4o5n
From Proteopedia
Crystal structure of A/Victoria/361/2011 (H3N2) influenza virus hemagglutinin
Structural highlights
Function[R9U684_9INFA] 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:SAAS000149_004_327643][RuleBase:RU003324] Publication Abstract from PubMedInfluenza viruses present a significant health challenge each year, as in the H3N2 epidemic of 2012-2013. Here we describe an antibody, F045-092, that possesses broadly neutralizing activity against the entire H3 subtype and accommodates the natural variation and additional glycosylation in all strains tested from 1963 to 2011. Crystal structures of F045-092 in complex with HAs from 1975 and 2011 H3N2 viruses reveal the structural basis for its neutralization breadth through insertion of its 23-residue HCDR3 into the receptor-binding site that involves striking receptor mimicry. F045-092 extends its recognition to divergent subtypes, including H1, H2 and H13, using the enhanced avidity of its IgG to overcome lower-affinity Fab binding, as observed with other antibodies that target the receptor-binding site. This unprecedented level of antibody cross-reactivity against the H3 subtype can potentially inform on development of a pan-H3 vaccine or small-molecule therapeutics. Receptor mimicry by antibody F045-092 facilitates universal binding to the H3 subtype of influenza virus.,Lee PS, Ohshima N, Stanfield RL, Yu W, Iba Y, Okuno Y, Kurosawa Y, Wilson IA Nat Commun. 2014 Apr 10;5:3614. doi: 10.1038/ncomms4614. PMID:24717798[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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