Crystal structure of the lipopolysaccharide outer core galactosyltransferase WaaB involved in pathogenic bacterial invasion of host cells

Lipopolysaccharide (LPS) is essential for most gram-negative bacteria and plays an important role in serum resistance, pathogenesis, drug protection from harsh environments. The outer core oligosaccharide of LPS involved bacterial recognition invasion host cells. D-galactosyltransferase WaaB responsible the addition D-galactose to LPS, which Salmonella typhimurium invasion. Here we report first crystal structures complex with UDP resolutions 1.8 1.9 Å, respectively. Mutagenesis enzyme activity assays confirmed that residues V186, K195, I216, W243, E276, E269 are binding hydrolysis UDP-galactose. elucidation catalytic mechanism great importance could potentially be used design novel therapeutic reagents.