Psb28 is involved in recovery of photosystem II at high temperature in Synechocystis sp. PCC 6803.
Psb28 is involved in recovery of photosystem II at high temperature in Synechocystis sp. PCC 6803.
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DOI：
10.1016/j.bbabio.2012.10.004
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
Shinya Sakata;N. Mizusawa;Hisako Kubota-Kawai;I. Sakurai;H. Wada
中科院分区：
文献类型：
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作者：
Shinya Sakata;N. Mizusawa;Hisako Kubota-Kawai;I. Sakurai;H. Wada
Psb28是光系统II(PSII)的一种外源蛋白，在从蓝藻到高等植物的光合作用生物中都是保守的。一株单细胞蓝藻，聚球藻。PCC 6803有两个Psb28的同源物，Psb28-1和Psb28-2。然而，这些蛋白质的作用仍然知之甚少。在本研究中，我们中断了聚球藻野生型的psb28-1(Sll1398)和psb28-2(Slr1739)基因。Psb28在光合作用中的生理作用。我们还在一个DGDA突变体中干扰了Psb28-1基因，该突变体在双半乳糖二酰甘油的生物合成中存在缺陷，其中Psb28-1在PSII中显著积累。野生型的psb28-1基因的缺失导致了在高温下强光条件下的生长迟缓，光损伤的光合作用机制的恢复率很低。在pSB28-1/dgda双突变株中，在正常生长温度下也观察到类似现象。相反，野生型和DGDA突变体中的Psb28-2的中断并没有影响宿主菌株的表型，这表明Psb28-2不有助于PSII的恢复。此外，对表达His标记的Psb28-1菌株的蛋白质分析表明，Psb28-1主要与不含CP43的PSII单体有关。在DGDA突变体中，缺乏CP43的PSII单体的积累程度大于野生型，其积累导致Psb28-1在PSII中的积累更多。这些结果表明，Psb28-1通过与无CP43的单体结合在PSII修复中发挥重要作用，特别是在高温下。
Psb28 is an extrinsic protein of photosystem II (PSII), which is conserved among photosynthetic organisms from cyanobacteria to higher plants. A unicellular cyanobacterium, Synechocystis sp. PCC 6803, has two homologs of Psb28, Psb28-1 and Psb28-2. However, the role of these proteins remains poorly understood. In this study, we disrupted the psb28-1 (sll1398) and psb28-2 (slr1739) genes in wild-type Synechocystis sp. PCC 6803 and examined their photosynthetic properties to elucidate the physiological role of Psb28 in photosynthesis. We also disrupted the psb28-1 gene in a dgdA mutant defective in the biosynthesis of digalactosyldiacylglycerol, in which Psb28-1 significantly accumulates in PSII. The disruption of the psb28-1 gene in the wild-type resulted in growth retardation under high-light conditions at high temperatures with a low rate of restoration of photodamaged photosynthetic machinery. Similar phenomena were observed at normal growth temperatures in the psb28-1/dgdA double mutant. In contrast, disruption of psb28-2 in the wild-type and dgdA mutant did not affect host strain phenotype, suggesting that Psb28-2 does not contribute to the recovery of PSII. In addition, protein analysis using strains expressing His-tagged Psb28-1 revealed that Psb28-1 is mainly associated with the CP43-less PSII monomer. In the dgdA mutant, the CP43-less PSII monomer accumulated to a greater extent than in the wild-type, and its accumulation caused greater accumulation of Psb28-1 in PSII. These results demonstrate that Psb28-1 plays an important role in PSII repair through association with the CP43-less monomer, particularly at high temperatures.