气候变化领域集成服务门户(CCPortal): Photosynthesis tunes quantum-mechanical mixing of electronic and vibrational states to steer exciton energy transfer

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DOI	10.1073/pnas.2018240118
	Photosynthesis tunes quantum-mechanical mixing of electronic and vibrational states to steer exciton energy transfer
	Higgins J.S.; Lloyd L.T.; Sohail S.H.; Allodi M.A.; Otto J.P.; Saer R.G.; Wood R.E.; Massey S.C.; Ting P.-C.; Blankenship R.E.; Engel G.S.
发表日期	2021
ISSN	00278424
卷号	118 期号:11
英文摘要	Photosynthetic species evolved to protect their light-harvesting apparatus from photoxidative damage driven by intracellular redox conditions or environmental conditions. The Fenna-Matthews-Olson (FMO) pigment-protein complex from green sulfur bacteria exhibits redox-dependent quenching behavior partially due to two internal cysteine residues. Here, we show evidence that a photosynthetic complex exploits the quantum mechanics of vibronic mixing to activate an oxidative photoprotective mechanism. We use two-dimensional electronic spectroscopy (2DES) to capture energy transfer dynamics in wild-type and cysteine-deficient FMO mutant proteins under both reducing and oxidizing conditions. Under reducing conditions, we find equal energy transfer through the exciton 4-1 and 4-2-1 pathways because the exciton 4-1 energy gap is vibronically coupled with a bacteriochlorophyll-a vibrational mode. Under oxidizing conditions, however, the resonance of the exciton 4-1 energy gap is detuned from the vibrational mode, causing excitons to preferentially steer through the indirect 4-2-1 pathway to increase the likelihood of exciton quenching. We use a Redfield model to show that the complex achieves this effect by tuning the site III energy via the redox state of its internal cysteine residues. This result shows how pigment-protein complexes exploit the quantum mechanics of vibronic coupling to steer energy transfer. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Excitonic energy transfer; Photosynthesis; Quantum effects in biology; Ultrafast spectroscopy; Vibronic coupling
语种	英语
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/180250
作者单位	Department of Chemistry, The University of Chicago, Chicago, IL 60637, United States; The Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, United States; The James Franck Institute, The University of Chicago, Chicago, IL 60637, United States; The Photosynthetic Antenna Research Center, Washington University in St. Louis, St. Louis, MO 63130, United States; Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, United States; Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, United States
推荐引用方式 GB/T 7714	Higgins J.S.,Lloyd L.T.,Sohail S.H.,et al. Photosynthesis tunes quantum-mechanical mixing of electronic and vibrational states to steer exciton energy transfer[J],2021,118(11).
APA	Higgins J.S..,Lloyd L.T..,Sohail S.H..,Allodi M.A..,Otto J.P..,...&Engel G.S..(2021).Photosynthesis tunes quantum-mechanical mixing of electronic and vibrational states to steer exciton energy transfer.Proceedings of the National Academy of Sciences of the United States of America,118(11).
MLA	Higgins J.S.,et al."Photosynthesis tunes quantum-mechanical mixing of electronic and vibrational states to steer exciton energy transfer".Proceedings of the National Academy of Sciences of the United States of America 118.11(2021).