Allodi Marco A, Otto John P, Sohail Sara H, Saer Rafael G, Wood Ryan E, Rolczynski Brian S, Massey Sara C, Ting Po-Chieh, Blankenship Robert E, Engel Gregory S
Department of Chemistry, The Institute for Biophysical Dynamics, The James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States.
J Phys Chem Lett. 2018 Jan 4;9(1):89-95. doi: 10.1021/acs.jpclett.7b02883. Epub 2017 Dec 19.
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.
光合天线中的色素 - 蛋白质复合物可能会受到太阳光捕获过程中产生的活性氧物种的氧化损伤。色素 - 蛋白质复合物的氧化还原环境如何在超快光捕获时间尺度上影响能量传输，目前仍知之甚少。利用二维电子光谱，我们观察到不同氧化还原条件下芬纳 - 马修斯 - 奥尔森（FMO）天线复合物中飞秒级能量转移过程的差异。我们将这些超快动力学的差异归因于特定发色团周围系统 - 浴耦合的变化，并识别出色素团附近显示出最大变化的高度保守的酪氨酸/色氨酸链。我们讨论了酪氨酸/色氨酸链氧化机制如何导致这些超快动力学的差异，这些差异可能会调节能量向下游形成活性氧物种的复合物的转移。这些结果突出了氧化还原条件对光合作用中能量超快传输的重要性。调整氧化还原环境可能有助于在合成光捕获系统中进行能量传输工程。
