Environmental stress inhibits the synthesis de novo of proteins involved in the photodamage-repair cycle of Photosystem II in Synechocystis sp PCC 6803
Environmental stress inhibits the synthesis de novo of proteins involved in the photodamage-repair cycle of Photosystem II in Synechocystis sp PCC 6803
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DOI：
10.1016/j.bbabio.2004.03.003
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发表时间：
2004-06-28
影响因子：
4.3
通讯作者：
Murata, N
中科院分区：
文献类型：
--
作者：
Allakhverdiev, SI;Murata, N
光系统。II复合物（PSII）易受强光失活，强光引起的失活称为光失活或光抑制。在光合生物中，光失活的PSII被迅速修复，光失活的程度反映了PSII的光损伤（photodamage）和PSII修复之间的平衡。在本研究中，我们分别定量地考察了这两个过程在胁迫条件下的蓝细菌聚胞藻sp. PCC 6803。在0 ~ 2000 μ ue m(-2) s（-1）的光强范围内，光损伤速率与光强成正比，且不受盐胁迫、H2O2氧化胁迫、低温等环境因素的影响。修复的速度也取决于光照强度。在弱光下表现出较高的发光速率，在300 μ ue m(-2) s（-1）下达到最大0.1 min（-1）。与光损伤率相比，上述环境因素显著降低了修复率。放射性标记蛋氨酸的脉冲标记实验表明，这些环境因素抑制了蛋白质的重新合成。这些蛋白包括在光损伤修复循环中起重要作用的D1蛋白。这些观察结果表明，PSII在环境胁迫下的修复可能是决定光损伤修复周期结果的关键步骤。(C) 2004 Elsevier B.V.版权所有
The Photosystem. II complex (PSII) is susceptible to inactivation by strong light, and the inactivation caused by strong light is referred to as photoinactivation or photoinhibition. In photosynthetic organisms, photoinactivated PSII is rapidly repaired and the extent of photoinactivation reflects the balance between the light-induced damage (photodamage) to PSII and the repair of PSII. In this study, we examined these two processes separately and quantitatively under stress conditions in the cyanobacterium Synechocystis sp. PCC 6803. The rate of photodamage was proportional to light intensity over a range of light intensities from 0 to 2000 muE m(-2) s(-1), and this relationship was not affected by environmental factors, such as salt stress, oxidative stress due to H2O2, and low temperature. The rate of repair also depended on light intensity. It was high under weak light and reached a maximum of 0.1 min(-1) at 300 muE m(-2) s(-1). By contrast to the rate of photodamage, the rate of repair was significantly reduced by the above-mentioned environmental factors. Pulse-labeling experiments with radiolabeled methionme revealed that these environmental factors inhibited the synthesis de novo of proteins. Such proteins included the D1 protein which plays an important role in the photodamage-repair cycle. These observations suggest that the repair of PSII under environmental stress might be the critical step that determines the outcome of the photodamage-repair cycle. (C) 2004 Elsevier B.V. All rights reserved.