Mutagenesis of Ser^(24) of cytochrome b559 α subunit affects PSII activities in Chlamydomonas reinhardtii

作     者：MA JingJing LI LiangBi JING YuXiang KUANG TingYun 

作者机构：Key Laboratory of Photosynthesis and Environmental Molecular Physiology Institute of Botany Chinese Academy of Sciences Beijing 100093 China Graduate University of Chinese Academy of Sciences Beijing 100049 China 

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

年 卷 期：2007年第52卷第7期

页      面：896-902页

核心收录：

学科分类：0710[理学-生物学] 071001[理学-植物学] 07[理学] 09[农学] 0903[农学-农业资源与环境] 090302[农学-植物营养学] 

基　　金：Supported by the National Basic Research Program (973 Program) (Grant No. G1988010100) the National Natural Science Foundation of China (Grant No. 088121A) 

主　　题：莱茵衣藻 细胞色素b559α亚基 丝氨酸残基 Ser24 突变 光系统II 光合活性 

摘      要：In order to study the functions of cytochrome b559 (Cyt b559) in photosystem two (PSII) activity, mutant S24F of Chlamydomonas reinhardtii was constructed using site directed mutagenesis, in which Serine24 (Ser24) locating downstream of Histidine23 (His23) in α subunit of Cyt b559 was replaced by Phenylalanine (Phe). Physiological and biochemical analysis showed that mutant S24F could be grown photoautotrophically or photoheterotrophically. However, their growth rate was slower either on HSM or TAP medium than that of the control; Analysis of PSII activity revealed that its oxygen evolution was about 71% of wild type (WT); The Photochemical efficiency of PSII (Fv/Fm) of S24F was reduced 0.23 compared with WT; S24F was more sensitive to strong light irradiance than the wild type; Furthermore, SDS-PAGE and Western-blotting analysis indicated that the expression levels of α subunit of Cyt b559, LHCII and PsbO of S24F were a little less than those of the wild type. Overall, these data suggests that Ser24 plays a significant role in making Cyt b559 structure maintain PSII complex activity of oxygen evolution although it is not directly bound to heme group.