Bucca G, Smith C P, Alberti M, Seidita G, Passantino R, Puglia A M
Department of Biochemistry and Applied Molecular Biology, U.M.I.S.T., Manchester, UK.
Gene. 1993 Aug 16;130(1):141-4. doi: 10.1016/0378-1119(93)90358-a.
The dnaK homologue of Streptomyces coelicolor A3(2) strain M145 has been cloned and sequenced. Nucleotide sequence analysis of a 2.5-kb region revealed an open reading frame (ORF) encoding a predicted DnaK protein of 618 amino acids (M(r) = 66,274). The dnaK coding sequence displays extreme codon bias and shows a strong preference for CGY and GGY, for Arg and Gly codons, respectively. The predicted DnaK sequence has a high Lys:Arg ratio which is not typical of streptomycete proteins. The region immediately downstream from dnaK contains an ORF for a GrpE-like protein; the predicted start codon of grpE overlaps the last two codons of dnaK, indicating that the two genes are translationally coupled. This organisation differs from that reported for other prokaryotes.
天蓝色链霉菌A3(2)菌株M145的dnaK同源物已被克隆并测序。对一个2.5kb区域的核苷酸序列分析揭示了一个开放阅读框（ORF），其编码一个预测的由618个氨基酸组成的DnaK蛋白（分子量=66,274）。dnaK编码序列显示出极端的密码子偏好性，分别对CGY和GGY密码子（即Arg和Gly密码子）有强烈偏好。预测的DnaK序列具有较高的赖氨酸:精氨酸比率，这在链霉菌蛋白中并不典型。dnaK下游紧邻区域包含一个编码类GrpE蛋白的ORF；grpE的预测起始密码子与dnaK的最后两个密码子重叠，表明这两个基因在翻译上是偶联的。这种基因组织方式与其他原核生物中报道的不同。
