4ln3
The crystal structure of hemagglutinin from a H7N9 influenza virus (A/Shanghai/1/2013)
Structural highlights
FunctionR4NN21_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:SAAS008980_004_327643] Publication Abstract from PubMedIn March 2013, the Chinese Centers for Disease Control and Prevention reported human infections with an H7N9 influenza virus, and by July 20th 2013, the numbers of laboratory-confirmed cases had climbed to 134, including 43 fatalities and 127 hospitalizations. The newly emerging H7N9 viruses constitute an obvious public health concern because of the apparent severity of this outbreak. Here we focus on the hemagglutinin (HA) of these viruses and assess its receptor binding phenotype in relation to previous HAs studied. Glycan microarray and kinetic analysis of recombinant A(H7N9) HAs was performed to compare the receptor binding profile of wild-type receptor binding site variants, at position 217, a residue analogous to one of two positions known to switch avian to human receptor preference in H2N2 and H3N2 viruses. Two recombinant A(H7N9) HAs were structurally characterized and a mutational study of the receptor binding site was performed to analyze important residues that can affect receptor preference and affinity. Results highlight a weak human receptor preference of the H7N9 HAs suggesting that these viruses require further adaptation in order to adapt fully to humans. Structural analysis of the hemagglutinin from the recent 2013 H7N9 influenza virus.,Yang H, Carney PJ, Chang JC, Villanueva JM, Stevens J J Virol. 2013 Sep 11. PMID:24027325[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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