Miyazaki T, Tanaka S, Fujita H, Itikawa H
Department of Applied Microbiology, Nippon Roche Research Center, Kanagawa, Japan.
J Bacteriol. 1992 Jun;174(11):3715-22. doi: 10.1128/jb.174.11.3715-3722.1992.
The DNA sequence of the dnaK gene of Escherichia coli was analyzed. The nucleotide sequence of the wild-type dnaK gene of E. coli B differed from that of E. coli K-12 in 15 bp, none of which altered the amino acid sequence. Two temperature-sensitive dnaK mutations were examined by cloning and sequence analyses. Results showed that one dnaK mutation, dnaK7(Ts), was a one-base substitution of T for C at nucleotide position 448 in the open reading frame yielding an amber nonsense codon. The other mutation, dnaK756(Ts), consisted of base substitutions (A for G) at three nucleotide positions, 95, 1364, and 1403, in the open reading frame resulting in an aspartic acid codon in place of a glycine codon.
对大肠杆菌dnaK基因的DNA序列进行了分析。大肠杆菌B野生型dnaK基因的核苷酸序列与大肠杆菌K-12的核苷酸序列在15个碱基对处存在差异，其中没有一个改变氨基酸序列。通过克隆和序列分析研究了两个温度敏感型dnaK突变。结果表明，一个dnaK突变体dnaK7（Ts）是开放阅读框中第448位核苷酸处的T被C单碱基取代，产生琥珀色无义密码子。另一个突变体dnaK756（Ts）由开放阅读框中三个核苷酸位置（95、1364和1403）的碱基取代（G被A取代）组成，导致甘氨酸密码子被天冬氨酸密码子取代。
