4lxv | pdb_00004lxv
Crystal Structure of the Hemagglutinin from a H1N1pdm A/WASHINGTON/5/2011 virus
Structural highlights
FunctionJ7MFR5_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).[RuleBase:RU003324][SAAS:SAAS001364_004_327643] Publication Abstract from PubMedThe non-covalent interactions that mediate trimerization of the influenza hemagglutinin (HA) are important determinants of its biological activities. Recent studies have demonstrated that mutations in the HA trimer interface affect the thermal and pH sensitivities of HA, suggesting a possible impact on vaccine stability (Farnsworth et al. 2011. Vaccine 29:: 1529-1533). We used size exclusion chromatography analysis of recombinant HA ectodomain to compare the differences among recombinant trimeric HA proteins from early 2009 pandemic H1N1 viruses, which dissociate to monomers, with those of more recent virus HAs that can be expressed as trimers. We analyzed differences amongst the HA sequences and identified inter-molecular interactions mediated by the residue at position 374 (HA0 numbering) of the HA2 sub-domain as critical for HA trimer stability. Crystallographic analyses of HA from the recent H1N1 virus A/Washington/5/2011 highlight the structural basis for this observed phenotype. It remains to be seen whether more recent viruses with this mutation will yield more stable vaccines in the future. IMPORTANCE: Hemagglutinins from the early 2009 H1N1 pandemic viruses are unable to maintain a trimeric complex when expressed in a recombinant system. However HAs from 2010 and 2011 strains are more stable and our work highlights the improvement in stability can be attributed to an E47K substitution in the HA2 subunit of the stalk that emerged naturally in the circulating viruses. Structural stability of influenza A(H1N1)pdm09 virus hemagglutinins.,Yang H, Chang JC, Guo Z, Carney PJ, Shore DA, Donis RO, Cox NJ, Villanueva JM, Klimov AI, Stevens J J Virol. 2014 Feb 12. PMID:24522930[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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