Laudenbach D E, Herbert S K, McDowell C, Fork D C, Grossman A R, Straus N A
Carnegie Institution of Washington, Department of Plant Biology, Stanford, California 94305.
Plant Cell. 1990 Sep;2(9):913-24. doi: 10.1105/tpc.2.9.913.
In cyanobacteria, the water-soluble cytochrome c-553 functions as a mobile carrier of electrons between the membrane-bound cytochrome b6-f complex and P-700 reaction centers of Photosystem I. The structural gene for cytochrome c-553 (designated cytA) of the cyanobacterium Synechococcus sp. PCC 7942 was cloned, and the deduced amino acid sequence was shown to be similar to known cyanobacterial cytochrome c-553 proteins. A deletion mutant was constructed that had no detectable cytochrome c-553 based on spectral analyses and tetramethylbenzidine-hydrogen peroxide staining of proteins resolved by polyacrylamide gel electrophoresis. The mutant strain was not impaired in overall photosynthetic activity. However, this mutant exhibited a decreased efficiency of cytochrome f oxidation. These results indicate that cytochrome c-553 is not an absolute requirement for reducing Photosystem I reaction centers in Synechococcus sp. PCC 7942.
在蓝细菌中，水溶性细胞色素c-553作为电子在膜结合的细胞色素b6-f复合物与光系统I的P-700反应中心之间的移动载体。蓝细菌聚球藻属PCC 7942的细胞色素c-553（命名为cytA）的结构基因被克隆，推导的氨基酸序列显示与已知的蓝细菌细胞色素c-553蛋白相似。构建了一个缺失突变体，基于光谱分析和通过聚丙烯酰胺凝胶电泳分离的蛋白质的四甲基联苯胺-过氧化氢染色，该突变体没有可检测到的细胞色素c-553。突变菌株的总体光合活性没有受损。然而，该突变体表现出细胞色素f氧化效率降低。这些结果表明，细胞色素c-553不是聚球藻属PCC 7942中还原光系统I反应中心的绝对必需物质。
