2p3j
From Proteopedia
Crystal structure of the Arg101Ala mutant protein of Rhesus rotavirus VP8*
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] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe rotavirus spike protein VP4 mediates attachment to host cells and subsequent membrane penetration. The VP8(*) domain of VP4 forms the spike tips and is proposed to recognize host-cell surface glycans. For sialidase-sensitive rotaviruses such as rhesus (RRV), this recognition involves terminal sialic acids. We show here that the RRV VP8(*)(64-224) protein competes with RRV infection of host cells, demonstrating its relevance to infection. In addition, we observe that the amino acids revealed by X-ray crystallography to be in direct contact with the bound sialic acid derivative methyl alpha-D-N-acetylneuraminide, and that are highly conserved amongst sialidase-sensitive rotaviruses, are residues that are also important in interactions with host-cell carbohydrates. Residues Arg101 and Ser190 of the RRV VP8(*) carbohydrate-binding site were mutated to assess their importance for binding to the sialic acid derivative and their competition with RRV infection of host cells. The crystallographic structure of the Arg(101)Ala mutant crystallized in the presence of the sialic acid derivative was determined at 295 K to a resolution of 1.9 A. Our multidisciplinary study using X-ray crystallography, saturation transfer difference nuclear magnetic resonance spectroscopy, isothermal titration calorimetry, and competitive virus infectivity assays to investigate RRV wild-type and mutant VP8(*) proteins has provided the first evidence that the carbohydrate-binding cavity in RRV VP8(*) is used for host-cell recognition, and this interaction is not only with the sialic acid portion but also with other parts of the glycan structure. Effects on sialic acid recognition of amino acid mutations in the carbohydrate-binding cleft of the rotavirus spike protein.,Kraschnefski MJ, Bugarcic A, Fleming FE, Yu X, von Itzstein M, Coulson BS, Blanchard H Glycobiology. 2009 Mar;19(3):194-200. Epub 2008 Oct 30. PMID:18974199[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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