Falah M, Gupta R S
Department of Biochemistry, McMaster University, Hamilton, Ontario, Canada.
J Bacteriol. 1994 Dec;176(24):7748-53. doi: 10.1128/jb.176.24.7748-7753.1994.
The genes for hsp70 (or dnaK) have been cloned and sequenced from Rhizobium meliloti and Pseudomonas cepacia, two bacterial species belonging to the alpha- and beta-subdivisions of gram-negative proteobacteria, respectively. On the basis of global alignment of HSP70 proteins, several sequence signatures have been identified that are distinctive of mitochondrial homologs and gram-negative proteobacteria on the one hand and the chloroplasts and cyanobacteria on the other. Detailed phylogenetic analyses of HSP70 sequences from various eubacteria and eukaryotic organellar and cytosolic homologs support the inference regarding the origin of mitochondria from a member of the alpha-proteobacteria and of chloroplasts from cyanobacteria. The analysis presented here also suggests a monophyletic origin of the mitochondrial homologs.
热休克蛋白70(或dnaK)的基因已从苜蓿根瘤菌和洋葱假单胞菌中克隆并测序,这两种细菌分别属于革兰氏阴性变形菌的α-和β-亚群。基于HSP70蛋白的全局比对,已鉴定出几个序列特征,一方面是线粒体同源物和革兰氏阴性变形菌所特有的,另一方面是叶绿体和蓝细菌所特有的。对来自各种真细菌、真核细胞器和胞质同源物的HSP70序列进行的详细系统发育分析支持了关于线粒体起源于α-变形菌的一个成员以及叶绿体起源于蓝细菌的推断。此处给出的分析还表明线粒体同源物有一个单系起源。