Characterization of two UDP-Gal:GalNAc-diphosphate-lipid β1,3-galactosyltransferases WbwC from Escherichia coli serotypes O104 and O5.

Escherichia coli displays O antigens on the outer membrane that play an important role in bacterial interactions with the environment. The O antigens of enterohemorrhagic E. coli O104 and O5 contain a Galβ1-3GalNAc disaccharide at the reducing end of the repeating unit.

Synthesis of a fluorescent acceptor substrate for glycosyltransferases involved in the assembly of O-antigens of enterohemorrhagic Escherichia coli O157 and O5.

The assembly of the repeating units of O-antigens in Gram negative bacteria is catalyzed by specific glycosyltransferases. Previously we used GlcNAc/GalNAcα-diphosphate-phenoxyundecyl as natural acceptor substrate analogs in assays of the transfer of radioactive sugars by bacterial glycosyltransferases. In order to develop new, fluorescence based assays we have synthesized a fluorescent acceptor P¹-[11-(anthracen-9-ylmethoxy)undecyl]-P²-(2-acetamido-2-deoxy-α-D-galactopyranosyl) diphosphate and have shown that the compound was an excellent acceptor for glucosyltransferase WbdN from Escherichia coli (E.