3m5g
Crystal structure of a H7 influenza virus hemagglutinin
Structural highlights
FunctionB7NY59_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.[RuleBase:RU003324][SAAS:SAAS00145386] 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 PubMedHuman infections with subtype H7 avian influenza viruses have been reported as early as 1979. In 1996, a genetically stable 24-nucleotide deletion emerged in North American H7 influenza virus hemagglutinins, resulting in an eight amino acid deletion in the receptor-binding site. The continuous circulation of these viruses in live bird markets, as well as its documented ability to infect humans, raises the question of how these viruses achieve structural stability and functionality. Here we report a detailed molecular analysis of the receptor binding site of the North American lineage subtype H7N2 virus A/New York/107/2003 (NY107), including complexes with an avian receptor analog (3'-sialyl-N-acetyllactosamine, 3'SLN) and two human receptor analogs (6'-sialyl-N-acetyllactosamine, 6'SLN; sialyllacto-N-tetraose b, LSTb). Structural results suggest a novel mechanism by which residues Arg220 and Arg229 (H3 numbering) are used to compensate for the deletion of the 220-loop and form interactions with the receptor analogs. Glycan microarray results reveal that NY107 maintains an avian-type (alpha2-3) receptor binding profile, with only moderate binding to human-type (alpha2-6) receptor. Thus despite its dramatically altered receptor binding site, this HA maintains functionality and confirms a need for continued influenza virus surveillance of avian and other animal reservoirs to define their zoonotic potential. Structures of receptor complexes of a North American H7N2 influenza hemagglutinin with a loop deletion in the receptor binding site.,Yang H, Chen LM, Carney PJ, Donis RO, Stevens J PLoS Pathog. 2010 Sep 2;6(9):e1001081. PMID:20824086[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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