The chloroplast ATP synthase in Chlamydomonas reinhardtii. II. Biochemical studies on its biogenesis using mutants defective in photophosphorylation.
The chloroplast ATP synthase in Chlamydomonas reinhardtii. II. Biochemical studies on its biogenesis using mutants defective in photophosphorylation.
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发表时间：
1989-06
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通讯作者：
C. Lemaire;F. Wollman
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作者：
C. Lemaire;F. Wollman
我们已经进行了分析的合成，细胞积累，和膜结合的叶绿体编码的ATP合酶（α，β，β，I，III和IV）的亚基在几个突变体的衣藻reinhardtii缺陷的磷酸化。这些数据提供了一些见解，在每个突变体的推定的遗传病变，并允许在类囊体膜的ATP合酶复合物的组装和稳定的一些表征。四个叶绿体突变体可能是改变叶绿体结构基因编码的耦合因子（CF）1亚基β和β和CF0亚基I和IV。第五个叶绿体突变体和三个核突变体的基因调节转录或翻译的叶绿体基因编码CF1亚基α和β和CF0亚基III和IV的改变。证据是（i）控制的合成速率的亚基β的亚基α在ATP合酶组装的情况下，和（ii）的α和β亚基之间的相互作用，在基质中的叶绿体，保护α亚基从蛋白水解降解。几个叶绿体编码的亚基CF0和CF1的稳定部分组装的ATP合酶的作用进行了讨论。我们的结论是，在ATP合酶组装的情况下，CF0不能积累在类囊体膜，而α和β亚基，大概从事可溶性CF1，可以积累在叶绿体的基质。
We have carried out an analysis of the synthesis, cellular accumulation, and membrane binding of the chloroplast-encoded subunits of the ATP synthase (alpha, beta, epsilon, I, III, and IV) in several mutants of Chlamydomonas reinhardtii defective in photophosphorylation. These data gave some insight on the putative genetic lesion in each mutant and allowed some characterization of the assembly and stabilization of the ATP synthase complex in the thylakoid membranes. Four chloroplast mutants are likely to be altered in chloroplast structural genes coding for coupling factor (CF) 1 subunits beta and epsilon and for CF0 subunits I and IV. A fifth chloroplast mutant and three nuclear mutants were altered in genes regulating either transcription or translation of chloroplast genes coding for CF1 subunits alpha and beta and CF0 subunits III and IV. Evidence is presented (i) for a control of the rate of synthesis of subunit beta by subunit alpha in the absence of ATP synthase assembly and (ii) for an interaction between alpha and beta subunits in the stroma of the chloroplast which protects alpha subunits from proteolytic degradation. The role of several chloroplast-encoded subunits of CF0 and CF1 in the stabilization of partially assembled ATP synthase is discussed. We conclude that in the absence of ATP synthase assembly, CF0 cannot accumulate in the thylakoid membranes, whereas alpha and beta subunits, presumably engaged in soluble CF1, can accumulate in the stroma of the chloroplast.