CRYSTAL-STRUCTURE OF PHAGE-P22 TAILSPIKE PROTEIN COMPLEXED WITH SALMONELLA SP O-ANTIGEN RECEPTORS

The O-antigenic repeating units of lipopolysaccharides from Salmonella serogroups A, B, and D1 serve as receptors for the phage P22 tailspik e protein, which also has receptor destroying endoglycosidase (endorha mnosidase) activity, integrating the functions of both hemagglutinin a nd neuraminidase in influenza virus, Crystal structures of the tailspi ke protein in complex with oligosaccharides, comprising two O-antigeni c repeating units from Salmonella typhiumurium, Salmonella enteritidis , and Salmonella typhi 253Ty were determined at 1.8 Angstrom resolutio n, The active-site topology with Asp-392, Asp-395, and Glu-359 as cata lytic residues was identified, Kinetics of binding and cleavage sugges t a role of the receptor destroying endorhamnosidase activity primaril y for detachment of newly assembled phages.