Acclimation to the growth temperature and thermosensitivity of photosystem II in a mesophilic cyanobacterium, Synechocystis sp PCC6803
Acclimation to the growth temperature and thermosensitivity of photosystem II in a mesophilic cyanobacterium, Synechocystis sp PCC6803
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DOI：
10.1093/pcp/pcl024
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发表时间：
2006-12-01
影响因子：
4.9
通讯作者：
Satoh, Kazuhiko
中科院分区：
文献类型：
--
作者：
Aminaka, Ryohta;Taira, Yoshiko;Satoh, Kazuhiko
研究了25℃和35℃条件下聚囊藻PCC6803对PSII活性的温度依赖性和热敏性的差异。在高温下或高温处理后的生长温度下测量细胞、类囊体膜和纯化PSII核心复合物的Hill反应。当2,5-二氯对苯醌作为电子受体，可以直接接受Q(A)的电子时，在类囊体膜和纯化的PSII复合物中，在25或35℃生长的细胞中，氧演化活性的温度依赖性几乎是相同的。纯化的PSII核心复合物对温度的依赖性相同，但从25和35℃培养的细胞中分离的类囊体与从25和35℃培养的细胞中分离的纯化PSII复合物之间的蛋白质组成没有显著差异。然而，通过流向P700的电子流测量的类囊体的流动性受到生长温度的影响。这些结果表明，引起PSII热敏性变化的主要因素之一是类囊体膜流动性的变化。对于类囊体PSII对高温的驯化，主要原因之一是在35℃下生长的细胞流动性降低，导致高温诱导的非q (B) PSII的形成减少。
Differences in the temperature dependence and thermosensitivities of PSII activities in Synechocystis sp. PCC6803 grown at 25 and 35 degrees C were studied. Hill reactions in cells, thylakoid membranes and purified PSII core complexes were measured at high temperatures or at their growth temperatures after high-temperature treatments. In the presence of 2,5-dichloro-p-benzoquinone as an electron acceptor, which can accept electrons directly from Q(A), the temperature dependence of the oxygen-evolving activity was almost the same in thylakoid membranes and in the purified PSII complexes from cells grown at 25 or 35 degrees C. When duroquinone, which accepts electrons only through Q(B) plastoquinone, was used as an electron acceptor, the temperature dependence was the same for purified PSII core complexes but was different between thylakoids isolated from the cells grown at 25 and 35 degrees C. No remarkable difference was observed in protein compositions between thylakoids and between purified PSII complexes from cells grown at 25 or 35 degrees C. However, the fluidity of thylakoids, measured by electron flow to P700, was affected by the growth temperature. These results suggest that one of the major factors which cause the changes in the thermosensitivity of PSII is the change in the fluidity of thylakoid membranes. As for the acclimation of PSII in thylakoids to high temperatures, one of the main causes is the decrease in the high-temperature-induced formation of non-Q(B) PSII due to the decreased fluidity in the cells grown at 35 degrees C.