绿色植物光系统Ⅰ及其光合作用调控的结构基础  

Structural Basis of Photosystem I and Its Photosynthesis Regulation in Green Plants

作　　者：苏小东 李梅[1] SU Xiao-Dong;LI Mei(National Laboratory of Biomacromolecules,Institute of Biophysics,Chinese Academy of Sciences,Beijing 100101,China;College of Life Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院生物物理研究所生物大分子重点实验室,北京100101 [2]中国科学院大学生命科学学院,北京100049

出　　处：《生物化学与生物物理进展》2024年第10期2298-2310,共13页Progress In Biochemistry and Biophysics

基　　金：国家自然科学基金(31930064,32171183,32371247);中国科学院青年创新促进会(Y2022038);中国科学院稳定支持基础研究领域青年团队计划(YSBR-015)资助项目。

摘　　要：光系统Ⅰ被认为是自然界中最高效的纳米光化学机器,其复杂的结构和精细的调控机制确保了光合作用的高效进行。绿色植物光系统Ⅰ由核心复合物和多样的外周捕光天线构成,并参与包括状态转换、环式电子传递等多种光合作用调节过程。本文主要以笔者所在实验室在绿色植物光系统Ⅰ及其参与光合作用调控的结构生物学方面取得的进展进行综述,使人们对这一领域有更深入的理解。Photosynthesis is one of the most important chemical reactions on earth.Oxygenic photosynthetic organisms convert solar energy into chemical energy and release oxygen,thus sustaining almost all life on this planet.Oxygenic phototrophs possess two photosystems,namely photosystem I(PSI)and photosystem II(PSII).Both photosystems are multi-subunit protein complexes embedded in the thylakoid membrane and bind numerous pigment molecules,thereby can efficiently harvest light energy and transfer it to the reaction center.PSI is one of the most efficient nano-photochemical machineries in nature.Its complex structure and sophisticated regulatory mechanisms are crucial for the high photosynthetic efficiency of oxygenic phototrophs.Eukaryotic PSI consists of a core complex where charge separation occurs and a peripheral antenna system that increases the light absorption cross section of the core.The PSI core possesses approximately 12-15 protein subunits,most of them are conserved during evolution,with only several small transmembrane subunits emerging or disappearing.The peripheral antenna system usually contains a number of light-harvesting complexes(LHCs).In contrast to the core,the protein composition and arrangement of LHC antennae vary considerably among different species of photosynthetic organisms.Previous results showed that in angiosperm plants(such as Pisum sativum and Zea mays),the PSI core binds four LHC proteins arranged as an arc-shaped belt,whereas in green algae,the PSI core is associated with more LHCs,presumably a result of adaption to the low-light aquatic environment.In addition,structures of several green algal PSI complexes indicated that green algae can dynamically regulate their light-harvesting capability by adjusting the size of PSI antennae,thereby better adapting to the changing natural environment.In addition to the light harvesting and energy conversion,PSI is also involved in several photosynthetic regulatory processes,including state transitions and cycle electron flow/transfer(CEF/CET).State

关 键 词：光系统I 蛋白质结构 光合作用调控 状态转换 环式电子传递 

分 类 号：Q71[生物学—分子生物学] Q615