Found 1 publication. Displayed publication 1
Expand all publications       Show all as text (SweetDB notation)
1. (Article ID: 3383)
 
Leipold MD, Vinogradov E, Whitfield C
Glycosyltransferases involved in biosynthesis of the outer core region of Escherichia coli lipopolysaccharides exhibit broader substrate specificities than is predicted from lipopolysaccharide structures
Journal of Biological Chemistry 282(37) (2007) 26786-26792
 

The waaJ, waaT, and waaR genes encode a-1,2-glycosyltransferases involved in synthesis of the outer core region of the lipopolysaccharide of Escherichia coli. They belong to glycosyltransferase CAZy family 8, characterized by the GT-A fold, DXD motifs, and by retention of configuration at the anomeric carbon of the donor sugar. Each enzyme adds a hexose residue at the same stage of core oligosaccharide backbone extension. However, they differ in the epimers for their donor nucleotide sugars, and in their acceptor residues. WaaJ is a UDP-glucose:(galactosyl) LPS a-1,2-glucosyltransferase, whereas WaaR and WaaT have UDP-glucose:(glucosyl) LPS a-1,2-glucosyltransferase and UDP-galactose:(glucosyl) LPS a-1,2-galactosyltransferase activities, respectively. The objective of this work was to examine their ability to utilize alternate donors and acceptors. When expressed in the heterologous host, each enzyme was able to extend the alternate LPS acceptor in vivo but they retained their natural donor specificity. In vitro assays were then performed to test the effect of substituting the epimeric donor sugar on incorporation efficiency with the enzyme's natural LPS acceptor. Although each enzyme could utilize the alternate donor epimer, activity was compromised due to significant decreases in k(cat) and corresponding increases in K(M(donor)). Finally, in vitro assays were performed to probe acceptor preference in the absence of cellular machinery. The results were enzyme-dependent: while an alternate acceptor had no significant effect on the kinetic behavior of His(6)-WaaT, His(6)-WaaJ showed a significantly decreased kcat and increased K(M(acceptor)). These results illustrate the differences in behavior between closely related glycosyltransferase enzymes involved in the synthesis of similar glycoconjugates and have implications for for glycoengineering applications

biosynthesis, Escherichia coli, core oligosaccharide, glycosyltransferases, lipopolysaccharide structure

The publication contains the following compound(s):
 

Expand this publication

Resort publications by:

New query Export IDs Home Help

Execution: 2 sec