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Reinot T, Khmelnitskiy A, Kell A, Jassas M, Jankowiak R. Exciton Lifetime Distributions and Population Dynamics in the FMO Protein Complex from Prosthecochloris aestuarii. ACS OMEGA 2021; 6:5990-6008. [PMID: 33681637 PMCID: PMC7931385 DOI: 10.1021/acsomega.1c00286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
Significant protein rearrangement upon excitation and energy transfer in Fenna-Matthews-Olson protein of Prosthecochloris aestuarii results in a modified energy landscape, which induces more changes in pigment site energies than predicted by the "standard" hole-burning theory. The energy changes are elucidated by simulations while investigating the effects of site-dependent disorder, both static (site-energy distribution widths) and dynamic (spectral density shapes). The resulting optimized site energies and their fluctuations are consistent with relative differences observed in inhomogeneous widths calculated by recent molecular dynamic simulations. Two sets of different spectral densities reveal how their shapes affect the population dynamics and distribution of exciton lifetimes. Calculations revealed the wavelength-dependent distributions of exciton lifetimes (T 1) in the femtosecond to picosecond time frame. We suggest that the calculated multimodal and asymmetric wavelength-dependent T 1 distributions offer more insight into the interpretation of resonant hole-burned (HB) spectra, kinetic traces in two-dimensional (2D) electronic spectroscopy experiments, and widely used global analyses in fitting data from transient absorption experiments.
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Affiliation(s)
- Tonu Reinot
- Department
of Chemistry, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Anton Khmelnitskiy
- Department
of Chemistry, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Adam Kell
- Department
of Chemistry, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Mahboobe Jassas
- Department
of Chemistry, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Ryszard Jankowiak
- Department
of Chemistry, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
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2
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Chen JH, Wu H, Xu C, Liu XC, Huang Z, Chang S, Wang W, Han G, Kuang T, Shen JR, Zhang X. Architecture of the photosynthetic complex from a green sulfur bacterium. Science 2021; 370:370/6519/eabb6350. [PMID: 33214250 DOI: 10.1126/science.abb6350] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 09/09/2020] [Indexed: 01/09/2023]
Abstract
The photosynthetic apparatus of green sulfur bacteria (GSB) contains a peripheral antenna chlorosome, light-harvesting Fenna-Matthews-Olson proteins (FMO), and a reaction center (GsbRC). We used cryo-electron microscopy to determine a 2.7-angstrom structure of the FMO-GsbRC supercomplex from Chlorobaculum tepidum The GsbRC binds considerably fewer (bacterio)chlorophylls [(B)Chls] than other known type I RCs do, and the organization of (B)Chls is similar to that in photosystem II. Two BChl layers in GsbRC are not connected by Chls, as seen in other RCs, but associate with two carotenoid derivatives. Relatively long distances of 22 to 33 angstroms were observed between BChls of FMO and GsbRC, consistent with the inefficient energy transfer between these entities. The structure contains common features of both type I and type II RCs and provides insight into the evolution of photosynthetic RCs.
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Affiliation(s)
- Jing-Hua Chen
- Department of Pathology of Sir Run Run Shaw Hospital and Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, 310058 Zhejiang, China.,Center of Cryo-Electron Microscopy, Zhejiang University, Hangzhou, 310058 Zhejiang, China
| | - Hangjun Wu
- Department of Pathology of Sir Run Run Shaw Hospital and Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, 310058 Zhejiang, China.,Center of Cryo-Electron Microscopy, Zhejiang University, Hangzhou, 310058 Zhejiang, China
| | - Caihuang Xu
- Department of Pathology of Sir Run Run Shaw Hospital and Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, 310058 Zhejiang, China
| | - Xiao-Chi Liu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 100093 Beijing, China
| | - Zihui Huang
- Department of Pathology of Sir Run Run Shaw Hospital and Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, 310058 Zhejiang, China
| | - Shenghai Chang
- Department of Pathology of Sir Run Run Shaw Hospital and Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, 310058 Zhejiang, China.,Center of Cryo-Electron Microscopy, Zhejiang University, Hangzhou, 310058 Zhejiang, China
| | - Wenda Wang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 100093 Beijing, China
| | - Guangye Han
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 100093 Beijing, China
| | - Tingyun Kuang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 100093 Beijing, China.
| | - Jian-Ren Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 100093 Beijing, China. .,Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, 700-8530 Okayama, Japan
| | - Xing Zhang
- Department of Pathology of Sir Run Run Shaw Hospital and Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, 310058 Zhejiang, China. .,Center of Cryo-Electron Microscopy, Zhejiang University, Hangzhou, 310058 Zhejiang, China.,Zhejiang Laboratory for System and Precision Medicine, Zhejiang University Medical Center, 1369 West Wenyi Road, Hangzhou, 311121 Zhejiang, China
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3
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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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4
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Kell A, Khmelnitskiy AY, Reinot T, Jankowiak R. On uncorrelated inter-monomer Förster energy transfer in Fenna-Matthews-Olson complexes. J R Soc Interface 2020; 16:20180882. [PMID: 30958204 DOI: 10.1098/rsif.2018.0882] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The Fenna-Matthews-Olson (FMO) light-harvesting antenna protein of green sulfur bacteria is a long-studied pigment-protein complex which funnels energy from the chlorosome to the reaction centre where photochemistry takes place. The structure of the FMO protein from Chlorobaculum tepidum is known as a homotrimeric complex containing eight bacteriochlorophyll a per monomer. Owing to this structure FMO has strong intra-monomer and weak inter-monomer electronic coupling constants. While long-lived (sub-picosecond) coherences within a monomer have been a prevalent topic of study over the past decade, various experimental evidence supports the presence of subsequent inter-monomer energy transfer on a picosecond time scale. The latter has been neglected by most authors in recent years by considering only sub-picosecond time scales or assuming that the inter-monomer coupling between low-energy states is too weak to warrant consideration of the entire trimer. However, Förster theory predicts that energy transfer of the order of picoseconds is possible even for very weak (less than 5 cm-1) electronic coupling between chromophores. This work reviews experimental data (with a focus on emission and hole-burned spectra) and simulations of exciton dynamics which demonstrate inter-monomer energy transfer. It is shown that the lowest energy 825 nm absorbance band cannot be properly described by a single excitonic state. The energy transfer through FMO is modelled by generalized Förster theory using a non-Markovian, reduced density matrix approach to describe the electronic structure. The disorder-averaged inter-monomer transfer time across the 825 nm band is about 27 ps. While only isolated FMO proteins are presented, the presence of inter-monomer energy transfer in the context of the overall photosystem is also briefly discussed.
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Affiliation(s)
- Adam Kell
- 1 Department of Chemistry, Kansas State University , Manhattan, KS , USA
| | | | - Tonu Reinot
- 1 Department of Chemistry, Kansas State University , Manhattan, KS , USA
| | - Ryszard Jankowiak
- 1 Department of Chemistry, Kansas State University , Manhattan, KS , USA.,2 Department of Physics, Kansas State University , Manhattan, KS , USA
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5
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Saer RG, Schultz RL, Blankenship RE. The influence of quaternary structure on the stability of Fenna-Matthews-Olson (FMO) antenna complexes. PHOTOSYNTHESIS RESEARCH 2019; 140:39-49. [PMID: 30315435 DOI: 10.1007/s11120-018-0591-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 10/03/2018] [Indexed: 06/08/2023]
Abstract
The trimeric nature of the Fenna-Matthews-Olson (FMO) protein antenna complex from green sulfur phototrophic bacteria was investigated. Mutations were introduced into the protein at positions 142 and 198, which were chosen to destabilize the intra-trimer salt bridges between adjacent monomers. Strains bearing the mutations R142L, R198L, or their combination, exhibited altered optical absorption spectra of purified membranes and fluoresced more intensely than the wild type. In particular, the introduction of the R142L mutation resulted in slower culture growth rates, as well as an FMO complex that was not able to be isolated in appreciable quantities, while the R198L mutation yielded an FMO complex with increased sensitivity to sodium thiocyanate and Triton X-100 treatments. Native and denaturing PAGE experiments suggest that much of the FMO complexes in the mutant strains pool with the insoluble material upon membrane solubilization with n-dodecyl β-D-maltoside, a mild nonionic detergent. Taken together, our results suggest that the quaternary structure of the FMO complex, the homotrimer, is an important factor in the maintenance of the complex's tertiary structure.
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Affiliation(s)
- Rafael G Saer
- Department of Biology, Washington University in St. Louis, 1 Brookings Drive, St. Louis, MO, 63130, USA
- Photosynthetic Antenna Research Center (PARC), Washington University in St. Louis, 1 Brookings Drive, St. Louis, MO, 63130, USA
| | - Rebecca L Schultz
- Department of Chemistry, Washington University in St. Louis, 1 Brookings Drive, St. Louis, MO, 63130, USA
- Department of Chemistry, University of Wisconsin Madison, Madison, WI, 53706, USA
| | - Robert E Blankenship
- Department of Biology, Washington University in St. Louis, 1 Brookings Drive, St. Louis, MO, 63130, USA.
- Department of Chemistry, Washington University in St. Louis, 1 Brookings Drive, St. Louis, MO, 63130, USA.
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6
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Khmelnitskiy A, Reinot T, Jankowiak R. Impact of Single-Point Mutations on the Excitonic Structure and Dynamics in a Fenna-Matthews-Olson Complex. J Phys Chem Lett 2018; 9:3378-3386. [PMID: 29863366 DOI: 10.1021/acs.jpclett.8b01396] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Hole burning (HB) spectroscopy and modeling studies reveal significant changes in the excitonic structure and dynamics in several mutants of the FMO trimer from the Chlorobaculum tepidum. The excited-state decay times ( T1) of the high-energy excitons are significantly modified when mutation occurs near bacteriochlorophyll (BChl) 1 (V152N mutant) or BChl 6 (W184F). Longer (averaged) T1 times of highest-energy excitons in V152N and W184F mutants suggest that site energies of BChls 1 and 6, believed to play an important role in receiving excitation from the baseplate BChls, likely play a critical role to ensure the femtosecond (fs) energy relaxation observed in wild-type FMO. HB spectroscopy reveals preferentially slower T1 times (about 1 ps on average) because fs times prohibit HB due to an extremely low HB quantum yield. Uncorrelated (incoherent) excitation energy transfer times between monomers, the composition of exciton states, and average, frequency-dependent, excited-state decay times ( T1) are discussed.
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7
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Khmelnitskiy A, Saer RG, Blankenship RE, Jankowiak R. Excitonic Energy Landscape of the Y16F Mutant of the Chlorobium tepidum Fenna-Matthews-Olson (FMO) Complex: High Resolution Spectroscopic and Modeling Studies. J Phys Chem B 2018; 122:3734-3743. [PMID: 29554425 DOI: 10.1021/acs.jpcb.7b11763] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We report high-resolution (low-temperature) absorption, emission, and nonresonant/resonant hole-burned (HB) spectra and results of excitonic calculations using a non-Markovian reduced density matrix theory (with an improved algorithm for parameter optimization in heterogeneous samples) obtained for the Y16F mutant of the Fenna-Matthews-Olson (FMO) trimer from the green sulfur bacterium Chlorobium tepidum. We show that the Y16F mutant is a mixture of FMO complexes with three independent low-energy traps (located near 817, 821, and 826 nm), in agreement with measured composite emission and HB spectra. Two of these traps belong to mutated FMO subpopulations characterized by significantly modified low-energy excitonic states. Hamiltonians for the two major subpopulations (Sub821 and Sub817) provide new insight into extensive changes induced by the single-point mutation in the vicinity of BChl 3 (where tyrosine Y16 was replaced with phenylalanine F16). The average decay time(s) from the higher exciton state(s) in the Y16F mutant depends on frequency and occurs on a picosecond time scale.
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Affiliation(s)
| | - Rafael G Saer
- Departments of Biology and Chemistry , Washington University in St. Louis , Saint Louis , Missouri 63130 , United States
| | - Robert E Blankenship
- Departments of Biology and Chemistry , Washington University in St. Louis , Saint Louis , Missouri 63130 , United States
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8
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Khmelnitskiy A, Kell A, Reinot T, Saer RG, Blankenship RE, Jankowiak R. Energy landscape of the intact and destabilized FMO antennas from C. tepidum and the L122Q mutant: Low temperature spectroscopy and modeling study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:165-173. [DOI: 10.1016/j.bbabio.2017.11.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/23/2017] [Accepted: 11/27/2017] [Indexed: 12/21/2022]
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9
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Tiwari V, Jonas DM. Electronic energy transfer through non-adiabatic vibrational-electronic resonance. II. 1D spectra for a dimer. J Chem Phys 2018; 148:084308. [DOI: 10.1063/1.5003193] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Vivek Tiwari
- Department of Chemistry and Biochemistry, University of Colorado, 215 UCB, Boulder, Colorado 80309, USA
| | - David M. Jonas
- Department of Chemistry and Biochemistry, University of Colorado, 215 UCB, Boulder, Colorado 80309, USA
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10
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Kell A, Blankenship RE, Jankowiak R. Effect of Spectral Density Shapes on the Excitonic Structure and Dynamics of the Fenna–Matthews–Olson Trimer from Chlorobaculum tepidum. J Phys Chem A 2016; 120:6146-54. [DOI: 10.1021/acs.jpca.6b03107] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
| | - Robert E. Blankenship
- Departments
of Chemistry and Biology, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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11
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Challenges facing an understanding of the nature of low-energy excited states in photosynthesis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1627-1640. [PMID: 27372198 DOI: 10.1016/j.bbabio.2016.06.010] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 06/27/2016] [Accepted: 06/28/2016] [Indexed: 01/09/2023]
Abstract
While the majority of the photochemical states and pathways related to the biological capture of solar energy are now well understood and provide paradigms for artificial device design, additional low-energy states have been discovered in many systems with obscure origins and significance. However, as low-energy states are naively expected to be critical to function, these observations pose important challenges. A review of known properties of low energy states covering eight photochemical systems, and options for their interpretation, are presented. A concerted experimental and theoretical research strategy is suggested and outlined, this being aimed at providing a fully comprehensive understanding.
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12
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Thyrhaug E, Žídek K, Dostál J, Bína D, Zigmantas D. Exciton Structure and Energy Transfer in the Fenna-Matthews-Olson Complex. J Phys Chem Lett 2016; 7:1653-1660. [PMID: 27082631 DOI: 10.1021/acs.jpclett.6b00534] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The Fenna-Matthews-Olson (FMO) photosynthetic complex found in green sulfur bacteria has over the last decades been one of the favorite "model" systems for biological energy transfer. However, even after 40 years of studies, quantitative knowledge about its energy-transfer properties is limited. Here, two-dimensional electronic spectroscopy with full polarization control is used to provide an accurate description of the electronic structure and population dynamics in the complex. The sensitivity of the technique has further allowed us to spectroscopically identify the eighth bacterio-chlorophyll molecule recently discovered in the crystal structure. The time evolution of the spectral structure, covering time scales from tens of femtoseconds up to a nanosecond, reflects the energy flow in FMO and enables us to extract an unambiguous energy-transfer scheme.
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Affiliation(s)
- Erling Thyrhaug
- Department of Chemical Physics, Lund University , P.O. Box 124, 22100 Lund, Sweden
| | - Karel Žídek
- Department of Chemical Physics, Lund University , P.O. Box 124, 22100 Lund, Sweden
| | - Jakub Dostál
- Department of Chemical Physics, Lund University , P.O. Box 124, 22100 Lund, Sweden
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg , Am Hubland, D-97074 Würzburg, Germany
| | - David Bína
- Biology Centre CAS, Branišovská 31, and Faculty of Science, University of South Bohemia , Branišovská 1760, 370 05 České Budějovice, Czech Republic
| | - Donatas Zigmantas
- Department of Chemical Physics, Lund University , P.O. Box 124, 22100 Lund, Sweden
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13
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Kihara S, Hartzler DA, Orf GS, Blankenship RE, Savikhin S. The Fate of the Triplet Excitations in the Fenna–Matthews–Olson Complex. J Phys Chem B 2015; 119:5765-72. [DOI: 10.1021/jp512222c] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Shigeharu Kihara
- Department
of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, Indiana 47907, United States
| | - Daniel A. Hartzler
- Department
of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, Indiana 47907, United States
| | - Gregory S. Orf
- Photosynthetic
Antenna Research Center, Departments of Chemistry and Biology, Washington University in St. Louis, St. Louis, Missouri 63110, United States
| | - Robert E. Blankenship
- Photosynthetic
Antenna Research Center, Departments of Chemistry and Biology, Washington University in St. Louis, St. Louis, Missouri 63110, United States
| | - Sergei Savikhin
- Department
of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, Indiana 47907, United States
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