View source for 4unx


==Structure of the A_Equine_Newmarket_2_93 H3 haemagglutinin in complex with 3SLN==
<StructureSection load='4unx' size='340' side='right'caption='[[4unx]], [[Resolution|resolution]] 3.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4unx]] is a 6 chain structure with sequence from [https://en.wikipedia.org/wiki/Influenza_A_virus_(A/eq/Newmarket/93/(H3N8)) Influenza A virus (A/eq/Newmarket/93/(H3N8))]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4UNX OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4UNX FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 3.2&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BMA:BETA-D-MANNOSE'>BMA</scene>, <scene name='pdbligand=FUC:ALPHA-L-FUCOSE'>FUC</scene>, <scene name='pdbligand=GAL:BETA-D-GALACTOSE'>GAL</scene>, <scene name='pdbligand=MAN:ALPHA-D-MANNOSE'>MAN</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=PRD_900067:3-sialyl-N-acetyllactosamine'>PRD_900067</scene>, <scene name='pdbligand=SIA:O-SIALIC+ACID'>SIA</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4unx FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4unx OCA], [https://pdbe.org/4unx PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4unx RCSB], [https://www.ebi.ac.uk/pdbsum/4unx PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4unx ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q82847_9INFA Q82847_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]
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== Publication Abstract from PubMed ==
In 2004 an hemagglutinin 3 neuraminidase 8 (H3N8) equine influenza virus was transmitted from horses to dogs in Florida and subsequently spread throughout the United States and to Europe. To understand the molecular basis of changes in the antigenicity of H3 hemagglutinins (HAs) that have occurred during virus evolution in horses, and to investigate the role of HA in the equine to canine cross-species transfer, we used X-ray crystallography to determine the structures of the HAs from two antigenically distinct equine viruses and from a canine virus. Structurally all three are very similar with the majority of amino acid sequence differences between the two equine HAs located on the virus membrane-distal molecular surface. HAs of canine viruses are distinct in containing a Trp-222--&gt;Leu substitution in the receptor binding site that influences specificity for receptor analogs. In the fusion subdomain of canine and recent equine virus HAs a unique difference is observed by comparison with all other HAs examined to date. Analyses of site-specific mutant HAs indicate that a single amino acid substitution, Thr-30--&gt;Ser, influences interactions between N-terminal and C-terminal regions of the subdomain that are important in the structural changes required for membrane fusion activity. Both structural modifications may have facilitated the transmission of H3N8 influenza from horses to dogs.

Recent evolution of equine influenza and the origin of canine influenza.,Collins PJ, Vachieri SG, Haire LF, Ogrodowicz RW, Martin SR, Walker PA, Xiong X, Gamblin SJ, Skehel JJ Proc Natl Acad Sci U S A. 2014 Jul 14. pii: 201406606. PMID:25024224<ref>PMID:25024224</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4unx" style="background-color:#fffaf0;"></div>

==See Also==
*[[Hemagglutinin 3D structures|Hemagglutinin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Collins PJ]]
[[Category: Gamblin SJ]]
[[Category: Haire LF]]
[[Category: Martin SR]]
[[Category: Ogrodowicz RW]]
[[Category: Skehel JJ]]
[[Category: Vachieri SG]]
[[Category: Walker PA]]
[[Category: Xiong X]]