植物光系统Ⅱ捕光过程的超分子结构基础

Supramolecular Structural Basis of The Light-Harvesting Process in Plants

光系统Ⅱ(photosystemⅡ,PSⅡ)是位于植物、藻类和蓝细菌等放氧光合生物类囊体膜上的重要超分子复合物,它可通过捕获光能用于激发反应中心的电荷分离并驱动电子传递过程,在常温常压下可将水分子裂解产生氧气和质子.植物光系统Ⅱ的外周存在主要和次要捕光复合物Ⅱ(major and minor light-harvesting complexⅡ,LHCⅡ),它们负责吸收光能并向光系统Ⅱ传递激发能,并且还参与非光化学淬灭和状态转换相关的捕光调节过程.近年来,围绕光系统Ⅱ和LHCⅡ的结构生物学研究取得了一系列重要进展,本文总结了PSⅡ、LHCⅡ和二者共同组成的PSII-LHCII超级复合物的结构生物学研究历程以及最新进展,并对该领域的未来研究方向做出展望.

Photosystem Ⅱ（PSⅡ） is an important supramolecular complex located in the thylakoid membranes of plants, algae and cyanobacteria. Powered by the energy harvested from light, PS Ⅱ carries out energy conversion through charge separation in the reaction center, drives the primary electron transport process and splits water molecules into oxygen and protons under ambient temperature and pressure. At the peripheral region of plant PSⅡ, there is a pool of major and minor light harvesting complexes Ⅱ（LHCⅡ） responsible for absorbing light energy and transferring excitation energy to PS Ⅱ. They are also involved in the regulation of light harvesting through the non-photochemical quenching and state-transition processes. In recent years, tremendous progresses have been made in structural biology studies of plant PS Ⅱ-LHC Ⅱ supercomplexes. Here we review the history and latest progresses concerning the structures of PSⅡ, LHCⅡ and the PSⅡ-LHCⅡ supercomplexes, and discuss the perspectives for future research.