Accumulation of Cyanobacterial Photosystem II Containing the 'Rogue' D1 Subunit Is Controlled by FtsH Protease and Synthesis of the Standard D1 Protein.
Accumulation of Cyanobacterial Photosystem II Containing the 'Rogue' D1 Subunit Is Controlled by FtsH Protease and Synthesis of the Standard D1 Protein.
复制标题
含有“Rogue”D1 亚基的蓝藻光系统 II 的积累受 FtsH 蛋白酶和标准 D1 蛋白合成的控制。
DOI：
10.1093/pcp/pcad027
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发表时间：
2023
影响因子：
4.9
通讯作者：
Masuda T
中科院分区：
文献类型：
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作者：
Masuda T
单细胞固氮蓝藻对海洋的光合生产力和分子氮的固定有重要贡献，光合作用发生在白天，氮固定在夜间。在Crocosphaera watsoniiWH 8501等物种中，夜间光合活性的下降伴随着放氧光系统II（PSII）复合物的分解。此外，在夜间阶段的后半部分，少量的流氓D1（rD 1），这是有关的标准形式的D1亚基中发现的氧气释放PSII，但未知的功能，积累，但在开始的光相迅速降解。我们发现rD 1的去除不依赖于rD 1的转录水平、类囊体氧化还原状态和反式类囊体pH值，但需要光照和活性蛋白质的合成。我们还发现，rD 1的最大水平与叶绿素（Chl）生物合成前体和酶的最大水平呈正相关，这表明流氓PSII（rPSII）在激活Chl生物合成的可能作用之前或之后的光，当新的光系统合成。通过研究表达CrocosphaerarD 1的集胞藻PCC 6803菌株，我们发现rD 1的积累是由标准D1蛋白的光依赖性合成控制的，这触发了rD 1的快速FtsH 2依赖性降解。FLAG标记的rD 1的亲和纯化明确地证明了将rD 1掺入到非氧释放PSII复合物中，我们称之为rPSII。该复合物缺乏稳定氧释放Mn 4CaO 5簇的外源蛋白，但含有Psb 27和Psb 28 -1组装因子。
Unicellular diazotrophic cyanobacteria contribute significantly to the photosynthetic productivity of the ocean and the fixation of molecular nitrogen, with photosynthesis occurring during the day and nitrogen fixation during the night. In species likeCrocosphaera watsoniiWH8501, the decline in photosynthetic activity in the night is accompanied by the disassembly of oxygen-evolving photosystem II (PSII) complexes. Moreover, in the second half of the night phase, a small amount of rogue D1 (rD1), which is related to the standard form of the D1 subunit found in oxygen-evolving PSII, but of unknown function, accumulates but is quickly degraded at the start of the light phase. We show here that the removal of rD1 is independent of the rD1 transcript level, thylakoid redox state andtrans-thylakoid pH but requires light and active protein synthesis. We also found that the maximal level of rD1 positively correlates with the maximal level of chlorophyll (Chl) biosynthesis precursors and enzymes, which suggests a possible role for rogue PSII (rPSII) in the activation of Chl biosynthesis just before or upon the onset of light, when new photosystems are synthesized. By studying strains ofSynechocystisPCC 6803 expressingCrocosphaerarD1, we found that the accumulation of rD1 is controlled by the light-dependent synthesis of the standard D1 protein, which triggers the fast FtsH2-dependent degradation of rD1. Affinity purification of FLAG-tagged rD1 unequivocally demonstrated the incorporation of rD1 into a non-oxygen-evolving PSII complex, which we term rPSII. The complex lacks the extrinsic proteins stabilizing the oxygen-evolving Mn4CaO5cluster but contains the Psb27 and Psb28-1 assembly factors.