3qqb: Difference between revisions

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-[[Image:3qqb.jpg|left|200px]]
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+==Crystal structure of HA2 R106H mutant of H2 hemagglutinin, neutral pH form==
-The line below this paragraph, containing "STRUCTURE_3qqb", creates the "Structure Box" on the page.
+<StructureSection load='3qqb' size='340' side='right'caption='[[3qqb]], [[Resolution|resolution]] 1.97&Aring;' scene=''>
-You may change the PDB parameter (which sets the PDB file loaded into the applet)
+== Structural highlights ==
-or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
+<table><tr><td colspan='2'>[[3qqb]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Influenza_A_virus_(A/Japan/305/1957(H2N2)) Influenza A virus (A/Japan/305/1957(H2N2))]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3QQB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3QQB FirstGlance]. <br>
-or leave the SCENE parameter empty for the default display.
+</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.97&#8491;</td></tr>
--->
+<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=PEG:DI(HYDROXYETHYL)ETHER'>PEG</scene></td></tr>
-{{STRUCTURE_3qqb|  PDB=3qqb  |  SCENE=  }}
+<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=3qqb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3qqb OCA], [https://pdbe.org/3qqb PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3qqb RCSB], [https://www.ebi.ac.uk/pdbsum/3qqb PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3qqb ProSAT]</span></td></tr>
+</table>
+== Function ==
+[https://www.uniprot.org/uniprot/C7S226_I57A0 C7S226_I57A0] 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:SAAS013829_004_327643]
+<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.
-===Crystal structure of HA2 R106H mutant of H2 hemagglutinin, neutral pH form===
+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&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
+</div>
+<div class="pdbe-citations 3qqb" style="background-color:#fffaf0;"></div>
-==About this Structure==
+==See Also==
-[[3qqb]] 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=3QQB OCA].
+*[[Hemagglutinin 3D structures|Hemagglutinin 3D structures]]
-[[Category: Influenza a virus]]
+== References ==
-[[Category: Wilson, I A.]]
+<references/>
-[[Category: Xu, R.]]
+__TOC__
+</StructureSection>
+[[Category: Large Structures]]
+[[Category: Wilson IA]]
+[[Category: Xu R]]