4yk4

From Proteopedia

Human antibody 641 I-9 in complex with influenza hemagglutinin H1 Solomon Islands/03/2006

Structural highlights

4yk4 is a 6 chain structure with sequence from Homo sapiens and Influenza A virus (A/Solomon Islands/3/2006(H1N1)). Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.8Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

A7UPX0_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.[RuleBase:RU003324][SAAS:SAAS00145386]

Publication Abstract from PubMed

Vaccines for rapidly evolving pathogens will confer lasting immunity if they elicit antibodies recognizing conserved epitopes, such as a receptor-binding site (RBS). From characteristics of an influenza-virus RBS-directed antibody, we devised a signature motif to search for similar antibodies. We identified, from three vaccinees, over 100 candidates encoded by 11 different VH genes. Crystal structures show that antibodies in this class engage the hemagglutinin RBS and mimic binding of the receptor, sialic acid, by supplying a critical dipeptide on their projecting, heavy-chain third complementarity determining region. They share contacts with conserved, receptor-binding residues but contact different residues on the RBS periphery, limiting the likelihood of viral escape when several such antibodies are present. These data show that related modes of RBS recognition can arise from different germline origins and mature through diverse affinity maturation pathways. Immunogens focused on an RBS-directed response will thus have a broad range of B cell targets.

Viral receptor-binding site antibodies with diverse germline origins.,Schmidt AG, Therkelsen MD, Stewart S, Kepler TB, Liao HX, Moody MA, Haynes BF, Harrison SC Cell. 2015 May 21;161(5):1026-34. doi: 10.1016/j.cell.2015.04.028. Epub 2015 May , 7. PMID:25959776^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Schmidt AG, Therkelsen MD, Stewart S, Kepler TB, Liao HX, Moody MA, Haynes BF, Harrison SC. Viral receptor-binding site antibodies with diverse germline origins. Cell. 2015 May 21;161(5):1026-34. doi: 10.1016/j.cell.2015.04.028. Epub 2015 May , 7. PMID:25959776 doi:http://dx.doi.org/10.1016/j.cell.2015.04.028