Nixon Peter J, Barker Myles, Boehm Marko, de Vries Remco, Komenda Josef
Wolfson Laboratories, Department of Biological Sciences, Imperial College London, S. Kensington campus, London SW7 2AZ, UK.
J Exp Bot. 2005 Jan;56(411):357-63. doi: 10.1093/jxb/eri021. Epub 2004 Nov 15.
A common feature of light stress in plants, algae, and cyanobacteria is the light-induced damage to the photosystem II complex (PSII), which catalyses the photosynthetic oxidation of water to molecular oxygen. A repair cycle operates to replace damaged subunits within PSII, in particular, the D1 reaction centre polypeptide, by newly synthesized copies. As yet the molecular details of this physiologically important process remain obscure. A key aspect of the process that has attracted much attention is the identity of the protease or proteases involved in D1 degradation. The results are summarized here of recent mutagenesis experiments that were designed to assess the functional importance of the DegP/HtrA and FtsH protease families in the cyanobacterium Synechocystis sp. PCC 6803. Based on these results and the analysis of Arabidopsis mutants, a general model for PSII repair is suggested in which FtsH complexes alone are able to degrade damaged D1.
植物、藻类和蓝细菌中光胁迫的一个共同特征是光诱导对光系统II复合体（PSII）的损伤，该复合体催化水的光合氧化生成分子氧。一个修复循环会通过新合成的拷贝来替换PSII内受损的亚基，特别是D1反应中心多肽。然而，这个生理上重要过程的分子细节仍不清楚。该过程中一个备受关注的关键方面是参与D1降解的一种或多种蛋白酶的身份。这里总结了最近的诱变实验结果，这些实验旨在评估DegP/HtrA和FtsH蛋白酶家族在集胞藻PCC 6803中的功能重要性。基于这些结果以及对拟南芥突变体的分析，提出了一个PSII修复的通用模型，其中仅FtsH复合体就能降解受损的D1。
