Nagashima K V, Shimada K, Matsuura K
Department of Biology, Tokyo Metropolitan University, Japan.
FEBS Lett. 1996 May 6;385(3):209-13. doi: 10.1016/0014-5793(96)00382-1.
A mutant lacking the reaction center-bound cytochrome subunit was constructed in a purple photosynthetic bacterium, Rubrivivax gelatinosus IL144, by inactivation of the cytochrome gene. Photosynthetic growth of the C244 mutant strain occurred at approximately half the rate of the wild-type strain. Although mutagenesis resulted in a greatly reduced amount of membrane-bound cytochromes c, illumination induced cyclic electron transfer and the generation of membrane potential in the mutant as observed in the wild-type strain. These findings are consistent with previous observations that the cytochrome subunit is absent in the reaction center complex in some species of purple bacteria and that the biochemical removal of the subunit did not significantly affect the in vitro electron transfer from the soluble cytochrome c to the photosynthetic reaction center. These results suggest that the cytochrome subunit in purple bacteria is not essential for photosynthetic electron transfer and growth, even in those species generally containing the subunit.
通过使细胞色素基因失活，在紫色光合细菌嗜胶红假单胞菌IL144中构建了一个缺少与反应中心结合的细胞色素亚基的突变体。C244突变菌株的光合生长速率约为野生型菌株的一半。尽管诱变导致膜结合细胞色素c的量大幅减少，但光照诱导的循环电子传递以及突变体中膜电位的产生与野生型菌株中观察到的情况相同。这些发现与之前的观察结果一致，即在某些紫色细菌物种的反应中心复合物中不存在细胞色素亚基，并且该亚基的生化去除对体外从可溶性细胞色素c到光合反应中心的电子传递没有显著影响。这些结果表明，紫色细菌中的细胞色素亚基对于光合电子传递和生长并非必不可少，即使在通常含有该亚基的物种中也是如此。
