Photosynthetic electron transport in genetically altered photosystem II reaction centers of chloroplasts.
Photosynthetic electron transport in genetically altered photosystem II reaction centers of chloroplasts.
复制标题
基因改变的叶绿体光系统 II 反应中心的光合电子传输。
DOI：
10.1073/pnas.88.20.9122
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发表时间：
1991
影响因子：
11.1
通讯作者：
Sayre,RT
中科院分区：
文献类型：
--
作者：
Roffey,RA;Golbeck,JH;Hille,CR;Sayre,RT
利用共转化系统鉴定莱茵衣藻的叶绿体转化子，我们将光系统II反应中心D1蛋白的组氨酸-195转化为酪氨酸残基。突变体的特征是光合放氧的量子效率降低，氧化人工供体为光系统II的能力降低，P680+还原动力学(微秒)基本上与野生型相似。此外，ESR在突变的光系统II颗粒中检测到暗稳定的自由基，而在野生型颗粒中没有检测到。该自由基在g值和线形上与叶绿素或类胡萝卜素阳离子相似，但可能来自酪氨酸-195阳离子。光系统II陷阱(P680+)氧化酪氨酸残基的能力表明突变的酪氨酸残基可以作为氧化还原敏感的探针来研究光系统II陷阱周围的环境。
Using a cotransformation system to identify chloroplast transformants in Chlamydomonas reinhardtii, we converted histidine-195 of the photosystem II reaction center D1 protein to a tyrosine residue. The mutants were characterized by a reduced quantum efficiency for photosynthetic oxygen evolution, which varied in a pH-dependent manner, a reduced capacity to oxidize artificial donors to photosystem II, and P680+ reduction kinetics (microsecond) that were essentially similar to wild type. In addition, a dark-stable radical was detected by ESR in mutant photosystem II particles but not in wild-type particles. This radical was similar in g value and lineshape to chlorophyll or carotenoid cations but could have arisen from a tyrosine-195 cation. The ability of the photosystem II trap (P680+) to oxidize tyrosine residues suggests that the mutant tyrosine residue could be used as a redox-sensitive probe to investigate the environment around the photosystem II trap.