Xie D L, Lill H, Hauska G, Maeda M, Futai M, Nelson N
Roche Institute of Molecular Biology, Roche Research Center, Nutley, NJ 07110.
Biochim Biophys Acta. 1993 Mar 20;1172(3):267-73. doi: 10.1016/0167-4781(93)90213-w.
The operon (atp2) encoding the beta and epsilon subunits of F-ATPase from Chlorobium limicola was cloned and sequenced. In contrast with purple bacteria these genes are arranged in a separate operon similar to the cyanobacteria. The operon terminates with a pronounced stem-loop structure. About 0.8 kb upstream of the beta subunit a gene encoding the enzyme phospho enol pyruvate carboxykinase was identified. This gene is transcribed in the opposite direction of the atp2 operon and also ends with a stem-loop structure. These genes of green bacteria are among the first to be sequenced, and therefore the genetic distance between these genes and corresponding genes from other bacteria and eukaryotes was studied. Even though the operon structure resembles that of cyanobacteria, the evolutionary tree compiled from these data places the chlorobium gene close to purple bacteria. Chlorobium limicola beta and epsilon subunits complemented Escherichia coli mutants defective in the corresponding subunits, indicating that the hybrid enzyme formed from subunits of the two bacteria is active in ATP synthesis.
编码嗜盐绿菌F-ATP酶β和ε亚基的操纵子（atp2）被克隆并测序。与紫色细菌不同，这些基因排列在一个类似于蓝细菌的独立操纵子中。该操纵子以明显的茎环结构终止。在β亚基上游约0.8 kb处鉴定出一个编码磷酸烯醇丙酮酸羧激酶的基因。该基因的转录方向与atp2操纵子相反，并且也以茎环结构结束。这些绿菌的基因是首批被测序的基因之一，因此研究了这些基因与其他细菌和真核生物相应基因之间的遗传距离。尽管操纵子结构类似于蓝细菌，但根据这些数据编制的进化树将嗜盐绿菌基因置于靠近紫色细菌的位置。嗜盐绿菌的β和ε亚基补充了在相应亚基上有缺陷的大肠杆菌突变体，这表明由两种细菌的亚基形成的杂合酶在ATP合成中具有活性。
