Binding and functional properties of four extrinsic proteins of photosystem II from a red alga, Cyanidium caldarium, as studied by release -: Reconstitution experiments
Binding and functional properties of four extrinsic proteins of photosystem II from a red alga, Cyanidium caldarium, as studied by release -: Reconstitution experiments
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DOI：
10.1021/bi9724624
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发表时间：
1998-03-03
期刊：
影响因子：
2.9
通讯作者：
Shen, JR
中科院分区：
文献类型：
--
作者：
Enami, I;Kikuchi, S;Shen, JR
来自红al，oa，Cyanidium caldarium的光系统II（PSII）含有33、20和12 kDa的四种外源蛋白和细胞色素（cyt）c（550）[Enami，I.，例如，（1995）Biochim. Biophys. Acta 1232，208-216]。通过释放-重构实验研究了这四种蛋白在红藻PSII中的结合和功能特性。在这四种组分中，33 kDa蛋白完全通过自身与PSII结合，而20 kDa蛋白在不存在其他蛋白的情况下与天然PSII结合的水平为61%。与此相反，细胞色素c（550）和12 kDa的蛋白不能有效地结合PSII本身，其有效的结合需要其他三个外源蛋白。特别是，观察到细胞色素c（550）和12 kDa的蛋白质之间的强相互作用，和细胞色素c（550）和20 kDa的蛋白质之间观察到较弱的相互作用。虽然单独的33 kDa蛋白质或在33和/或20 kDa蛋白质存在下cyt c（550）和12 kDa蛋白质的结合通常增强了氧释放，但20 kDa蛋白质的结合没有增强。在没有cyt c（550）和12 kDa蛋白的情况下，氧释放强烈依赖于Ca 2+和Cl-，这表明这两种蛋白在更高平面的PSII中具有与23和17 kDa蛋白相似的功能。从这些结果中，我们提出，独特的20 kDa的外源蛋白，发现只有在红藻PSII的功能，在保持适当的结合的细胞色素C（550）和12 kDa的蛋白质，但不直接参与氧的演变。结合和功能特性的这四个蛋白质进行了比较，在蓝藻和高等植物PSII中发现的三个外源蛋白质在进化的角度来看。
Photosystem II (PSII) from a red al,oa, Cyanidium caldarium, contains four extrinsic proteins of 33, 20, and 12 kDa and cytochrome (cyt) c(550) [Enami, I., et al., (1995) Biochim. Biophys. Acta 1232, 208-216]. The binding and functional properties of these four proteins in the red algal PSII were studied by release-reconstitution experiments. Of the four components, the 33 kDa protein binds to PSII completely by itself, and the 20 kDa protein binds to a level 61% of that in native PSII in the absence of other proteins. In contrast, cyt c(550) and the 12 kDa protein cannot bind to PSII efficiently by themselves; their effective binding requires the other three extrinsic proteins. In particular, a strong interaction was observed between cyt c(550) and the 12 kDa protein, and a weaker interaction was observed between cyt c(550) and the 20 kDa protein. While binding of the 33 kDa protein alone or cyt c(550) and the 12 kDa protein in the presence of the 33 and/or the 20 kDa protein generally enhanced oxygen evolution, binding of the 20 kDa protein did not. Oxygen evolution was strongly dependent on Ca2+ and Cl- in the absence of cyt c(550) and the 12 kDa protein, suggesting that these two proteins have functions similar to those of the 23 and 17 kDa proteins in higher plane PSII. From these results, we propose that the unique 20 kDa extrinsic protein found only in the red algal PSII functions in maintaining the proper binding of cyt c(550) and the 12 kDa protein but is not involved directly in oxygen evolution. The binding and functional properties of these four proteins were compared with those of the three extrinsic proteins found in cyanobacterial and higher plant PSII in an evolutionary point of view.