3tb0 | pdb_00003tb0
Crystal structure of Rhesus Rotavirus VP8* in complex with N-Glycolylneuraminic acid
Structural highlights
Function[VP4_ROTRH] Spike-forming protein that mediates virion attachment to the host epithelial cell receptors and plays a major role in cell penetration, determination of host range restriction and virulence. It is subsequently lost, together with VP7, following virus entry into the host cell. Rotavirus attachment and entry into the host cell probably involves multiple sequential contacts between the outer capsid proteins VP4 and VP7, and the cell receptors. In sialic acid-dependent and/or integrin-dependent strains, VP4 seems to essentially target sialic acid and/or the integrin heterodimer ITGA2/ITGB1.[1] Outer capsid protein VP5*: forms the spike "foot" and "body". Acts as a membrane permeabilization protein that mediates release of viral particles from endosomal compartments into the cytoplasm. In integrin-dependent strains, VP5* targets the integrin heterodimer ITGA2/ITGB1 for cell attachment.[2] VP8* forms the head of the spikes. It is the viral hemagglutinin and an important target of neutralizing antibodies. In sialic acid-dependent strains, VP8* binds to host cell sialic acid, most probably a ganglioside, providing the initial contact.[3] Publication Abstract from PubMedThe rotavirus spike protein domain VP8* is essential for recognition of cell-surface carbohydrate receptors, notably those incorporating N-acylneuraminic acids (members of the sialic acid family). N-acetylneuraminic acids occur naturally in both animals and humans whereas N-glycolylneuraminic acids are present only through dietary uptake in normal human tissues. The preference of animal rotaviruses towards these natural N-acylneuraminic acids has not been comprehensively established, and detailed structural information regarding the interactions of different rotaviruses with N-glycolylneuraminic acids is lacking. In this study, distinct specificities of VP8* towards N-acetyl- and N-glycolylneuraminic acids were revealed using biophysical techniques. VP8* protein from porcine rotavirus CRW-8 and bovine rotavirus NCDV showed preference for N-glycolyl- over N-acetylneuraminic acids, contrasting with monkey rotavirus RRV. Crystallographic structures of VP8* from CRW-8 and RRV with bound methyl N-glycolylneuraminide revealed the atomic details of their interactions. We examined the influence of amino acid type at position 157, which is proximal to the ligand's N-acetyl- or N-glycolyl-moiety and can mutate upon cell culture adaptation. A structure-based hypothesis derived from these results could account for rotavirus discrimination between the N-acylneuraminic acid forms. Infectivity blockade experiments demonstrated that the determined carbohydrate specificities of these VP8* directly correlate with those of the corresponding infectious virus. This includes an association between CRW-8 adaption to cell culture, decreased competition by N-glycolylneuraminic acid for CRW-8 infectivity, and a Pro157 to Ser157 mutation in VP8* that reduces binding affinity for N-glycolylneuraminic acid. Structural basis of rotavirus strain preference towards N-acetyl- or N-glycolylneuraminic acid-containing receptors.,Yu X, Dang VT, Fleming FE, von Itzstein M, Coulson BS, Blanchard H J Virol. 2012 Oct 3. PMID:23035213[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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