Role of visible light in the recovery of photosystem II structure and function from ultraviolet-B stress in higher plants
Role of visible light in the recovery of photosystem II structure and function from ultraviolet-B stress in higher plants
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DOI：
10.1093/jxb/erg180
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发表时间：
2003-07-01
影响因子：
6.9
通讯作者：
Barbato, R
中科院分区：
文献类型：
--
作者：
Bergo, E;Segalla, A;Barbato, R
本文研究了可见光对UV-B辐射处理的植物光系统Ⅱ反应中心D1蛋白的影响。结果发现，20 kDa的C-末端片段的D1蛋白在紫外线-B光照射过程中产生的植物在黑暗中孵育时是稳定的，但被降解时，植物在可见光下孵育。在此条件下，还观察到光合活性的恢复。即使是低水平的白色光也足以促进片段的进一步降解和活性的恢复。在此阶段，D1蛋白是主要合成的类囊体多肽，表明其他光系统II蛋白在恢复过程中被回收。尽管20 kDa片段的降解和D1的再合成都是光依赖性现象，但它们并不密切相关，因为即使在不存在D1合成的情况下也可能发生20 kDa片段的降解。通过比较影响紫外-B光下片段形成和白色光下片段降解的化学和物理因素，得出结论：紫外-B光下片段的形成是一个光化学过程，而白色光下片段的降解是一个蛋白酶介导的过程。
The effect of visible light on photosystem II reaction centre D1 protein in plants treated with ultraviolet-B light was studied. It was found that a 20 kDa C-terminal fragment of D1 protein generated during irradiation with ultraviolet-B light was stable when plants were incubated in the dark, but was degraded when plants were incubated in visible light. In this condition the recovery of photosynthetic activity was also observed. Even a low level of white light was sufficient to promote both further degradation of the fragment and recovery of activity. During this phase, the D1 protein is the main synthesized thylakoid polypeptide, indicating that other photosystem II proteins are recycled in the recovery process. Although both degradation of the 20 kDa fragment and resynthesis of D1 are light-dependent phenomena, they are not closely related, as degradation of the 20 kDa fragment may occur even in the absence of D1 synthesis. Comparing chemical and physical factors affecting the formation of the fragment in ultraviolet-B light and its degradation in white light, it was concluded that the formation of the fragment in ultraviolet-B light is a photochemical process, whereas the degradation of the fragment in white light is a protease-mediated process.