Biochemical characterization of the novel α-1, 3-galactosyltransferase WclR from Escherichia coli O3

Glycosyltransferases (GTs) catalyze the formation of regio- and stereo-specific glycosidic linkages between specific sugar donors and recipients. In this study, the function of the gene wclR from the Escherichia coli O3 O-antigen gene cluster that encodes an a 1, 3-galactosyltransferase (GalT) that acts on the linkage Gal alpha 1, 3-GlcNAc was biochemically characterized. WclR was expressed in E. coli BL21 (DE3), and the enzymatic product was identified by liquid chromatography-mass spectrometry (LC-MS), collision-induced dissociation electrospray ionization ion trap multiple tandem MS (CID-ESI-IT-MSn) and galactosidase digestion, using UDP-Gal as the donor substrate and the synthetic acceptor substrate GlcNAc-PP-De (decyl diphosphate N-acetylglucosamine). The physiochemical properties and the substrate specificity of WclR were investigated. WclR is the first bacterial GalT characterized that acts on the linkage Gal alpha 1, 3-GlcNAc. This study enhanced our knowledge of the diversified functions of GTs and provided a novel enzyme source for possible pharmaceutical application. (C) 2016 Elsevier Ltd. All rights reserved.

糖基转移酶（GTS）催化特定糖供体和受体之间的区域和立体特异性糖苷连接的形成。在这项研究中，来自a 1、3-乳糖基转移酶（GALT）的大肠杆菌O3 O-抗原基因簇的基因WCLR的功能，该基因簇（GALT）作用于链接的GAL Alpha 1，3-GlCNAC的功能。 WclR was expressed in E. coli BL21 (DE3), and the enzymatic product was identified by liquid chromatography-mass spectrometry (LC-MS), collision-induced dissociation electrospray ionization ion trap multiple tandem MS (CID-ESI-IT-MSn) and galactosidase digestion, using UDP-Gal as the donor substrate and the synthetic acceptor substrate GlcNAC-PP-DE（Decyl二磷酸N-乙酰葡萄糖）。研究了WCLR的生理化学特性和底物特异性。 WCLR是第一个作用于连锁gal alpha 1，3-glcnac的细菌galt。这项研究增强了我们对GTS多元化功能的了解，并为可能的药物应用提供了一种新颖的酶来源。 （c）2016 Elsevier Ltd.保留所有权利。