Gagnon G, Vadeboncoeur C, Levesque R C, Frenette M
Département de Biochimie (Sciences), Université Laval, Ste-Foy, Québec, Canada.
Gene. 1992 Nov 2;121(1):71-8. doi: 10.1016/0378-1119(92)90163-j.
We present the cloning and sequencing of the ptsI gene, encoding enzyme I (EI) of the phosphoenolpyruvate (PEP): sugar phosphotransferase (PTS) transport system from Streptococcus salivarius. The ptsI gene corresponds to an open reading frame of 1731 nucleotides, which translates into a putative 577-amino acid (aa) protein with a M(r) of 62,948 and a pI of 4.49. The EI was produced in Escherichia coli under the control of its own promoter located immediately upstream of ptsI, a situation never previously reported for any other gene coding for an EI. The deduced aa sequence of the S. salivarius EI shows a high degree of similarity with the E. coli EI and the EI moiety of the multiphosphoryl transfer protein from Rhodobacter capsulatus. The S. salivarius EI also shares a highly conserved aa cluster with a non-PTS protein, the maize pyruvate:orthophosphate dikinase. The conserved cluster is located in a domain which is hypothesized to be the PEP-binding site.
我们展示了唾液链球菌磷酸烯醇丙酮酸（PEP）：糖磷酸转移酶（PTS）转运系统中编码酶I（EI）的ptsI基因的克隆与测序。ptsI基因对应一个1731个核苷酸的开放阅读框，其编码一个推定的577个氨基酸（aa）的蛋白质，分子量为62948，等电点为4.49。EI在大肠杆菌中由位于ptsI上游紧邻位置的自身启动子控制下产生，这种情况此前从未在任何其他编码EI的基因中报道过。唾液链球菌EI的推导氨基酸序列与大肠杆菌EI以及红假单胞菌多磷酸转移蛋白的EI部分显示出高度相似性。唾液链球菌EI还与一种非PTS蛋白——玉米丙酮酸：正磷酸二激酶共享一个高度保守的氨基酸簇。该保守簇位于一个被假设为PEP结合位点的结构域中。
