Malke H, Roe B, Ferretti J J
Gene. 1985;34(2-3):357-62. doi: 10.1016/0378-1119(85)90145-3.
The entire nucleotide sequence of a cloned 2568-bp PstI fragment from the genome of Streptococcus equisimilis H46A encoding the streptokinase gene (skc) has been determined. The longest open reading frame comprises 1320 bp which code for streptokinase. The protein is synthesized with a 26-amino acid residue N-terminal extension having properties characteristic of a signal peptide. Comparison of the deduced amino acid sequence with the available amino acid sequence of a commercial streptokinase reveals minor primary structure differences. The nucleotide sequencing of skc does not support the hypothesis that the gene has evolved by duplication and fusion, as suggested by internal twofold amino acid homologies of its product. Furthermore, the skc gene sequence shows no extended regions homologous to the staphylokinase gene. Upstream from the skc gene, the putative skc promoter and the ribosome-binding site sequence have been identified; downstream from the coding region, inverted repeat sequences thought to function as transcription terminators have been detected.
已确定从马链球菌兽疫亚种H46A基因组中克隆的编码链激酶基因（skc）的2568 bp PstI片段的完整核苷酸序列。最长的开放阅读框包含1320 bp，编码链激酶。该蛋白质合成时带有一个26个氨基酸残基的N端延伸，具有信号肽的特征性质。将推导的氨基酸序列与市售链激酶的可用氨基酸序列进行比较，发现一级结构存在细微差异。skc的核苷酸测序不支持该基因通过复制和融合进化的假说，如其产物内部的双重氨基酸同源性所表明的那样。此外，skc基因序列未显示与葡萄球菌激酶基因同源的延伸区域。在skc基因上游，已鉴定出推定的skc启动子和核糖体结合位点序列；在编码区下游，已检测到被认为起转录终止子作用的反向重复序列。
