1
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Wang P, Christianson BM, Ugurlar D, Mao R, Zhang Y, Liu ZK, Zhang YY, Gardner AM, Gao J, Zhang YZ, Liu LN. Architectures of photosynthetic RC-LH1 supercomplexes from Rhodobacter blasticus. SCIENCE ADVANCES 2024; 10:eadp6678. [PMID: 39383221 PMCID: PMC11463270 DOI: 10.1126/sciadv.adp6678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 09/06/2024] [Indexed: 10/11/2024]
Abstract
The reaction center-light-harvesting complex 1 (RC-LH1) plays an essential role in the primary reactions of bacterial photosynthesis. Here, we present high-resolution structures of native monomeric and dimeric RC-LH1 supercomplexes from Rhodobacter (Rba.) blasticus using cryo-electron microscopy. The RC-LH1 monomer is composed of an RC encircled by an open LH1 ring comprising 15 αβ heterodimers and a PufX transmembrane polypeptide. In the RC-LH1 dimer, two crossing PufX polypeptides mediate dimerization. Unlike Rhodabacter sphaeroides counterpart, Rba. blasticus RC-LH1 dimer has a less bent conformation, lacks the PufY subunit near the LH1 opening, and includes two extra LH1 αβ subunits, forming a more enclosed S-shaped LH1 ring. Spectroscopic assays reveal that these unique structural features are accompanied by changes in the kinetics of quinone/quinol trafficking between RC-LH1 and cytochrome bc1. Our findings reveal the assembly principles and structural variability of photosynthetic RC-LH1 supercomplexes, highlighting diverse strategies used by phototrophic bacteria to optimize light-harvesting and electron transfer in competitive environments.
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Affiliation(s)
- Peng Wang
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Bern M. Christianson
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, L69 7ZB Liverpool, United Kingdom
| | - Deniz Ugurlar
- Thermo Fisher Scientific, Life Sciences EMEA, Achtseweg Noord 5, 5651 GG Eindhoven, Netherlands
| | - Ruichao Mao
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Yi Zhang
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Ze-Kun Liu
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Ying-Yue Zhang
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, L69 7ZB Liverpool, United Kingdom
| | - Adrian M. Gardner
- Department of Chemistry, Stephenson Institute of Renewable Energy, and Early Career Laser Laboratory, University of Liverpool, L69 7ZF Liverpool, UK
| | - Jun Gao
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Yu-Zhong Zhang
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Lu-Ning Liu
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, L69 7ZB Liverpool, United Kingdom
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Reiter S, Gordiy I, Kollmannsberger KL, Liu F, Thyrhaug E, Leister D, Warnan J, Hauer J, de Vivie-Riedle R. Molecular interactions of photosystem I and ZIF-8 in bio-nanohybrid materials. Phys Chem Chem Phys 2024; 26:23228-23239. [PMID: 39192757 DOI: 10.1039/d4cp03021d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/29/2024]
Abstract
Bio-nanohybrid devices featuring natural photocatalysts bound to a nanostructure hold great promise in the search for sustainable energy conversion. One of the major challenges of integrating biological systems is protecting them against harsh environmental conditions while retaining, or ideally enhancing their photophysical properties. In this mainly computational work we investigate an assembly of cyanobacterial photosystem I (PS I) embedded in a metal-organic framework (MOF), namely the zeolitic imidazolate framework ZIF-8. This complex has been reported experimentally [Bennett et al., Nanoscale Adv., 2019, 1, 94] but so far the molecular interactions between PS I and the MOF remained elusive. We show via absorption spectroscopy that PS I remains intact throughout the encapsulation-release cycle. Molecular dynamics (MD) simulations further confirm that the encapsulation has no noticeable structural impact on the photosystem. However, the MOF building blocks frequently coordinate to the Mg2+ ions of chlorophylls in the periphery of the antenna complex. High-level quantum mechanical calculations reveal charge-transfer interactions, which affect the excitonic network and thereby may reversibly change the fluorescence properties of PS I. Nevertheless, our results highlight the stability of PS I in the MOF, as the reaction center remains unimpeded by the heterogeneous environment, paving the way for applications in the foreseeable future.
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Affiliation(s)
- Sebastian Reiter
- Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstr. 11, 81377 Munich, Germany.
| | - Igor Gordiy
- Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstr. 11, 81377 Munich, Germany.
| | - Kathrin L Kollmannsberger
- Chair of Inorganic and Metal-Organic Chemistry, Department of Chemistry and Catalysis Research Center (CRC), TUM School of Natural Sciences, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Feng Liu
- Faculty of Biology, Ludwig-Maximilians-Universität München, Großhaderner Str. 2-4, 82152 Planegg-Martinsried, Germany
| | - Erling Thyrhaug
- Professorship of Dynamic Spectroscopy, Department of Chemistry and Catalysis Research Center (CRC), TUM School of Natural Sciences, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany.
| | - Dario Leister
- Faculty of Biology, Ludwig-Maximilians-Universität München, Großhaderner Str. 2-4, 82152 Planegg-Martinsried, Germany
| | - Julien Warnan
- Chair of Inorganic and Metal-Organic Chemistry, Department of Chemistry and Catalysis Research Center (CRC), TUM School of Natural Sciences, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Jürgen Hauer
- Professorship of Dynamic Spectroscopy, Department of Chemistry and Catalysis Research Center (CRC), TUM School of Natural Sciences, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany.
| | - Regina de Vivie-Riedle
- Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstr. 11, 81377 Munich, Germany.
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3
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Drosou M, Bhattacharjee S, Pantazis DA. Combined Multireference-Multiscale Approach to the Description of Photosynthetic Reaction Centers. J Chem Theory Comput 2024; 20. [PMID: 39116215 PMCID: PMC11360140 DOI: 10.1021/acs.jctc.4c00578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 07/02/2024] [Accepted: 07/12/2024] [Indexed: 08/10/2024]
Abstract
A first-principles description of the primary photochemical processes that drive photosynthesis and sustain life on our planet remains one of the grand challenges of modern science. Recent research established that explicit incorporation of protein electrostatics in excited-state calculations of photosynthetic pigments, achieved for example with quantum-mechanics/molecular-mechanics (QM/MM) approaches, is essential for a meaningful description of the properties and function of pigment-protein complexes. Although time-dependent density functional theory has been used productively so far in QM/MM approaches for the study of such systems, this methodology has limitations. Here we pursue for the first time a QM/MM description of the reaction center in the principal enzyme of oxygenic photosynthesis, Photosystem II, using multireference wave function theory for the high-level QM region. We identify best practices and establish guidelines regarding the rational choice of active space and appropriate state-averaging for the efficient and reliable use of complete active space self-consistent field (CASSCF) and the N-electron valence state perturbation theory (NEVPT2) in the prediction of low-lying excited states of chlorophyll and pheophytin pigments. Given that the Gouterman orbitals are inadequate as a minimal active space, we define specific minimal and extended active spaces for the NEVPT2 description of electronic states that fall within the Q and B bands. Subsequently, we apply our multireference-QM/MM protocol to the description of all pigments in the reaction center of Photosystem II. The calculations reproduce the electrochromic shifts induced by the protein matrix and the ordering of site energies consistent with the identity of the primary donor (ChlD1) and the experimentally known asymmetric and directional electron transfer. The optimized protocol sets the stage for future multireference treatments of multiple pigments, and hence for multireference studies of charge separation, while it is transferable to the study of any photoactive embedded tetrapyrrole system.
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Affiliation(s)
- Maria Drosou
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Sinjini Bhattacharjee
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Dimitrios A. Pantazis
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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4
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Sarngadharan P, Holtkamp Y, Kleinekathöfer U. Protein Effects on the Excitation Energies and Exciton Dynamics of the CP24 Antenna Complex. J Phys Chem B 2024; 128:5201-5217. [PMID: 38756003 PMCID: PMC11145653 DOI: 10.1021/acs.jpcb.4c01637] [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: 03/12/2024] [Revised: 04/29/2024] [Accepted: 05/06/2024] [Indexed: 05/18/2024]
Abstract
In this study, the site energy fluctuations, energy transfer dynamics, and some spectroscopic properties of the minor light-harvesting complex CP24 in a membrane environment were determined. For this purpose, a 3 μs-long classical molecular dynamics simulation was performed for the CP24 complex. Furthermore, using the density functional tight binding/molecular mechanics molecular dynamics (DFTB/MM MD) approach, we performed excited state calculations for the chlorophyll a and chlorophyll b molecules in the complex starting from five different positions of the MD trajectory. During the extended simulations, we observed variations in the site energies of the different sets as a result of the fluctuating protein environment. In particular, a water coordination to Chl-b 608 occurred only after about 1 μs in the simulations, demonstrating dynamic changes in the environment of this pigment. From the classical and the DFTB/MM MD simulations, spectral densities and the (time-dependent) Hamiltonian of the complex were determined. Based on these results, three independent strongly coupled chlorophyll clusters were revealed within the complex. In addition, absorption and fluorescence spectra were determined together with the exciton relaxation dynamics, which reasonably well agrees with experimental time scales.
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Affiliation(s)
- Pooja Sarngadharan
- School of Science, Constructor
University, Campus Ring
1, 28759 Bremen, Germany
| | - Yannick Holtkamp
- School of Science, Constructor
University, Campus Ring
1, 28759 Bremen, Germany
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5
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Ahad S, Lin C, Reppert M. PigmentHunter: A point-and-click application for automated chlorophyll-protein simulations. J Chem Phys 2024; 160:154111. [PMID: 38639311 DOI: 10.1063/5.0198443] [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: 01/18/2024] [Accepted: 03/21/2024] [Indexed: 04/20/2024] Open
Abstract
Chlorophyll proteins (CPs) are the workhorses of biological photosynthesis, working together to absorb solar energy, transfer it to chemically active reaction centers, and control the charge-separation process that drives its storage as chemical energy. Yet predicting CP optical and electronic properties remains a serious challenge, driven by the computational difficulty of treating large, electronically coupled molecular pigments embedded in a dynamically structured protein environment. To address this challenge, we introduce here an analysis tool called PigmentHunter, which automates the process of preparing CP structures for molecular dynamics (MD), running short MD simulations on the nanoHUB.org science gateway, and then using electrostatic and steric analysis routines to predict optical absorption, fluorescence, and circular dichroism spectra within a Frenkel exciton model. Inter-pigment couplings are evaluated using point-dipole or transition-charge coupling models, while site energies can be estimated using both electrostatic and ring-deformation approaches. The package is built in a Jupyter Notebook environment, with a point-and-click interface that can be used either to manually prepare individual structures or to batch-process many structures at once. We illustrate PigmentHunter's capabilities with example simulations on spectral line shapes in the light harvesting 2 complex, site energies in the Fenna-Matthews-Olson protein, and ring deformation in photosystems I and II.
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Affiliation(s)
- S Ahad
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - C Lin
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - M Reppert
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
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6
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Cupellini L, Qian P, Nguyen-Phan TC, Gardiner AT, Cogdell RJ. Quantum chemical elucidation of a sevenfold symmetric bacterial antenna complex. PHOTOSYNTHESIS RESEARCH 2023; 156:75-87. [PMID: 35672557 PMCID: PMC10070313 DOI: 10.1007/s11120-022-00925-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 05/12/2022] [Indexed: 06/15/2023]
Abstract
The light-harvesting complex 2 (LH2) of purple bacteria is one of the most studied photosynthetic antenna complexes. Its symmetric structure and ring-like bacteriochlorophyll arrangement make it an ideal system for theoreticians and spectroscopists. LH2 complexes from most bacterial species are thought to have eightfold or ninefold symmetry, but recently a sevenfold symmetric LH2 structure from the bacterium Mch. purpuratum was solved by Cryo-Electron microscopy. This LH2 also possesses unique near-infrared absorption and circular dichroism (CD) spectral properties. Here we use an atomistic strategy to elucidate the spectral properties of Mch. purpuratum LH2 and understand the differences with the most commonly studied LH2 from Rbl. acidophilus. Our strategy exploits a combination of molecular dynamics simulations, multiscale polarizable quantum mechanics/molecular mechanics calculations, and lineshape simulations. Our calculations reveal that the spectral properties of LH2 complexes are tuned by site energies and exciton couplings, which in turn depend on the structural fluctuations of the bacteriochlorophylls. Our strategy proves effective in reproducing the absorption and CD spectra of the two LH2 complexes, and in uncovering the origin of their differences. This work proves that it is possible to obtain insight into the spectral tuning strategies of purple bacteria by quantitatively simulating the spectral properties of their antenna complexes.
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Affiliation(s)
- Lorenzo Cupellini
- Department of Chemistry and Industrial Chemistry, University of Pisa, 56124, Pisa, Italy.
| | - Pu Qian
- Materials and Structure Analysis, Thermofisher Scientific, Achtseweg Nordic 5, 5651 GTC, Eindhoven, The Netherlands
| | - Tu C Nguyen-Phan
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Alastair T Gardiner
- Laboratory of Anoxygenic Phototrophs, Centre Algatech, Novohradská 237 - Opatovický mlýn, 379 01, Třeboň, Czech Republic
| | - Richard J Cogdell
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, G12 8QQ, UK
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7
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Reiter S, Kiss FL, Hauer J, de Vivie-Riedle R. Thermal site energy fluctuations in photosystem I: new insights from MD/QM/MM calculations. Chem Sci 2023; 14:3117-3131. [PMID: 36970098 PMCID: PMC10034153 DOI: 10.1039/d2sc06160k] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 02/03/2023] [Indexed: 02/09/2023] Open
Abstract
Cyanobacterial photosystem I (PSI) is one of the most efficient photosynthetic machineries found in nature. Due to the large scale and complexity of the system, the energy transfer mechanism from the antenna complex to the reaction center is still not fully understood. A central element is the accurate evaluation of the individual chlorophyll excitation energies (site energies). Such an evaluation must include a detailed treatment of site specific environmental influences on structural and electrostatic properties, but also their evolution in the temporal domain, because of the dynamic nature of the energy transfer process. In this work, we calculate the site energies of all 96 chlorophylls in a membrane-embedded model of PSI. The employed hybrid QM/MM approach using the multireference DFT/MRCI method in the QM region allows to obtain accurate site energies under explicit consideration of the natural environment. We identify energy traps and barriers in the antenna complex and discuss their implications for energy transfer to the reaction center. Going beyond previous studies, our model also accounts for the molecular dynamics of the full trimeric PSI complex. Via statistical analysis we show that the thermal fluctuations of single chlorophylls prevent the formation of a single prominent energy funnel within the antenna complex. These findings are also supported by a dipole exciton model. We conclude that energy transfer pathways may form only transiently at physiological temperatures, as thermal fluctuations overcome energy barriers. The set of site energies provided in this work sets the stage for theoretical and experimental studies on the highly efficient energy transfer mechanisms in PSI.
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Affiliation(s)
- Sebastian Reiter
- Department of Chemistry, Ludwig-Maximilians-Universität München Butenandtstr. 11 81377 Munich Germany
| | - Ferdinand L Kiss
- Department of Chemistry, Ludwig-Maximilians-Universität München Butenandtstr. 11 81377 Munich Germany
| | - Jürgen Hauer
- Department of Chemistry, Technical University of Munich Lichtenbergstr. 4, Garching 85747 Germany
| | - Regina de Vivie-Riedle
- Department of Chemistry, Ludwig-Maximilians-Universität München Butenandtstr. 11 81377 Munich Germany
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8
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Mao R, Zhang H, Bie L, Liu LN, Gao J. Million-atom molecular dynamics simulations reveal the interfacial interactions and assembly of plant PSII-LHCII supercomplex. RSC Adv 2023; 13:6699-6712. [PMID: 36860540 PMCID: PMC9969236 DOI: 10.1039/d2ra08240c] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 02/07/2023] [Indexed: 03/02/2023] Open
Abstract
Protein-protein interface interactions dictate efficient excitation energy transfer from light-harvesting antennas to the photosystem II (PSII) core. In this work, we construct a 1.2 million atom-scale model of plant C2S2-type PSII-LHCII supercomplex and perform microsecond-scale molecular dynamics (MD) simulations to explore the interactions and assembly mechanisms of the sizeable PSII-LHCII supercomplex. We optimize the nonbonding interactions of the PSII-LHCII cryo-EM structure using microsecond-scale MD simulations. Binding free energy calculations with component decompositions reveal that hydrophobic interactions predominantly drive antenna-core association and the antenna-antenna interactions are relatively weak. Despite the positive electrostatic interaction energies, hydrogen bonds and salt bridges mainly provide directional or anchoring forces for interface binding. Analysis of the roles of small intrinsic subunits of PSII suggests that LHCII and CP26 first interact with small intrinsic subunits and then bind to the core proteins, whereas CP29 adopts a one-step binding process to the PSII core without the assistance of other factors. Our study provides insights into the molecular underpinnings of the self-organization and regulation of plant PSII-LHCII. It lays the framework for deciphering the general assembly principles of photosynthetic supercomplexes and possibly other macromolecular structures. The finding also has implications for repurposing photosynthetic systems to enhance photosynthesis.
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Affiliation(s)
- Ruichao Mao
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University Wuhan 430070 Hubei China
| | - Han Zhang
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University Wuhan 430070 Hubei China
| | - Lihua Bie
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University Wuhan 430070 Hubei China
| | - Lu-Ning Liu
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool Liverpool L69 7ZB UK .,Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China Qingdao 266003 China
| | - Jun Gao
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University Wuhan 430070 Hubei China
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9
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Braasch-Turi MM, Koehn JT, Crans DC. Chemistry of Lipoquinones: Properties, Synthesis, and Membrane Location of Ubiquinones, Plastoquinones, and Menaquinones. Int J Mol Sci 2022; 23:12856. [PMID: 36361645 PMCID: PMC9656164 DOI: 10.3390/ijms232112856] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 10/20/2022] [Accepted: 10/21/2022] [Indexed: 07/30/2023] Open
Abstract
Lipoquinones are the topic of this review and are a class of hydrophobic lipid molecules with key biological functions that are linked to their structure, properties, and location within a biological membrane. Ubiquinones, plastoquinones, and menaquinones vary regarding their quinone headgroup, isoprenoid sidechain, properties, and biological functions, including the shuttling of electrons between membrane-bound protein complexes within the electron transport chain. Lipoquinones are highly hydrophobic molecules that are soluble in organic solvents and insoluble in aqueous solution, causing obstacles in water-based assays that measure their chemical properties, enzyme activities and effects on cell growth. Little is known about the location and ultimately movement of lipoquinones in the membrane, and these properties are topics described in this review. Computational studies are particularly abundant in the recent years in this area, and there is far less experimental evidence to verify the often conflicting interpretations and conclusions that result from computational studies of very different membrane model systems. Some recent experimental studies have described using truncated lipoquinone derivatives, such as ubiquinone-2 (UQ-2) and menaquinone-2 (MK-2), to investigate their conformation, their location in the membrane, and their biological function. Truncated lipoquinone derivatives are soluble in water-based assays, and hence can serve as excellent analogs for study even though they are more mobile in the membrane than the longer chain counterparts. In this review, we will discuss the properties, location in the membrane, and syntheses of three main classes of lipoquinones including truncated derivatives. Our goal is to highlight the importance of bridging the gap between experimental and computational methods and to incorporate properties-focused considerations when proposing future studies relating to the function of lipoquinones in membranes.
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Affiliation(s)
| | - Jordan T. Koehn
- Chemistry Department, Colorado State University, Fort Collins, CO 80523, USA
| | - Debbie C. Crans
- Chemistry Department, Colorado State University, Fort Collins, CO 80523, USA
- Cell & Molecular Biology Program, Colorado State University, Fort Collins, CO 80523, USA
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10
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Wei RJ, Zhang Y, Mao J, Kaur D, Khaniya U, Gunner MR. Comparison of proton transfer paths to the Q A and Q B sites of the Rb. sphaeroides photosynthetic reaction centers. PHOTOSYNTHESIS RESEARCH 2022; 152:153-165. [PMID: 35344134 DOI: 10.1007/s11120-022-00906-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 02/18/2022] [Indexed: 06/14/2023]
Abstract
The photosynthetic bacterial reaction centers from purple non-sulfur bacteria use light energy to drive the transfer of electrons from cytochrome c to ubiquinone. Ubiquinone bound in the QA site cycles between quinone, QA, and anionic semiquinone, QA·-, being reduced once and never binding protons. In the QB site, ubiquinone is reduced twice by QA·-, binds two protons and is released into the membrane as the quinol, QH2. The network of hydrogen bonds formed in a molecular dynamics trajectory was drawn to investigate proton transfer pathways from the cytoplasm to each quinone binding site. QA is isolated with no path for protons to enter from the surface. In contrast, there is a complex and tangled network requiring residues and waters that can bring protons to QB. There are three entries from clusters of surface residues centered around HisH126, GluH224, and HisH68. The network is in good agreement with earlier studies, Mutation of key nodes in the network, such as SerL223, were previously shown to slow proton delivery. Mutational studies had also shown that double mutations of residues such as AspM17 and AspL210 along multiple paths in the network presented here slow the reaction, while single mutations do not. Likewise, mutation of both HisH126 and HisH128, which are at the entry to two paths reduce the rate of proton uptake.
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Affiliation(s)
- Rongmei Judy Wei
- Ph.D. Program in Chemistry, The Graduate Center, City University of New York, New York, NY, 10016, USA
- Department of Physics, City College of New York, New York, NY, 10031, USA
| | - Yingying Zhang
- Department of Physics, City College of New York, New York, NY, 10031, USA
- Ph.D. Program in Physics, The Graduate Center of the City University of New York, New York, NY, 10016, USA
| | - Junjun Mao
- Department of Physics, City College of New York, New York, NY, 10031, USA
| | - Divya Kaur
- Department of Chemistry, Brock University, 500 Glenridge Avenue, St. Catharines, ON, L2S 3A1, Canada
| | - Umesh Khaniya
- Department of Physics, City College of New York, New York, NY, 10031, USA
- Ph.D. Program in Physics, The Graduate Center of the City University of New York, New York, NY, 10016, USA
| | - M R Gunner
- Ph.D. Program in Chemistry, The Graduate Center, City University of New York, New York, NY, 10016, USA.
- Department of Physics, City College of New York, New York, NY, 10031, USA.
- Ph.D. Program in Physics, The Graduate Center of the City University of New York, New York, NY, 10016, USA.
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11
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Cignoni E, Slama V, Cupellini L, Mennucci B. The atomistic modeling of light-harvesting complexes from the physical models to the computational protocol. J Chem Phys 2022; 156:120901. [DOI: 10.1063/5.0086275] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The function of light-harvesting complexes is determined by a complex network of dynamic interactions among all the different components: the aggregate of pigments, the protein, and the surrounding environment. Complete and reliable predictions on these types of composite systems can be only achieved with an atomistic description. In the last few decades, there have been important advances in the atomistic modeling of light-harvesting complexes. These advances have involved both the completeness of the physical models and the accuracy and effectiveness of the computational protocols. In this Perspective, we present an overview of the main theoretical and computational breakthroughs attained so far in the field, with particular focus on the important role played by the protein and its dynamics. We then discuss the open problems in their accurate modeling that still need to be addressed. To illustrate an effective computational workflow for the modeling of light harvesting complexes, we take as an example the plant antenna complex CP29 and its H111N mutant.
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Affiliation(s)
- Edoardo Cignoni
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
| | - Vladislav Slama
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
| | - Lorenzo Cupellini
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
| | - Benedetta Mennucci
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
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12
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Braasch-Turi MM, Koehn JT, Kostenkova K, Van Cleave C, Ives JW, Murakami HA, Crick DC, Crans DC. Electron Transport Lipids Fold Within Membrane-Like Interfaces. Front Chem 2022; 10:827530. [PMID: 35350775 PMCID: PMC8957872 DOI: 10.3389/fchem.2022.827530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 01/07/2022] [Indexed: 12/23/2022] Open
Abstract
Lipoquinones, such as ubiquinones (UQ) and menaquinones (MK), function as essential lipid components of the electron transport system (ETS) by shuttling electrons and protons to facilitate the production of ATP in eukaryotes and prokaryotes. Lipoquinone function in membrane systems has been widely studied, but the exact location and conformation within membranes remains controversial. Lipoquinones, such as Coenzyme Q (UQ-10), are generally depicted simply as "Q" in life science diagrams or in extended conformations in primary literature even though specific conformations are important for function in the ETS. In this study, our goal was to determine the location, orientation, and conformation of UQ-2, a truncated analog of UQ-10, in model membrane systems and to compare our results to previously studied MK-2. Herein, we first carried out a six-step synthesis to yield UQ-2 and then demonstrated that UQ-2 adopts a folded conformation in organic solvents using 1H-1H 2D NOESY and ROESY NMR spectroscopic studies. Similarly, using 1H-1H 2D NOESY NMR spectroscopic studies, UQ-2 was found to adopt a folded, U-shaped conformation within the interface of an AOT reverse micelle model membrane system. UQ-2 was located slightly closer to the surfactant-water interface compared to the more hydrophobic MK-2. In addition, Langmuir monolayer studies determined UQ-2 resided within the monolayer water-phospholipid interface causing expansion, whereas MK-2 was more likely to be compressed out and reside within the phospholipid tails. All together these results support the model that lipoquinones fold regardless of the headgroup structure but that the polarity of the headgroup influences lipoquinone location within the membrane interface. These results have implications regarding the redox activity near the interface as quinone vs. quinol forms may facilitate locomotion of lipoquinones within the membrane. The location, orientation, and conformation of lipoquinones are critical for their function in generating cellular energy within membrane ETS, and the studies described herein shed light on the behavior of lipoquinones within membrane-like environments.
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Affiliation(s)
| | - Jordan T. Koehn
- Chemistry Department, Colorado State University, Fort Collins, CO, United States
| | - Kateryna Kostenkova
- Chemistry Department, Colorado State University, Fort Collins, CO, United States
| | - Cameron Van Cleave
- Chemistry Department, Colorado State University, Fort Collins, CO, United States
| | - Jacob W. Ives
- Chemistry Department, Colorado State University, Fort Collins, CO, United States
| | - Heide A. Murakami
- Chemistry Department, Colorado State University, Fort Collins, CO, United States
| | - Dean C. Crick
- Cell and Molecular Biology Program, Colorado State University, Fort Collins, CO, United States
- Microbiology, Immunology, and Pathology Department, Colorado State University, Fort Collins, CO, United States
| | - Debbie C. Crans
- Chemistry Department, Colorado State University, Fort Collins, CO, United States
- Cell and Molecular Biology Program, Colorado State University, Fort Collins, CO, United States
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13
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Structure of the stress-related LHCSR1 complex determined by an integrated computational strategy. Commun Biol 2022; 5:145. [PMID: 35177775 PMCID: PMC8854571 DOI: 10.1038/s42003-022-03083-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 01/25/2022] [Indexed: 11/08/2022] Open
Abstract
Light-harvesting complexes (LHCs) are pigment-protein complexes whose main function is to capture sunlight and transfer the energy to reaction centers of photosystems. In response to varying light conditions, LH complexes also play photoregulation and photoprotection roles. In algae and mosses, a sub-family of LHCs, light-harvesting complex stress-related (LHCSR), is responsible for photoprotective quenching. Despite their functional and evolutionary importance, no direct structural information on LHCSRs is available that can explain their unique properties. In this work, we propose a structural model of LHCSR1 from the moss P. patens, obtained through an integrated computational strategy that combines homology modeling, molecular dynamics, and multiscale quantum chemical calculations. The model is validated by reproducing the spectral properties of LHCSR1. Our model reveals the structural specificity of LHCSR1, as compared with the CP29 LH complex, and poses the basis for understanding photoprotective quenching in mosses. The structure of the moss P. patens light-harvesting complex stress-related 1 (LHCSR1) is determined using a multi-scale computational approach for investigations of its photoprotective function.
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14
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Petry S, Götze JP. Effect of protein matrix on CP29 spectra and energy transfer pathways. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148521. [PMID: 34896078 DOI: 10.1016/j.bbabio.2021.148521] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 10/25/2021] [Accepted: 12/02/2021] [Indexed: 06/14/2023]
Abstract
We investigate energy transfer pathways between strongly coupled chlorophylls (Chls) in the CP29 (LHCII B4.1) antenna complex of Pisum sativum, including the possibility of higher energy states. We test for the environmental effects caused by the protein, membrane and solvent using a hybrid QM/MM approach. Classical molecular dynamics simulations of the full CP29 complex embedded in a DOPC membrane have been performed, followed by calculations of the time dependent DFT spectra of all Chls at several timesteps. The relative orientations of transition dipole moments (TDMs) were specifically analyzed, including and excluding the point charge field (PCF) of the surrounding environment. The PCF is found to drastically shift the spectra of specific Chls, while the majority of Chls is mostly unaffected. The net effect on the sum spectrum is however found to be negligible: The few strong changes in Chl spectra cancel each other due to being opposite in sign. We further find that the spectra of the Chls coordinating to water show a blue shift upon introduction of the environment. Conversely, the spectra of the Chls coordinating to glutamine show a red shift upon activation of the PCF. As the main influence of the PCF for tuning the couplings, we identify the energetic position of the individual chromophores. The fine-tuning, especially for states energetically above the Qy state, is however controlled by the changes in the TDM orientations. We also find an indication for the PCF to steer potentially harmful high energy excitations away from the PSII core complex.
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Affiliation(s)
- S Petry
- Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Berlin, Germany.
| | - J P Götze
- Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Berlin, Germany.
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15
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Mao R, Wang X, Gao J. Bridging Carotenoid-to-Bacteriochlorophyll Energy Transfer of Purple Bacteria LH2 With Temperature Variations: Insights From Conformational Changes. Front Chem 2021; 9:764107. [PMID: 34671594 PMCID: PMC8521103 DOI: 10.3389/fchem.2021.764107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 09/20/2021] [Indexed: 11/13/2022] Open
Abstract
Photosynthesis is a key process for converting light energy into chemical energy and providing food for lives on Earth. Understanding the mechanism for the energy transfers could provide insights into regulating energy transfers in photosynthesis and designing artificial photosynthesis systems. Many efforts have been devoted to exploring the mechanism of temperature variations affecting the excitonic properties of LH2. In this study, we performed all-atom molecular dynamics (MD) simulations and quantum mechanics calculations for LH2 complex from purple bacteria along with its membrane environment under three typical temperatures: 270, 300, and 330 K. The structural analysis from validated MD simulations showed that the higher temperature impaired interactions at N-terminus of both α and β polypeptide helices and led to the dissociation of this hetero polypeptide dimer. Rhodopin-β-D-glucosides (RG1) moved centripetally with α polypeptide helices when temperature increased and enlarged their distances with bacteriochlorophylls molecules that have the absorption peak at 850 nm (B850), which resulted in reducing the coupling strengths between RG1 and B850 molecules. The present study reported a cascading mechanism for temperature regulating the energy transfers in LH2 of purple bacteria.
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Affiliation(s)
- Ruichao Mao
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, China
| | - Xiaocong Wang
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, China
| | - Jun Gao
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, China
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16
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Maity S, Sarngadharan P, Daskalakis V, Kleinekathöfer U. Time-dependent atomistic simulations of the CP29 light-harvesting complex. J Chem Phys 2021; 155:055103. [PMID: 34364345 DOI: 10.1063/5.0053259] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Light harvesting as the first step in photosynthesis is of prime importance for life on earth. For a theoretical description of photochemical processes during light harvesting, spectral densities are key quantities. They serve as input functions for modeling the excitation energy transfer dynamics and spectroscopic properties. Herein, a recently developed procedure is applied to determine the spectral densities of the pigments in the minor antenna complex CP29 of photosystem II, which has recently gained attention because of its active role in non-photochemical quenching processes in higher plants. To this end, the density functional-based tight binding (DFTB) method has been employed to enable simulation of the ground state dynamics in a quantum-mechanics/molecular mechanics (QM/MM) scheme for each chlorophyll pigment. Subsequently, the time-dependent extension of the long-range corrected DFTB approach has been used to obtain the excitation energy fluctuations along the ground-state trajectories also in a QM/MM setting. From these results, the spectral densities have been determined and compared for different force fields and to spectral densities from other light-harvesting complexes. In addition, time-dependent and time-independent excitonic Hamiltonians of the system have been constructed and applied to the determination of absorption spectra as well as exciton dynamics.
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Affiliation(s)
- Sayan Maity
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Pooja Sarngadharan
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Vangelis Daskalakis
- Department of Chemical Engineering, Cyprus University of Technology, 30 Archbishop Kyprianou Str. 3603, Limassol, Cyprus
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
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17
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Ultrafast structural changes within a photosynthetic reaction centre. Nature 2021; 589:310-314. [PMID: 33268896 DOI: 10.1038/s41586-020-3000-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 09/28/2020] [Indexed: 01/29/2023]
Abstract
Photosynthetic reaction centres harvest the energy content of sunlight by transporting electrons across an energy-transducing biological membrane. Here we use time-resolved serial femtosecond crystallography1 using an X-ray free-electron laser2 to observe light-induced structural changes in the photosynthetic reaction centre of Blastochloris viridis on a timescale of picoseconds. Structural perturbations first occur at the special pair of chlorophyll molecules of the photosynthetic reaction centre that are photo-oxidized by light. Electron transfer to the menaquinone acceptor on the opposite side of the membrane induces a movement of this cofactor together with lower amplitude protein rearrangements. These observations reveal how proteins use conformational dynamics to stabilize the charge-separation steps of electron-transfer reactions.
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18
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Klinger A, Lindorfer D, Müh F, Renger T. Normal mode analysis of spectral density of FMO trimers: Intra- and intermonomer energy transfer. J Chem Phys 2020; 153:215103. [PMID: 33291900 DOI: 10.1063/5.0027994] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The intermolecular contribution to the spectral density of the exciton-vibrational coupling of the homotrimeric Fenna-Matthews-Olson (FMO) light-harvesting protein of green sulfur bacteria P. aestuarii is analyzed by combining a normal mode analysis of the protein with the charge density coupling method for the calculation of local transition energies of the pigments. Correlations in site energy fluctuations across the whole FMO trimer are found at low vibrational frequencies. Including, additionally, the high-frequency intrapigment part of the spectral density, extracted from line-narrowing spectra, we study intra- and intermonomer exciton transfer. Whereas the intrapigment part of the spectral density is important for fast intramonomer exciton relaxation, the intermolecular contributions (due to pigment-environment coupling) determine the intermonomer exciton transfer. Neither the variations of the local Huang-Rhys factors nor the correlations in site energy fluctuations have a critical influence on energy transfer. At room temperature, the intermonomer transfer in the FMO protein occurs on a 10 ps time scale, whereas intramonomer exciton equilibration is roughly two orders of magnitude faster. At cryogenic temperatures, intermonomer transfer limits the lifetimes of the lowest exciton band. The lifetimes are found to increase between 20 ps in the center of this band up to 100 ps toward lower energies, which is in very good agreement with the estimates from hole burning data. Interestingly, exciton delocalization in the FMO monomers is found to slow down intermonomer energy transfer, at both physiological and cryogenic temperatures.
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Affiliation(s)
- Alexander Klinger
- Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Str. 69, 4040 Linz, Austria
| | - Dominik Lindorfer
- Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Str. 69, 4040 Linz, Austria
| | - Frank Müh
- Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Str. 69, 4040 Linz, Austria
| | - Thomas Renger
- Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Str. 69, 4040 Linz, Austria
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19
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Sirohiwal A, Neese F, Pantazis DA. Protein Matrix Control of Reaction Center Excitation in Photosystem II. J Am Chem Soc 2020; 142:18174-18190. [PMID: 33034453 PMCID: PMC7582616 DOI: 10.1021/jacs.0c08526] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Indexed: 02/06/2023]
Abstract
Photosystem II (PSII) is a multisubunit pigment-protein complex that uses light-induced charge separation to power oxygenic photosynthesis. Its reaction center chromophores, where the charge transfer cascade is initiated, are arranged symmetrically along the D1 and D2 core polypeptides and comprise four chlorophyll (PD1, PD2, ChlD1, ChlD2) and two pheophytin molecules (PheoD1 and PheoD2). Evolution favored productive electron transfer only via the D1 branch, with the precise nature of primary excitation and the factors that control asymmetric charge transfer remaining under investigation. Here we present a detailed atomistic description for both. We combine large-scale simulations of membrane-embedded PSII with high-level quantum-mechanics/molecular-mechanics (QM/MM) calculations of individual and coupled reaction center chromophores to describe reaction center excited states. We employ both range-separated time-dependent density functional theory and the recently developed domain based local pair natural orbital (DLPNO) implementation of the similarity transformed equation of motion coupled cluster theory with single and double excitations (STEOM-CCSD), the first coupled cluster QM/MM calculations of the reaction center. We find that the protein matrix is exclusively responsible for both transverse (chlorophylls versus pheophytins) and lateral (D1 versus D2 branch) excitation asymmetry, making ChlD1 the chromophore with the lowest site energy. Multipigment calculations show that the protein matrix renders the ChlD1 → PheoD1 charge-transfer the lowest energy excitation globally within the reaction center, lower than any pigment-centered local excitation. Remarkably, no low-energy charge transfer states are located within the "special pair" PD1-PD2, which is therefore excluded as the site of initial charge separation in PSII. Finally, molecular dynamics simulations suggest that modulation of the electrostatic environment due to protein conformational flexibility enables direct excitation of low-lying charge transfer states by far-red light.
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Affiliation(s)
- Abhishek Sirohiwal
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
- Fakultät
für Chemie und Biochemie, Ruhr-Universität
Bochum, 44780 Bochum, Germany
| | - Frank Neese
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Dimitrios A. Pantazis
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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20
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Maity S, Bold BM, Prajapati JD, Sokolov M, Kubař T, Elstner M, Kleinekathöfer U. DFTB/MM Molecular Dynamics Simulations of the FMO Light-Harvesting Complex. J Phys Chem Lett 2020; 11:8660-8667. [PMID: 32991176 DOI: 10.1021/acs.jpclett.0c02526] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Because of the size of light-harvesting complexes and the involvement of electronic degrees of freedom, computationally these systems need to be treated with a combined quantum-classical description. To this end, Born-Oppenheimer molecular dynamics simulations have been employed in a quantum mechanics/molecular mechanics (QM/MM) fashion for the ground state followed by excitation energy calculations again in a QM/MM scheme for the Fenna-Matthews-Olson (FMO) complex. The self-consistent-charge density functional tight-binding (DFTB) method electrostatically coupled to a classical description of the environment was applied to perform the ground-state dynamics. Subsequently, long-range-corrected time-dependent DFTB calculations were performed to determine the excitation energy fluctuations of the individual bacteriochlorophyll a molecules. The spectral densities obtained using this approach show an excellent agreement with experimental findings. In addition, the fluctuating site energies and couplings were used to estimate the exciton transfer dynamics.
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Affiliation(s)
- Sayan Maity
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Beatrix M Bold
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | | | - Monja Sokolov
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | - Tomáš Kubař
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | - Marcus Elstner
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76131 Karlsruhe, Germany
- Institute of Biological Interfaces, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
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21
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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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22
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Kaliakin DS, Nakata H, Kim Y, Chen Q, Fedorov DG, Slipchenko LV. FMOxFMO: Elucidating Excitonic Interactions in the Fenna-Matthews-Olson Complex with the Fragment Molecular Orbital Method. J Chem Theory Comput 2020; 16:1175-1187. [PMID: 31841349 DOI: 10.1021/acs.jctc.9b00621] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In order to study Förster resonance energy transfer (FRET), the fragment molecular orbital (FMO) method is extended to compute electronic couplings between local excitations via the excited state transition density model, enabling efficient calculations of nonlocal excitations in a large molecular system and overcoming the previous limitation of being able to compute only local excitations. The results of these simple but accurate models are validated against full quantum calculations without fragmentation. The developed method is applied to a very important photosynthetic pigment-protein complex, the Fenna-Matthews-Olson complex (FMOc), that is responsible for the energy transfer from a chlorosome to the reaction center in the green sulfur bacteria. Absorption and circular dichroism spectra of FMOc are simulated, and the role of the molecular environment on the excitations is revealed.
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Affiliation(s)
- Danil S Kaliakin
- Department of Chemistry , Purdue University , 560 Oval Drive , West Lafayette , Indiana 47907 , United States
| | - Hiroya Nakata
- Research Institute for Advanced Materials and Devices , Kyocera , 5-3 Hikaridai-3 , Seika-cho Soraku-gun, Kyoto 619-0237 , Japan
| | - Yongbin Kim
- Department of Chemistry , Purdue University , 560 Oval Drive , West Lafayette , Indiana 47907 , United States
| | - Qifeng Chen
- Department of Chemistry , Purdue University , 560 Oval Drive , West Lafayette , Indiana 47907 , United States
| | - Dmitri G Fedorov
- Research Center for Computational Design of Advanced Functional Materials (CD-FMat) , National Institute of Advanced Industrial Science and Technology (AIST) , Central 2, Umezono 1-1-1 , Tsukuba 305-8568 , Japan
| | - Lyudmila V Slipchenko
- Department of Chemistry , Purdue University , 560 Oval Drive , West Lafayette , Indiana 47907 , United States
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23
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Ogata K, Hatakeyama M, Sakamoto Y, Nakamura S. Investigation of a Pathway for Water Delivery in Photosystem II Protein by Molecular Dynamics Simulation. J Phys Chem B 2019; 123:6444-6452. [DOI: 10.1021/acs.jpcb.9b04838] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Koji Ogata
- Nakamura Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Makoto Hatakeyama
- Nakamura Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yuki Sakamoto
- Nakamura Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Biological Information, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
| | - Shinichiro Nakamura
- Nakamura Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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24
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Saggu M, Fried SD, Boxer SG. Local and Global Electric Field Asymmetry in Photosynthetic Reaction Centers. J Phys Chem B 2019; 123:1527-1536. [PMID: 30668130 DOI: 10.1021/acs.jpcb.8b11458] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The origin of unidirectional electron transfer in photosynthetic reaction centers (RCs) has been widely discussed. Despite the high level of structural similarity between the two branches of pigments that participate in the initial electron transfer steps of photosynthesis, electron transfer only occurs along one branch. One possible explanation for this functional asymmetry is the differences in the electrostatic environment between the active and the inactive branches arising from the charges and dipoles of the organized protein structure. We present an analysis of electric fields in the RC of the purple bacterium Rhodobacter sphaeroides using the intrinsic carbonyl groups of the pigments as vibrational reporters whose vibrational frequency shifts can be converted into electric fields based on the vibrational Stark effect and also provide Stark effect data for plant pigments that can be used in future studies. The carbonyl stretches of the isolated pigments show pronounced Stark effects. We use these data, solvatochromism, molecular dynamics simulations, and data in the literature from IR and Raman spectra to evaluate differences in fields at symmetry-related positions, in particular at the 9-keto and 2-acetyl positions of the pigments involved in primary charge separation.
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Affiliation(s)
- Miguel Saggu
- Department of Chemistry , Stanford University , Stanford , California 94305-5080 , United States
| | - Stephen D Fried
- Department of Chemistry , Stanford University , Stanford , California 94305-5080 , United States
| | - Steven G Boxer
- Department of Chemistry , Stanford University , Stanford , California 94305-5080 , United States
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25
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Claridge K, Troisi A. Developing Consistent Molecular Dynamics Force Fields for Biological Chromophores via Force Matching. J Phys Chem B 2018; 123:428-438. [DOI: 10.1021/acs.jpcb.8b10746] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kirsten Claridge
- Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, U.K
| | - Alessandro Troisi
- Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, U.K
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26
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Mallus MI, Shakya Y, Prajapati JD, Kleinekathöfer U. Environmental effects on the dynamics in the light-harvesting complexes LH2 and LH3 based on molecular simulations. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.08.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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27
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Nottoli M, Jurinovich S, Cupellini L, Gardiner AT, Cogdell R, Mennucci B. The role of charge-transfer states in the spectral tuning of antenna complexes of purple bacteria. PHOTOSYNTHESIS RESEARCH 2018; 137:215-226. [PMID: 29502240 DOI: 10.1007/s11120-018-0492-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 02/23/2018] [Indexed: 05/21/2023]
Abstract
The LH2 antenna complexes of purple bacteria occur, depending on light conditions, in various different spectroscopic forms, with a similar structure but different absorption spectra. The differences are related to point changes in the primary amino acid sequence, but the molecular-level relationship between these changes and the resulting spectrum is still not well understood. We undertook a systematic quantum chemical analysis of all the main factors that contribute to the exciton structure, looking at how the environment modulates site energies and couplings in the B800-850 and B800-820 spectroscopic forms of LH2. A multiscale approach combining quantum chemistry and an atomistic classical embedding has been used where mutual polarization effects between the two parts are taken into account. We find that the loss of hydrogen bonds following amino acid changes can only explain a part of the observed blue-shift in the B850 band. The coupling of excitonic states to charge-transfer states, which is different in the two forms, contributes with a similar amount to the overall blue-shift.
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Affiliation(s)
- Michele Nottoli
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi 13, I-56124, Pisa, Italy
| | - Sandro Jurinovich
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi 13, I-56124, Pisa, Italy
| | - Lorenzo Cupellini
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi 13, I-56124, Pisa, Italy
| | - Alastair T Gardiner
- Glasgow Biomedical Research Centre, Institute of Molecular Cell and Systems Biology, University of Glasgow, 126 University Place, Glasgow, G12 8TA, Scotland, UK
| | - Richard Cogdell
- Glasgow Biomedical Research Centre, Institute of Molecular Cell and Systems Biology, University of Glasgow, 126 University Place, Glasgow, G12 8TA, Scotland, UK
| | - Benedetta Mennucci
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi 13, I-56124, Pisa, Italy.
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28
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Absorption-energy calculations of chlorophyll a and b with an explicit solvent model. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2017.10.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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29
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Pavlova A, Parks JM, Gumbart JC. Development of CHARMM-Compatible Force-Field Parameters for Cobalamin and Related Cofactors from Quantum Mechanical Calculations. J Chem Theory Comput 2018; 14:784-798. [PMID: 29334459 DOI: 10.1021/acs.jctc.7b01236] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Corrinoid cofactors such as cobalamin are used by many enzymes and are essential for most living organisms. Therefore, there is broad interest in investigating cobalamin-protein interactions with molecular dynamics simulations. Previously developed parameters for cobalamins are based mainly on crystal structure data. Here, we report CHARMM-compatible force field parameters for several corrinoids developed from quantum mechanical calculations. We provide parameters for corrinoids in three oxidation states, Co3+, Co2+, and Co1+, and with various axial ligands. Lennard-Jones parameters for the cobalt center in the Co(II) and Co(I) states were optimized using a helium atom probe, and partial atomic charges were obtained with a combination of natural population analysis (NPA) and restrained electrostatic potential (RESP) fitting approaches. The Force Field Toolkit was used to optimize all bonded terms. The resulting parameters, determined solely from calculations of cobalamin alone or in water, were then validated by assessing their agreement with density functional theory geometries and by analyzing molecular dynamics simulation trajectories of several corrinoid proteins for which X-ray crystal structures are available. In each case, we obtained excellent agreement with the reference data. In comparison to previous CHARMM-compatible parameters for cobalamin, we observe a better agreement for the fold angle and lower RMSD in the cobalamin binding site. The approach described here is readily adaptable for developing CHARMM-compatible force-field parameters for other corrinoids or large biomolecules.
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Affiliation(s)
- Anna Pavlova
- School of Physics, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Jerry M Parks
- Biosciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.,School of Chemistry and Biochemistry, Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
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30
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Balevičius V, Fox KF, Bricker WP, Jurinovich S, Prandi IG, Mennucci B, Duffy CDP. Fine control of chlorophyll-carotenoid interactions defines the functionality of light-harvesting proteins in plants. Sci Rep 2017; 7:13956. [PMID: 29066753 PMCID: PMC5655323 DOI: 10.1038/s41598-017-13720-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 09/26/2017] [Indexed: 11/08/2022] Open
Abstract
Photosynthetic antenna proteins can be thought of as "programmed solvents", which bind pigments at specific mutual orientations, thus tuning the overall energetic landscape and ensuring highly efficient light-harvesting. While positioning of chlorophyll cofactors is well understood and rationalized by the principle of an "energy funnel", the carotenoids still pose many open questions. Particularly, their short excited state lifetime (<25 ps) renders them potential energy sinks able to compete with the reaction centers and drastically undermine light-harvesting efficiency. Exploration of the orientational phase-space revealed that the placement of central carotenoids minimizes their interaction with the nearest chlorophylls in the plant antenna complexes LHCII, CP26, CP29 and LHCI. At the same time we show that this interaction is highly sensitive to structural perturbations, which has a profound effect on the overall lifetime of the complex. This links the protein dynamics to the light-harvesting regulation in plants by the carotenoids.
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Affiliation(s)
- Vytautas Balevičius
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Kieran F Fox
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - William P Bricker
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Sandro Jurinovich
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi 13, Pisa, 56124, Italy
| | - Ingrid G Prandi
- Department of Chemistry, Federal University of Lavras, 37200-000, Lavras, Brazil
- Laboratory of Molecular Modeling Applied to the Chemical and Biological Defense, Military Institute of Engineering, Praça Gen, Tibúrcio, 80, Rio de Janeiro, Brazil
| | - Benedetta Mennucci
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi 13, Pisa, 56124, Italy
| | - Christopher D P Duffy
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK.
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31
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Mallus MI, Schallwig M, Kleinekathöfer U. Relation between Vibrational Dephasing Time and Energy Gap Fluctuations. J Phys Chem B 2017. [PMID: 28625060 DOI: 10.1021/acs.jpcb.7b02693] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dephasing processes are present in basically all applications in which quantum mechanics plays a role. These applications certainly include excitation energy and charge transfer in biological systems. In a previous study, we have analyzed the vibrational dephasing time as a function of energy gap fluctuation for a large set of molecular simulations. In that investigation, individual molecular subunits were the focus of the calculations. The set of studied molecules included bacteriochlorophylls in Fenna-Matthews-Olson and light-harvesting system 2 complexes as well as bilins in PE545 aggregates. The present work extends this study to entire complexes, including the respective intermolecular couplings. Again, it can be concluded that a universal and inverse proportionality exists between dephasing time and variance of the excitonic energy gap fluctuations, whereas the respective proportionality constants can be rationalized using the energy gap autocorrelation functions. Furthermore, these findings can be extended to the gaps between higher-lying neighboring excitonic states.
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Affiliation(s)
- Maria Ilaria Mallus
- Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany
| | - Maximilian Schallwig
- Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany
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32
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Sakashita N, Watanabe HC, Ikeda T, Saito K, Ishikita H. Origins of Water Molecules in the Photosystem II Crystal Structure. Biochemistry 2017; 56:3049-3057. [DOI: 10.1021/acs.biochem.7b00220] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Naoki Sakashita
- Department
of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - Hiroshi C. Watanabe
- Department
of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
- Research
Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Takuya Ikeda
- Department
of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - Keisuke Saito
- Department
of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
- Research
Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Hiroshi Ishikita
- Department
of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
- Research
Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
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33
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Sisto A, Stross C, van der Kamp MW, O’Connor M, McIntosh-Smith S, Johnson GT, Hohenstein EG, Manby FR, Glowacki DR, Martinez TJ. Atomistic non-adiabatic dynamics of the LH2 complex with a GPU-accelerated ab initio exciton model. Phys Chem Chem Phys 2017; 19:14924-14936. [DOI: 10.1039/c7cp00492c] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We present GPU-accelerated ab initio molecular dynamics simulations of nonadiabatic dynamics in the LH2 complex in full atomistic detail.
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Affiliation(s)
- Aaron Sisto
- PULSE Institute and Department of Chemistry
- Stanford University
- Stanford
- USA
- SLAC National Accelerator Laboratory
| | - Clem Stross
- School of Chemistry
- University of Bristol
- Bristol
- UK
| | | | - Michael O’Connor
- School of Chemistry
- University of Bristol
- Bristol
- UK
- Department of Computer Science
| | | | - Graham T. Johnson
- California Institute for Quantitative Biosciences (QB3)
- University of California
- San Francisco
- USA
- Department of Bioengineering and Therapeutic Sciences
| | | | | | - David R. Glowacki
- School of Chemistry
- University of Bristol
- Bristol
- UK
- Department of Computer Science
| | - Todd J. Martinez
- PULSE Institute and Department of Chemistry
- Stanford University
- Stanford
- USA
- SLAC National Accelerator Laboratory
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34
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Kim CW, Rhee YM. Constructing an Interpolated Potential Energy Surface of a Large Molecule: A Case Study with Bacteriochlorophyll a Model in the Fenna-Matthews-Olson Complex. J Chem Theory Comput 2016; 12:5235-5246. [PMID: 27760297 DOI: 10.1021/acs.jctc.6b00647] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Constructing a reliable potential energy surface (PES) is a key step toward computationally studying the chemical dynamics of any molecular system. The interpolation scheme is a useful tool that can closely follow the accuracy of quantum chemical means at a dramatically reduced computational cost. However, applying interpolation to building a PES of a large molecule is not a straightforward black-box approach, as it frequently encounters practical difficulties associated with its large dimensionality. Here, we present detailed courses of applying interpolation toward building a PES of a large chromophore molecule. We take the example of S0 and S1 electronic states of bacteriochlorophyll a (BChla) molecules in the Fenna-Matthews-Olson light harvesting complex. With a reduced model molecule that bears BChla's main π-conjugated ring, various practical approaches are designed for improving the PES quality in a stable manner and for fine-tuning the final surface such that the surface can be adopted for long time molecular dynamics simulations. Combined with parallel implementation, we show that interpolated mechanics/molecular mechanics (IM/MM) simulations of the entire complex in the nanosecond time scale can be conducted readily without any practical issues. With 1500 interpolation data points for each chromophore unit, the PES error relative to the reference quantum chemical calculation is found to be ∼0.15 eV in the thermally accessible region of the conformational space, together with ∼0.01 eV error in S0 - S1 transition energies. The performance issue related to the use of a large interpolation database within the framework of our parallel routines is also discussed.
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Affiliation(s)
- Chang Woo Kim
- Center for Self-assembly and Complexity, Institute for Basic Science (IBS) , Pohang 37673, Korea.,Department of Chemistry, Pohang University of Science and Technology (POSTECH) , Pohang 37673, Korea
| | - Young Min Rhee
- Center for Self-assembly and Complexity, Institute for Basic Science (IBS) , Pohang 37673, Korea.,Department of Chemistry, Pohang University of Science and Technology (POSTECH) , Pohang 37673, Korea
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35
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Cupellini L, Jurinovich S, Campetella M, Caprasecca S, Guido CA, Kelly SM, Gardiner AT, Cogdell R, Mennucci B. An Ab Initio Description of the Excitonic Properties of LH2 and Their Temperature Dependence. J Phys Chem B 2016; 120:11348-11359. [PMID: 27791372 DOI: 10.1021/acs.jpcb.6b06585] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The spectroscopic properties of light-harvesting (LH) antennae in photosyntehtic organisms represent a fingerprint that is unique for each specific pigment-protein complex. Because of that, spectroscopic observations are generally combined with structural data from X-ray crystallography to obtain an indirect representation of the excitonic properties of the system. Here, an alternative strategy is presented which goes beyond this empirical approach and introduces an ab initio computational description of both structural and electronic properties and their dependence on the temperature. The strategy is applied to the peripheral light-harvesting antenna complex (LH2) present in purple bacteria. By comparing this model with the one based on the crystal structure, a detailed, molecular level explanation of the absorption and circular dichroism (CD) spectra and their temperature dependence is achieved. The agreement obtained with the experiments at both low and room temperature lays the groundwork for an atomistic understanding of the excitation dynamics in the LH2 system.
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Affiliation(s)
- Lorenzo Cupellini
- Dipartimento di Chimica e Chimica Industriale, University of Pisa , Via G. Moruzzi 13, I-56124 Pisa, Italy
| | - Sandro Jurinovich
- Dipartimento di Chimica e Chimica Industriale, University of Pisa , Via G. Moruzzi 13, I-56124 Pisa, Italy
| | - Marco Campetella
- Dipartimento di Chimica e Chimica Industriale, University of Pisa , Via G. Moruzzi 13, I-56124 Pisa, Italy
| | - Stefano Caprasecca
- Dipartimento di Chimica e Chimica Industriale, University of Pisa , Via G. Moruzzi 13, I-56124 Pisa, Italy
| | - Ciro A Guido
- Dipartimento di Chimica e Chimica Industriale, University of Pisa , Via G. Moruzzi 13, I-56124 Pisa, Italy
| | - Sharon M Kelly
- Life Sciences Biomolecular Sci, Joseph Black Building, University of Glasgow , Glasgow G12 8QQ, Scotland
| | - Alastair T Gardiner
- Glasgow Biomedical Research Centre, Institute of Molecular Cell and Systems Biology, University of Glasgow , 126 University Place, Glasgow G12 8TA, Scotland
| | - Richard Cogdell
- Glasgow Biomedical Research Centre, Institute of Molecular Cell and Systems Biology, University of Glasgow , 126 University Place, Glasgow G12 8TA, Scotland
| | - Benedetta Mennucci
- Dipartimento di Chimica e Chimica Industriale, University of Pisa , Via G. Moruzzi 13, I-56124 Pisa, Italy
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36
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Markovich T, Blau SM, Parkhill J, Kreisbeck C, Sanders JN, Andrade X, Aspuru-Guzik A. Accelerating the computation of bath spectral densities with super-resolution. Theor Chem Acc 2016. [DOI: 10.1007/s00214-016-1954-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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37
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Häse F, Valleau S, Pyzer-Knapp E, Aspuru-Guzik A. Machine learning exciton dynamics. Chem Sci 2016; 7:5139-5147. [PMID: 30155164 PMCID: PMC6020119 DOI: 10.1039/c5sc04786b] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 04/01/2016] [Indexed: 12/19/2022] Open
Abstract
Obtaining the exciton dynamics of large photosynthetic complexes by using mixed quantum mechanics/molecular mechanics (QM/MM) is computationally demanding. We propose a machine learning technique, multi-layer perceptrons, as a tool to reduce the time required to compute excited state energies. With this approach we predict time-dependent density functional theory (TDDFT) excited state energies of bacteriochlorophylls in the Fenna-Matthews-Olson (FMO) complex. Additionally we compute spectral densities and exciton populations from the predictions. Different methods to determine multi-layer perceptron training sets are introduced, leading to several initial data selections. In addition, we compute spectral densities and exciton populations. Once multi-layer perceptrons are trained, predicting excited state energies was found to be significantly faster than the corresponding QM/MM calculations. We showed that multi-layer perceptrons can successfully reproduce the energies of QM/MM calculations to a high degree of accuracy with prediction errors contained within 0.01 eV (0.5%). Spectral densities and exciton dynamics are also in agreement with the TDDFT results. The acceleration and accurate prediction of dynamics strongly encourage the combination of machine learning techniques with ab initio methods.
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Affiliation(s)
- Florian Häse
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , 02138 , USA . ; Tel: +1-617-384-8188
- Physik-Department T38 , Technische Universität München , Garching , 85748 , Germany
| | - Stéphanie Valleau
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , 02138 , USA . ; Tel: +1-617-384-8188
| | - Edward Pyzer-Knapp
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , 02138 , USA . ; Tel: +1-617-384-8188
| | - Alán Aspuru-Guzik
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , 02138 , USA . ; Tel: +1-617-384-8188
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38
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Mallus MI, Aghtar M, Chandrasekaran S, Lüdemann G, Elstner M, Kleinekathöfer U. Relation between Dephasing Time and Energy Gap Fluctuations in Biomolecular Systems. J Phys Chem Lett 2016; 7:1102-1108. [PMID: 26950038 DOI: 10.1021/acs.jpclett.6b00134] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Excitation energy and charge transfer are fundamental processes in biological systems. Because of their quantum nature, the effect of dephasing on these processes is of interest especially when trying to understand their efficiency. Moreover, recent experiments have shown quantum coherences in such systems. As a first step toward a better understanding, we studied the relationship between dephasing time and energy gap fluctuations of the individual molecular subunits. A larger set of molecular simulations has been investigated to shed light on this dependence. This set includes bacterio-chlorophylls in Fenna-Matthews-Olson complexes, the PE545 aggregate, the LH2 complexes, DNA, photolyase, and cryptochromes. For the individual molecular subunits of these aggregates it has been confirmed quantitatively that an inverse proportionality exists between dephasing time and average gap energy fluctuation. However, for entire complexes including the respective intermolecular couplings, such a relation still needs to be verified.
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Affiliation(s)
- Maria Ilaria Mallus
- Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany
| | - Mortaza Aghtar
- Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany
| | | | - Gesa Lüdemann
- Institute of Physical Chemistry, Karlsruhe Institute of Technology , 76131 Karlsruhe, Germany
| | - Marcus Elstner
- Institute of Physical Chemistry, Karlsruhe Institute of Technology , 76131 Karlsruhe, Germany
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany
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39
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Jurinovich S, Viani L, Prandi IG, Renger T, Mennucci B. Towards an ab initio description of the optical spectra of light-harvesting antennae: application to the CP29 complex of photosystem II. Phys Chem Chem Phys 2016; 17:14405-16. [PMID: 25872495 DOI: 10.1039/c4cp05647g] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Light-harvesting pigment-protein complexes (PPC) represent the fundamental units through which the photosynthetic organisms absorb sunlight and funnel the energy to the reaction centre for carrying out the primary energy conversion reactions of photosynthesis. Here we apply a multiscale computational strategy to a specific PPC present in the photosystem II of plants and algae (CP29) to investigate in what detail should the environment effects due to protein and membrane/solvent be included for an accurate description of optical spectra. We find that a refinement of the crystal structure is needed before any meaningful quantum chemical calculations of pigment transition energies can be performed. For this purpose we apply classical molecular dynamics simulations of the PPC within its natural environment and we perform ab initio computations of the exciton Hamiltonian of the complex, including the environment either implicitly by the polarizable continuum model (PCM) or explicitly using the polarizable QM/MM methodology (MMPol). However, PCM essentially leads to an unspecific redshift of all transition energies, and MMPol is able to reveal site-specific changes in the optical properties of the pigments. Based on the latter and the excitonic couplings obtained within a polarizable QM/MM methodology, optical spectra are calculated, which are in good qualitative agreement with experimental data. A weakness of the approach is however found in the overestimation of the fluctuations of the excitonic parameters of the pigments along the MD trajectory. An explanation for such a finding in terms of the limits of the force fields commonly used for protein cofactors is presented and discussed.
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Affiliation(s)
- Sandro Jurinovich
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi 3, I-56124 Pisa, Italy.
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40
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Prandi IG, Viani L, Andreussi O, Mennucci B. Combining classical molecular dynamics and quantum mechanical methods for the description of electronic excitations: The case of carotenoids. J Comput Chem 2016; 37:981-91. [PMID: 26748488 DOI: 10.1002/jcc.24286] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 11/28/2015] [Accepted: 12/02/2015] [Indexed: 01/19/2023]
Abstract
Carotenoids are important actors both in light-harvesting (LH) and in photoprotection functions of photosynthetic pigment-protein complexes. A deep theoretical investigation of this multiple role is still missing owing to the difficulty of describing the delicate interplay between electronic and nuclear degrees of freedom. A possible strategy is to combine accurate quantum mechanical (QM) methods with classical molecular dynamics. To do this, however, accurate force-fields (FF) are necessary. This article presents a new FF for the different carotenoids present in LH complexes of plants. The results show that all the important structural properties described by the new FF are in very good agreement with QM reference values. This increased accuracy in the simulation of the structural fluctuations is also reflected in the description of excited states. Both the energy order and the different nature of the lowest singlet states are preserved during the dynamics when the new FF is used, whereas an unphysical mixing is found when a standard FF is used.
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Affiliation(s)
- Ingrid G Prandi
- Dipartimento Di Chimica E Chimica Industriale, University of Pisa, via G. Moruzzi 13, Pisa, I-56124, Italy
| | - Lucas Viani
- Dipartimento Di Chimica E Chimica Industriale, University of Pisa, via G. Moruzzi 13, Pisa, I-56124, Italy.,Institute for Fluid Dynamics, Nanoscience and Industrial Mathematics, Universidad Carlos III De Madrid, Av. De La Universidad 30, Leganés, E-28911, Spain
| | - Oliviero Andreussi
- Dipartimento Di Chimica E Chimica Industriale, University of Pisa, via G. Moruzzi 13, Pisa, I-56124, Italy
| | - Benedetta Mennucci
- Dipartimento Di Chimica E Chimica Industriale, University of Pisa, via G. Moruzzi 13, Pisa, I-56124, Italy
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41
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Rosnik AM, Curutchet C. Theoretical Characterization of the Spectral Density of the Water-Soluble Chlorophyll-Binding Protein from Combined Quantum Mechanics/Molecular Mechanics Molecular Dynamics Simulations. J Chem Theory Comput 2015; 11:5826-37. [DOI: 10.1021/acs.jctc.5b00891] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andreana M. Rosnik
- Department
de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, Barcelona, Barcelona 08028, Spain
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
| | - Carles Curutchet
- Department
de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, Barcelona, Barcelona 08028, Spain
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42
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Milanovsky GE, Shuvalov VA, Semenov AY, Cherepanov DA. Elastic Vibrations in the Photosynthetic Bacterial Reaction Center Coupled to the Primary Charge Separation: Implications from Molecular Dynamics Simulations and Stochastic Langevin Approach. J Phys Chem B 2015; 119:13656-67. [PMID: 26148224 DOI: 10.1021/acs.jpcb.5b03036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Primary electron transfer reactions in the bacterial reaction center are difficult for theoretical explication: the reaction kinetics, almost unalterable over a wide range of temperature and free energy changes, revealed oscillatory features observed initially by Shuvalov and coauthors (1997, 2002). Here the reaction mechanism was studied by molecular dynamics and analyzed within a phenomenological Langevin approach. The spectral function of polarization around the bacteriochlorophyll special pair PLPM and the dielectric response upon the formation of PL(+)PM(-) dipole within the special pair were calculated. The system response was approximated by Langevin oscillators; the respective frequencies, friction, and energy coupling coefficients were determined. The protein dynamics around PL and PM were distinctly asymmetric. The polarization around PL included slow modes with the frequency 30-80 cm(-1) and the total amplitude of 130 mV. Two main low-frequency modes of protein response around PM had frequencies of 95 and 155 cm(-1) and the total amplitude of 30 mV. In addition, a slowly damping mode with the frequency of 118 cm(-1) and the damping time >1.1 ps was coupled to the formation of PL(+)PM(-) dipole. It was attributed to elastic vibrations of α-helices in the vicinity of PLPM. The proposed trapping of P excitation energy in the form of the elastic vibrations can rationalize the observed properties of the primary electron transfer reactions, namely, the unusual temperature and ΔG dependences, the oscillating phenomena in kinetics, and the asymmetry of the charge separation reactions.
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Affiliation(s)
- Georgy E Milanovsky
- A. N. Belozersky Institute of Physical-Chemical Biology, Moscow State University , Leninskiye Gory, 119992 Moscow, Russia
| | - Vladimir A Shuvalov
- A. N. Belozersky Institute of Physical-Chemical Biology, Moscow State University , Leninskiye Gory, 119992 Moscow, Russia.,N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences , Kosygina st., 4, 117977 Moscow, Russia
| | - Alexey Yu Semenov
- A. N. Belozersky Institute of Physical-Chemical Biology, Moscow State University , Leninskiye Gory, 119992 Moscow, Russia.,N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences , Kosygina st., 4, 117977 Moscow, Russia
| | - Dmitry A Cherepanov
- A. N. Belozersky Institute of Physical-Chemical Biology, Moscow State University , Leninskiye Gory, 119992 Moscow, Russia.,A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences , 31, Leninsky Prospect, 119071 Moscow, Russia
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Chandrasekaran S, Aghtar M, Valleau S, Aspuru-Guzik A, Kleinekathöfer U. Influence of Force Fields and Quantum Chemistry Approach on Spectral Densities of BChl a in Solution and in FMO Proteins. J Phys Chem B 2015; 119:9995-10004. [DOI: 10.1021/acs.jpcb.5b03654] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
| | - Mortaza Aghtar
- Department
of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Stéphanie Valleau
- Department
of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Alán Aspuru-Guzik
- Department
of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Ulrich Kleinekathöfer
- Department
of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
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44
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de Jong DH, Liguori N, van den Berg T, Arnarez C, Periole X, Marrink SJ. Atomistic and Coarse Grain Topologies for the Cofactors Associated with the Photosystem II Core Complex. J Phys Chem B 2015; 119:7791-803. [PMID: 26053327 DOI: 10.1021/acs.jpcb.5b00809] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electron transfers within and between protein complexes are core processes of the electron transport chains occurring in thylakoid (chloroplast), mitochondrial, and bacterial membranes. These electron transfers involve a number of cofactors. Here we describe the derivation of molecular mechanics parameters for the cofactors associated with the function of the photosystem II core complex: plastoquinone, plastoquinol, heme b, chlorophyll A, pheophytin, and β-carotene. Parameters were also obtained for ubiquinol and ubiquinone, related cofactors involved in the respiratory chain. Parameters were derived at both atomistic and coarse grain (CG) resolutions, compatible with the building blocks of the GROMOS united-atom and Martini CG force fields, respectively. Structural and thermodynamic properties of the cofactors were compared to experimental values when available. The topologies were further tested in molecular dynamics simulations of the cofactors in their physiological environment, e.g., either in a lipid membrane environment or in complex with the heme binding protein bacterioferritin.
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Affiliation(s)
| | - Nicoletta Liguori
- ‡Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
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45
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Vermaas JV, Taguchi AT, Dikanov SA, Wraight CA, Tajkhorshid E. Redox potential tuning through differential quinone binding in the photosynthetic reaction center of Rhodobacter sphaeroides. Biochemistry 2015; 54:2104-16. [PMID: 25734689 DOI: 10.1021/acs.biochem.5b00033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ubiquinone forms an integral part of the electron transport chain in cellular respiration and photosynthesis across a vast number of organisms. Prior experimental results have shown that the photosynthetic reaction center (RC) from Rhodobacter sphaeroides is only fully functional with a limited set of methoxy-bearing quinones, suggesting that specific interactions with this substituent are required to drive electron transport and the formation of quinol. The nature of these interactions has yet to be determined. Through parameterization of a CHARMM-compatible quinone force field and subsequent molecular dynamics simulations of the quinone-bound RC, we have investigated and characterized the interactions of the protein with the quinones in the Q(A) and Q(B) sites using both equilibrium simulation and thermodynamic integration. In particular, we identify a specific interaction between the 2-methoxy group of ubiquinone in the Q(B) site and the amide nitrogen of GlyL225 that we implicate in locking the orientation of the 2-methoxy group, thereby tuning the redox potential difference between the quinones occupying the Q(A) and Q(B) sites. Disruption of this interaction leads to weaker binding in a ubiquinone analogue that lacks a 2-methoxy group, a finding supported by reverse electron transfer electron paramagnetic resonance experiments of the Q(A)⁻Q(B)⁻ biradical and competitive binding assays.
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Affiliation(s)
- Josh V Vermaas
- †Center for Biophysics and Computational Biology, ‡Department of Biochemistry, §Beckman Institute, and ∥Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Alexander T Taguchi
- †Center for Biophysics and Computational Biology, ‡Department of Biochemistry, §Beckman Institute, and ∥Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Sergei A Dikanov
- †Center for Biophysics and Computational Biology, ‡Department of Biochemistry, §Beckman Institute, and ∥Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Colin A Wraight
- †Center for Biophysics and Computational Biology, ‡Department of Biochemistry, §Beckman Institute, and ∥Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Emad Tajkhorshid
- †Center for Biophysics and Computational Biology, ‡Department of Biochemistry, §Beckman Institute, and ∥Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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Wang X, Ritschel G, Wüster S, Eisfeld A. Open quantum system parameters for light harvesting complexes from molecular dynamics. Phys Chem Chem Phys 2015; 17:25629-41. [DOI: 10.1039/c5cp03891j] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We elucidate the difference between various parameter extraction methods and demonstrate sensitivity to molecular dynamics equilibration.
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Affiliation(s)
- Xiaoqing Wang
- Max-Planck-Institut für Physik komplexer Systeme
- D-01187 Dresden
- Germany
| | - Gerhard Ritschel
- Max-Planck-Institut für Physik komplexer Systeme
- D-01187 Dresden
- Germany
| | - Sebastian Wüster
- Max-Planck-Institut für Physik komplexer Systeme
- D-01187 Dresden
- Germany
| | - Alexander Eisfeld
- Max-Planck-Institut für Physik komplexer Systeme
- D-01187 Dresden
- Germany
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47
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Fokas AS, Cole DJ, Chin AW. Constrained geometric dynamics of the Fenna-Matthews-Olson complex: the role of correlated motion in reducing uncertainty in excitation energy transfer. PHOTOSYNTHESIS RESEARCH 2014; 122:275-292. [PMID: 25034014 DOI: 10.1007/s11120-014-0027-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 06/30/2014] [Indexed: 06/03/2023]
Abstract
The trimeric Fenna-Mathews-Olson (FMO) complex of green sulphur bacteria is a well-studied example of a photosynthetic pigment-protein complex, in which the electronic properties of the pigments are modified by the protein environment to promote efficient excitonic energy transfer from antenna complexes to the reaction centres. By a range of simulation methods, many of the electronic properties of the FMO complex can be extracted from knowledge of the static crystal structure. However, the recent observation and analysis of long-lasting quantum dynamics in the FMO complex point to protein dynamics as a key factor in protecting and generating quantum coherence under laboratory conditions. While fast inter- and intra-molecular vibrations have been investigated extensively, the slow, conformational dynamics which effectively determine the optical inhomogeneous broadening of experimental ensembles has received less attention. The following study employs constrained geometric dynamics to study the flexibility in the protein network by efficiently generating the accessible conformational states from the published crystal structure. Statistical and principle component analyses reveal highly correlated low frequency motions between functionally relevant elements, including strong correlations between pigments that are excitonically coupled. Our analysis reveals a hierarchy of structural interactions which enforce these correlated motions, from the level of monomer-monomer interfaces right down to the α-helices, β-sheets and pigments. In addition to inducing strong spatial correlations across the conformational ensemble, we find that the overall rigidity of the FMO complex is exceptionally high. We suggest that these observations support the idea of highly correlated inhomogeneous disorder of the electronic excited states, which is further supported by the remarkably low variance (typically <5%) of the excitonic couplings of the conformational ensemble.
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Affiliation(s)
- Alexander S Fokas
- The Theory of Condensed Matter Group Group, Cavendish Laboratory, 19 JJ Thomson Avenue, Cambridge, CB3 0HE, UK,
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48
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Higashi M, Kosugi T, Hayashi S, Saito S. Theoretical study on excited states of bacteriochlorophyll a in solutions with density functional assessment. J Phys Chem B 2014; 118:10906-18. [PMID: 25153487 DOI: 10.1021/jp507259g] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The excited-state properties of bacteriochlorophyll (BChl) a in triethylamine, 1-propanol, and methanol are investigated with the time-dependent density functional theory by using the quantum mechanical and molecular mechanical reweighting free energy self-consistant field method. It is found that no prevalent density functionals can reproduce the experimental excited-state properties, i.e., the absorption and reorganization energies, of BChl a in the solutions. The parameter μ in the range-separated hybrid functional is therefore optimized to reproduce the differences of the absorption energies in the solutions. We examine the origin of the differences of the absorption energies in the solutions and find that sensitive balance between contributions of structural changes and solute-solvent interactions determines the differences. The accurate description of the excitation with the density functional with the adjusted parameter is therefore essential to the understanding of the excited-state properties of BChl a in proteins and also the mechanism of the photosynthetic systems.
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Affiliation(s)
- Masahiro Higashi
- Department of Chemistry, Biology and Marine Science, University of the Ryukyus , 1 Senbaru, Nishihara, Okinawa 903-0213, Japan
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Arnlund D, Johansson LC, Wickstrand C, Barty A, Williams GJ, Malmerberg E, Davidsson J, Milathianaki D, DePonte DP, Shoeman RL, Wang D, James D, Katona G, Westenhoff S, White TA, Aquila A, Bari S, Berntsen P, Bogan M, van Driel TB, Doak RB, Kjær KS, Frank M, Fromme R, Grotjohann I, Henning R, Hunter MS, Kirian RA, Kosheleva I, Kupitz C, Liang M, Martin AV, Nielsen MM, Messerschmidt M, Seibert MM, Sjöhamn J, Stellato F, Weierstall U, Zatsepin NA, Spence JCH, Fromme P, Schlichting I, Boutet S, Groenhof G, Chapman HN, Neutze R. Visualizing a protein quake with time-resolved X-ray scattering at a free-electron laser. Nat Methods 2014; 11:923-6. [PMID: 25108686 DOI: 10.1038/nmeth.3067] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 07/09/2014] [Indexed: 01/07/2023]
Abstract
We describe a method to measure ultrafast protein structural changes using time-resolved wide-angle X-ray scattering at an X-ray free-electron laser. We demonstrated this approach using multiphoton excitation of the Blastochloris viridis photosynthetic reaction center, observing an ultrafast global conformational change that arises within picoseconds and precedes the propagation of heat through the protein. This provides direct structural evidence for a 'protein quake': the hypothesis that proteins rapidly dissipate energy through quake-like structural motions.
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Affiliation(s)
- David Arnlund
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Linda C Johansson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Cecilia Wickstrand
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Anton Barty
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - Garth J Williams
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California, USA
| | - Erik Malmerberg
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Jan Davidsson
- Department of Chemistry - Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Despina Milathianaki
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California, USA
| | - Daniel P DePonte
- 1] Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany. [2] Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California, USA
| | - Robert L Shoeman
- 1] Max-Planck-Institut für medizinische Forschung, Heidelberg, Germany. [2] Max Planck Advanced Study Group, Center for Free-Electron Laser Science, Hamburg, Germany
| | - Dingjie Wang
- Department of Physics, Arizona State University, Tempe, Arizona, USA
| | - Daniel James
- Department of Physics, Arizona State University, Tempe, Arizona, USA
| | - Gergely Katona
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Sebastian Westenhoff
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Thomas A White
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - Andrew Aquila
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - Sadia Bari
- 1] Max Planck Advanced Study Group, Center for Free-Electron Laser Science, Hamburg, Germany. [2] Max-Planck-Institut für Kernphysik, Heidelberg, Germany
| | - Peter Berntsen
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Mike Bogan
- PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California, USA
| | | | - R Bruce Doak
- 1] Max-Planck-Institut für medizinische Forschung, Heidelberg, Germany. [2] Department of Physics, Arizona State University, Tempe, Arizona, USA
| | - Kasper Skov Kjær
- 1] Department of Physics, Technical University of Denmark, Lyngby, Denmark. [2] Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Matthias Frank
- Lawrence Livermore National Laboratory, Livermore, California, USA
| | - Raimund Fromme
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona, USA
| | - Ingo Grotjohann
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona, USA
| | | | - Mark S Hunter
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona, USA
| | - Richard A Kirian
- Department of Physics, Arizona State University, Tempe, Arizona, USA
| | | | - Christopher Kupitz
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona, USA
| | - Mengning Liang
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - Andrew V Martin
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | | | - Marc Messerschmidt
- 1] Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany. [2] Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California, USA
| | - M Marvin Seibert
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California, USA
| | - Jennie Sjöhamn
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Francesco Stellato
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - Uwe Weierstall
- Department of Physics, Arizona State University, Tempe, Arizona, USA
| | - Nadia A Zatsepin
- Department of Physics, Arizona State University, Tempe, Arizona, USA
| | - John C H Spence
- Department of Physics, Arizona State University, Tempe, Arizona, USA
| | - Petra Fromme
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona, USA
| | - Ilme Schlichting
- 1] Max-Planck-Institut für medizinische Forschung, Heidelberg, Germany. [2] Max Planck Advanced Study Group, Center for Free-Electron Laser Science, Hamburg, Germany
| | - Sébastien Boutet
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California, USA
| | - Gerrit Groenhof
- 1] Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland. [2] Department of Chemistry, University of Jyväskylä, Jyväskylä, Finland
| | - Henry N Chapman
- 1] Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany. [2] Department of Physics, University of Hamburg, Hamburg, Germany. [3] Centre for Ultrafast Imaging, Hamburg, Germany
| | - Richard Neutze
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
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50
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Jurinovich S, Curutchet C, Mennucci B. The Fenna-Matthews-Olson protein revisited: a fully polarizable (TD)DFT/MM description. Chemphyschem 2014; 15:3194-204. [PMID: 25080315 DOI: 10.1002/cphc.201402244] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Indexed: 01/21/2023]
Abstract
We report a combined molecular dynamics and quantum mechanics (QM)/molecular mechanics (MM) analysis of the excitonic properties of the Fenna-Matthews-Olson (FMO) protein by using a polarizable MM model combined with a time-dependent density functional theory description. Overall, our results indicate that structural fluctuations, electrostatic interactions, and short-range quantum effects can significantly modulate the model Hamiltonian parameters (site energies and couplings). We find that the specific interactions with the axial ligand and the hydrogen-bonded residues are responsible for the energy ladder, with their effects being mainly due to electrostatic interactions, but with short-range quantum contributions that are not negligible. In addition, a striking modulation of the screening effects experienced by the BChl pairs, due to the heterogeneous polarizability of the FMO and solvent environment, is observed. Finally, we find that the exciton model gives a reliable description of the delocalized excited states in the complex.
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Affiliation(s)
- Sandro Jurinovich
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via Risorgimento 35, I-56126 Pisa (Italy)
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