Role of the PsbI protein in photosystem II assembly and repair in the cyanobacterium Synechocystis sp PCC 6803
Role of the PsbI protein in photosystem II assembly and repair in the cyanobacterium Synechocystis sp PCC 6803
复制标题
DOI：
10.1104/pp.107.107805
复制
发表时间：
2007-12-01
期刊：
影响因子：
7.4
通讯作者：
Komenda, Josef
中科院分区：
文献类型：
--
作者：
Dobakova, Marika;Tichy, Martin;Komenda, Josef
PsbI蛋白参与光系统II （PSII）复合体的组装和修复已经在蓝细菌中进行了研究。野生型菌株的PSII复合物分析表明，PsbI蛋白存在于二聚体和单体核心复合物、缺乏CP43的核心复合物以及含有D1、D2和细胞色素b-559的反应中心复合物中。此外，免疫沉淀实验和组氨酸标记的PsbI衍生物的使用表明，在类囊体膜中存在含有PsbI的组装复合物，以及D1的前体或成熟形式。PSII在psbI缺失突变体和缺乏psbI的菌株中与其他PSII亚基一起组装的分析表明，psbI不需要形成PSII反应中心复合物或核心复合物，尽管缺乏psbI时未组装的D1水平降低。然而，PsbI的缺失导致CP43在单体和二聚体PSII核心复合物中的结合剧烈不稳定。尽管PSII复合体中D1和PsbI的结构关系密切，但PsbI的翻转速度比D1慢得多，而在没有PsbI的情况下，强光诱导的D1的翻转速度加快。总之，我们的研究结果表明，PsbI是D1的早期组装伙伴，它在稳定CP43在PSII全酶中的结合中起功能作用。
The involvement of the PsbI protein in the assembly and repair of the photosystem II (PSII) complex has been studied in the cyanobacterium Synechocystis sp. PCC 6803. Analysis of PSII complexes in the wild-type strain showed that the PsbI protein was present in dimeric and monomeric core complexes, core complexes lacking CP43, and in reaction center complexes containing D1, D2, and cytochrome b-559. In addition, immunoprecipitation experiments and the use of a histidine- tagged derivative of PsbI have revealed the presence in the thylakoid membrane of assembly complexes containing PsbI and either the precursor or mature forms of D1. Analysis of PSII assembly in the psbI deletion mutant and in strains lacking PsbI together with other PSII subunits showed that PsbI was not required for formation of PSII reaction center complexes or core complexes, although levels of unassembled D1 were reduced in its absence. However, loss of PsbI led to a dramatic destabilization of CP43 binding within monomeric and dimeric PSII core complexes. Despite the close structural relationship between D1 and PsbI in the PSII complex, PsbI turned over much slower than D1, whereas high light- induced turnover of D1 was accelerated in the absence of PsbI. Overall, our results suggest that PsbI is an early assembly partner for D1 and that it plays a functional role in stabilizing the binding of CP43 in the PSII holoenzyme.