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Lichtinger SM, Biggin PC. Tackling Hysteresis in Conformational Sampling: How to Be Forgetful with MEMENTO. J Chem Theory Comput 2023. [PMID: 37285481 DOI: 10.1021/acs.jctc.3c00140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The structure of proteins has long been recognized to hold the key to understanding and engineering their function, and rapid advances in structural biology and protein structure prediction are now supplying researchers with an ever-increasing wealth of structural information. Most of the time, however, structures can only be determined in free energy minima, one at a time. While conformational flexibility may thus be inferred from static end-state structures, their interconversion mechanisms─a central ambition of structural biology─are often beyond the scope of direct experimentation. Given the dynamical nature of the processes in question, many studies have attempted to explore conformational transitions using molecular dynamics (MD). However, ensuring proper convergence and reversibility in the predicted transitions is extremely challenging. In particular, a commonly used technique to map out a path from a starting to a target conformation called steered MD (SMD) can suffer from starting-state dependence (hysteresis) when combined with techniques such as umbrella sampling (US) to compute the free energy profile of a transition. Here, we study this problem in detail on conformational changes of increasing complexity. We also present a new, history-independent approach that we term "MEMENTO" (Morphing End states by Modelling Ensembles with iNdependent TOpologies) to generate paths that alleviate hysteresis in the construction of conformational free energy profiles. MEMENTO utilizes template-based structure modelling to restore physically reasonable protein conformations based on coordinate interpolation (morphing) as an ensemble of plausible intermediates, from which a smooth path is picked. We compare SMD and MEMENTO on well-characterized test cases (the toy peptide deca-alanine and the enzyme adenylate kinase) before discussing its use in more complicated systems (the kinase P38α and the bacterial leucine transporter LeuT). Our work shows that for all but the simplest systems SMD paths should not in general be used to seed umbrella sampling or related techniques, unless the paths are validated by consistent results from biased runs in opposite directions. MEMENTO, on the other hand, performs well as a flexible tool to generate intermediate structures for umbrella sampling. We also demonstrate that extended end-state sampling combined with MEMENTO can aid the discovery of collective variables on a case-by-case basis.
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Affiliation(s)
| | - Philip C Biggin
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, U.K
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2
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Lu J, Scheerer D, Haran G, Li W, Wang W. Role of Repeated Conformational Transitions in Substrate Binding of Adenylate Kinase. J Phys Chem B 2022; 126:8188-8201. [PMID: 36222098 PMCID: PMC9589722 DOI: 10.1021/acs.jpcb.2c05497] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The catalytic cycle of the enzyme adenylate kinase involves large conformational motions between open and closed states. A previous single-molecule experiment showed that substrate binding tends to accelerate both the opening and the closing rates and that a single turnover event often involves multiple rounds of conformational switching. In this work, we showed that the repeated conformational transitions of adenylate kinase are essential for the relaxation of incorrectly bound substrates into the catalytically competent conformation by combining all-atom and coarse-grained molecular simulations. In addition, free energy calculations based on all-atom and coarse-grained models demonstrated that the enzyme with incorrectly bound substrates has much a lower free energy barrier for domain opening compared to that with the correct substrate conformation, which may explain the the acceleration of the domain opening rate by substrate binding. The results of this work provide mechanistic understanding to previous experimental observations and shed light onto the interplay between conformational dynamics and enzyme catalysis.
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Affiliation(s)
- Jiajun Lu
- Department
of Physics, National Laboratory of Solid State Microstructure, Nanjing University, Nanjing210093, China,Wenzhou
Key Laboratory of Biophysics, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang325000, China
| | - David Scheerer
- Department
of Chemical and Biological Physics, Weizmann
Institute of Science, Rehovot761001, Israel
| | - Gilad Haran
- Department
of Chemical and Biological Physics, Weizmann
Institute of Science, Rehovot761001, Israel,
| | - Wenfei Li
- Department
of Physics, National Laboratory of Solid State Microstructure, Nanjing University, Nanjing210093, China,Wenzhou
Key Laboratory of Biophysics, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang325000, China,
| | - Wei Wang
- Department
of Physics, National Laboratory of Solid State Microstructure, Nanjing University, Nanjing210093, China,
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3
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Orädd F, Ravishankar H, Goodman J, Rogne P, Backman L, Duelli A, Nors Pedersen M, Levantino M, Wulff M, Wolf-Watz M, Andersson M. Tracking the ATP-binding response in adenylate kinase in real time. SCIENCE ADVANCES 2021; 7:eabi5514. [PMID: 34788091 PMCID: PMC8597995 DOI: 10.1126/sciadv.abi5514] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 09/27/2021] [Indexed: 05/25/2023]
Abstract
The biological function of proteins is critically dependent on dynamics inherent to the native structure. Such structural dynamics obey a predefined order and temporal timing to execute the specific reaction. Determination of the cooperativity of key structural rearrangements requires monitoring protein reactions in real time. In this work, we used time-resolved x-ray solution scattering (TR-XSS) to visualize structural changes in the Escherichia coli adenylate kinase (AdK) enzyme upon laser-induced activation of a protected ATP substrate. A 4.3-ms transient intermediate showed partial closing of both the ATP- and AMP-binding domains, which indicates a cooperative closing mechanism. The ATP-binding domain also showed local unfolding and breaking of an Arg131-Asp146 salt bridge. Nuclear magnetic resonance spectroscopy data identified similar unfolding in an Arg131Ala AdK mutant, which refolded in a closed, substrate-binding conformation. The observed structural dynamics agree with a “cracking mechanism” proposed to underlie global structural transformation, such as allostery, in proteins.
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Affiliation(s)
- Fredrik Orädd
- Department of Chemistry, Umeå University, Linnaeus Väg 10, 901 87 Umeå, Sweden
| | - Harsha Ravishankar
- Department of Chemistry, Umeå University, Linnaeus Väg 10, 901 87 Umeå, Sweden
| | - Jack Goodman
- Department of Chemistry, Umeå University, Linnaeus Väg 10, 901 87 Umeå, Sweden
| | - Per Rogne
- Department of Chemistry, Umeå University, Linnaeus Väg 10, 901 87 Umeå, Sweden
| | - Lars Backman
- Department of Chemistry, Umeå University, Linnaeus Väg 10, 901 87 Umeå, Sweden
| | - Annette Duelli
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
| | - Martin Nors Pedersen
- ESRF—The European Synchrotron, 71 Avenue des Martyrs, CS40220, 38043 Grenoble, Cedex 9, France
| | - Matteo Levantino
- ESRF—The European Synchrotron, 71 Avenue des Martyrs, CS40220, 38043 Grenoble, Cedex 9, France
| | - Michael Wulff
- ESRF—The European Synchrotron, 71 Avenue des Martyrs, CS40220, 38043 Grenoble, Cedex 9, France
| | - Magnus Wolf-Watz
- Department of Chemistry, Umeå University, Linnaeus Väg 10, 901 87 Umeå, Sweden
| | - Magnus Andersson
- Department of Chemistry, Umeå University, Linnaeus Väg 10, 901 87 Umeå, Sweden
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4
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Wu Y, Qian R, Yang Y, Sheng Y, Li W, Wang W. Activation Pathways and Free Energy Landscapes of the SARS-CoV-2 Spike Protein. ACS OMEGA 2021; 6:23432-23441. [PMID: 34514271 PMCID: PMC8424691 DOI: 10.1021/acsomega.1c03384] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 08/24/2021] [Indexed: 05/09/2023]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) uses a spike protein (S-protein) to recognize the receptor protein ACE2 of human cells and initiate infection, during which the conformational transition of the S-protein from inactive (down) state to active (up) state is one of the key molecular events determining the infectivity but the underlying mechanism remains poorly understood. In this work, we investigated the activation pathways and free energy landscape of the S-protein of SARS-CoV-2 and compared with those of the closely related counterpart SARS-CoV using molecular dynamics simulations. Our results revealed a large difference between the activation pathways of the two S-proteins. The transition from inactive to an active state for the S-protein of SARS-CoV-2 is more cooperative, involving simultaneous disruptions of several key interfacial hydrogen bonds, and the transition encounters a much higher free energy barrier. In addition, the conformational equilibrium of the SARS-CoV-2 S-protein is more biased to the inactive state compared to that of the SARS-CoV S-protein, suggesting the transient feature of the active state before binding to the receptor protein of the host cell. The key interactions contributing to the difference of the activation pathways and free energy landscapes were discussed. The results provide insights into the molecular mechanism involved in the initial stage of the SARS-CoV-2 infection.
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Affiliation(s)
- Yichao Wu
- Department of Physics, National
Laboratory of Solid State Microstructure, Nanjing University, Nanjing 210093, China
| | - Ruixin Qian
- Department of Physics, National
Laboratory of Solid State Microstructure, Nanjing University, Nanjing 210093, China
| | - Yan Yang
- Department of Physics, National
Laboratory of Solid State Microstructure, Nanjing University, Nanjing 210093, China
| | - Yuebiao Sheng
- Department of Physics, National
Laboratory of Solid State Microstructure, Nanjing University, Nanjing 210093, China
| | - Wenfei Li
- Department of Physics, National
Laboratory of Solid State Microstructure, Nanjing University, Nanjing 210093, China
| | - Wei Wang
- Department of Physics, National
Laboratory of Solid State Microstructure, Nanjing University, Nanjing 210093, China
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Hua XF, Du XZ, Zhang ZY. Ligand binding and release investigated by contact-guided iterative multiple independent molecular dynamics simulations. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2010181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Xin-fan Hua
- National Science Center for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Xin-zheng Du
- National Science Center for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Zhi-yong Zhang
- National Science Center for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
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6
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Kong J, Li J, Lu J, Li W, Wang W. Role of substrate-product frustration on enzyme functional dynamics. Phys Rev E 2020; 100:052409. [PMID: 31869999 DOI: 10.1103/physreve.100.052409] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Indexed: 01/19/2023]
Abstract
Natural enzymes often have enormous catalytic power developed by evolution. Revealing the underlying physical strategy used by enzymes to achieve high catalysis efficiency is one of the central focuses in the field of biological physics. Our recent work demonstrated that multisubstrate enzymes can utilize steric frustration encountered in the substrate-product cobound complex to overcome the bottleneck of the enzymatic cycle [W. Li et al., Phys. Rev. Lett. 122, 238102 (2019)10.1103/PhysRevLett.122.238102]. However, the key atomic-level interactions by which the steric frustration contributes to the enzymatic cycle remain elusive. In this work we study the microscopic mechanism for the role of the substrate-product frustration on the key physical steps in the enzymatic cycle of adenylate kinase (AdK), a multisubstrate enzyme catalyzing the reversible phosphoryl transfer reaction ATP+AMP⇋ADP+ADP. By using atomistic molecular dynamics simulations with enhanced sampling, we showed that the competitive interactions from the phosphate groups of the substrate ATP and product ADP in the ATP-ADP cobound complex of the AdK lead to local frustration in the binding pockets. Such local frustration disrupts the hydrogen bond network around the binding pockets, which causes lowered barrier height for the opening of the enzyme conformations and expedited release of the bottleneck product ADP. Our results directly demonstrated from the atomistic level that the local frustration in the active sites of the enzyme can be utilized to facilitate the key physical steps of the enzymatic cycle, providing numerical evidence to the predictions of the previous theoretical work.
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Affiliation(s)
- Jianyang Kong
- National Laboratory of Solid State Microstructure, Department of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Jiachen Li
- National Laboratory of Solid State Microstructure, Department of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Jiajun Lu
- National Laboratory of Solid State Microstructure, Department of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Wenfei Li
- National Laboratory of Solid State Microstructure, Department of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Wei Wang
- National Laboratory of Solid State Microstructure, Department of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
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7
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Li D, Ji B. Protein conformational transitions coupling with ligand interactions: Simulations from molecules to medicine. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2019. [DOI: 10.1016/j.medntd.2019.100026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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