Effects of different aggregation forms of LHC Ⅱ from Bryopsis corticulans on the excited state properties of Chl a

作     者：ZUO Ping CHEN Hui WU Yishi SHEN Shihua WANG Peng AI Xicheng ZHANG Jianping LI Liangbi KUANG Tingyun 

作者机构：State Key Laboratory for Structural Chemistry of Stable and Unstable Species Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China Key Laboratory of Photosynthesis and Environmental Molecular Physiology Institute of Botany Chinese Academy of Sciences Beijing 100093 China 

出 版 物：《Chinese Science Bulletin》 (CHINESE SCIENCE BULLETIN)

年 卷 期：2006年第51卷第12期

页      面：1444-1451页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 070304[理学-物理化学(含∶化学物理)] 08[工学] 0817[工学-化学工程与技术] 0703[理学-化学] 

基　　金：This work was supported by the National Natural Science Foundation of China(Grant No.20273077) the Knowledge Innovation Program of Chinese Academy of Sciences(Grant No.KSCX2-SW-130) 

主　　题：LHC Ⅱ 聚集形式 Chl a 荧光 光捕获化合物 能量转变 

摘      要：Steady-state and time-resolved fluo- rescence spectroscopies have been used to study the excited state properties of Chl a in different ag- gregation forms of light-harvesting complex II (LHC II) from an intertidal green alga, Bryopsis corticulans, i.e. LHC II monomer, trimer and oligomer. When either Chl a or Chl b was selectively excited, the observed decrease in Chl a fluorescence in the oligomer is proved to be caused mainly by the fast fluorescence quenching among Chl a molecules, rather than by the decrease in Chl b-to-Chl a singlet excitation transfer efficiency. Analyses of the picosecond time-resolved fluorescence kinetics identified two exponential de- cay components in all of the three forms of LHC II: a longer-lived component (4.1―4.7 ns) originating from fluorescence emission of Chl a, and a shorter-lived one (135―540 ps) from the rapid equilibration of singlet excitation among Chl a molecules. The time constant of excitation equilibration is 135 ps in oli- gomer, 520 ps in trimer and 540 ps in monomer. These results imply that LHC II in oligomer form is inherently able to quench Chl a excitation, a mecha- nism which may be related to the photoprotection of PS II via changing the degree of LHC II aggregation in Bryopsis corticulans.