute to the selection mechanism: a cation-π interaction with the guanidinium group of Arg+ and an anion-π interaction involving Glu208.
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25
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Reißer S, Strandberg E, Steinbrecher T, Elstner M, Ulrich AS. Best of Two Worlds? How MD Simulations of Amphiphilic Helical Peptides in Membranes Can Complement Data from Oriented Solid-State NMR. J Chem Theory Comput 2018; 14:6002-6014. [PMID: 30289704 DOI: 10.1021/acs.jctc.8b00283] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The membrane alignment of helical amphiphilic peptides in oriented phospholipid bilayers can be obtained as ensemble and time averages from solid state 2H NMR by fitting the quadrupolar splittings to ideal α-helices. At the same time, molecular dynamics (MD) simulations can provide atomistic insight into peptide-membrane systems. Here, we evaluate the potential of MD simulations to complement the experimental NMR data that is available on three exemplary systems: the natural antimicrobial peptide PGLa and the two designer-made peptides MSI-103 and KIA14, whose sequences were derived from PGLa. Each peptide was simulated for 1 μs in a DMPC lipid bilayer. We calculated from the MD simulations the local angles which define the side chain geometry with respect to the peptide helix. The peptide orientation was then calculated (i) directly from the simulation, (ii) from back-calculated MD-derived NMR splittings, and (iii) from experimental 2H NMR splittings. Our findings are that (1) the membrane orientation and secondary structure of the peptides found in the NMR analysis are generally well reproduced by the simulations; (2) the geometry of the side chains with respect to the helix backbone can deviate significantly from the ideal structure depending on the specific residue, but on average all side chains have the same orientation; and (3) for all of our peptides, the azimuthal rotation angle found from the MD-derived splittings is about 15° smaller than the experimental value.
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Affiliation(s)
- Sabine Reißer
- Institute of Organic Chemistry , Karlsruhe Institute of Technology (KIT) , Fritz-Haber-Weg 6 , 76131 Karlsruhe , Germany
| | - Erik Strandberg
- Institute of Biological Interfaces (IBG-2), KIT , P.O. Box 3640, 76012 Karlsruhe , Germany
| | - Thomas Steinbrecher
- Institute of Physical Chemistry, KIT , Fritz-Haber-Weg 6 , 76131 Karlsruhe , Germany
| | - Marcus Elstner
- Institute of Physical Chemistry, KIT , Fritz-Haber-Weg 6 , 76131 Karlsruhe , Germany
| | - Anne S Ulrich
- Institute of Organic Chemistry , Karlsruhe Institute of Technology (KIT) , Fritz-Haber-Weg 6 , 76131 Karlsruhe , Germany.,Institute of Biological Interfaces (IBG-2), KIT , P.O. Box 3640, 76012 Karlsruhe , Germany
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26
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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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27
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Role of the cell membrane interface in modulating production and uptake of Alzheimer's beta amyloid protein. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1639-1651. [PMID: 29572033 DOI: 10.1016/j.bbamem.2018.03.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/13/2018] [Accepted: 03/14/2018] [Indexed: 12/22/2022]
Abstract
The beta amyloid protein (Aβ) plays a central role in Alzheimer's disease (AD) pathogenesis and its interaction with cell membranes in known to promote mutually disruptive structural perturbations that contribute to amyloid deposition and neurodegeneration in the brain. In addition to protein aggregation at the membrane interface and disruption of membrane integrity, growing reports demonstrate an important role for the membrane in modulating Aβ production and uptake into cells. The aim of this review is to highlight and summarize recent literature that have contributed insight into the implications of altered membrane composition on amyloid precursor protein (APP) proteolysis, production of Aβ, its internalization in to cells via permeabilization and receptor mediated uptake. Here, we also review the various membrane model systems and experimental tools used for probing Aβ-membrane interactions to investigate the key mechanistic aspects underlying the accumulation and toxicity of Aβ in AD.
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28
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Structural insights into positive and negative allosteric regulation of a G protein-coupled receptor through protein-lipid interactions. Sci Rep 2018. [PMID: 29535353 PMCID: PMC5849739 DOI: 10.1038/s41598-018-22735-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Lipids are becoming known as essential allosteric modulators of G protein-coupled receptor (GPCRs). However, how they exert their effects on GPCR conformation at the atomic level is still unclear. In light of recent experimental data, we have performed several long-timescale molecular dynamics (MD) simulations, totalling 24 μs, to rigorously map allosteric modulation and conformational changes in the β2 adrenergic receptor (β2AR) that occur as a result of interactions with three different phospholipids. In particular, we identify different sequential mechanisms behind receptor activation and deactivation, respectively, mediated by specific lipid interactions with key receptor regions. We show that net negatively charged lipids stabilize an active-like state of β2AR that is able to dock Gsα protein. Clustering of anionic lipids around the receptor with local distortion of membrane thickness is also apparent. On the other hand, net-neutral zwitterionic lipids inactivate the receptor, generating either fully inactive or intermediate states, with kinetics depending on lipid headgroup charge distribution and hydrophobicity. These chemical differences alter membrane thickness and density, which differentially destabilize the β2AR active state through lateral compression effects.
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29
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Liao C, Zhao X, Liu J, Schneebeli ST, Shelley JC, Li J. Capturing the multiscale dynamics of membrane protein complexes with all-atom, mixed-resolution, and coarse-grained models. Phys Chem Chem Phys 2018; 19:9181-9188. [PMID: 28317993 DOI: 10.1039/c7cp00200a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The structures and dynamics of protein complexes are often challenging to model in heterogeneous environments such as biological membranes. Herein, we meet this fundamental challenge at attainable cost with all-atom, mixed-resolution, and coarse-grained models of vital membrane proteins. We systematically simulated five complex models formed by two distinct G protein-coupled receptors (GPCRs) in the lipid-bilayer membrane on the ns-to-μs timescales. These models, which suggest the swinging motion of an intracellular loop, for the first time, provide the molecular details for the regulatory role of such a loop. For the models at different resolutions, we observed consistent structural stability but various levels of speed-ups in protein dynamics. The mixed-resolution and coarse-grained models show two and four times faster protein diffusion than the all-atom models, in addition to a 4- and 400-fold speed-up in the simulation performance. Furthermore, by elucidating the strengths and challenges of combining all-atom models with reduced resolution models, this study can serve as a guide to simulating other complex systems in heterogeneous environments efficiently.
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Affiliation(s)
- Chenyi Liao
- Department of Chemistry, The University of Vermont, Burlington, VT 05405, USA.
| | - Xiaochuan Zhao
- Department of Chemistry, The University of Vermont, Burlington, VT 05405, USA.
| | - Jiyuan Liu
- Department of Chemistry, The University of Vermont, Burlington, VT 05405, USA.
| | | | - John C Shelley
- Schrödinger, Inc., 101 SW Main Street, Suite 1300, Portland, OR 97204, USA
| | - Jianing Li
- Department of Chemistry, The University of Vermont, Burlington, VT 05405, USA.
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30
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Hung HM, Hang TD, Nguyen MT. Molecular details of spontaneous insertion and interaction of HCV non-structure 3 protease protein domain with PIP2-containing membrane. Proteins 2018; 86:423-433. [PMID: 29341226 DOI: 10.1002/prot.25458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 01/02/2018] [Accepted: 01/11/2018] [Indexed: 12/16/2022]
Abstract
Hepatitis C virus (HCV), known as the leading cause of liver cirrhosis, viral hepatitis, and hepatocellular carcinoma, has been affecting more than 150 million people globally. The HCV non-structure 3 (NS3) protease protein domain plays a key role in HCV replication and pathogenesis; and is currently a primary target for HCV antiviral therapy. Through unbiased molecular dynamics simulations which take advantage of the novel highly mobile membrane mimetic model, we constructed the membrane-bound state of the protein domain at the atomic level. Our results indicated that protease domain of HCV NS3 protein can spontaneously bind and penetrate to an endoplasmic reticulum complex membrane containing phosphatidylinositol 4,5-bisphosphate (PIP2). An amphipathic helix α0 and loop S1 show their anchoring role to keep the protein on the membrane surface. Proper orientation of the protein domain at membrane surface was identified through measuring tilt angles of two specific vectors, wherein residue R161 plays a crucial role in its final orientation. Remarkably, PIP2 molecules were observed to bind to three main sites of the protease domain via specific electrostatic contacts and hydrogen bonds. PIP2-interaction determines the protein orientation at the membrane while both hydrophobic interplay and PIP2-interaction can stabilize the NS3 - membrane complex. Simulated results provide us with a detailed characterization of insertion, orientation and PIP2-interaction of NS3 protease domain at membrane environment, thus enhancing our understanding of structural functions and mechanism for the association of HCV non-structure 3 protein with respect to ER membranes.
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Affiliation(s)
- Huynh Minh Hung
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, Leuven, B-3001, Belgium.,Department of Chemistry, Quy Nhon University, Quy Nhon, Vietnam
| | - Tran Dieu Hang
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, Leuven, B-3001, Belgium.,Department of Chemistry, Quy Nhon University, Quy Nhon, Vietnam
| | - Minh Tho Nguyen
- Computational Chemistry Research Group, Ton Duc Thang University, Ho Chi Minh City, Vietnam.,Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam.,Department of Chemistry, KU Leuven, Celestijnenlaan 200F, Leuven, B-3001, Belgium
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31
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Cacciotto P, Ramaswamy VK, Malloci G, Ruggerone P, Vargiu AV. Molecular Modeling of Multidrug Properties of Resistance Nodulation Division (RND) Transporters. Methods Mol Biol 2018; 1700:179-219. [PMID: 29177832 DOI: 10.1007/978-1-4939-7454-2_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Efflux pumps of the resistance nodulation division (RND) superfamily are among the major contributors to intrinsic and acquired multidrug resistance in Gram-negative bacteria. Structural information on AcrAB-TolC and MexAB-OprM, major efflux pumps of Escherichia coli and Pseudomonas aeruginosa respectively, boosted intensive research aimed at understanding the molecular mechanisms ruling the active extrusion processes. In particular, several studies were devoted to the understanding of the determinants behind the extraordinary broad specificity of the RND transporters AcrB and MexB. In this chapter, we discuss the ever-growing role computational methods have been playing in deciphering key structural and dynamical features of these transporters and of their interaction with substrates and inhibitors. We further discuss and illustrate examples from our lab of how molecular docking, homology modeling, all-atom molecular dynamics simulations and in silico free energy estimations can all together give precious insights into the processes of recognition and extrusion of substrates, as well as on the possible inhibition strategies.
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Affiliation(s)
- Pierpaolo Cacciotto
- Department of Physics, University of Cagliari, s.p. 8, 09042, Monserrato, CA, Italy
| | - Venkata K Ramaswamy
- Department of Physics, University of Cagliari, s.p. 8, 09042, Monserrato, CA, Italy
| | - Giuliano Malloci
- Department of Physics, University of Cagliari, s.p. 8, 09042, Monserrato, CA, Italy
| | - Paolo Ruggerone
- Department of Physics, University of Cagliari, s.p. 8, 09042, Monserrato, CA, Italy
| | - Attilio V Vargiu
- Department of Physics, University of Cagliari, s.p. 8, 09042, Monserrato, CA, Italy.
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32
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Migration of PIP 2 on KCNQ2 Surface Revealed by Molecular Dynamics Simulations. Methods Mol Biol 2017. [PMID: 29058190 DOI: 10.1007/978-1-4939-7362-0_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Lipids and membrane proteins are the main components of cell membranes. Lipid-protein interactions are dynamic because these interactions typically occur on shallow protein surface clefts. Molecular dynamics (MD) simulations provide a tool for studying the dynamics of these interactions. Here, we describe the interactions of phosphatidylinositol-4,5-bisphosphate (PIP2) with both the open and closed states of a KCNQ2 channel. Through these methods, we show that a lipid can migrate between different binding sites in a protein and this migration modulates protein functions.
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33
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Rouse SL, Hawthorne WJ, Berry JL, Chorev DS, Ionescu SA, Lambert S, Stylianou F, Ewert W, Mackie U, Morgan RML, Otzen D, Herbst FA, Nielsen PH, Dueholm M, Bayley H, Robinson CV, Hare S, Matthews S. A new class of hybrid secretion system is employed in Pseudomonas amyloid biogenesis. Nat Commun 2017; 8:263. [PMID: 28811582 PMCID: PMC5557850 DOI: 10.1038/s41467-017-00361-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 06/23/2017] [Indexed: 11/25/2022] Open
Abstract
Gram-negative bacteria possess specialised biogenesis machineries that facilitate the export of amyloid subunits for construction of a biofilm matrix. The secretion of bacterial functional amyloid requires a bespoke outer-membrane protein channel through which unfolded amyloid substrates are translocated. Here, we combine X-ray crystallography, native mass spectrometry, single-channel electrical recording, molecular simulations and circular dichroism measurements to provide high-resolution structural insight into the functional amyloid transporter from Pseudomonas, FapF. FapF forms a trimer of gated β-barrel channels in which opening is regulated by a helical plug connected to an extended coil-coiled platform spanning the bacterial periplasm. Although FapF represents a unique type of secretion system, it shares mechanistic features with a diverse range of peptide translocation systems. Our findings highlight alternative strategies for handling and export of amyloid protein sequences. Gram-negative bacteria assemble biofilms from amyloid fibres, which translocate across the outer membrane as unfolded amyloid precursors through a secretion system. Here, the authors characterise the structural details of the amyloid transporter FapF in Pseudomonas.
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Affiliation(s)
- Sarah L Rouse
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK
| | - William J Hawthorne
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK
| | - Jamie-Lee Berry
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK
| | - Dror S Chorev
- Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK
| | - Sandra A Ionescu
- Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK
| | - Sebastian Lambert
- Duke-NUS Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Fisentzos Stylianou
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK
| | - Wiebke Ewert
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK
| | - Uma Mackie
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK.,Walthamstow School for Girls, London, E17 9RZ, UK
| | - R Marc L Morgan
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK
| | - Daniel Otzen
- Interdisciplinary Nanoscience Center (iNANO), Centre for Insoluble Protein Structures (inSPIN), Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | - Florian-Alexander Herbst
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Per H Nielsen
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Morten Dueholm
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Hagan Bayley
- Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK
| | - Carol V Robinson
- Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK
| | - Stephen Hare
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK
| | - Stephen Matthews
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK.
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34
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Sezgin E, Levental I, Mayor S, Eggeling C. The mystery of membrane organization: composition, regulation and roles of lipid rafts. Nat Rev Mol Cell Biol 2017; 18:361-374. [PMID: 28356571 PMCID: PMC5500228 DOI: 10.1038/nrm.2017.16] [Citation(s) in RCA: 1260] [Impact Index Per Article: 180.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Cellular plasma membranes are laterally heterogeneous, featuring a variety of distinct subcompartments that differ in their biophysical properties and composition. A large number of studies have focused on understanding the basis for this heterogeneity and its physiological relevance. The membrane raft hypothesis formalized a physicochemical principle for a subtype of such lateral membrane heterogeneity, in which the preferential associations between cholesterol and saturated lipids drive the formation of relatively packed (or ordered) membrane domains that selectively recruit certain lipids and proteins. Recent studies have yielded new insights into this mechanism and its relevance in vivo, owing primarily to the development of improved biochemical and biophysical technologies.
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Affiliation(s)
- Erdinc Sezgin
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford OX3 9DS, UK
| | - Ilya Levental
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, 6431 Fannin Street, Houston, Texas 77030, USA
| | - Satyajit Mayor
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, Bellary Road, Bangalore 560065, India
| | - Christian Eggeling
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford OX3 9DS, UK
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35
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Genheden S, Essex JW, Lee AG. G protein coupled receptor interactions with cholesterol deep in the membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:268-281. [DOI: 10.1016/j.bbamem.2016.12.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/28/2016] [Accepted: 12/01/2016] [Indexed: 01/20/2023]
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36
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Kuyucak S, Kayser V. Biobetters From an Integrated Computational/Experimental Approach. Comput Struct Biotechnol J 2017; 15:138-145. [PMID: 28179976 PMCID: PMC5279740 DOI: 10.1016/j.csbj.2017.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 01/05/2017] [Accepted: 01/10/2017] [Indexed: 02/04/2023] Open
Abstract
Biobetters are new drugs designed from existing peptide or protein-based therapeutics by improving their properties such as affinity and selectivity for the target epitope, and stability against degradation. Computational methods can play a key role in such design problems—by predicting the changes that are most likely to succeed, they can drastically reduce the number of experiments to be performed. Here we discuss the computational and experimental methods commonly used in drug design problems, focusing on the inverse relationship between the two, namely, the more accurate the computational predictions means the less experimental effort is needed for testing. Examples discussed include efforts to design selective analogs from toxin peptides targeting ion channels for treatment of autoimmune diseases and monoclonal antibodies which are the fastest growing class of therapeutic agents particularly for cancers and autoimmune diseases.
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Affiliation(s)
- Serdar Kuyucak
- School of Physics, University of Sydney, NSW 2006, Australia
- Corresponding author.
| | - Veysel Kayser
- Faculty of Pharmacy, University of Sydney, NSW 2006, Australia
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37
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The role of interfacial lipids in stabilizing membrane protein oligomers. Nature 2017; 541:421-424. [PMID: 28077870 DOI: 10.1038/nature20820] [Citation(s) in RCA: 288] [Impact Index Per Article: 41.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Accepted: 11/23/2016] [Indexed: 12/20/2022]
Abstract
Oligomerization of membrane proteins in response to lipid binding has a critical role in many cell-signalling pathways but is often difficult to define or predict. Here we report the development of a mass spectrometry platform to determine simultaneously the presence of interfacial lipids and oligomeric stability and to uncover how lipids act as key regulators of membrane-protein association. Evaluation of oligomeric strength for a dataset of 125 α-helical oligomeric membrane proteins reveals an absence of interfacial lipids in the mass spectra of 12 membrane proteins with high oligomeric stability. For the bacterial homologue of the eukaryotic biogenic transporters (LeuT, one of the proteins with the lowest oligomeric stability), we found a precise cohort of lipids within the dimer interface. Delipidation, mutation of lipid-binding sites or expression in cardiolipin-deficient Escherichia coli abrogated dimer formation. Molecular dynamics simulation revealed that cardiolipin acts as a bidentate ligand, bridging across subunits. Subsequently, we show that for the Vibrio splendidus sugar transporter SemiSWEET, another protein with low oligomeric stability, cardiolipin shifts the equilibrium from monomer to functional dimer. We hypothesized that lipids are essential for dimerization of the Na+/H+ antiporter NhaA from E. coli, which has the lowest oligomeric strength, but not for the substantially more stable homologous Thermus thermophilus protein NapA. We found that lipid binding is obligatory for dimerization of NhaA, whereas NapA has adapted to form an interface that is stable without lipids. Overall, by correlating interfacial strength with the presence of interfacial lipids, we provide a rationale for understanding the role of lipids in both transient and stable interactions within a range of α-helical membrane proteins, including G-protein-coupled receptors.
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38
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Abstract
Membrane proteins are involved in a large variety of functions. Most of these protein functions are regulated by ligand binding with diverse modes of action: agonists, partial agonists, antagonists, and allosteric modulators, potentiators and inhibitors. From the pharmacological point of view, membrane proteins are one if not the major target for drug development. However, experimental structure determination of membrane proteins in complex or in free form still represents a great challenge. Molecular dynamics (MD) simulations commonly reach the microsecond scale on membrane systems. This numerical tool is mature enough to predict and add molecular details on the different ligand-binding modes. In the present chapter, I will present the different steps to design, simulate, and analyze a MD simulation system containing a protein embedded in a membrane and surrounded by water and ligand. As an illustration, the simulation of the ligand-gated ion channel γ-aminobutyric acid type A receptor (GABAAR) surrounded by one of its allosteric potentiators, bromoform, will be presented and discussed.
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Affiliation(s)
- Samuel Murail
- Laboratoire de Biochimie Théorique, CNRS, UPR9080, University Paris Diderot, Sorbonne Paris Cité, 13 rue Pierre et Marie Curie, F-75005, Paris, France.
- Air Liquide, Centre de Recherches Paris-Saclay, Boite Postale 126, Les Loges-en-Josas, Jouy-en-Josas, 78354, France.
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39
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Alcock F, Stansfeld PJ, Basit H, Habersetzer J, Baker MA, Palmer T, Wallace MI, Berks BC. Assembling the Tat protein translocase. eLife 2016; 5. [PMID: 27914200 PMCID: PMC5201420 DOI: 10.7554/elife.20718] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 11/29/2016] [Indexed: 12/18/2022] Open
Abstract
The twin-arginine protein translocation system (Tat) transports folded proteins across the bacterial cytoplasmic membrane and the thylakoid membranes of plant chloroplasts. The Tat transporter is assembled from multiple copies of the membrane proteins TatA, TatB, and TatC. We combine sequence co-evolution analysis, molecular simulations, and experimentation to define the interactions between the Tat proteins of Escherichia coli at molecular-level resolution. In the TatBC receptor complex the transmembrane helix of each TatB molecule is sandwiched between two TatC molecules, with one of the inter-subunit interfaces incorporating a functionally important cluster of interacting polar residues. Unexpectedly, we find that TatA also associates with TatC at the polar cluster site. Our data provide a structural model for assembly of the active Tat translocase in which substrate binding triggers replacement of TatB by TatA at the polar cluster site. Our work demonstrates the power of co-evolution analysis to predict protein interfaces in multi-subunit complexes. DOI:http://dx.doi.org/10.7554/eLife.20718.001
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Affiliation(s)
- Felicity Alcock
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | | | - Hajra Basit
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Johann Habersetzer
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Matthew Ab Baker
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Tracy Palmer
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Mark I Wallace
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Ben C Berks
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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40
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Pan C, Weng J, Wang W. Conformational Dynamics and Protein-Substrate Interaction of ABC Transporter BtuCD at the Occluded State Revealed by Molecular Dynamics Simulations. Biochemistry 2016; 55:6897-6907. [PMID: 27951660 DOI: 10.1021/acs.biochem.6b00386] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
ATP-binding cassette (ABC) transporters are ubiquitous in all three kingdoms of life and are implicated in many clinically relevant physiological processes. They couple the energy released by ATP hydrolysis to facilitate substrate translocation across cell membranes. The crystal structures of type II ABC importers have revealed their unique transmembrane domain architecture consisting of 10 transmembrane helices and their structurally conserved nucleotide-binding domains among all ABC transporters. However, molecular details of the interactions between the importers and their substrate remain largely elusive. Taking vitamin B12 importer BtuCD as an exemplar of type II importers, we investigated the dynamics of its occluded state and the detailed protein-substrate interactions using molecular dynamics simulation. Our trajectories show that the importer accommodates the substrate through a nonspecific binding mode as the substrate undergoes evident vertical and tilt motions inside the translocation cavity. Extensive hydrogen bond and hydrophobic interactions were observed between the substrate and the importer; however, most of these interactions are weak, with <38% occurrence. The presence of substrate leads to enlargement of the translocation cavity, especially at its cytoplasmic end, which may activate cytoplasmic regions and probably facilitate the transportation. The perturbations caused by periplasmic binding protein and nucleotides were also investigated. The study provides deeper insight into the translocation mechanism of BtuCD.
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Affiliation(s)
- Chao Pan
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, and Institutes of Biomedical Sciences, Fudan University , Shanghai, P. R. China
| | - Jingwei Weng
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, and Institutes of Biomedical Sciences, Fudan University , Shanghai, P. R. China
| | - Wenning Wang
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, and Institutes of Biomedical Sciences, Fudan University , Shanghai, P. R. China
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41
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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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42
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Chavent M, Duncan AL, Sansom MS. Molecular dynamics simulations of membrane proteins and their interactions: from nanoscale to mesoscale. Curr Opin Struct Biol 2016; 40:8-16. [PMID: 27341016 PMCID: PMC5404110 DOI: 10.1016/j.sbi.2016.06.007] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 06/06/2016] [Accepted: 06/07/2016] [Indexed: 11/21/2022]
Abstract
Molecular dynamics simulations provide a computational tool to probe membrane proteins and systems at length scales ranging from nanometers to close to a micrometer, and on microsecond timescales. All atom and coarse-grained simulations may be used to explore in detail the interactions of membrane proteins and specific lipids, yielding predictions of lipid binding sites in good agreement with available structural data. Building on the success of protein-lipid interaction simulations, larger scale simulations reveal crowding and clustering of proteins, resulting in slow and anomalous diffusional dynamics, within realistic models of cell membranes. Current methods allow near atomic resolution simulations of small membrane organelles, and of enveloped viruses to be performed, revealing key aspects of their structure and functionally important dynamics.
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Affiliation(s)
- Matthieu Chavent
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Anna L Duncan
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Mark Sp Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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43
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Eggeling C, Honigmann A. Closing the gap: The approach of optical and computational microscopy to uncover biomembrane organization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2558-2568. [DOI: 10.1016/j.bbamem.2016.03.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 03/23/2016] [Accepted: 03/24/2016] [Indexed: 12/15/2022]
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van Eerden FJ, van den Berg T, Frederix PWJM, de Jong DH, Periole X, Marrink SJ. Molecular Dynamics of Photosystem II Embedded in the Thylakoid Membrane. J Phys Chem B 2016; 121:3237-3249. [PMID: 27624992 DOI: 10.1021/acs.jpcb.6b06865] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Photosystem II (PSII) is one of the key protein complexes in photosynthesis. We introduce a coarse grained model of PSII and present the analysis of 60 μs molecular dynamics simulations of PSII in both monomeric and dimeric form, embedded in a thylakoid membrane model that reflects its native lipid composition. We describe in detail the setup of the protein complex and the many natural cofactors and characterize their mobility. Overall we find that the protein subunits and cofactors are more flexible toward the periphery of the complex as well as near the PLQ exchange cavity and at the dimer interface. Of all cofactors, β-carotenes show the highest mobility. Some of the β-carotenes diffuse in and out of the protein complex via the thylakoid membrane. In contrast with the PSII dimer, the monomeric form adopts a tilted conformation in the membrane, with strong interactions between the soluble PsbO subunit and the glycolipid headgroups. Interestingly, the tilted conformation causes buckling of the membrane. Together, our results provide an unprecedented view of PSII dynamics on a microsecond time scale. Our data may be used as basis for the interpretation of experimental data as well as for theoretical models describing exciton energy transfer.
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Affiliation(s)
- Floris J van Eerden
- Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials, University of Groningen , Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Tom van den Berg
- Department of Physics and Astronomy, Faculteit der Exacte Wetenschappen, Vrije Universiteit , De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Pim W J M Frederix
- Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials, University of Groningen , Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Djurre H de Jong
- Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials, University of Groningen , Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Xavier Periole
- Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials, University of Groningen , Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials, University of Groningen , Nijenborgh 7, 9747 AG, Groningen, The Netherlands
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45
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Wang LY, Ravi VM, Leblanc G, Padrós E, Cladera J, Perálvarez-Marín A. Helical unwinding and side-chain unlocking unravel the outward open conformation of the melibiose transporter. Sci Rep 2016; 6:33776. [PMID: 27658476 PMCID: PMC5034317 DOI: 10.1038/srep33776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 08/30/2016] [Indexed: 11/09/2022] Open
Abstract
Molecular dynamics simulations have been used to study the alternate access mechanism of the melibiose transporter from Escherichia coli. Starting from the outward-facing partially occluded form, 2 out of 12 simulations produced an outward full open form and one partially open, whereas the rest yielded fully or partially occluded forms. The shape of the outward-open form resembles other outward-open conformations of secondary transporters. During the transporter opening, conformational changes in some loops are followed by changes in the periplasm region of transmembrane helix 7. Helical curvature relaxation and unlocking of hydrophobic and ionic locks promote the outward opening of the transporter making accessible the substrate binding site. In particular, FRET studies on mutants of conserved aromatic residues of extracellular loop 4 showed lack of substrate binding, emphasizing the importance of this loop for making crucial interactions that control the opening of the periplasmic side. This study indicates that the alternate access mechanism for the melibiose transporter fits better into a flexible gating mechanism rather than the archetypical helical rigid-body rocker-switch mechanism.
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Affiliation(s)
- Li-Ying Wang
- Unitat de Biofísica, Departament de Bioquímica i de Biologia Molecular, Facultat de Medicina, and Centre d'Estudis en Biofísica, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Vidhya M Ravi
- Unitat de Biofísica, Departament de Bioquímica i de Biologia Molecular, Facultat de Medicina, and Centre d'Estudis en Biofísica, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Gérard Leblanc
- Direction des Sciences du Vivant, Direction des programmes et valorization, CEA Fontenay-aux-Roses, 92265 Fontenay-aux-Roses CEDEX France
| | - Esteve Padrós
- Unitat de Biofísica, Departament de Bioquímica i de Biologia Molecular, Facultat de Medicina, and Centre d'Estudis en Biofísica, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Josep Cladera
- Unitat de Biofísica, Departament de Bioquímica i de Biologia Molecular, Facultat de Medicina, and Centre d'Estudis en Biofísica, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Alex Perálvarez-Marín
- Unitat de Biofísica, Departament de Bioquímica i de Biologia Molecular, Facultat de Medicina, and Centre d'Estudis en Biofísica, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
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46
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Qi Y, Cheng X, Lee J, Vermaas JV, Pogorelov TV, Tajkhorshid E, Park S, Klauda JB, Im W. CHARMM-GUI HMMM Builder for Membrane Simulations with the Highly Mobile Membrane-Mimetic Model. Biophys J 2016; 109:2012-22. [PMID: 26588561 DOI: 10.1016/j.bpj.2015.10.008] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 10/06/2015] [Accepted: 10/09/2015] [Indexed: 12/12/2022] Open
Abstract
Slow diffusion of the lipids in conventional all-atom simulations of membrane systems makes it difficult to sample large rearrangements of lipids and protein-lipid interactions. Recently, Tajkhorshid and co-workers developed the highly mobile membrane-mimetic (HMMM) model with accelerated lipid motion by replacing the lipid tails with small organic molecules. The HMMM model provides accelerated lipid diffusion by one to two orders of magnitude, and is particularly useful in studying membrane-protein associations. However, building an HMMM simulation system is not easy, as it requires sophisticated treatment of the lipid tails. In this study, we have developed CHARMM-GUI HMMM Builder (http://www.charmm-gui.org/input/hmmm) to provide users with ready-to-go input files for simulating HMMM membrane systems with/without proteins. Various lipid-only and protein-lipid systems are simulated to validate the qualities of the systems generated by HMMM Builder with focus on the basic properties and advantages of the HMMM model. HMMM Builder supports all lipid types available in CHARMM-GUI and also provides a module to convert back and forth between an HMMM membrane and a full-length membrane. We expect HMMM Builder to be a useful tool in studying membrane systems with enhanced lipid diffusion.
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Affiliation(s)
- Yifei Qi
- Department of Molecular Biosciences and Center for Computational Biology, The University of Kansas, Lawrence, Kansas
| | - Xi Cheng
- Department of Molecular Biosciences and Center for Computational Biology, The University of Kansas, Lawrence, Kansas
| | - Jumin Lee
- Department of Molecular Biosciences and Center for Computational Biology, The University of Kansas, Lawrence, Kansas
| | - Josh V Vermaas
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois; Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Taras V Pogorelov
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois; School of Chemical Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois; National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, Illinois; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Emad Tajkhorshid
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois; Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Soohyung Park
- Department of Molecular Biosciences and Center for Computational Biology, The University of Kansas, Lawrence, Kansas
| | - Jeffery B Klauda
- Department of Chemical and Biomolecular Engineering and the Biophysics Program, The University of Maryland, College Park, Maryland
| | - Wonpil Im
- Department of Molecular Biosciences and Center for Computational Biology, The University of Kansas, Lawrence, Kansas.
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47
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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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48
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Buchoux S. FATSLiM: a fast and robust software to analyze MD simulations of membranes. Bioinformatics 2016; 33:133-134. [DOI: 10.1093/bioinformatics/btw563] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 08/19/2016] [Accepted: 08/25/2016] [Indexed: 11/14/2022] Open
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49
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Landreh M, Marty MT, Gault J, Robinson CV. A sliding selectivity scale for lipid binding to membrane proteins. Curr Opin Struct Biol 2016; 39:54-60. [PMID: 27155089 PMCID: PMC5287393 DOI: 10.1016/j.sbi.2016.04.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 03/11/2016] [Accepted: 04/20/2016] [Indexed: 01/24/2023]
Abstract
Biological membranes form barriers that are essential for cellular integrity and compartmentalisation. Proteins in the membrane have co-evolved with their hydrophobic lipid environment, which serves as a solvent for proteins with very diverse requirements. As a result, their interactions range from non-selective to highly discriminating. Mass spectrometry enables us to monitor how lipids interact with membrane proteins and assess their effects on structure and dynamics. Recent studies illustrate the ability to differentiate specific lipid binding, preferential interactions with lipid subsets, and nonselective annular contacts. Here, we consider the biological implications of different lipid-binding scenarios and propose that binding occurs on a sliding selectivity scale, in line with the view of biological membranes as facilitators of dynamic protein and lipid organization.
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Affiliation(s)
- Michael Landreh
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, Oxfordshire, OX1 3QZ, United Kingdom
| | - Michael T Marty
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, Oxfordshire, OX1 3QZ, United Kingdom
| | - Joseph Gault
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, Oxfordshire, OX1 3QZ, United Kingdom
| | - Carol V Robinson
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, Oxfordshire, OX1 3QZ, United Kingdom.
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50
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Im W, Liang J, Olson A, Zhou HX, Vajda S, Vakser IA. Challenges in structural approaches to cell modeling. J Mol Biol 2016; 428:2943-64. [PMID: 27255863 PMCID: PMC4976022 DOI: 10.1016/j.jmb.2016.05.024] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Revised: 05/19/2016] [Accepted: 05/24/2016] [Indexed: 11/17/2022]
Abstract
Computational modeling is essential for structural characterization of biomolecular mechanisms across the broad spectrum of scales. Adequate understanding of biomolecular mechanisms inherently involves our ability to model them. Structural modeling of individual biomolecules and their interactions has been rapidly progressing. However, in terms of the broader picture, the focus is shifting toward larger systems, up to the level of a cell. Such modeling involves a more dynamic and realistic representation of the interactomes in vivo, in a crowded cellular environment, as well as membranes and membrane proteins, and other cellular components. Structural modeling of a cell complements computational approaches to cellular mechanisms based on differential equations, graph models, and other techniques to model biological networks, imaging data, etc. Structural modeling along with other computational and experimental approaches will provide a fundamental understanding of life at the molecular level and lead to important applications to biology and medicine. A cross section of diverse approaches presented in this review illustrates the developing shift from the structural modeling of individual molecules to that of cell biology. Studies in several related areas are covered: biological networks; automated construction of three-dimensional cell models using experimental data; modeling of protein complexes; prediction of non-specific and transient protein interactions; thermodynamic and kinetic effects of crowding; cellular membrane modeling; and modeling of chromosomes. The review presents an expert opinion on the current state-of-the-art in these various aspects of structural modeling in cellular biology, and the prospects of future developments in this emerging field.
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Affiliation(s)
- Wonpil Im
- Center for Computational Biology and Department of Molecular Biosciences, The University of Kansas, Lawrence, KS 66047, United States.
| | - Jie Liang
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, United States.
| | - Arthur Olson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, United States.
| | - Huan-Xiang Zhou
- Department of Physics and Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, United States.
| | - Sandor Vajda
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, United States.
| | - Ilya A Vakser
- Center for Computational Biology and Department of Molecular Biosciences, The University of Kansas, Lawrence, KS 66047, United States.
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