4f3z
Crystal structure of a swine H1N2 influenza virus hemagglutinin
Structural highlights
FunctionQ8QT89_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] Publication Abstract from PubMedThe 2009 H1N1 influenza pandemic is the first human pandemic in decades and was of swine origin. Although swine are believed to be an intermediate host in the emergence of new human influenza viruses, there is still little known about the host barriers that keep swine influenza viruses from entering the human population. We surveyed swine progenitors and human viruses from the 2009 pandemic and measured the activities of the hemagglutinin (HA) and neuraminidase (NA), which are the two viral surface proteins that interact with host glycan receptors. A functional balance of these two activities (HA binding and NA cleavage) is found in human viruses, but not in the swine progenitors. The human 2009 H1N1 pandemic virus exhibited both low HA avidity for glycan receptors as a result of mutations near the receptor-binding site and weak NA enzymatic activity. Thus, a functional match between the hemagglutinin and neuraminidase appears to be necessary for efficient transmission between humans and may be an indicator of the pandemic potential of zoonotic viruses. Functional Balance of the Hemagglutinin and Neuraminidase Activities Accompanies the Emergence of the 2009 H1N1 Influenza Pandemic.,Xu R, Zhu X, McBride R, Nycholat CM, Yu W, Paulson JC, Wilson IA J Virol. 2012 Jun 20. PMID:22718832[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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