Ma Fei, Chen Xiao-Bo, Sang Min, Wang Peng, Zhang Jian-Ping, Li Liang-Bi, Kuang Ting-Yun
Beijing National Laboratory for Molecular Science, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China.
Photosynth Res. 2009 Apr;100(1):19-28. doi: 10.1007/s11120-009-9418-2. Epub 2009 Mar 31.
We have attempted to investigate the correlation between the detergent-perturbed structural integrity of the Cyt b (6) f complex from the marine green alga Bryopsis corticulans and its photo-protective properties, for which the nonionic detergents n-octyl-beta-D-glucopyranoside (beta-OG) and n-dodecyl-beta-D-maltoside (beta-DM), respectively, were used for the preparation of Cyt b (6) f, and the singlet oxygen ((1)O(2)) production as well as the triplet excited-state chlorophyll a ((3)Chl a) formation and deactivation were examined by spectroscopic means. Near-infrared luminescence of (1)O(2)* (approximately 1,270 nm) on photo-irradiation was detected for the beta-OG preparation where the complex is mainly in oligomeric state, but not for the beta-DM one in which the complex exists in dimeric form. Under anaerobic condition, photo-excitation of Chl a in the beta-DM preparation generated (3)Chl a* with a lower quantum yield of Phi(T) approximately 0.02 and a longer lifetime of approximately 600 micros with respect to those as in the case of beta-OG preparation, Phi(T) approximately 0.12 and 200-300 micros. These results prove that the enzymatically active and intact Cyt b (6) f complex on photo-excitation tends to produce little (3)Chl a* or (1)O(2)*, which implies that the pigment-protein assembly of Cyt b (6) f complex per se is crucial for photo-protection.
我们试图研究来自海洋绿藻皮层管藻的细胞色素b（6）f复合体经去污剂扰动后的结构完整性与其光保护特性之间的相关性。为此，分别使用非离子去污剂正辛基-β-D-葡萄糖苷（β-OG）和正十二烷基-β-D-麦芽糖苷（β-DM）来制备细胞色素b（6）f，并通过光谱手段检测单线态氧（（1）O（2））的产生以及三线态激发态叶绿素a（（3）Chl a）的形成和失活。对于主要以寡聚体状态存在的β-OG制剂，在光照射下检测到（1）O（2）的近红外发光（约1270 nm），而对于以二聚体形式存在的β-DM制剂则未检测到。在厌氧条件下，β-DM制剂中叶绿素a的光激发产生（3）Chl a，其量子产率较低，约为0.02，寿命较长，约为600微秒，而β-OG制剂的量子产率约为0.12，寿命为200 - 300微秒。这些结果证明，光激发时具有酶活性且完整的细胞色素b（6）f复合体倾向于产生很少的（3）Chl a或（1）O（2），这意味着细胞色素b（6）f复合体本身的色素 - 蛋白质组装对于光保护至关重要。
