Characterization and synthetic application of a novel β1,3-galactosyltransferase from Escherichia coli O55:H7

A β1,3-galactosyltransferase (WbgO) was identified in Escherichia coli O55:H7. Its function was confirmed by radioactive activity assay and structure analysis of the disaccharide synthesized with the recombinant enzyme. WbgO requires a divalent metal ion, either Mn2+ or Mg2+, for its activity and is active between pH 6.0–8.0 with a pH optimum of 7.0. N-acetylglucosamine (GlcNAc) and oligosaccharides with GlcNAc at the non-reducing end were shown to be its preferred substrates and it can be used for the synthesis of type 1 glycan chains from these substrates. Together with a recombinant bacterial GlcNAc-transferase, benzyl β-lacto-N-tetraoside was synthesized with the purified WbgO to demonstrate the synthetic utility of WbgO.

The β1,3-galactosyltransferase (WbgO) involved in Escherichia coli O55:H7 O-antigen biosynthesis was recombinant expressed and characterized. Incorporated with LgtA catalyzed N-acetylglucosamine transferring reaction, lacto-N-tetraose was synthesized with recombinant WbgO.Figure optionsDownload as PowerPoint slide