3ubq
From Proteopedia
Influenza hemagglutinin from the 2009 pandemic in complex with ligand 3SLN
Structural highlights
FunctionC3W5S1_I09A0 Binds to sialic acid-containing receptors on the cell surface, bringing about the attachment of the virus particle to the cell. This attachment induces virion internalization of about two third of the virus particles through clathrin-dependent endocytosis and about one third through a clathrin- and caveolin-independent pathway. Plays a major role in the determination of host range restriction and virulence. Class I viral fusion protein. Responsible for penetration of the virus into the cell cytoplasm by mediating the fusion of the membrane of the endocytosed virus particle with the endosomal membrane. Low pH in endosomes induces an irreversible conformational change in HA2, releasing the fusion hydrophobic peptide. Several trimers are required to form a competent fusion pore (By similarity).[SAAS:SAAS013829_004_327643][RuleBase:RU003324] Publication Abstract from PubMedInfluenza hemagglutinin (HA) is the viral envelope protein that mediates viral attachment to host cells and elicits membrane fusion. The HA receptor-binding specificity is a key determinant for the host range and transmissibility of influenza viruses. In human pandemics of the 20(th) century, the HA has normally acquired specificity for human-like receptors before widespread infection. Crystal structures of the H1 HA from the 2009 human pandemic (CA04, A/California/04/2009) in complex with human and avian receptor analogs reveals conserved recognition of the terminal sialic acid of the glycan ligands. However, favorable interactions beyond the sialic acid are found only for alpha2-6-linked glycans and are mediated by Asp190 and Asp225, which hydrogen bond with Gal-2 and GlcNAc-3. For alpha2-3-linked glycan receptors, no specific interactions beyond the terminal sialic acid are observed. Our structural and glycan microarray analyses, in the context of other high resolution HA structures with alpha2-6 and alpha2-3-linked glycans, now elucidate the structural basis of receptor binding specificity for H1 HAs in human and avian viruses and provide an structural explanation for the preference for alpha2-6 siaylated glycan receptors for the 2009 pandemic swine flu virus. Structural characterization of the hemagglutinin receptor specificity from the 2009 H1N1 influenza pandemic.,Xu R, McBride R, Nycholat CM, Paulson JC, Wilson IA J Virol. 2011 Nov 9. PMID:22072785[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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