3qqi: Difference between revisions
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==Crystal structure of the HA1 receptor binding domain of H2 hemagglutinin== | |||
<StructureSection load='3qqi' size='340' side='right' caption='[[3qqi]], [[Resolution|resolution]] 1.65Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[3qqi]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Influenza_a_virus Influenza a virus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3QQI OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3QQI FirstGlance]. <br> | |||
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=EPE:4-(2-HYDROXYETHYL)-1-PIPERAZINE+ETHANESULFONIC+ACID'>EPE</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene></td></tr> | |||
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[3qqb|3qqb]], [[3qqe|3qqe]], [[3qqo|3qqo]]</td></tr> | |||
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">HA, hemagglutinin ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=11320 Influenza A virus])</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=3qqi FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3qqi OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3qqi RCSB], [http://www.ebi.ac.uk/pdbsum/3qqi PDBsum]</span></td></tr> | |||
</table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The hemagglutinin (HA) envelope protein of influenza virus mediates viral entry through membrane fusion in the acidic environment of the endosome. Crystal structures of HA in pre- and post-fusion states have laid the foundation for proposals for a general fusion mechanism for viral envelope proteins. The large-scale conformational rearrangement of HA at low pH is triggered by a loop-to-helix transition of an inter-helical loop (B loop) within the fusion domain, and is often referred to as the "spring-loaded" mechanism. Although the receptor-binding HA1 subunit is believed to act as "clamp" to keep the B loop in its metastable pre-fusion state at neutral pH, the "pH sensors" that are responsible for the clamp release and the ensuing structural transitions have remained elusive. Here we identify a mutation in the HA2 fusion domain from the influenza H2 subtype that stabilizes the HA trimer in a prefusion-like state at and below fusogenic pH. Crystal structures of this putative early intermediate state reveal disruptions of ionic interactions at the HA1-HA2 interface at acidic pH and deformation of the HA1 membrane distal domain. Along with neutralization of glutamate residues on the B loop, these changes cause a rotation of the B loop and solvent exposure of conserved phenylalanines, which are key residues at the trimer interface of the post-fusion structure. Thus, our study reveals the possible initial structural event that leads to release of the B loop from its pre-fusion conformation, which is aided by unexpected structural changes within the membrane-distal HA1 domain at low pH. | |||
Structural characterization of an early fusion intermediate of influenza virus hemagglutinin.,Xu R, Wilson IA J Virol. 2011 Mar 2. PMID:21367895<ref>PMID:21367895</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | ==See Also== | ||
*[[Hemagglutinin|Hemagglutinin]] | *[[Hemagglutinin|Hemagglutinin]] | ||
== References == | |||
== | <references/> | ||
< | __TOC__ | ||
</StructureSection> | |||
[[Category: Influenza a virus]] | [[Category: Influenza a virus]] | ||
[[Category: Wilson, I A | [[Category: Wilson, I A]] | ||
[[Category: Xu, R | [[Category: Xu, R]] | ||
[[Category: Hemagglutinin]] | [[Category: Hemagglutinin]] | ||
[[Category: Viral envelope protein]] | [[Category: Viral envelope protein]] | ||
[[Category: Viral fusion protein]] | [[Category: Viral fusion protein]] | ||
[[Category: Viral protein]] | [[Category: Viral protein]] | ||
