Trieu-Cuot P, Courvalin P
Gene. 1983 Sep;23(3):331-41. doi: 10.1016/0378-1119(83)90022-7.
We have cloned in Escherichia coli and sequenced a 1489-bp DNA fragment conferring resistance to kanamycin and originating from the streptococcal plasmid pJH1. The resistance gene was located by analysis of the initiation and termination codons in an open reading frame (ORF) of 792 bp. The deduced gene product, a 3'5''-aminoglycoside phosphotransferase of type III, has an Mr of 29,200. Comparison of its amino acid sequence with those of type I (Oka et al., 1981) and type II (Beck et al., 1982) 3' phosphotransferase, from transposable elements Tn903 and Tn5, respectively, indicated a statistically significant structural relationship between these enzymes from phylogenetically remote bacterial genera. The degree of homology observed indicate that phosphotransferase type III and type I genes have diverged from a common ancestor and that the phosphotransferase type II gene has emerged more recently from the type I evolutionary pathway.
我们已在大肠杆菌中克隆了一段来自链球菌质粒pJH1的1489碱基对DNA片段，并对其进行了测序，该片段赋予对卡那霉素的抗性。通过分析一个792碱基对开放阅读框（ORF）中的起始密码子和终止密码子来定位抗性基因。推导的基因产物是一种III型3'5''-氨基糖苷磷酸转移酶，分子量为29,200。将其氨基酸序列分别与来自转座元件Tn903和Tn5的I型（冈田等人，1981年）和II型（贝克等人，1982年）3'磷酸转移酶的氨基酸序列进行比较，结果表明，这些来自系统发育上遥远细菌属的酶之间存在统计学上显著的结构关系。观察到的同源程度表明，III型磷酸转移酶基因和I型磷酸转移酶基因已从共同祖先分化而来，而II型磷酸转移酶基因是最近从I型进化途径中出现的。
