New Insights into the Mechanism of Uphill Excitation Energy Transfer from Core Antenna to Reaction Center in Purple Photosynthetic Bacteria
New Insights into the Mechanism of Uphill Excitation Energy Transfer from Core Antenna to Reaction Center in Purple Photosynthetic Bacteria
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紫色光合细菌从核心天线到反应中心的上坡激发能量转移机制的新见解
DOI：
10.1021/acs.jpclett.8b01197
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发表时间：
2018
影响因子：
5.7
通讯作者：
Zhang Jian Ping
中科院分区：
文献类型：
--
作者：
Tan Li Ming;Yu Jie;Kawakami Tomoaki;Kobayash Masayuki;Wang Peng;Wang Otomo Zheng Yu;Zhang Jian Ping
在室温条件下，通过比较球状红杆菌突变株的天然LH1-RC和杂交种LH1-RC，研究了紫色光合细菌从核心天线(LH1)到反应中心(Rc)的上行激发能量转移(EET)。后者与Tch-LH1和Rba-RC嵌合的蛋白质显示出更大的RC到LH1的能量差(ΔE=630 cm-1)，热能(3kBT)。根据最新报道的Tch的高分辨结构，讨论了光谱和动力学结果。TepidumLH1-RC，这允许我们提出一个由LH1BChl形成的通道的存在，这有助于LH1→RC EET。EET速率对Δ的半对数曲线在ΔE的很大范围内是线性的，这巩固了由RC的LH1荧光和特殊对吸收之间的光谱重叠所促进的热激活机制。
The uphill excitation energy transfer (EET) from the core antenna (LH1) to the reaction center (RC) of purple photosynthetic bacteria was investigated at room temperature by comparing the native LH1-RC fromThermochromatium(Tch.)tepidumwith the hybrid LH1-RC from a mutant strain ofRhodobacter(Rba.)sphaeroides. The latter protein with chimericTch-LH1 andRba-RC exhibits a substantially larger RC-to-LH1 energy difference (ΔE= 630 cm–1) of 3-fold thermal energy (3kBT). The spectroscopic and kinetics results are discussed on the basis of the newly reported high-resolution structures ofTch. tepidumLH1-RC, which allow us to propose the existence of a passage formed by LH1 BChls that facilitates the LH1 → RC EET. The semilogarithmic plot of the EET rate against ΔEwas found to be linear over a broad range of ΔE, which consolidates the mechanism of thermal activation as promoted by the spectral overlap between the LH1 fluorescence and the special pair absorption of RC.