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Bartoš L, Drabinová M, Vácha R. Optimizing properties of translocation-enhancing transmembrane proteins. Biophys J 2024; 123:1240-1252. [PMID: 38615194 PMCID: PMC11140465 DOI: 10.1016/j.bpj.2024.04.009] [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: 01/07/2024] [Revised: 03/31/2024] [Accepted: 04/09/2024] [Indexed: 04/15/2024] Open
Abstract
Cell membranes act as semi-permeable barriers, often restricting the entry of large or hydrophilic molecules. Nonetheless, certain amphiphilic molecules, such as antimicrobial and cell-penetrating peptides, can cross these barriers. In this study, we demonstrate that specific properties of transmembrane proteins/peptides can enhance membrane permeation of amphiphilic peptides. Using coarse-grained molecular dynamics with free-energy calculations, we identify key translocation-enhancing attributes of transmembrane proteins/peptides: a continuous hydrophilic patch, charged residues preferably in the membrane center, and aromatic hydrophobic residues. By employing both coarse-grained and atomistic simulations, complemented by experimental validation, we show that these properties not only enhance peptide translocation but also speed up lipid flip-flop. The enhanced flip-flop reinforces the idea that proteins such as scramblases and insertases not only share structural features but also operate through identical biophysical mechanisms enhancing the insertion and translocation of amphiphilic molecules. Our insights offer guidelines for the designing of translocation-enhancing proteins/peptides that could be used in medical and biotechnological applications.
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Affiliation(s)
- Ladislav Bartoš
- CEITEC - Central European Institute of Technology, Masaryk University, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Martina Drabinová
- CEITEC - Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Robert Vácha
- CEITEC - Central European Institute of Technology, Masaryk University, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic; Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Brno, Czech Republic.
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2
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Wilson MA, Pohorille A. Structure and Computational Electrophysiology of Ac-LS3, a Synthetic Ion Channel. J Phys Chem B 2022; 126:8985-8999. [PMID: 36306164 DOI: 10.1021/acs.jpcb.2c05965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Computer simulations are reported on Ac-LS3, a synthetic ion channel, containing 21 residues with a Leu-Ser-Ser-Leu-Leu-Ser-Leu heptad repeat, which forms ions channels upon application of voltage. A hexameric, coiled-coil bundle initially positioned perpendicular to the membrane settled into a stable, tilted structure after 1.5 μs, most likely to improve contacts between the non-polar exterior of the channel and the hydrophobic core of the membrane. Once tilted, the bundle remained in this state during subsequent simulations of nearly 10 μs at voltages ranging from 200 to -100 mV. In contrast, attempts to identify a stable pentameric structure failed, thus supporting the hypothesis that the channel is a hexamer. Results at 100 mV were used to reconstruct the free energy profiles for K+ and Cl- in the channel. This was done by way of several methods in which results of molecular dynamics (MD) simulations were combined with the electrodiffusion model. Two of them developed recently do not require knowledge of the diffusivity. Instead, they utilize one-sided density profiles and committor probabilities. The consistency between different methods is very good, supporting the utility of the newly developed methods for reconstructing free energies of ions in channels. The flux of K+, which accounts for most of the current through the channel, calculated directly from MD matches well the total measured current. However, the current of Cl- is somewhat overestimated, possibly due to a slightly unbalanced force field involving chloride. The current-voltage dependence was also reconstructed by way of a recently developed, efficient method that requires simulations only at a single voltage, yielding good agreement with the experiment. Taken together, the results demonstrate that computational electrophysiology has become a reliable tool for studying how channels mediate ion transport through membranes.
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Affiliation(s)
- Michael A Wilson
- Exobiology Branch, MS239-4, NASA Ames Research Center, Moffett Field, California94035, United States.,SETI Institute, 189 Bernardo Avenue, Suite 200, Mountain View, California94043, United States
| | - Andrew Pohorille
- Exobiology Branch, MS239-4, NASA Ames Research Center, Moffett Field, California94033, United States.,Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California94132, United States
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3
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Modeling Adsorption, Conformation, and Orientation of the Fis1 Tail Anchor at the Mitochondrial Outer Membrane. MEMBRANES 2022; 12:membranes12080752. [PMID: 36005667 PMCID: PMC9413518 DOI: 10.3390/membranes12080752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 07/28/2022] [Accepted: 07/28/2022] [Indexed: 12/04/2022]
Abstract
Proteins can be targeted to organellar membranes by using a tail anchor (TA), a stretch of hydrophobic amino acids found at the polypeptide carboxyl-terminus. The Fis1 protein (Fis1p), which promotes mitochondrial and peroxisomal division in the yeast Saccharomyces cerevisiae, is targeted to those organelles by its TA. Substantial evidence suggests that Fis1p insertion into the mitochondrial outer membrane can occur without the need for a translocation machinery. However, recent findings raise the possibility that Fis1p insertion into mitochondria might be promoted by a proteinaceous complex. Here, we have performed atomistic and coarse-grained molecular dynamics simulations to analyze the adsorption, conformation, and orientation of the Fis1(TA). Our results support stable insertion at the mitochondrial outer membrane in a monotopic, rather than a bitopic (transmembrane), configuration. Once inserted in the monotopic orientation, unassisted transition to the bitopic orientation is expected to be blocked by the highly charged nature of the TA carboxyl-terminus and by the Fis1p cytosolic domain. Our results are consistent with a model in which Fis1p does not require a translocation machinery for insertion at mitochondria.
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4
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Gupta S, Mandal T. Simulation study of domain formation in a model bacterial membrane. Phys Chem Chem Phys 2022; 24:18133-18143. [PMID: 35856570 DOI: 10.1039/d2cp01873j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent experimental studies revealed that functional membrane microdomains (FMMs) are formed in prokaryotic cells which are structurally and functionally similar to the lipid rafts formed in eukaryotic cells. In this study, we employ coarse-grained molecular dynamics simulations to investigate the mechanism of domain formation and its physiochemical properties in a model methicillin-resistant staphylococcus aureus (MRSA) cell membrane. We find that domains are formed through lateral segregation of staphyloxanthin (STX), a carotenoid which shields the bacteria from the host's immune because of its antioxidant nature. Simulation results suggest that membrane integrity increases with the size of the domain, which is assessed by computing bond order parameter of the lipid tails, membrane expansion modulus and water permeability across the membrane. Various membrane domain proteins such as flotillin-like protein floA and penicillin binding protein (PBP2a) preferentially bind with the STX and accumulate in the membrane domain which is consistent with the recent experimental results.
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Affiliation(s)
- Shivam Gupta
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Taraknath Mandal
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur-208016, India.
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5
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Patra P, Banerjee R, Chakrabarti J. Effect of biphosphate salt on dipalmitoylphosphatidylcholine bilayer deformation by Tat polypeptide. Biopolymers 2022; 113:e23518. [PMID: 35621373 DOI: 10.1002/bip.23518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 05/12/2022] [Accepted: 05/13/2022] [Indexed: 11/06/2022]
Abstract
Translocation of positively charged cell penetrating peptides (CPP) through cell membrane is important in drug delivery. Here we report all-atom molecular dynamics simulations to investigate how a biphosphate salt in a solvent affects the interaction of a CPP, HIV-1 Tat peptide with model dipalmitoylphosphatidylcholine (DPPC) lipid bilayer. Tat peptide has a large number of basic arginines and a couple of polar glutamines. We observe that in absence of salt, the basic residues of the polypeptide get localized in the vicinity of the membrane without altering the bilayer properties much; polypeptide induce local thinning of the bilayer membrane at the area of localization. In presence of biphosphate salt, the basic residues, dressed by the biphosphate ions, are repelled by the phosphate head groups of the lipid molecules. However, polar glutamine prefers to stay in the vicinity of the bilayer. This leads to larger local bilayer thickness at the contact point by the polar residue and non-uniform bilayer thickness profile. The thickness deformation of bilayer structure disappears upon mutating the polar residue, suggesting importance of the polar residue in bilayer deformation. Our studies point to control bilayer deformation by appropriate peptide sequence and solvent conditions.
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Affiliation(s)
- Piya Patra
- Maulana Abul Kalam Azad University of Technology, West Bengal, Haringhata, Nadia, West Bengal, India
| | - Raja Banerjee
- Maulana Abul Kalam Azad University of Technology, West Bengal, Haringhata, Nadia, West Bengal, India
| | - Jaydeb Chakrabarti
- Department of Chemical, Biological and Macro-Molecular Sciences, Thematic Unit of Excellence on Computational Materials Science and Technical Research Centre, S. N. Bose National Centre for Basic Sciences, Salt Lake, Kolkata, West Bengal, India
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6
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Cholesterol plays a decisive role in tetraspanin assemblies during bilayer deformations. Biosystems 2021; 209:104505. [PMID: 34403719 DOI: 10.1016/j.biosystems.2021.104505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 07/30/2021] [Accepted: 08/07/2021] [Indexed: 11/22/2022]
Abstract
The tetraspanin family plays key roles in many physiological processes, such as, tumour invasion, cell motility, virus infection, cell attachment and entry. Tetraspanins function as molecular scaffolds organized in microdomains with interesting downstream cellular consequences. However, despite their relevance in human physiology, the precise mechanisms of their various functions remain elusive. In particular, the full-length CD81 tetraspanin has interesting cholesterol-related properties that modulate its activity in cells. In this work, we study the opening transition of CD81 under different conditions. We propose that such conformational change is a collaborative process enhanced by simultaneous interactions between multiple identical CD81 tetraspanins. With molecular dynamics simulations we describe the crucial role of a ternary lipid bilayer with cholesterol in CD81 conformational dynamics, observing two emergent properties: first, clusters of CD81 collectively segregate one tetraspanin while favouring one opening transition, second, cumulative cholesterol sequestering by CD81 tetraspanins inhibits large membrane deformations due to local density variations.
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7
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Li Y, Tang H, Andrikopoulos N, Javed I, Cecchetto L, Nandakumar A, Kakinen A, Davis TP, Ding F, Ke PC. The membrane axis of Alzheimer's nanomedicine. ADVANCED NANOBIOMED RESEARCH 2021; 1:2000040. [PMID: 33748816 PMCID: PMC7971452 DOI: 10.1002/anbr.202000040] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Alzheimer's disease (AD) is a major neurological disorder impairing its carrier's cognitive function, memory and lifespan. While the development of AD nanomedicine is still nascent, the field is evolving into a new scientific frontier driven by the diverse physicochemical properties and theranostic potential of nanomaterials and nanocomposites. Characteristic to the AD pathology is the deposition of amyloid plaques and tangles of amyloid beta (Aβ) and tau, whose aggregation kinetics may be curbed by nanoparticle inhibitors via sequence-specific targeting or nonspecific interactions with the amyloidogenic proteins. As literature implicates cell membrane as a culprit in AD pathogenesis, here we summarize the membrane axis of AD nanomedicine and present a new rationale that the field development may greatly benefit from harnessing our existing knowledge of Aβ-membrane interaction, nanoparticle-membrane interaction and Aβ-nanoparticle interaction.
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Affiliation(s)
- Yuhuan Li
- Zhongshan Hospital, Fudan University, 111 Yixueyuan Rd, Xuhui District, Shanghai, 200032, China
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Huayuan Tang
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, United States
| | - Nicholas Andrikopoulos
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Ibrahim Javed
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld 4072, Australia
| | - Luca Cecchetto
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
- Department of Chemical and Pharmaceutical Science, University of Trieste, Via Licio Giorgieri 1, 34127 Trieste, Italy
| | - Aparna Nandakumar
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Aleksandr Kakinen
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld 4072, Australia
| | - Thomas P. Davis
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld 4072, Australia
| | - Feng Ding
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, United States
| | - Pu Chun Ke
- Zhongshan Hospital, Fudan University, 111 Yixueyuan Rd, Xuhui District, Shanghai, 200032, China
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
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8
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Caparotta M, Tomes CN, Mayorga LS, Masone D. The Synaptotagmin-1 C2B Domain Is a Key Regulator in the Stabilization of the Fusion Pore. J Chem Theory Comput 2020; 16:7840-7851. [DOI: 10.1021/acs.jctc.0c00734] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Marcelo Caparotta
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo (UNCuyo), Mendoza 5500, Argentina
| | - Claudia N. Tomes
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo (UNCuyo), Mendoza 5500, Argentina
- Instituto de Histología y Embriología de Mendoza (IHEM) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Cuyo (UNCuyo), Mendoza 5500, Argentina
| | - Luis S. Mayorga
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo (UNCuyo), Mendoza 5500, Argentina
- Instituto de Histología y Embriología de Mendoza (IHEM) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Cuyo (UNCuyo), Mendoza 5500, Argentina
| | - Diego Masone
- Instituto de Histología y Embriología de Mendoza (IHEM) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Cuyo (UNCuyo), Mendoza 5500, Argentina
- Facultad de Ingeniería, Universidad Nacional de Cuyo (UNCuyo), Mendoza 5500, Argentina
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9
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Study of the Interaction of a Novel Semi-Synthetic Peptide with Model Lipid Membranes. MEMBRANES 2020; 10:membranes10100294. [PMID: 33086635 PMCID: PMC7603383 DOI: 10.3390/membranes10100294] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/14/2020] [Accepted: 10/16/2020] [Indexed: 12/31/2022]
Abstract
Most linear peptides directly interact with membranes, but the mechanisms of interaction are far from being completely understood. Here, we present an investigation of the membrane interactions of a designed peptide containing a non-natural, synthetic amino acid. We selected a nonapeptide that is reported to interact with phospholipid membranes, ALYLAIRKR, abbreviated as ALY. We designed a modified peptide (azoALY) by substituting the tyrosine residue of ALY with an antimicrobial azobenzene-bearing amino acid. Both of the peptides were examined for their ability to interact with model membranes, assessing the penetration of phospholipid monolayers, and leakage across the bilayer of large unilamellar vesicles (LUVs) and giant unilamellar vesicles (GUVs). The latter was performed in a microfluidic device in order to study the kinetics of leakage of entrapped calcein from the vesicles at the single vesicle level. Both types of vesicles were prepared from a 9:1 (mol/mol) mixture of POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) and POPG (1-palmitoyl-2-oleoyl-sn-glycero-3-phospho(1′-rac-glycerol). Calcein leakage from the vesicles was more pronounced at a low concentration in the case of azoALY than for ALY. Increased vesicle membrane disturbance in the presence of azoALY was also evident from an enzymatic assay with LUVs and entrapped horseradish peroxidase. Molecular dynamics simulations of ALY and azoALY in an anionic POPC/POPG model bilayer showed that ALY peptide only interacts with the lipid head groups. In contrast, azoALY penetrates the hydrophobic core of the bilayers causing a stronger membrane perturbation as compared to ALY, in qualitative agreement with the experimental results from the leakage assays.
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10
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Srinivasan S, Waghu FH, Idicula-Thomas S, Venkatesh KV. A steady-state modeling approach for simulation of antimicrobial peptide-cell membrane interaction. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183242. [DOI: 10.1016/j.bbamem.2020.183242] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 02/08/2020] [Accepted: 02/12/2020] [Indexed: 01/17/2023]
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11
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Caparotta M, Bustos DM, Masone D. Order–disorder skewness in alpha-synuclein: a key mechanism to recognize membrane curvature. Phys Chem Chem Phys 2020; 22:5255-5263. [DOI: 10.1039/c9cp04951g] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Currently, membrane curvature is understood as an active mechanism to control cells spatial organization and activity.
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Affiliation(s)
- Marcelo Caparotta
- Facultad de Ciencias Exactas y Naturales
- Universidad Nacional de Cuyo (UNCuyo)
- Mendoza
- Argentina
| | - Diego M. Bustos
- Facultad de Ciencias Exactas y Naturales
- Universidad Nacional de Cuyo (UNCuyo)
- Mendoza
- Argentina
- Instituto de Histología y Embriología de Mendoza (IHEM) – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
| | - Diego Masone
- Instituto de Histología y Embriología de Mendoza (IHEM) – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
- Universidad Nacional de Cuyo (UNCuyo)
- Mendoza
- Argentina
- Facultad de Ingeniería
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12
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Lien YH, Ram Mahato D, Hoppe-Seyler F, Fischer WB. Membrane partitioning of peptide aggregates: coarse-grained molecular dynamics simulations. J Biomol Struct Dyn 2019; 38:524-532. [PMID: 30774024 DOI: 10.1080/07391102.2019.1581660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Coarse-grained molecular dynamics (CGMD) simulation technique (MARTINI force field) is applied to monitor the aggregation of helical peptides representing the transmembrane sequence and its extension of bone marrow stromal cell antigen 2 (BST-2). One of the peptides is coupled with a protein transducing domain (PTD) of nine arginine residues (R9) at its N-terminal side as well as a peptide, pep11**, which has been shown to bind to human papilloma virus 16 (HPV16) E6 oncoprotein. A short hydrophobic stretch of the transmembrane domain (TMD) of BST-2 aggregates the fastest and inserts into a lipid membrane. An aggregate of R9-pep11** attaches to the membrane via simultaneous contact of many arginine residues. Monomers from the aggregates of the shortest of the hydrophobic TMDs dissolve into the opposing leaflet when the aggregate spans the bilayer. A 'flipping' of the individual monomeric peptides is not observed.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Yu-Hsien Lien
- Institute of Biophotonics, Biophotonics & Molecular Imaging Research Center (BMIRC), School of Biomedical Science and Engineering, National Yang-Ming University, Taipei, Taiwan
| | - Dhani Ram Mahato
- Institute of Biophotonics, Biophotonics & Molecular Imaging Research Center (BMIRC), School of Biomedical Science and Engineering, National Yang-Ming University, Taipei, Taiwan
| | | | - Wolfgang B Fischer
- Institute of Biophotonics, Biophotonics & Molecular Imaging Research Center (BMIRC), School of Biomedical Science and Engineering, National Yang-Ming University, Taipei, Taiwan
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13
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Masone D, Bustos DM. Transmembrane domain dimerization induces cholesterol rafts in curved lipid bilayers. Phys Chem Chem Phys 2019; 21:268-274. [DOI: 10.1039/c8cp06783j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Are the dimerization of transmembrane (TM) domains and the reorganization of the lipid bilayer two independent events?
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Affiliation(s)
- Diego Masone
- Instituto de Histología y Embriología de Mendoza (IHEM) – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
- Universidad Nacional de Cuyo (UNCuyo)
- Mendoza
- Argentina
- Facultad de Ingeniería
| | - Diego M. Bustos
- Instituto de Histología y Embriología de Mendoza (IHEM) – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
- Universidad Nacional de Cuyo (UNCuyo)
- Mendoza
- Argentina
- Facultad de Ciencias Exactas y Naturales
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14
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Ulmschneider JP, Smith JC, White SH, Ulmschneider MB. The importance of the membrane interface as the reference state for membrane protein stability. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2539-2548. [PMID: 30293965 DOI: 10.1016/j.bbamem.2018.09.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 09/14/2018] [Accepted: 09/16/2018] [Indexed: 11/26/2022]
Abstract
The insertion of nascent polypeptide chains into lipid bilayer membranes and the stability of membrane proteins crucially depend on the equilibrium partitioning of polypeptides. For this, the transfer of full sequences of amino-acid residues into the bilayer, rather than individual amino acids, must be understood. Earlier studies have revealed that the most likely reference state for partitioning very hydrophobic sequences is the membrane interface. We have used μs-scale simulations to calculate the interface-to-transmembrane partitioning free energies ΔGS→TM for two hydrophobic carrier sequences in order to estimate the insertion free energy for all 20 amino acid residues when bonded to the center of a partitioning hydrophobic peptide. Our results show that prior single-residue scales likely overestimate the partitioning free energies of polypeptides. The correlation of ΔGS→TM with experimental full-peptide translocon insertion data is high, suggesting an important role for the membrane interface in translocon-based insertion. The choice of carrier sequence greatly modulates the contribution of each single-residue mutation to the overall partitioning free energy. Our results demonstrate the importance of quantifying the observed full-peptide partitioning equilibrium, which is between membrane interface and transmembrane inserted, rather than combining individual water-to-membrane amino acid transfer free energies.
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Affiliation(s)
- Jakob P Ulmschneider
- School of Physics and Astronomy and the Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai, China.
| | - Jeremy C Smith
- Center for Molecular Biophysics, Oak Ridge National Laboratory, Oak Ridge, TN, USA; Department of Biochemistry & Cellular Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | - Stephen H White
- Department of Physiology & Biophysics, University of California at Irvine, Irvine, CA, USA
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15
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Hills RD. Refining amino acid hydrophobicity for dynamics simulation of membrane proteins. PeerJ 2018; 6:e4230. [PMID: 29340240 PMCID: PMC5767086 DOI: 10.7717/peerj.4230] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 12/14/2017] [Indexed: 11/20/2022] Open
Abstract
Coarse-grained (CG) models have been successful in simulating the chemical properties of lipid bilayers, but accurate treatment of membrane proteins and lipid-protein molecular interactions remains a challenge. The CgProt force field, original developed with the multiscale coarse graining method, is assessed by comparing the potentials of mean force for sidechain insertion in a DOPC bilayer to results reported for atomistic molecular dynamics simulations. Reassignment of select CG sidechain sites from the apolar to polar site type was found to improve the attractive interfacial behavior of tyrosine, phenylalanine and asparagine as well as charged lysine and arginine residues. The solvation energy at membrane depths of 0, 1.3 and 1.7 nm correlates with experimental partition coefficients in aqueous mixtures of cyclohexane, octanol and POPC, respectively, for sidechain analogs and Wimley-White peptides. These experimental values serve as important anchor points in choosing between alternate CG models based on their observed permeation profiles, particularly for Arg, Lys and Gln residues where the all-atom OPLS solvation energy does not agree well with experiment. Available partitioning data was also used to reparameterize the representation of the peptide backbone, which needed to be made less attractive for the bilayer hydrophobic core region. The newly developed force field, CgProt 2.4, correctly predicts the global energy minimum in the potentials of mean force for insertion of the uncharged membrane-associated peptides LS3 and WALP23. CgProt will find application in studies of lipid-protein interactions and the conformational properties of diverse membrane protein systems.
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Affiliation(s)
- Ronald D Hills
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New England, Portland, ME, United States of America
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16
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Sahoo BR, Fujiwara T. Conformational states of HAMP domains interacting with sensory rhodopsin membrane systems: an integrated all-atom and coarse-grained molecular dynamics simulation approach. MOLECULAR BIOSYSTEMS 2017; 13:193-207. [PMID: 27901172 DOI: 10.1039/c6mb00730a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Understanding the downstream signaling mechanism of sensory rhodopsin and its cognate transducer complex (srII-htrII) has long been a challenge in the field of photoreceptor research. Here, an integration of all-atom and coarse-grained (CG) molecular dynamics (MD) simulations in different srII-htrII complex states is carried out. It is shown that the cytoplasmic four-helix HAMP dimer gives rise to a gear-box model interaction with discrete hydrophobic packing in Natronomonas pharaonis (Np). Structural analysis in all-atom and CG-MD reveals a stable conformational state in the physiological environment (323 K and 1.15 M salt). Comparative analysis in the ground and intermediate state conformations reveals substantial inter-HAMP interactions in the intermediate state with uniform clockwise (+10° to +30°) and counterclockwise (-20° to -40°) rotations in the α1 helix and the α2 helix of the monomer, respectively. Low temperature and low salt environments (283 K and 0.15 M) significantly affect srII-htrII binding affinity in both states with unusual helix bending. The distinguished control cable, knob-into-holes packing and piston-like movements in HAMP helices are found in the intermediate state complex. The N-terminal htrII (159 residues) coupled with srII yields a binding energy (ΔGbind) of -309.22, -436.53 and -331.11 kJ mol-1 in the MM/PBSA calculation for the NphtrII homodimer, the NpsrII-htrII ground state conformation and the NpsrII-htrII intermediate state conformation, respectively. Only the HAMP1 domain shows a very low ΔGbind value (-21.03 kJ mol-1) for the ground state in comparison to that for the intermediate state (-54.68 kJ mol-1). The structural analysis highlights the key residues that include Y199srII, T189srII, E43htrII, T86htrII, M100htrII, E116htrII, E126htrII and S130htrII for complex stabilization and signal transduction.
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Affiliation(s)
- Bikash Ranjan Sahoo
- Laboratory of Molecular Biophysics, Institute for Protein Research, Osaka University, 5650871, Japan.
| | - Toshimichi Fujiwara
- Laboratory of Molecular Biophysics, Institute for Protein Research, Osaka University, 5650871, Japan.
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17
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Fosso-Tande J, Black C, G. Aller S, Lu L, D. Hills Jr R. Simulation of lipid-protein interactions with the CgProt force field. AIMS MOLECULAR SCIENCE 2017. [DOI: 10.3934/molsci.2017.3.352] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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18
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Pulawski W, Jamroz M, Kolinski M, Kolinski A, Kmiecik S. Coarse-Grained Simulations of Membrane Insertion and Folding of Small Helical Proteins Using the CABS Model. J Chem Inf Model 2016; 56:2207-2215. [PMID: 27775349 DOI: 10.1021/acs.jcim.6b00350] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The CABS coarse-grained model is a well-established tool for modeling globular proteins (predicting their structure, dynamics, and interactions). Here we introduce an extension of the CABS representation and force field (CABS-membrane) to the modeling of the effect of the biological membrane environment on the structure of membrane proteins. We validate the CABS-membrane model in folding simulations of 10 short helical membrane proteins not using any knowledge about their structure. The simulations start from random protein conformations placed outside the membrane environment and allow for full flexibility of the modeled proteins during their spontaneous insertion into the membrane. In the resulting trajectories, we have found models close to the experimental membrane structures. We also attempted to select the correctly folded models using simple filtering followed by structural clustering combined with reconstruction to the all-atom representation and all-atom scoring. The CABS-membrane model is a promising approach for further development toward modeling of large protein-membrane systems.
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Affiliation(s)
- Wojciech Pulawski
- Faculty of Chemistry, University of Warsaw , Pasteura 1, 02-093 Warsaw, Poland
| | - Michal Jamroz
- Faculty of Chemistry, University of Warsaw , Pasteura 1, 02-093 Warsaw, Poland
| | - Michal Kolinski
- Bioinformatics Laboratory, Mossakowski Medical Research Center of the Polish Academy of Sciences , Pawinskiego 5, 02-106 Warsaw, Poland
| | - Andrzej Kolinski
- Faculty of Chemistry, University of Warsaw , Pasteura 1, 02-093 Warsaw, Poland
| | - Sebastian Kmiecik
- Faculty of Chemistry, University of Warsaw , Pasteura 1, 02-093 Warsaw, Poland
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19
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Lee LF, Mariappan V, Vellasamy KM, Lee VS, Vadivelu J. Antimicrobial activity of Tachyplesin 1 against Burkholderia pseudomallei: an in vitro and in silico approach. PeerJ 2016; 4:e2468. [PMID: 27812400 PMCID: PMC5088614 DOI: 10.7717/peerj.2468] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 08/21/2016] [Indexed: 11/20/2022] Open
Abstract
Burkholderia pseudomallei, the causative agent of melioidosis, is intrinsically resistant to many conventional antibiotics. Therefore, alternative antimicrobial agents such as antimicrobial peptides (AMPs) are extensively studied to combat this issue. Our study aims to identify and understand the mode of action of the potential AMP(s) that are effective against B. pseudomallei in both planktonic and biofilm state as well as to predict the possible binding targets on using in vitro and in silico approaches. In the in vitro study, 11 AMPs were tested against 100 B. pseudomallei isolates for planktonic cell susceptibility, where LL-37, and PG1, demonstrated 100.0% susceptibility and TP1 demonstrated 83% susceptibility. Since the B. pseudomallei activity was reported on LL-37 and PG1, TP1 was selected for further investigation. TP1 inhibited B. pseudomallei cells at 61.69 μM, and membrane blebbing was observed using scanning electron microscopy. Moreover, TP1 inhibited B. pseudomallei cell growth, reaching bactericidal endpoint within 2 h post exposure as compared to ceftazidime (CAZ) (8 h). Furthermore, TP1 was shown to suppress the growth of B. pseudomallei cells in biofilm state at concentrations above 221 μM. However, TP1 was cytotoxic to the mammalian cell lines tested. In the in silico study, molecular docking revealed that TP1 demonstrated a strong interaction to the common peptide or inhibitor binding targets for lipopolysaccharide of Escherichia coli, as well as autolysin, pneumolysin, and pneumococcal surface protein A (PspA) of Streptococcus pneumoniae. Homology modelled B. pseudomallei PspA protein (YDP) also showed a favourable binding with a strong electrostatic contribution and nine hydrogen bonds. In conclusion, TP1 demonstrated a good potential as an anti-B. pseudomallei agent.
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Affiliation(s)
- Lyn-Fay Lee
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya , Kuala Lumpur , Malaysia
| | - Vanitha Mariappan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya , Kuala Lumpur , Malaysia
| | - Kumutha Malar Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya , Kuala Lumpur , Malaysia
| | - Vannajan Sanghiran Lee
- Department of Chemistry, Faculty of Science, University of Malaya , Kuala Lumpur , Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya , Kuala Lumpur , Malaysia
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20
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Bereau T, Bennett WFD, Pfaendtner J, Deserno M, Karttunen M. Folding and insertion thermodynamics of the transmembrane WALP peptide. J Chem Phys 2016; 143:243127. [PMID: 26723612 DOI: 10.1063/1.4935487] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The anchor of most integral membrane proteins consists of one or several helices spanning the lipid bilayer. The WALP peptide, GWW(LA)n (L)WWA, is a common model helix to study the fundamentals of protein insertion and folding, as well as helix-helix association in the membrane. Its structural properties have been illuminated in a large number of experimental and simulation studies. In this combined coarse-grained and atomistic simulation study, we probe the thermodynamics of a single WALP peptide, focusing on both the insertion across the water-membrane interface, as well as folding in both water and a membrane. The potential of mean force characterizing the peptide's insertion into the membrane shows qualitatively similar behavior across peptides and three force fields. However, the Martini force field exhibits a pronounced secondary minimum for an adsorbed interfacial state, which may even become the global minimum-in contrast to both atomistic simulations and the alternative PLUM force field. Even though the two coarse-grained models reproduce the free energy of insertion of individual amino acids side chains, they both underestimate its corresponding value for the full peptide (as compared with atomistic simulations), hinting at cooperative physics beyond the residue level. Folding of WALP in the two environments indicates the helix as the most stable structure, though with different relative stabilities and chain-length dependence.
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Affiliation(s)
- Tristan Bereau
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - W F Drew Bennett
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Jim Pfaendtner
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98195, USA
| | - Markus Deserno
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Mikko Karttunen
- Department of Mathematics and Computer Science & Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, MetaForum, 5600 MB Eindhoven, The Netherlands
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21
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Kmiecik S, Gront D, Kolinski M, Wieteska L, Dawid AE, Kolinski A. Coarse-Grained Protein Models and Their Applications. Chem Rev 2016; 116:7898-936. [DOI: 10.1021/acs.chemrev.6b00163] [Citation(s) in RCA: 555] [Impact Index Per Article: 69.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Sebastian Kmiecik
- Faculty
of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Dominik Gront
- Faculty
of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Michal Kolinski
- Bioinformatics
Laboratory, Mossakowski Medical Research Center of the Polish Academy of Sciences, Pawinskiego 5, 02-106 Warsaw, Poland
| | - Lukasz Wieteska
- Faculty
of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
- Department
of Medical Biochemistry, Medical University of Lodz, Mazowiecka 6/8, 92-215 Lodz, Poland
| | | | - Andrzej Kolinski
- Faculty
of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
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22
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Affiliation(s)
- Iwona Siuda
- Department of Biological
Sciences and Centre for Molecular Simulation, University of Calgary, 2500 University Drive North West, Calgary, Alberta T2N 1N4, Canada
| | - D. Peter Tieleman
- Department of Biological
Sciences and Centre for Molecular Simulation, University of Calgary, 2500 University Drive North West, Calgary, Alberta T2N 1N4, Canada
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23
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Molecular dynamics methods to predict peptide locations in membranes: LAH4 as a stringent test case. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:581-92. [DOI: 10.1016/j.bbamem.2014.11.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 10/22/2014] [Accepted: 11/05/2014] [Indexed: 01/07/2023]
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24
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Exploring the dynamics and interaction of a full ErbB2 receptor and Trastuzumab-Fab antibody in a lipid bilayer model using Martini coarse-grained force field. J Comput Aided Mol Des 2014; 28:1093-107. [DOI: 10.1007/s10822-014-9787-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 08/07/2014] [Indexed: 02/01/2023]
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25
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Wells SA, Crennell SJ, Danson MJ. Structures of mesophilic and extremophilic citrate synthases reveal rigidity and flexibility for function. Proteins 2014; 82:2657-70. [PMID: 24948467 DOI: 10.1002/prot.24630] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Revised: 05/23/2014] [Accepted: 06/11/2014] [Indexed: 11/07/2022]
Abstract
Citrate synthase (CS) catalyses the entry of carbon into the citric acid cycle and is highly-conserved structurally across the tree of life. Crystal structures of dimeric CSs are known in both "open" and "closed" forms, which differ by a substantial domain motion that closes the substrate-binding clefts. We explore both the static rigidity and the dynamic flexibility of CS structures from mesophilic and extremophilic organisms from all three evolutionary domains. The computational expense of this wide-ranging exploration is kept to a minimum by the use of rigidity analysis and rapid all-atom simulations of flexible motion, combining geometric simulation and elastic network modeling. CS structures from thermophiles display increased structural rigidity compared with the mesophilic enzyme. A CS structure from a psychrophile, stabilized by strong ionic interactions, appears to display likewise increased rigidity in conventional rigidity analysis; however, a novel modified analysis, taking into account the weakening of the hydrophobic effect at low temperatures, shows a more appropriate decreased rigidity. These rigidity variations do not, however, affect the character of the flexible dynamics, which are well conserved across all the structures studied. Simulation trajectories not only duplicate the crystallographically observed symmetric open-to-closed transitions, but also identify motions describing a previously unidentified antisymmetric functional motion. This antisymmetric motion would not be directly observed in crystallography but is revealed as an intrinsic property of the CS structure by modeling of flexible motion. This suggests that the functional motion closing the binding clefts in CS may be independent rather than symmetric and cooperative.
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Affiliation(s)
- Stephen A Wells
- Department of Chemistry/Department of Physics, University of Bath, BATH, BA2 7AY, United Kingdom
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26
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Aci-Sèche S, Sawma P, Hubert P, Sturgis JN, Bagnard D, Jacob L, Genest M, Garnier N. Transmembrane recognition of the semaphorin co-receptors neuropilin 1 and plexin A1: coarse-grained simulations. PLoS One 2014; 9:e97779. [PMID: 24858828 PMCID: PMC4032258 DOI: 10.1371/journal.pone.0097779] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 04/23/2014] [Indexed: 12/13/2022] Open
Abstract
The cancer associated class 3 semaphorins require direct binding to neuropilins and association to plexins to trigger cell signaling. Here, we address the role of the transmembrane domains of neuropilin 1 and plexin A1 for the dimerization of the two receptors by characterizing the assembly in lipid bilayers using coarse-grained molecular dynamics simulations. From experimental evidence using a two-hybrid system showing the biochemical association of the two receptors transmembrane domains, we performed molecular simulations in DOPC and POPC demonstrating spontaneously assembly to form homodimers and heterodimers with a very high propensity for right-handed packing of the helices. Inversely, left-handed packing was observed with a very low propensity. This mode of packing was observed uniquely when the plexin A1 transmembrane domain was involved in association. Potential of mean force calculations were used to predict a hierarchy of self-association for the monomers: the two neuropilin 1 transmembrane domains strongly associated, neuropilin 1 and plexin A1 transmembrane domains associated less and the two plexin A1 transmembrane domains weakly but significantly associated. We demonstrated that homodimerization and heterodimerization are driven by GxxxG motifs, and that the sequence context modulates the packing mode of the plexin A1 transmembrane domains. This work presents major advances towards our understanding of membrane signaling platforms assembly through membrane domains and provides exquisite information for the design of antagonist drugs defining a novel class of therapeutic agents.
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Affiliation(s)
- Samia Aci-Sèche
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR, Université d’Orléans, Orléans, France
| | - Paul Sawma
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires UMR, Université d’Aix-Marseille, Marseille, France
| | - Pierre Hubert
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires UMR, Université d’Aix-Marseille, Marseille, France
| | - James N. Sturgis
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires UMR, Université d’Aix-Marseille, Marseille, France
| | - Dominique Bagnard
- Institut National de la Santé et de la Recherche Médicale, Labex Medalis, Université de Strasbourg, Strasbourg, France
| | - Laurent Jacob
- Institut National de la Santé et de la Recherche Médicale, Labex Medalis, Université de Strasbourg, Strasbourg, France
| | - Monique Genest
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR, Université d’Orléans, Orléans, France
- * E-mail: (NG); (MG)
| | - Norbert Garnier
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR, Université d’Orléans, Orléans, France
- * E-mail: (NG); (MG)
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27
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Morriss-Andrews A, Brown FLH, Shea JE. A coarse-grained model for peptide aggregation on a membrane surface. J Phys Chem B 2014; 118:8420-32. [PMID: 24791936 DOI: 10.1021/jp502871m] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The aggregation of peptides on a lipid bilayer is studied using coarse-grained molecular dynamics in implicit solvent. Peptides bind to and self-assemble on the membrane surface into β-rich fibrillar aggregates, even under conditions where only disordered oligomers form in bulk solution. Relative to a solid surface, the membrane surface facilitates peptide mobility and a more complex network of morphology transitions as aggregation proceeds. Additionally, final aggregate structures realized on the membrane surface are distinct from those observed on a comparable solid surface. The aggregated fibrils alter the local structure and material properties of the lipid bilayer in their immediate vicinity but have only a modest effect on the overall bending rigidity of the bilayer.
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Affiliation(s)
- Alex Morriss-Andrews
- Department of Physics, University of California Santa Barbara , Santa Barbara, California 93106, United States
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28
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Hall BA, Halim KA, Buyan A, Emmanouil B, Sansom MSP. Sidekick for Membrane Simulations: Automated Ensemble Molecular Dynamics Simulations of Transmembrane Helices. J Chem Theory Comput 2014; 10:2165-75. [PMID: 26580541 PMCID: PMC4871227 DOI: 10.1021/ct500003g] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The interactions of transmembrane (TM) α-helices with the phospholipid membrane and with one another are central to understanding the structure and stability of integral membrane proteins. These interactions may be analyzed via coarse grained molecular dynamics (CGMD) simulations. To obtain statistically meaningful analysis of TM helix interactions, large (N ca. 100) ensembles of CGMD simulations are needed. To facilitate the running and analysis of such ensembles of simulations, we have developed Sidekick, an automated pipeline software for performing high throughput CGMD simulations of α-helical peptides in lipid bilayer membranes. Through an end-to-end approach, which takes as input a helix sequence and outputs analytical metrics derived from CGMD simulations, we are able to predict the orientation and likelihood of insertion into a lipid bilayer of a given helix of a family of helix sequences. We illustrate this software via analyses of insertion into a membrane of short hydrophobic TM helices containing a single cationic arginine residue positioned at different positions along the length of the helix. From analyses of these ensembles of simulations, we estimate apparent energy barriers to insertion which are comparable to experimentally determined values. In a second application, we use CGMD simulations to examine the self-assembly of dimers of TM helices from the ErbB1 receptor tyrosine kinase and analyze the numbers of simulation repeats necessary to obtain convergence of simple descriptors of the mode of packing of the two helices within a dimer. Our approach offers a proof-of-principle platform for the further employment of automation in large ensemble CGMD simulations of membrane proteins.
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Affiliation(s)
- Benjamin A Hall
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU
- current address: Microsoft Research Cambridge, 21 Station Road, Cambridge, CB1 2FB
| | - Khairul Abd Halim
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU
| | - Amanda Buyan
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU
| | - Beatrice Emmanouil
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU
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29
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Hills RD. Balancing bond, nonbond, and gō-like terms in coarse grain simulations of conformational dynamics. Methods Mol Biol 2014; 1084:123-140. [PMID: 24061919 DOI: 10.1007/978-1-62703-658-0_7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Characterization of the protein conformational landscape remains a challenging problem, whether it concerns elucidating folding mechanisms, predicting native structures or modeling functional transitions. Coarse-grained molecular dynamics simulation methods enable exhaustive sampling of the energetic landscape at resolutions of biological interest. The general utility of structure-based models is reviewed along with their differing levels of approximation. Simple Gō models incorporate attractive native interactions and repulsive nonnative contacts, resulting in an ideal smooth landscape. Non-Gō coarse-grained models reduce the parameter set as needed but do not include bias to any desired native structure. While non-Gō models have achieved limited success in protein coarse-graining, they can be combined with native structured-based potentials to create a balanced and powerful force field. Recent applications of such Gō-like models have yielded insight into complex folding mechanisms and conformational transitions in large macromolecules. The accuracy and usefulness of reduced representations are also revealed to be a function of the mathematical treatment of the intrinsic bonded topology.
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Affiliation(s)
- Ronald D Hills
- Department of Pharmaceutical Sciences, University of New England, Portland, ME, USA
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30
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Vicatos S, Rychkova A, Mukherjee S, Warshel A. An effective Coarse-grained model for biological simulations: Recent refinements and validations. Proteins 2013; 82:1168-85. [DOI: 10.1002/prot.24482] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Spyridon Vicatos
- Department of Chemistry; University of Southern California; Los Angeles California 90089-1062
| | - Anna Rychkova
- Department of Chemistry; University of Southern California; Los Angeles California 90089-1062
| | - Shayantani Mukherjee
- Department of Chemistry; University of Southern California; Los Angeles California 90089-1062
| | - Arieh Warshel
- Department of Chemistry; University of Southern California; Los Angeles California 90089-1062
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31
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Bacteriocin AS-48 binding to model membranes and pore formation as revealed by coarse-grained simulations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2524-31. [DOI: 10.1016/j.bbamem.2013.05.036] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2012] [Revised: 05/24/2013] [Accepted: 05/31/2013] [Indexed: 02/05/2023]
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32
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He Y, Lazaridis T. Activity determinants of helical antimicrobial peptides: a large-scale computational study. PLoS One 2013; 8:e66440. [PMID: 23776672 PMCID: PMC3680375 DOI: 10.1371/journal.pone.0066440] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 05/09/2013] [Indexed: 12/14/2022] Open
Abstract
Antimicrobial peptides (AMPs), produced by a wide range of organisms, have attracted attention due to their potential use as novel antibiotics. The majority of these peptides are cationic and are thought to function by permeabilizing the bacterial membrane, either by making pores or by dissolving it ('carpet' model). A key hypothesis in the literature is that antimicrobial and hemolytic activity correlate with binding affinity to anionic and zwitterionic membranes, respectively. Here we test this hypothesis by using binding free energy data collected from the literature and theoretical binding energies calculated from implicit membrane models for 53 helical AMPs. We indeed find a correlation between binding energy and biological activity, depending on membrane anionic content: antibacterial activity correlates best with transfer energy to membranes with anionic lipid fraction higher than 30% and hemolytic activity correlates best with transfer energy to a 10% anionic membrane. However, the correlations are weak, with correlation coefficient up to 0.4. Weak correlations of the biological activities have also been found with other physical descriptors of the peptides, such as surface area occupation, which correlates significantly with antibacterial activity; insertion depth, which correlates significantly with hemolytic activity; and structural fluctuation, which correlates significantly with both activities. The membrane surface coverage by many peptides at the MIC is estimated to be much lower than would be required for the 'carpet' mechanism. Those peptides that are active at low surface coverage tend to be those identified in the literature as pore-forming. The transfer energy from planar membrane to cylindrical and toroidal pores was also calculated for these peptides. The transfer energy to toroidal pores is negative in almost all cases while that to cylindrical pores is more favorable in neutral than in anionic membranes. The transfer energy to pores correlates with the deviation from predictions of the 'carpet' model.
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Affiliation(s)
- Yi He
- Department of Chemistry, City College of New York, New York, New York, United States of America
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33
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Lindau M, Hall BA, Chetwynd A, Beckstein O, Sansom MSP. Coarse-grain simulations reveal movement of the synaptobrevin C-terminus in response to piconewton forces. Biophys J 2013; 103:959-69. [PMID: 23009845 DOI: 10.1016/j.bpj.2012.08.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 07/20/2012] [Accepted: 08/02/2012] [Indexed: 12/18/2022] Open
Abstract
Fusion of neurosecretory vesicles with the plasma membrane is mediated by SNARE proteins, which transfer a force to the membranes. However, the mechanism by which this force transfer induces fusion pore formation is still unknown. The neuronal vesicular SNARE protein synaptobrevin 2 (syb2) is anchored in the vesicle membrane by a single C-terminal transmembrane (TM) helix. In coarse-grain molecular-dynamics simulations, self-assembly of the membrane occurred with the syb2 TM domain inserted, as expected from experimental data. The free-energy profile for the position of the syb2 membrane anchor in the membrane was determined using umbrella sampling. To predict the free-energy landscapes for a reaction pathway pulling syb2 toward the extravesicular side of the membrane, which is the direction of the force transfer from the SNARE complex, harmonic potentials were applied to the peptide in its unbiased position, pulling it toward new biased equilibrium positions. Application of piconewton forces to the extravesicular end of the TM helix in the simulation detached the synaptobrevin C-terminus from the vesicle's inner-leaflet lipid headgroups and pulled it deeper into the membrane. This C-terminal movement was facilitated and hindered by specific mutations in parallel with experimentally observed facilitation and inhibition of fusion. Direct application of such forces to the intravesicular end of the TM domain resulted in tilting motion of the TM domain through the membrane with an activation energy of ∼70 kJ/mol. The results suggest a mechanism whereby fusion pore formation is induced by movement of the charged syb2 C-terminus within the membrane in response to pulling and tilting forces generated by C-terminal zippering of the SNARE complex.
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Affiliation(s)
- Manfred Lindau
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York, USA.
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Lomize AL, Pogozheva ID. Solvation models and computational prediction of orientations of peptides and proteins in membranes. Methods Mol Biol 2013; 1063:125-42. [PMID: 23975775 DOI: 10.1007/978-1-62703-583-5_7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Membrane-associated peptides and proteins function in the highly heterogeneous environment of the lipid bilayer whose physico-chemical properties change non-monotonically along the bilayer normal. To simulate insertion of peptides and proteins into membranes and correctly reproduce the energetics of this process, an adequate solvation model and physically realistic representation of the lipid bilayer should be employed. We present a brief overview of the existing solvation models and their application for prediction of binding affinities and orientations of proteins in membranes. Particular emphasis is placed on the recently proposed PPM method, the corresponding web server, and the OPM database that were designed for positioning in membranes of integral and peripheral proteins with known three-dimensional structures.
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Affiliation(s)
- Andrei L Lomize
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA
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Crowet JM, Parton DL, Hall BA, Steinhauer S, Brasseur R, Lins L, Sansom MSP. Multi-Scale Simulation of the Simian Immunodeficiency Virus Fusion Peptide. J Phys Chem B 2012; 116:13713-21. [DOI: 10.1021/jp3027385] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Jean-Marc Crowet
- Centre de Biophysique Moléculaire
Numérique, Gembloux Agro-Bio Tech, University of Liège, 2 Passage des déportés,
B-5030 Gembloux, Belgium
| | - Daniel L. Parton
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1
3QU, United Kingdom
| | - Benjamin A. Hall
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1
3QU, United Kingdom
| | - Sven Steinhauer
- Centre de Biophysique Moléculaire
Numérique, Gembloux Agro-Bio Tech, University of Liège, 2 Passage des déportés,
B-5030 Gembloux, Belgium
| | - Robert Brasseur
- Centre de Biophysique Moléculaire
Numérique, Gembloux Agro-Bio Tech, University of Liège, 2 Passage des déportés,
B-5030 Gembloux, Belgium
| | - Laurence Lins
- Centre de Biophysique Moléculaire
Numérique, Gembloux Agro-Bio Tech, University of Liège, 2 Passage des déportés,
B-5030 Gembloux, Belgium
| | - Mark S. P. Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1
3QU, United Kingdom
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Vostrikov VV, Hall BA, Sansom MSP, Koeppe RE. Accommodation of a central arginine in a transmembrane peptide by changing the placement of anchor residues. J Phys Chem B 2012; 116:12980-90. [PMID: 23030363 DOI: 10.1021/jp308182b] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Both Trp and Arg in transmembrane protein domains make important interactions with lipids at the membrane/water interface, but at different depths. Derivatives of the designed peptide GWALP23, acetyl-GGALW(5)LALALALALALALW(19)LAGA-amide, with single Trp anchors, have proven useful for characterizing such interactions. Indeed, previous work revealed quite different effects emanating from Arg substitutions at positions 12 and 14 within GWALP23, with the R12 peptide exhibiting multiple positions and orientations with respect to DOPC bilayer membranes (Vostrikov et al. J. Am. Chem. Soc. 2010, 132, 5803-5811). To gain further understanding of the multistate behavior, we moved the Trp "anchor" residues to more outer positions 3 and 21 in GWALP23 itself, and in the R12 and R14 derivatives. The locations and orientations of the peptides with respect to lipid bilayer membranes of differing thickness were investigated by means of solid-state (2)H NMR spectroscopy, using labeled alanines, and coarse-grained molecular dynamics simulations. Interestingly, relatively intense and narrow (2)H resonances from selected backbone C(α) deuterons were observed over quite narrow ranges of frequency and sample orientation. The backbone resonances reflect dynamic complexities and at the same time provide important contributions for the analysis of peptide transmembrane orientation. With the Trp(3,21) anchors relatively far from the peptide and bilayer center, the results indicate significantly large apparent tilt angles, for example, close to 30° for the new R12 and R14 peptides with respect to the bilayer normal of DLPC membranes. The R12 side chain indeed is "rescued" to a stable position, where it is accommodated within the transmembrane helix, when the Trp anchors are moved outward and to another face of the helix. At the same time, the R14 side chain of transmembrane GW(3,21)ALP23 also retains a stable favored position.
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Affiliation(s)
- Vitaly V Vostrikov
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, United States
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Hall BA, Armitage JP, Sansom MSP. Mechanism of bacterial signal transduction revealed by molecular dynamics of Tsr dimers and trimers of dimers in lipid vesicles. PLoS Comput Biol 2012; 8:e1002685. [PMID: 23028283 PMCID: PMC3447960 DOI: 10.1371/journal.pcbi.1002685] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 07/22/2012] [Indexed: 02/02/2023] Open
Abstract
Bacterial chemoreceptors provide an important model for understanding signalling processes. In the serine receptor Tsr from E. coli, a binding event in the periplasmic domain of the receptor dimer causes a shift in a single transmembrane helix of roughly 0.15 nm towards the cytoplasm. This small change is propagated through the ∼22 nm length of the receptor, causing downstream inhibition of the kinase CheA. This requires interactions within a trimer of receptor dimers. Additionally, the signal is amplified across a 53,000 nm2 array of chemoreceptor proteins, including ∼5,200 receptor trimers-of-dimers, at the cell pole. Despite a wealth of experimental data on the system, including high resolution structures of individual domains and extensive mutagenesis data, it remains uncertain how information is communicated across the receptor from the binding event to the downstream effectors. We present a molecular model of the entire Tsr dimer, and examine its behaviour using coarse-grained molecular dynamics and elastic network modelling. We observe a large bending in dimer models between the linker domain HAMP and coiled-coil domains, which is supported by experimental data. Models of the trimer of dimers, built from the dimer models, are more constrained and likely represent the signalling state. Simulations of the models in a 70 nm diameter vesicle with a biologically realistic lipid mixture reveal specific lipid interactions and oligomerisation of the trimer of dimers. The results indicate a mechanism whereby small motions of a single helix can be amplified through HAMP domain packing, to initiate large changes in the whole receptor structure. To understand cell signalling events requires a physical model of the structure and behaviour of the signalling proteins involved. The methyl-accepting chemoreceptor proteins direct bacterial movement towards food sources and away from toxins. Based on experimental data we have built structural models of the serine chemoreceptor (Tsr) as a dimer, which is incapable of activating the downstream kinase CheA, and as a trimer of dimers, which can activate CheA. We have performed molecular dynamics simulation to reveal the behaviour of these two forms in a planar lipid bilayer and in a 70 nm diameter lipid vesicle with a mixture of lipids mimicking the E. coli inner membrane. We show that in isolation the dimers undergo a bending movement around the central HAMP domain, whereas the trimer-of-dimers model does not. Comparison with published experimental data suggests that these bending motions are real, and that they occur in the trimer of dimers only in response to ligand binding. Drawing together these observations with studies showing that the signalling event involves small piston motions in the transmembrane helices suggests that the bending motion is frustrated in the unliganded trimer of dimers, and that ligand binding induces bending by repacking the HAMP interface.
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Affiliation(s)
| | | | - Mark S. P. Sansom
- Oxford Centre for Integrative Systems Biology, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- * E-mail:
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Wang C, An M, Yang P, Zhang J. Prediction of a new leveler (N-butyl-methyl piperidinium bromide) for through-hole electroplating using molecular dynamics simulations. Electrochem commun 2012. [DOI: 10.1016/j.elecom.2012.02.028] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Hall BA, Armitage JP, Sansom MSP. Transmembrane helix dynamics of bacterial chemoreceptors supports a piston model of signalling. PLoS Comput Biol 2011; 7:e1002204. [PMID: 22028633 PMCID: PMC3197627 DOI: 10.1371/journal.pcbi.1002204] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2011] [Accepted: 09/03/2011] [Indexed: 11/18/2022] Open
Abstract
Transmembrane α-helices play a key role in many receptors, transmitting a signal from one side to the other of the lipid bilayer membrane. Bacterial chemoreceptors are one of the best studied such systems, with a wealth of biophysical and mutational data indicating a key role for the TM2 helix in signalling. In particular, aromatic (Trp and Tyr) and basic (Arg) residues help to lock α-helices into a membrane. Mutants in TM2 of E. coli Tar and related chemoreceptors involving these residues implicate changes in helix location and/or orientation in signalling. We have investigated the detailed structural basis of this via high throughput coarse-grained molecular dynamics (CG-MD) of Tar TM2 and its mutants in lipid bilayers. We focus on the position (shift) and orientation (tilt, rotation) of TM2 relative to the bilayer and how these are perturbed in mutants relative to the wildtype. The simulations reveal a clear correlation between small (ca. 1.5 Å) shift in position of TM2 along the bilayer normal and downstream changes in signalling activity. Weaker correlations are seen with helix tilt, and little/none between signalling and helix twist. This analysis of relatively subtle changes was only possible because the high throughput simulation method allowed us to run large (n = 100) ensembles for substantial numbers of different helix sequences, amounting to ca. 2000 simulations in total. Overall, this analysis supports a swinging-piston model of transmembrane signalling by Tar and related chemoreceptors.
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Affiliation(s)
- Benjamin A. Hall
- Oxford Centre for Integrative Systems Biology, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Judith P. Armitage
- Oxford Centre for Integrative Systems Biology, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Mark S. P. Sansom
- Oxford Centre for Integrative Systems Biology, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- * E-mail:
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Kalli A, Hall B, Campbell I, Sansom M. A helix heterodimer in a lipid bilayer: prediction of the structure of an integrin transmembrane domain via multiscale simulations. Structure 2011; 19:1477-84. [PMID: 22000516 PMCID: PMC3195670 DOI: 10.1016/j.str.2011.07.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2011] [Revised: 06/27/2011] [Accepted: 07/13/2011] [Indexed: 11/09/2022]
Abstract
Dimerization of transmembrane (TM) α helices of membrane receptors plays a key role in signaling. We show that molecular dynamics simulations yield models of integrin TM helix heterodimers, which agree well with available NMR structures. We use a multiscale simulation approach, combining coarse-grained and subsequent atomistic simulation, to model the dimerization of wild-type (WT) and mutated sequences of the αIIb and β3 integrin TM helices. The WT helices formed a stable, right-handed dimer with the same helix-helix interface as in the published NMR structure (PDB: 2K9J). In contrast, the presence of disruptive mutations perturbed the interface between the helices, altering the conformational stability of the dimer. The αIIb/β3 interface was more flexible than that of, e.g., glycophorin A. This is suggestive of a role for alternative packing modes of the TM helices in transbilayer signaling.
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Affiliation(s)
- Antreas C. Kalli
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Benjamin A. Hall
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Iain D. Campbell
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Mark S.P. Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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