NdhV subunit regulates the activity of type-1 NAD(P)H dehydrogenase under high light conditions in cyanobacterium Synechocystis sp. PCC 6803.
NdhV subunit regulates the activity of type-1 NAD(P)H dehydrogenase under high light conditions in cyanobacterium Synechocystis sp. PCC 6803.
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NdhV 亚基在强光条件下调节蓝藻集胞藻 PCC 6803 中 1 型 NAD(P)H 脱氢酶的活性
DOI：
10.1038/srep28361
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发表时间：
2016-06-22
影响因子：
4.6
通讯作者：
Mi H
中科院分区：
文献类型：
--
作者：
Chen X;He Z;Xu M;Peng L;Mi H
蓝藻NAD(P)H脱氢酶（NDH-1）复合物在多种生物能量反应中起着至关重要的作用。然而，NDH-1在应激条件下的调控机制尚不清楚。在这项研究中，我们检测到NdhV缺失突变体（ΔndhV）在低光条件下对蓝细菌Synechocystis sp. PCC 6803的NDH-1活性部分受损，但NDH-1复合物的积累几乎没有受到影响。在低pH或低CO2无机碳限制条件下，ΔndhV在弱光条件下生长正常，在高光条件下生长缓慢，且在pH 8.0条件下CO2吸收活性明显低于野生型。NdhV在类囊体中的积累严格依赖于ndh1亲水亚复合物的存在。此外，NdhV与NDH-1的亲水亚基共存，与NDH-1L、NDH-1MS和NDH-1M复合物松散相关。高光条件下NdhV水平显著升高，NdhV的缺失抑制了NDH-1活性的上调，导致pH 6.5和高光条件下光合出氧速率降低。这些数据表明，NdhV是ndh1亲水亚配合物的内在亚基，是光系统I周围循环电子传递和强光下CO2吸收的有效运行所必需的。
The cyanobacterial NAD(P)H dehydrogenase (NDH-1) complexes play crucial roles in variety of bioenergetic reactions. However, the regulative mechanism of NDH-1 under stressed conditions is still unclear. In this study, we detected that the NDH-1 activity is partially impaired, but the accumulation of NDH-1 complexes was little affected in the NdhV deleted mutant (ΔndhV) at low light in cyanobacterium Synechocystis sp. PCC 6803. ΔndhV grew normally at low light but slowly at high light under inorganic carbon limitation conditions (low pH or low CO2), meanwhile the activity of CO2 uptake was evidently lowered than wild type even at pH 8.0. The accumulation of NdhV in thylakoids strictly relies on the presence of the hydrophilic subcomplex of NDH-1. Furthermore, NdhV was co-located with hydrophilic subunits of NDH-1 loosely associated with the NDH-1L, NDH-1MS′ and NDH-1M complexes. The level of the NdhV was significantly increased at high light and deletion of NdhV suppressed the up-regulation of NDH-1 activity, causing the lowered the photosynthetic oxygen evolution at pH 6.5 and high light. These data indicate that NdhV is an intrinsic subunit of hydrophilic subcomplex of NDH-1, required for efficient operation of cyclic electron transport around photosystem I and CO2 uptake at high lights.