7trh

From Proteopedia

Human antibody K03.28 in complex with the influenza hemagglutinin head domain of A/California/07/2009(H1N1)(X-181)

Structural highlights

7trh is a 3 chain structure with sequence from Homo sapiens and Influenza A virus (A/reassortant/NYMC X-181(California/07/2009 x NYMC X-157)(H1N1)). Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 3Å
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

C9EL84_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:SAAS00363335]

Publication Abstract from PubMed

Antibody titers that inhibit the influenza virus hemagglutinin (HA) from engaging its receptor are the accepted correlate of protection from infection. Many potent antibodies with broad, intra-subtype specificity bind HA at the receptor binding site (RBS). One barrier to broad H1-H3 cross-subtype neutralization is an insertion (133a) between positions 133 and 134 on the rim of the H1 HA RBS. We describe here a class of antibodies that overcomes this barrier. These genetically unrestricted antibodies are abundant in the human B cell memory compartment. Analysis of the affinities of selected members of this class for historical H1 and H3 isolates suggest that they were elicited by H3 exposure and broadened or diverted by later exposure(s) to H1 HA. RBS mutations in egg-adapted vaccine strains cause the new H1 specificity of these antibodies to depend on the egg adaptation. The results suggest that suitable immunogens might elicit 133a-independent, H1-H3 cross neutralization by RBS-directed antibodies.

A new class of antibodies that overcomes a steric barrier to cross-group neutralization of influenza viruses.,Simmons HC, Watanabe A, Oguin Iii TH, Van Itallie ES, Wiehe KJ, Sempowski GD, Kuraoka M, Kelsoe G, McCarthy KR PLoS Biol. 2023 Dec 21;21(12):e3002415. doi: 10.1371/journal.pbio.3002415. , eCollection 2023 Dec. PMID:38127922^[1]

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

References

↑ Simmons HC, Watanabe A, Oguin Iii TH, Van Itallie ES, Wiehe KJ, Sempowski GD, Kuraoka M, Kelsoe G, McCarthy KR. A new class of antibodies that overcomes a steric barrier to cross-group neutralization of influenza viruses. PLoS Biol. 2023 Dec 21;21(12):e3002415. PMID:38127922 doi:10.1371/journal.pbio.3002415