View source for 6d7c


==The crystal structure of hemagglutinin from A/Hong Kong/61/2016 H7N9 influenza virus==
<StructureSection load='6d7c' size='340' side='right' caption='[[6d7c]], [[Resolution|resolution]] 2.95&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6d7c]] is a 12 chain structure with sequence from [http://en.wikipedia.org/wiki/9infa 9infa]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6D7C OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6D7C FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene></td></tr>
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">HA ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=11320 9INFA])</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6d7c FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6d7c OCA], [http://pdbe.org/6d7c PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6d7c RCSB], [http://www.ebi.ac.uk/pdbsum/6d7c PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6d7c ProSAT]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/A0A0C4ZYE2_9INFA A0A0C4ZYE2_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 either through clathrin-dependent endocytosis or through 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.[HAMAP-Rule:MF_04072][SAAS:SAAS01039073]  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] [[http://www.uniprot.org/uniprot/S4V1Z7_9INFA S4V1Z7_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 either through clathrin-dependent endocytosis or through 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.[HAMAP-Rule:MF_04072][SAAS:SAAS01039073]  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] 
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== Publication Abstract from PubMed ==
The avian influenza A(H7N9) virus continues to cause human infections in China and is a major ongoing public health concern. Five epidemic waves of A(H7N9) infection have occurred since 2013, and the recent fifth epidemic wave saw the emergence of two distinct lineages with elevated numbers of human infection cases and broader geographic distribution of viral diseases compared to the first four epidemic waves. Moreover, highly pathogenic avian influenza (HPAI) A(H7N9) viruses were also isolated during the fifth epidemic wave. Here, we present a detailed structural and biochemical analysis of the surface hemagglutinin (HA) antigen from viruses isolated during this recent epidemic wave. Results highlight that when compared to the 2013 virus HAs, the fifth wave virus HAs remained a weak binder to human glycan receptor analogs. We also studied three mutations, V177K-K184T-G219S, that were recently reported to switch a 2013 A(H7N9)HA to human-type receptor specificity. Our results indicate that these mutations could also switch the H7 HA receptor preference to a predominantly human binding specificity for both fifth wave H7 HAs analyzed in this study.IMPORTANCE The A(H7N9) viruses circulating in China are of great public health concern. Herein, we report a molecular and structural study of the major surface proteins from several recent A(H7N9) influenza viruses. Our results improve the understanding of these evolving viruses and provide important information on their receptor preference that is central to ongoing pandemic risk assessment.

Structural and Molecular Characterization of the Hemagglutinin from the Fifth Epidemic Wave A(H7N9) Influenza Viruses.,Yang H, Carney PJ, Chang JC, Guo Z, Stevens J J Virol. 2018 May 30. pii: JVI.00375-18. doi: 10.1128/JVI.00375-18. PMID:29848588<ref>PMID:29848588</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6d7c" style="background-color:#fffaf0;"></div>

==See Also==
*[[Hemagglutinin|Hemagglutinin]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Stevens, J]]
[[Category: Yang, H]]
[[Category: H7n9]]
[[Category: Influenza virus]]
[[Category: Surface protein]]
[[Category: Viral protein]]