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Pirnia A, Maqdisi R, Mittal S, Sener M, Singharoy A. Perspective on Integrative Simulations of Bioenergetic Domains. J Phys Chem B 2024; 128:3302-3319. [PMID: 38562105 DOI: 10.1021/acs.jpcb.3c07335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Bioenergetic processes in cells, such as photosynthesis or respiration, integrate many time and length scales, which makes the simulation of energy conversion with a mere single level of theory impossible. Just like the myriad of experimental techniques required to examine each level of organization, an array of overlapping computational techniques is necessary to model energy conversion. Here, a perspective is presented on recent efforts for modeling bioenergetic phenomena with a focus on molecular dynamics simulations and its variants as a primary method. An overview of the various classical, quantum mechanical, enhanced sampling, coarse-grained, Brownian dynamics, and Monte Carlo methods is presented. Example applications discussed include multiscale simulations of membrane-wide electron transport, rate kinetics of ATP turnover from electrochemical gradients, and finally, integrative modeling of the chromatophore, a photosynthetic pseudo-organelle.
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Affiliation(s)
- Adam Pirnia
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1004, United States
| | - Ranel Maqdisi
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1004, United States
| | - Sumit Mittal
- VIT Bhopal University, Sehore 466114, Madhya Pradesh, India
| | - Melih Sener
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1004, United States
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Abhishek Singharoy
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1004, United States
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2
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Mai M, Zazubovich V, Mansbach RA. Identification of Residues Potentially Involved in Optical Shifts in the Water-Soluble Chlorophyll a-Binding Protein through Molecular Dynamics Simulations. J Phys Chem B 2024; 128:1371-1384. [PMID: 38299975 PMCID: PMC10876061 DOI: 10.1021/acs.jpcb.3c06889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 01/15/2024] [Accepted: 01/16/2024] [Indexed: 02/02/2024]
Abstract
Reversible light and thermally induced spectral shifts are universally observed in a wide variety of pigment-protein complexes at temperatures ranging from cryogenic to ambient. In this paper, we employed large-scale molecular dynamics (MD) simulations of a prototypical pigment-protein complex to better understand these shifts at a molecular scale. Although multiple mechanisms have been proposed over the years, no verification of these proposals via MD simulations has thus far been performed; our work represents the first step in this direction. From simulations of the water-soluble chlorophyll-binding protein complex, we determined that rearrangements of long hydrogen bonds were unlikely to be the origin of the multiwell landscape features necessary to explain observed spectral shifts. We also assessed small motions of amino acid residues and identified side chain rotations of some of these residues as likely candidates for the origin of relevant multiwell landscape features. The protein free-energy landscapes associated with side chain rotations feature energy barriers of around 1100-1600 cm-1, in agreement with optical spectroscopy results, with the most promising residue type associated with experimental signatures being serine, which possesses a symmetric triple-well landscape and moment of inertia of a relevant magnitude.
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Affiliation(s)
- Martina Mai
- Department of Physics, Concordia
University, Montréal, Quebec H4B 1R6, Canada
| | - Valter Zazubovich
- Department of Physics, Concordia
University, Montréal, Quebec H4B 1R6, Canada
| | - Rachael A. Mansbach
- Department of Physics, Concordia
University, Montréal, Quebec H4B 1R6, Canada
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3
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Unravelling viral dynamics through molecular dynamics simulations - A brief overview. Biophys Chem 2022; 291:106908. [DOI: 10.1016/j.bpc.2022.106908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 09/28/2022] [Accepted: 10/05/2022] [Indexed: 11/24/2022]
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Liguori N, Croce R, Marrink SJ, Thallmair S. Molecular dynamics simulations in photosynthesis. PHOTOSYNTHESIS RESEARCH 2020; 144:273-295. [PMID: 32297102 PMCID: PMC7203591 DOI: 10.1007/s11120-020-00741-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 03/24/2020] [Indexed: 05/12/2023]
Abstract
Photosynthesis is regulated by a dynamic interplay between proteins, enzymes, pigments, lipids, and cofactors that takes place on a large spatio-temporal scale. Molecular dynamics (MD) simulations provide a powerful toolkit to investigate dynamical processes in (bio)molecular ensembles from the (sub)picosecond to the (sub)millisecond regime and from the Å to hundreds of nm length scale. Therefore, MD is well suited to address a variety of questions arising in the field of photosynthesis research. In this review, we provide an introduction to the basic concepts of MD simulations, at atomistic and coarse-grained level of resolution. Furthermore, we discuss applications of MD simulations to model photosynthetic systems of different sizes and complexity and their connection to experimental observables. Finally, we provide a brief glance on which methods provide opportunities to capture phenomena beyond the applicability of classical MD.
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Affiliation(s)
- Nicoletta Liguori
- Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics, Faculty of Sciences, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
| | - Roberta Croce
- Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics, Faculty of Sciences, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Sebastian Thallmair
- Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands.
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Clark ST, Arras MML, Sarles SA, Frymier PD. Lipid shape determination of detergent solubilization in mixed-lipid liposomes. Colloids Surf B Biointerfaces 2019; 187:110609. [PMID: 31806354 DOI: 10.1016/j.colsurfb.2019.110609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 09/17/2019] [Accepted: 10/21/2019] [Indexed: 11/16/2022]
Abstract
The effects of lipid charge and head group size on liposome partitioning by detergents is an important consideration for applications such as liposomal drug delivery or proteoliposome formation. Yet, the solubilization of mixed-lipid liposomes, those containing multiple types of lipids, by detergents has received insufficient attention. This study examines the incorporation into and subsequent dissolution of mixed-lipid liposomes comprised of both egg phosphatidylcholine (ePC) and egg phosphatidic acid (ePA) by the detergent Triton-X100 (TX). Liposomes were prepared with mixtures of the two lipids, ePC and ePA, at molar ratios from 0 to 1, then step-wise solubilized with TX. Changes in turbidity, size distribution, and molar heat power at constant temperature throughout the solubilization process were assessed. The data suggest that the difference in lipid shapes (shape factors = 0.74 and 1.4 [1,2]) affects packing in membranes, and hence influences how much TX can be incorporated before disruption. As such, liposomes containing the observed ratios of ePA incorporated higher concentrations of TX before initiating dissolution into detergent and lipid mixed-micelles. The cause was concluded to be increased mismatching in the bilayer from the conical shape of ePA compared to the cylindrical shape of ePC. Additionally, the degree to which ePA is approximated as conical versus cylindrical was modulated with pH. It was confirmed that less conical ePA behaved more similarly to ePC than more conical ePA. The understanding gained here on lipid shape in liposome incorporation of TX enables research to use in vitro liposomes that more closely mimic native membranes.
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Affiliation(s)
- Samantha T Clark
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, 1512 Middle Dr, Knoxville, TN 37996, USA
| | - Matthias M L Arras
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Stephen A Sarles
- Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, 1512 Middle Drive, 414 Dougherty Engineering Building, Knoxville, TN 37996, USA
| | - Paul D Frymier
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, 1512 Middle Dr, Knoxville, TN 37996, USA.
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Travers T, Wang KJ, López CA, Gnanakaran S. Sequence- and structure-based computational analyses of Gram-negative tripartite efflux pumps in the context of bacterial membranes. Res Microbiol 2018; 169:414-424. [DOI: 10.1016/j.resmic.2018.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 12/28/2017] [Accepted: 01/21/2018] [Indexed: 01/12/2023]
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Cherepanov DA, Milanovsky GE, Petrova AA, Tikhonov AN, Semenov AY. Electron Transfer through the Acceptor Side of Photosystem I: Interaction with Exogenous Acceptors and Molecular Oxygen. BIOCHEMISTRY (MOSCOW) 2018; 82:1249-1268. [PMID: 29223152 DOI: 10.1134/s0006297917110037] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This review considers the state-of-the-art on mechanisms and alternative pathways of electron transfer in photosynthetic electron transport chains of chloroplasts and cyanobacteria. The mechanisms of electron transport control between photosystems (PS) I and II and the Calvin-Benson cycle are considered. The redistribution of electron fluxes between the noncyclic, cyclic, and pseudocyclic pathways plays an important role in the regulation of photosynthesis. Mathematical modeling of light-induced electron transport processes is considered. Particular attention is given to the electron transfer reactions on the acceptor side of PS I and to interactions of PS I with exogenous acceptors, including molecular oxygen. A kinetic model of PS I and its interaction with exogenous electron acceptors has been developed. This model is based on experimental kinetics of charge recombination in isolated PS I. Kinetic and thermodynamic parameters of the electron transfer reactions in PS I are scrutinized. The free energies of electron transfer between quinone acceptors A1A/A1B in the symmetric redox cofactor branches of PS I and iron-sulfur clusters FX, FA, and FB have been estimated. The second-order rate constants of electron transfer from PS I to external acceptors have been determined. The data suggest that byproduct formation of superoxide radical in PS I due to the reduction of molecular oxygen in the A1 site (Mehler reaction) can exceed 0.3% of the total electron flux in PS I.
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Affiliation(s)
- D A Cherepanov
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, 119992, Russia.
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Malferrari M, Savitsky A, Mamedov MD, Milanovsky GE, Lubitz W, Möbius K, Semenov AY, Venturoli G. Trehalose matrix effects on charge-recombination kinetics in Photosystem I of oxygenic photosynthesis at different dehydration levels. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1440-1454. [DOI: 10.1016/j.bbabio.2016.05.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 05/03/2016] [Accepted: 05/06/2016] [Indexed: 10/21/2022]
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9
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Harris BJ, Cheng X, Frymier P. Structure and Function of Photosystem I–[FeFe] Hydrogenase Protein Fusions: An All-Atom Molecular Dynamics Study. J Phys Chem B 2016; 120:599-609. [DOI: 10.1021/acs.jpcb.5b07812] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bradley J. Harris
- College
of Engineering and Computer Science, University of Tennessee, Chattanooga, Tennessee 37403, United States
| | - Xiaolin Cheng
- Center for
Molecular Biophysics, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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From light-harvesting to photoprotection: structural basis of the dynamic switch of the major antenna complex of plants (LHCII). Sci Rep 2015; 5:15661. [PMID: 26493782 PMCID: PMC4616226 DOI: 10.1038/srep15661] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 09/30/2015] [Indexed: 12/17/2022] Open
Abstract
Light-Harvesting Complex II (LHCII) is largely responsible for light absorption and excitation energy transfer in plants in light-limiting conditions, while in high-light it participates in photoprotection. It is generally believed that LHCII can change its function by switching between different conformations. However, the underlying molecular picture has not been elucidated yet. The available crystal structures represent the quenched form of the complex, while solubilized LHCII has the properties of the unquenched state. To determine the structural changes involved in the switch and to identify potential quenching sites, we have explored the structural dynamics of LHCII, by performing a series of microsecond Molecular Dynamics simulations. We show that LHCII in the membrane differs substantially from the crystal and has the signatures that were experimentally associated with the light-harvesting state. Local conformational changes at the N-terminus and at the xanthophyll neoxanthin are found to strongly correlate with changes in the interactions energies of two putative quenching sites. In particular conformational disorder is observed at the terminal emitter resulting in large variations of the excitonic coupling strength of this chlorophyll pair. Our results strongly support the hypothesis that light-harvesting regulation in LHCII is coupled with structural changes.
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Najafi M, Zazubovich V. Monte Carlo Modeling of Spectral Diffusion Employing Multiwell Protein Energy Landscapes: Application to Pigment-Protein Complexes Involved in Photosynthesis. J Phys Chem B 2015; 119:7911-21. [PMID: 26020801 DOI: 10.1021/acs.jpcb.5b02764] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We are reporting development and initial applications of the light-induced and thermally induced spectral diffusion modeling software, covering nonphotochemical spectral hole burning (NPHB), hole recovery, and single-molecule spectroscopy and involving random generation of the multiwell protein energy landscapes. The model includes tunneling and activated barrier-hopping in both ground and excited states of a protein-chromophore system. Evolution of such a system is predicted by solving the system of rate equations. Using the barrier parameters from the range typical for the energy landscapes of the pigment-protein complexes involved in photosynthesis, we (a) show that realistic cooling of the sample must result in proteins quite far from thermodynamic equilibrium, (b) demonstrate hole evolution in the cases of burning, fixed-temperature recovery and thermocycling that mostly agrees with the experiment and modeling based on the NPHB master equation, and (c) explore the effects of different protein energy landscapes on the antihole shape. Introducing the multiwell energy landscapes and starting the hole burning experiments in realistic nonequilibrium conditions are not sufficient to explain all experimental observations even qualitatively. Therefore, for instance, one is required to invoke the modified NPHB mechanism where a complex interplay of several small conformational changes is poising the energy landscape of the pigment-protein system for downhill tunneling.
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Affiliation(s)
- Mehdi Najafi
- Department of Physics, Concordia University, Montreal H4B 1R6, Quebec, Canada
| | - Valter Zazubovich
- Department of Physics, Concordia University, Montreal H4B 1R6, Quebec, Canada
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12
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Molecular dynamics simulations of large macromolecular complexes. Curr Opin Struct Biol 2015; 31:64-74. [PMID: 25845770 DOI: 10.1016/j.sbi.2015.03.007] [Citation(s) in RCA: 264] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 03/13/2015] [Accepted: 03/16/2015] [Indexed: 12/11/2022]
Abstract
Connecting dynamics to structural data from diverse experimental sources, molecular dynamics simulations permit the exploration of biological phenomena in unparalleled detail. Advances in simulations are moving the atomic resolution descriptions of biological systems into the million-to-billion atom regime, in which numerous cell functions reside. In this opinion, we review the progress, driven by large-scale molecular dynamics simulations, in the study of viruses, ribosomes, bioenergetic systems, and other diverse applications. These examples highlight the utility of molecular dynamics simulations in the critical task of relating atomic detail to the function of supramolecular complexes, a task that cannot be achieved by smaller-scale simulations or existing experimental approaches alone.
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Le RK, Raeeszadeh-Sarmazdeh M, Boder ET, Frymier PD. Sortase-mediated ligation of PsaE-modified photosystem I from Synechocystis sp. PCC 6803 to a conductive surface for enhanced photocurrent production on a gold electrode. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:1180-1188. [PMID: 25535846 DOI: 10.1021/la5031284] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Sortase-mediated ligation was used to attach the photosystem I (PSI) complex from Synechocystis sp. PCC 6803 in a preferential orientation to enhance photoinduced electron flow to a conductive gold surface. Ideally, this method can result in a uniform monolayer of protein, covalently bound unidirectionally to the electrode surface. The exposed C-termini of the psaE subunits of the PSI trimer were targeted to contain an LPETG-sortase recognition sequence to increase noncompeting electron transfer by uniformly orienting the PSI stromal side proximal to the surface. Surface characterization with atomic force microscopy suggested that monolayer formation and optimal surface coverage occurred when the gold surfaces were incubated with peptide at 100 to 500 μM concentrations. When photochronoamperometry with potassium ferrocyanide and ferricyanide as redox mediators was used, photocurrents in the range of 100 to 200 nA/cm(2) were produced, which is an improvement over other attachment techniques for photosystem monolayers that produce approximately 100 nA/cm(2) or less. This work demonstrated that sortase-mediated ligation aided in the control of PSI orientation on modified gold surfaces with a distribution of 94% stromal side proximal and 6% lumenal side proximal to the surface for current-producing PSI.
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Affiliation(s)
- Rosemary K Le
- Department of Chemical and Biomolecular Engineering, ‡Institute for Biomedical Engineering, and §Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee-Knoxville , Knoxville, Tennessee 37966-2200, United States
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