3qqe

Crystal structure of HA2 R106H mutant of H2 hemagglutinin, re-neutralized formCrystal structure of HA2 R106H mutant of H2 hemagglutinin, re-neutralized form

Structural highlights 3qqe is a 2 chain structure with sequence from I57a0. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: , , Related: 3qqb, 3qqi, 3qqo Gene: HA, hemagglutinin (I57A0) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [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] 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 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Hemagglutinin

spinqualitylabelsall models 3qqe, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image