细菌磷酸烯醇式丙酮酸：糖磷酸转移酶系统（PTS）的碳水化合物转运蛋白。

Carbohydrate transporters of the bacterial phosphoenolpyruvate: sugar phosphotransferase system (PTS).

作者信息

Siebold C, Flükiger K, Beutler R, Erni B

机构信息

Departement für Chemie und Biochemie, Universität Bern, CH-3012, Bern, Switzerland

出版信息

FEBS Lett. 2001 Aug 31;504(3):104-11. doi: 10.1016/s0014-5793(01)02705-3.

DOI:10.1016/s0014-5793(01)02705-3

PMID:11532441

Abstract

The glucose transporter of Escherichia coli couples translocation with phosphorylation of glucose. The IICB(Glc) subunit spans the membrane eight times. Split, circularly permuted and cyclized forms of IICB(Glc) are described. The split variant was 30 times more active when the two proteins were encoded by a dicistronic mRNA than by two genes. The stability and activity of circularly permuted forms was improved when they were expressed as fusion proteins with alkaline phosphatase. Cyclized IICB(Glc) and IIA(Glc) were produced in vivo by RecA intein-mediated trans-splicing. Purified, cyclized IIA(Glc) and IICB(Glc) had 100% and 30% of wild-type glucose phosphotransferase activity, respectively. Cyclized IIA(Glc) displayed increased stability against temperature and GuHCl-induced unfolding.

摘要

大肠杆菌的葡萄糖转运蛋白将葡萄糖的转运与磷酸化偶联起来。IICB(Glc)亚基跨膜8次。文中描述了IICB(Glc)的拆分、环形排列和环化形式。当两种蛋白质由双顺反子mRNA编码时，拆分变体的活性比由两个基因编码时高30倍。当环形排列形式与碱性磷酸酶作为融合蛋白表达时，其稳定性和活性得到了提高。环化的IICB(Glc)和IIA(Glc)通过RecA内含肽介导的反式剪接在体内产生。纯化的环化IIA(Glc)和IICB(Glc)分别具有野生型葡萄糖磷酸转移酶活性的100%和30%。环化的IIA(Glc)对温度和盐酸胍诱导的去折叠表现出更高的稳定性。