3by2
Norwalk P polypeptide (228-523)
OverviewOverview
Noroviruses are positive sense, single-stranded RNA viruses that cause acute gastroenteritis. They recognize human histo-blood group antigens as receptors in a strain-specific manner. The structures presented here sought to elucidate the structural basis for differences in ligand recognition of noroviruses from different genogroups, the prototypic Norwalk virus (NV, GI-1) and VA387 (GII-4), which recognize the same A-antigen, but differ in the inability of NV to bind to the B-antigen. Two forms of the receptor-binding domain of the norovirus coat protein, the P domain and the P polypeptide, that were previously shown to differ in receptor binding and P particle formation properties were studied. Comparison of the structures of the NV P domain with and without A-trisaccharide and the NV P polypeptide reveal no major ligand-induced changes. The 2.3 A co-crystal structure reveals that the A-trisaccharide binds to the NV P domain through interactions with residues Ser377, Asp327, His329, and Ser380 in a mode distinct from that previously reported for the VA387 P domain-A trisaccharide complex. Mutational analyses confirm the importance of these residues in NV P particle binding to native A-antigen. The alpha-GalNac residue unique to the A-trisaccharide is buried deeply in the NV binding pocket, unlike in the structures of A- and B-trisaccharides bound to VA387 P domain where the alpha-fucose residue forms the most protein contacts. The A-trisaccharide binding mode seen in the NV P domain complex cannot be sterically accommodated in the VA387 P domain.
About this StructureAbout this Structure
3BY2 is a Single protein structure of sequence from Norwalk virus. Full crystallographic information is available from OCA.
ReferenceReference
Structural basis for the receptor binding specificity of the Norwalk virus., Bu W, Mamedova A, Tan M, Xia M, Jiang X, Hegde RS, J Virol. 2008 Apr 2;. PMID:18385236 Page seeded by OCA on Thu Apr 24 09:49:59 2008