BIOGENESIS FACTOR REQUIRED FOR ATP SYNTHASE 3 Facilitates Assembly of the Chloroplast ATP Synthase Complex1
BIOGENESIS FACTOR REQUIRED FOR ATP SYNTHASE 3 Facilitates Assembly of the Chloroplast ATP Synthase Complex1
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DOI：
10.1104/pp.16.00248
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发表时间：
2016-04
期刊：
影响因子：
7.4
通讯作者：
Lin Zhang;Zhikun Duan;Jiao Zhang;Lianwei Peng
中科院分区：
文献类型：
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作者：
Lin Zhang;Zhikun Duan;Jiao Zhang;Lianwei Peng
核编码因子通过与CF1 β亚基特异性相互作用参与叶绿体ATP合酶的组装。类囊体膜定位的叶绿体ATP酶利用光合电子传递产生的质子动力从ADP产生ATP。叶绿体ATP合成酶由20多种蛋白质组成，其化学计量比为α 3 β 3 γ 1 ε 1 δ 1I1II1III14IV1，但其生物合成过程尚不清楚。为了阐明叶绿体ATP合酶生物发生的分子机制，我们进行了广泛的筛选分离ATP合酶突变体在拟南芥（拟南芥）。在最近鉴定的bfa3（ATP合成酶3所需的生物合成因子）突变体中，叶绿体ATP合成酶亚基的水平降低到野生型水平的约25%。在体内标记分析表明，组装的叶绿体ATP合酶的CF1组件是不太有效的bfa3比野生型，表明BFA3是所需的CF1大会。BFA 3编码一种叶绿体基质蛋白，在高等植物、绿色藻类和其他一些真核藻类中是保守的，并且特异性地与CF 1 β亚基相互作用。将BFA 3结合位点定位于CF 1 β催化位点的区域。真核生物CF1 β中的几个高度保守的残基对BFA 3-CF1 β相互作用至关重要，表明BFA 3和CF1 β之间存在共进化关系。BFA 3似乎是一种分子伴侣，在其催化位点与未组装的CF 1 β短暂结合，并在叶绿体ATP合酶的CF 1亚复合物组装过程中促进随后与CF 1 α的结合。
A nucleus-encoded factor is involved in the assembly of the chloroplast ATP synthase via a specific interaction with CF1β subunit. Thylakoid membrane-localized chloroplast ATP synthases use the proton motive force generated by photosynthetic electron transport to produce ATP from ADP. Although it is well known that the chloroplast ATP synthase is composed of more than 20 proteins with α3β3γ1ε1δ1I1II1III14IV1 stoichiometry, its biogenesis process is currently unclear. To unravel the molecular mechanisms underlying the biogenesis of chloroplast ATP synthase, we performed extensive screening for isolating ATP synthase mutants in Arabidopsis (Arabidopsis thaliana). In the recently identified bfa3 (biogenesis factors required for ATP synthase 3) mutant, the levels of chloroplast ATP synthase subunits were reduced to approximately 25% of wild-type levels. In vivo labeling analysis showed that assembly of the CF1 component of chloroplast ATP synthase was less efficient in bfa3 than in the wild type, indicating that BFA3 is required for CF1 assembly. BFA3 encodes a chloroplast stromal protein that is conserved in higher plants, green algae, and a few species of other eukaryotic algae, and specifically interacts with the CF1β subunit. The BFA3 binding site was mapped to a region in the catalytic site of CF1β. Several residues highly conserved in eukaryotic CF1β are crucial for the BFA3–CF1β interaction, suggesting a coevolutionary relationship between BFA3 and CF1β. BFA3 appears to function as a molecular chaperone that transiently associates with unassembled CF1β at its catalytic site and facilitates subsequent association with CF1α during assembly of the CF1 subcomplex of chloroplast ATP synthase.