The NdhV subunit is required to stabilize the chloroplast NADH dehydrogenase-like complex in Arabidopsis
The NdhV subunit is required to stabilize the chloroplast NADH dehydrogenase-like complex in Arabidopsis
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NdhV 亚基是稳定拟南芥叶绿体 NADH 脱氢酶样复合物所必需的
DOI：
10.1111/tpj.12807
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发表时间：
2015-04-01
期刊：
影响因子：
7.2
通讯作者：
Peng, Lianwei
中科院分区：
文献类型：
--
作者：
Fan, Xiangyuan;Zhang, Jiao;Peng, Lianwei
叶绿体NADH脱氢酶样（NDH）复合体参与光系统i （PSI）周围的循环电子传递和氯呼吸。虽然NDH复合物早在20多年前就被发现，但其丰度低且易碎的性质使其难以分析，并且认为其一些亚基仍有待鉴定。在这里，我们发现NDH亚基NdhV在洗涤剂、盐和碱性溶液存在下很容易从NDH复合物中解离。拟南芥ndhv突变体在NDH亚复合物a （SubA）和subbe的积累上存在部分缺陷，导致NDH活性受损。NdhV主要在野生型类囊体膜中检测到，其在类囊体中的积累严格依赖于NDH复合物的存在。定量免疫印迹分析显示NdhV和NdhN在接近等摩尔浓度下发生。此外，利用化学交联和亲和层析相结合的方法，几种NDH亚基与NdhV共免疫纯化。这些数据表明NdhV是NDH的一个固有亚基。我们发现NdhV对NDH活性没有直接影响，但在强光处理下，NdhV对NDH SubA和subbe的降解速度比野生型快。我们认为NdhV是一个NDH亚基，它稳定了这个复合物，特别是在强光条件下。这项工作确定了叶绿体NADH脱氢酶样（NDH）亚基NdhV，它位于NDH复合体最脆弱的部分。NdhV与NDH亚络合物A和E相互作用并使其稳定，特别是在强光条件下。
The chloroplast NADH dehydrogenase-like (NDH) complex is involved in cyclic electron transport around photosystemI (PSI) and chlororespiration. Although the NDH complex was discovered more than 20years ago, its low abundance and fragile nature render it recalcitrant to analysis, and it is thought that some of its subunits remain to be identified. Here, we identified the NDH subunit NdhV that readily disassociates from the NDH complex in the presence of detergent, salt and alkaline solutions. The Arabidopsis ndhv mutant is partially defective in the accumulation of NDH subcomplexA (SubA) and SubE, resulting in impaired NDH activity. NdhV was mainly detected in the wild-type thylakoid membrane, and its accumulation in thylakoids strictly depended on the presence of the NDH complex. Quantitative immunoblot analysis revealed that NdhV and NdhN occur at close to equimolar concentrations. Furthermore, several NDH subunits were co-immunopurified with NdhV using a combination of chemical crosslinking and an affinity chromatography assay. These data indicate that NdhV is an intrinsic subunit of NDH. We found that NdhV did not directly affect NDH activity, but that NDH SubA and SubE were more rapidly degraded in ndhv than in the wild type under high-light treatment. We propose that NdhV is an NDH subunit that stabilizes this complex, especially under high-light conditions.Significance Statement This work identifies the chloroplast NADH dehydrogenase-like (NDH) subunit NdhV, which is located on the most fragile part of the NDH complex. NdhV interacts with and stabilizes the NDH subcomplexes A and E, especially under high-light conditions.