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Mondragón-Solórzano G, Sandoval-Lira J, Nochebuena J, Cisneros GA, Barroso-Flores J. Electronic Structure Effects Related to the Origin of the Remarkable Near-Infrared Absorption of Blastochloris viridis' Light Harvesting 1-Reaction Center Complex. J Chem Theory Comput 2022; 18:4555-4564. [PMID: 35767461 PMCID: PMC10408377 DOI: 10.1021/acs.jctc.2c00497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Various photosynthetic organisms have evolved to absorb light in different regions of the visible light spectrum, thus adapting to the various lighting conditions available on Earth. While most of these autotrophic organisms absorb wavelengths around the 700-800 nm region, some are capable of red-shifted absorptions above this range, but none as remarkably as Blastochloris viridis whose main absorption is observed at 1015 nm, approximately 220 nm (0.34 eV) lower in energy than their main constituent pigments, BChl-b, whose main absorption is observed at 795 nm. The structure of its light harvesting 1-reaction center was recently elucidated by cryo-EM; however, the electronic structure details behind this red-shifted absorption remain unattended. We used hybrid quantum mechanics/molecular mechanics (QM/MM) calculations to optimize one of the active centers and performed classical molecular dynamics (MD) simulations to sample conformations beyond the optimized structure. We did excited state calculations with the time-dependent density functional theory method at the CAM-B3LYP/cc-pVDZ level of theory. We reproduced the near IR absorption by sequentially modifying the number of components involved in our systems using representative structures from the calculated MD ensemble. Natural transition orbital analysis reveals the participation of the BChl-b fragments to the main transition in the native structure and the structures obtained from the QM/MM and MD simulations. H-bonding pigment-protein interactions play a role on the conformation stabilization and orientation; however, the bacteriochlorin ring conformations and the exciton delocalization are the most relevant factors to explain the red-shifting phenomenon.
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Affiliation(s)
- Gustavo Mondragón-Solórzano
- Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM. Carretera Toluca-Atlacomulco Km. 14.5, Unidad San Cayetano. Toluca de Lerdo 50200, México
- Instituto de Química. Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, CDMX 04510, México
| | - Jacinto Sandoval-Lira
- Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM. Carretera Toluca-Atlacomulco Km. 14.5, Unidad San Cayetano. Toluca de Lerdo 50200, México
- Instituto de Química. Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, CDMX 04510, México
- Departamento de Ingeniería Ambiental, Instituto Tecnológico Superior de San Martín Texmelucan, TecNM, Camino a la Barranca de Pesos, C.P. 74120 San Martín Texmelucan, Puebla, México
| | - Jorge Nochebuena
- Department of Physics, University of Texas at Dallas, Richardson, Texas 75801, United States
| | - G Andrés Cisneros
- Department of Physics, University of Texas at Dallas, Richardson, Texas 75801, United States
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas 75801, United States
| | - Joaquín Barroso-Flores
- Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM. Carretera Toluca-Atlacomulco Km. 14.5, Unidad San Cayetano. Toluca de Lerdo 50200, México
- Instituto de Química. Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, CDMX 04510, México
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Suzuki Y, Watanabe H, Okiyama Y, Ebina K, Tanaka S. Comparative study on model parameter evaluations for the energy transfer dynamics in Fenna–Matthews–Olson complex. Chem Phys 2020. [DOI: 10.1016/j.chemphys.2020.110903] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Scholes GD. Polaritons and excitons: Hamiltonian design for enhanced coherence. Proc Math Phys Eng Sci 2020; 476:20200278. [PMID: 33223931 PMCID: PMC7655764 DOI: 10.1098/rspa.2020.0278] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 09/21/2020] [Indexed: 12/11/2022] Open
Abstract
The primary questions motivating this report are: Are there ways to increase coherence and delocalization of excitation among many molecules at moderate electronic coupling strength? Coherent delocalization of excitation in disordered molecular systems is studied using numerical calculations. The results are relevant to molecular excitons, polaritons, and make connections to classical phase oscillator synchronization. In particular, it is hypothesized that it is not only the magnitude of electronic coupling relative to the standard deviation of energetic disorder that decides the limits of coherence, but that the structure of the Hamiltonian-connections between sites (or molecules) made by electronic coupling-is a significant design parameter. Inspired by synchronization phenomena in analogous systems of phase oscillators, some properties of graphs that define the structure of different Hamiltonian matrices are explored. The report focuses on eigenvalues and ensemble density matrices of various structured, random matrices. Some reasons for the special delocalization properties and robustness of polaritons in the single-excitation subspace (the star graph) are discussed. The key result of this report is that, for some classes of Hamiltonian matrix structure, coherent delocalization is not easily defeated by energy disorder, even when the electronic coupling is small compared to disorder.
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Ozaki K, Thompson KJ, Simister RL, Crowe SA, Reinhard CT. Anoxygenic photosynthesis and the delayed oxygenation of Earth's atmosphere. Nat Commun 2019; 10:3026. [PMID: 31289261 PMCID: PMC6616575 DOI: 10.1038/s41467-019-10872-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 05/28/2019] [Indexed: 12/03/2022] Open
Abstract
The emergence of oxygenic photosynthesis created a new niche with dramatic potential to transform energy flow through Earth's biosphere. However, more primitive forms of photosynthesis that fix CO2 into biomass using electrons from reduced species like Fe(II) and H2 instead of water would have competed with Earth's early oxygenic biosphere for essential nutrients. Here, we combine experimental microbiology, genomic analyses, and Earth system modeling to demonstrate that competition for light and nutrients in the surface ocean between oxygenic phototrophs and Fe(II)-oxidizing, anoxygenic photosynthesizers (photoferrotrophs) translates into diminished global photosynthetic O2 release when the ocean interior is Fe(II)-rich. These results provide a simple ecophysiological mechanism for inhibiting atmospheric oxygenation during Earth's early history. We also find a novel positive feedback within the coupled C-P-O-Fe cycles that can lead to runaway planetary oxygenation as rising atmospheric pO2 sweeps the deep ocean of the ferrous iron substrate for photoferrotrophy.
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Affiliation(s)
- Kazumi Ozaki
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- NASA Astrobiology Institute, Alternative Earths Team, Riverside, CA, USA
- NASA Postdoctoral Program, Universities Space Research Association, Columbia, MD, 21046, USA
- Department of Environmental Science, Toho University, Funabashi, Chiba, 274-8510, Japan
| | - Katharine J Thompson
- Departments of Microbiology & Immunology and Earth, Ocean, & Atmospheric Sciences, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Rachel L Simister
- Departments of Microbiology & Immunology and Earth, Ocean, & Atmospheric Sciences, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Sean A Crowe
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- Departments of Microbiology & Immunology and Earth, Ocean, & Atmospheric Sciences, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Christopher T Reinhard
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
- NASA Astrobiology Institute, Alternative Earths Team, Riverside, CA, USA.
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Allodi MA, Otto JP, Sohail SH, Saer RG, Wood RE, Rolczynski BS, Massey SC, Ting PC, Blankenship RE, Engel GS. Redox Conditions Affect Ultrafast Exciton Transport in Photosynthetic Pigment-Protein Complexes. J Phys Chem Lett 2018; 9:89-95. [PMID: 29236502 DOI: 10.1021/acs.jpclett.7b02883] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Pigment-protein complexes in photosynthetic antennae can suffer oxidative damage from reactive oxygen species generated during solar light harvesting. How the redox environment of a pigment-protein complex affects energy transport on the ultrafast light-harvesting time scale remains poorly understood. Using two-dimensional electronic spectroscopy, we observe differences in femtosecond energy-transfer processes in the Fenna-Matthews-Olson (FMO) antenna complex under different redox conditions. We attribute these differences in the ultrafast dynamics to changes to the system-bath coupling around specific chromophores, and we identify a highly conserved tyrosine/tryptophan chain near the chromophores showing the largest changes. We discuss how the mechanism of tyrosine/tryptophan chain oxidation may contribute to these differences in ultrafast dynamics that can moderate energy transfer to downstream complexes where reactive oxygen species are formed. These results highlight the importance of redox conditions on the ultrafast transport of energy in photosynthesis. Tailoring the redox environment may enable energy transport engineering in synthetic light-harvesting systems.
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Affiliation(s)
- Marco A Allodi
- Department of Chemistry, The Institute for Biophysical Dynamics, The James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States
| | - John P Otto
- Department of Chemistry, The Institute for Biophysical Dynamics, The James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States
| | - Sara H Sohail
- Department of Chemistry, The Institute for Biophysical Dynamics, The James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States
| | | | - Ryan E Wood
- Department of Chemistry, The Institute for Biophysical Dynamics, The James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States
| | - Brian S Rolczynski
- Department of Chemistry, The Institute for Biophysical Dynamics, The James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States
| | - Sara C Massey
- Department of Chemistry, The Institute for Biophysical Dynamics, The James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States
| | - Po-Chieh Ting
- Department of Chemistry, The Institute for Biophysical Dynamics, The James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States
| | | | - Gregory S Engel
- Department of Chemistry, The Institute for Biophysical Dynamics, The James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States
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Häse F, Kreisbeck C, Aspuru-Guzik A. Machine learning for quantum dynamics: deep learning of excitation energy transfer properties. Chem Sci 2017; 8:8419-8426. [PMID: 29619189 PMCID: PMC5863613 DOI: 10.1039/c7sc03542j] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Accepted: 10/23/2017] [Indexed: 12/20/2022] Open
Abstract
Understanding the relationship between the structure of light-harvesting systems and their excitation energy transfer properties is of fundamental importance in many applications including the development of next generation photovoltaics. Natural light harvesting in photosynthesis shows remarkable excitation energy transfer properties, which suggests that pigment-protein complexes could serve as blueprints for the design of nature inspired devices. Mechanistic insights into energy transport dynamics can be gained by leveraging numerically involved propagation schemes such as the hierarchical equations of motion (HEOM). Solving these equations, however, is computationally costly due to the adverse scaling with the number of pigments. Therefore virtual high-throughput screening, which has become a powerful tool in material discovery, is less readily applicable for the search of novel excitonic devices. We propose the use of artificial neural networks to bypass the computational limitations of established techniques for exploring the structure-dynamics relation in excitonic systems. Once trained, our neural networks reduce computational costs by several orders of magnitudes. Our predicted transfer times and transfer efficiencies exhibit similar or even higher accuracies than frequently used approximate methods such as secular Redfield theory.
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Affiliation(s)
- Florian Häse
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , 02138 , USA . ; ; Tel: +1-617-384-8188
| | - Christoph Kreisbeck
- 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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Barroso-Flores J. Evolution of the Fenna-Matthews-Olson Complex and Its Quantum Coherence Features. Which Led the Way? ACS CENTRAL SCIENCE 2017; 3:1061-1062. [PMID: 29104921 PMCID: PMC5658753 DOI: 10.1021/acscentsci.7b00386] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
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