Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

A complex epistatic network limits the mutational reversibility in the influenza hemagglutinin receptor-binding site.

ABSTRACT: The hemagglutinin (HA) receptor-binding site (RBS) in human influenza A viruses is critical for attachment to host cells, which imposes a functional constraint on its natural evolution. On the other hand, being part of the major antigenic sites, the HA RBS of human H3N2 viruses needs to constantly mutate to evade the immune system. From large-scale mutagenesis experiments, we here show that several of the natural RBS substitutions become integrated into an extensive epistatic network that prevents substitution reversion. X-ray structural analysis reveals the mechanistic consequences as well as changes in the mode of receptor binding. Further studies are necessary to elucidate whether such entrenchment limits future options for immune escape or adversely affect long-term viral fitness.

SUBMITTER: Wu NC

PROVIDER: S-EPMC5871881 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

A complex epistatic network limits the mutational reversibility in the influenza hemagglutinin receptor-binding site.

Wu Nicholas C NC Thompson Andrew J AJ Xie Jia J Lin Chih-Wei CW Nycholat Corwin M CM Zhu Xueyong X Lerner Richard A RA Paulson James C JC Wilson Ian A IA

Nature communications 20180328 1

The hemagglutinin (HA) receptor-binding site (RBS) in human influenza A viruses is critical for attachment to host cells, which imposes a functional constraint on its natural evolution. On the other hand, being part of the major antigenic sites, the HA RBS of human H3N2 viruses needs to constantly mutate to evade the immune system. From large-scale mutagenesis experiments, we here show that several of the natural RBS substitutions become integrated into an extensive epistatic network that preven ...[more]

PMID: 29593268

Similar Datasets

The structural variability of the influenza A hemagglutinin receptor-binding site.

Project description:Hemagglutinin (HA) is a transmembrane protein of the influenza A virus and a key component in its life cycle. The protein allows the virus to enter a host cell by recognizing specific glycans attached to transmembrane proteins of the host, which leads to viral endocytosis. In recent years, significant progress has been made in understanding the structural relationship between changes in the HA receptor-binding site (RBS) and the sialylated glycans that bind them. Several mutations were identified in the HA RBS that allows the virus to change host tropism. Their impact on binding the analogs of human and avian receptors was determined with X-ray crystallography. In this article, we provide a short overview of the HA protein structure and briefly discuss the adaptive mutations introduced to different HA subtypes.

| S-EPMC6252403 | biostudies-literature

Antibody recognition of the pandemic H1N1 Influenza virus hemagglutinin receptor binding site.

Project description:Influenza virus is a global health concern due to its unpredictable pandemic potential. This potential threat was realized in 2009 when an H1N1 virus emerged that resembled the 1918 virus in antigenicity but fortunately was not nearly as deadly. 5J8 is a human antibody that potently neutralizes a broad spectrum of H1N1 viruses, including the 1918 and 2009 pandemic viruses. Here, we present the crystal structure of 5J8 Fab in complex with a bacterially expressed and refolded globular head domain from the hemagglutinin (HA) of the A/California/07/2009 (H1N1) pandemic virus. 5J8 recognizes a conserved epitope in and around the receptor binding site (RBS), and its HCDR3 closely mimics interactions of the sialic acid receptor. Electron microscopy (EM) reconstructions of 5J8 Fab in complex with an HA trimer from a 1986 H1 strain and with an engineered stabilized HA trimer from the 2009 H1 pandemic virus showed a similar mode of binding. As for other characterized RBS-targeted antibodies, 5J8 uses avidity to extend its breadth and affinity against divergent H1 strains. 5J8 selectively interacts with HA insertion residue 133a, which is conserved in pandemic H1 strains and has precluded binding of other RBS-targeted antibodies. Thus, the RBS of divergent HAs is targeted by 5J8 and adds to the growing arsenal of common recognition motifs for design of therapeutics and vaccines. Moreover, consistent with previous studies, the bacterially expressed H1 HA properly refolds, retaining its antigenic structure, and presents a low-cost and rapid alternative for engineering and manufacturing candidate flu vaccines.

| S-EPMC3807900 | biostudies-literature

Antibodies That Engage the Hemagglutinin Receptor-Binding Site of Influenza B Viruses.

Project description:We describe cross-reactive human antibodies recognizing influenza B viruses spanning nearly 80 years of antigenic drift. Structures show that they engage the receptor-binding site (RBS) of the viral hemagglutinin with strong similarities to their influenza A counterparts, despite structural differences between the RBS of influenza A and B. Our data show that these antibodies readily cross-react with both influenza B Victoria and Yamagata lineages. We also note that all antibodies are encoded by IGHV3-9/IGK1-33. Future research will provide insight into the prevalence of these antibodies in the human population.

| S-EPMC8276581 | biostudies-literature

Computational design of trimeric influenza-neutralizing proteins targeting the hemagglutinin receptor binding site.

Project description:Many viral surface glycoproteins and cell surface receptors are homo-oligomers, and thus can potentially be targeted by geometrically matched homo-oligomers that engage all subunits simultaneously to attain high avidity and/or lock subunits together. The adaptive immune system cannot generally employ this strategy since the individual antibody binding sites are not arranged with appropriate geometry to simultaneously engage multiple sites in a single target homo-oligomer. We describe a general strategy for the computational design of homo-oligomeric protein assemblies with binding functionality precisely matched to homo-oligomeric target sites. In the first step, a small protein is designed that binds a single site on the target. In the second step, the designed protein is assembled into a homo-oligomer such that the designed binding sites are aligned with the target sites. We use this approach to design high-avidity trimeric proteins that bind influenza A hemagglutinin (HA) at its conserved receptor binding site. The designed trimers can both capture and detect HA in a paper-based diagnostic format, neutralizes influenza in cell culture, and completely protects mice when given as a single dose 24 h before or after challenge with influenza.

| S-EPMC5512607 | biostudies-literature

Diversity of Functionally Permissive Sequences in the Receptor-Binding Site of Influenza Hemagglutinin.

Project description:Influenza A virus hemagglutinin (HA) initiates viral entry by engaging host receptor sialylated glycans via its receptor-binding site (RBS). The amino acid sequence of the RBS naturally varies across avian and human influenza virus subtypes and is also evolvable. However, functional sequence diversity in the RBS has not been fully explored. Here, we performed a large-scale mutational analysis of the RBS of A/WSN/33 (H1N1) and A/Hong Kong/1/1968 (H3N2) HAs. Many replication-competent mutants not yet observed in nature were identified, including some that could escape from an RBS-targeted broadly neutralizing antibody. This functional sequence diversity is made possible by pervasive epistasis in the RBS 220-loop and can be buffered by avidity in viral receptor binding. Overall, our study reveals that the HA RBS can accommodate a much greater range of sequence diversity than previously thought, which has significant implications for the complex evolutionary interrelationships between receptor specificity and immune escape.

| S-EPMC5553561 | biostudies-literature

Crystallographic detection of a second ligand binding site in influenza virus hemagglutinin.

Project description:X-ray crystal structures have been determined for several complexes between influenza virus hemagglutinin and derivatives of its cell-surface receptor, sialic acid (Neu5Ac). Difference electron density maps establish the existence of a second binding site in addition to the primary site characterized previously. Three compounds bind to both sites: Neu5Ac(alpha 2-3)Gal(beta 1-4)Glc [(alpha 2-3)sialyllactose], alpha-2-O-(4'-benzylamidocarboxybutyl)-5-N-acetylneuraminic acid, and alpha-2-O-(4'-methylamidocarboxybutyl)-5-N-acetylneuraminic acid; and four other compounds bind only to the primary site: Neu5Ac(alpha 2-6)Gal(beta 1-4)Glc [(alpha 2-6)sialyllactose], alpha-2-O-methyl-5-N-acetylneuraminic acid, 4-]-acetyl-alpha-2-O-methyl-5-N-acetylneuraminic acid, and 9-amino-9-deoxy-alpha-2-O-methyl-5-N-acetylneuraminic acid. The maps also extend earlier results by showing the location of all three sugar residues of (alpha 2-3)sialyllactose in the primary binding site. The affinity of (alpha 2-3)sialyllactose for the second site was estimated by collecting x-ray diffraction data at various ligand concentrations and was found to be at least four times weaker than its affinity for the primary site. Although it is not yet known whether the second binding site participates in the infection process, it nevertheless offers a potential target for the design of antiviral drugs.

| S-EPMC48229 | biostudies-other

A recurring motif for antibody recognition of the receptor-binding site of influenza hemagglutinin.

Project description:Influenza virus hemagglutinin (HA) mediates receptor binding and viral entry during influenza infection. The development of receptor analogs as viral-entry blockers has not been successful, which suggests that sialic acid may not be an ideal scaffold to obtain broad, potent HA inhibitors. Here, we report crystal structures of Fab fragments from three human antibodies that neutralize the 1957 pandemic H2N2 influenza virus in complex with H2 HA. All three antibodies use an aromatic residue to plug a conserved cavity in the HA receptor-binding site. Each antibody interacts with the absolutely conserved HA1 Trp153 at the cavity base through ?-? stacking with the signature Phe54 of two VH1-69-encoded antibodies or a tyrosine from HCDR3 in the other antibody. This highly conserved interaction can be used as a starting point to design inhibitors targeting this conserved hydrophobic pocket in influenza viruses.

| S-EPMC3594569 | biostudies-literature

Heterosubtypic antibody recognition of the influenza virus hemagglutinin receptor binding site enhanced by avidity.

Project description:Continual and rapid mutation of seasonal influenza viruses by antigenic drift necessitates the almost annual reformulation of flu vaccines, which may offer little protection if the match to the dominant circulating strain is poor. S139/1 is a cross-reactive antibody that neutralizes multiple HA strains and subtypes, including those from H1N1 and H3N2 viruses that currently infect humans. The crystal structure of the S139/1 Fab in complex with the HA from the A/Victoria/3/1975 (H3N2) virus reveals that the antibody targets highly conserved residues in the receptor binding site and contacts antigenic sites A, B, and D. Binding and plaque reduction assays show that the monovalent Fab alone can protect against H3 strains, but the enhanced avidity from binding of bivalent IgG increases the breadth of neutralization to additional strains from the H1, H2, H13, and H16 subtypes. Thus, antibodies making relatively low affinity Fab interactions with the receptor binding site can have significant antiviral activity when enhanced by avidity through bivalent interactions of the IgG, thereby extending the breadth of binding and neutralization to highly divergent influenza virus strains and subtypes.

| S-EPMC3479480 | biostudies-literature

ER proteostasis and temperature differentially impact the mutational tolerance of influenza hemagglutinin

Project description:Here, we present a systematic and quantitative test of the hypothesis that the composition and activities of the endoplasmic reticulum (ER) proteostasis network impact mutational tolerance of secretory pathway client proteins. We focus on influenza hemagluttinin (HA), a viral coat protein that folds in the host’s ER via a complex but well-characterized pathway. By integrating chemical methods to modulate the unfolded protein response with deep mutational scanning to assess mutational tolerance, we discover that upregulation of ER chaperones broadly enhances HA mutational tolerance across numerous sites and secondary/tertiary structure elements, including sites targeted by host antibodies. Remarkably, this host chaperone-enhanced mutational tolerance is observed at the same HA sites where mutational tolerance is most reduced by propagation at a fever-like temperature. Thus, host ER proteostasis mechanisms and temperature modulate HA mutational tolerance in opposite directions. This finding has important implications for influenza evolution, because influenza immune escape is contingent on HA possessing sufficient mutational tolerance to acquire antibody resistance while still maintaining the capacity to fold and function. More broadly, this work provides the first experimental evidence that the composition and activities of the ER proteostasis network critically define the mutational tolerance and, therefore, the evolution of secretory pathway client proteins.

2018-09-10 | GSE115168 | GEO

The inherent mutational tolerance and antigenic evolvability of influenza hemagglutinin.

Project description:Influenza is notable for its evolutionary capacity to escape immunity targeting the viral hemagglutinin. We used deep mutational scanning to examine the extent to which a high inherent mutational tolerance contributes to this antigenic evolvability. We created mutant viruses that incorporate most of the ≈10(4) amino-acid mutations to hemagglutinin from A/WSN/1933 (H1N1) influenza. After passaging these viruses in tissue culture to select for functional variants, we used deep sequencing to quantify mutation frequencies before and after selection. These data enable us to infer the preference for each amino acid at each site in hemagglutinin. These inferences are consistent with existing knowledge about the protein's structure and function, and can be used to create a model that describes hemagglutinin's evolution far better than existing phylogenetic models. We show that hemagglutinin has a high inherent tolerance for mutations at antigenic sites, suggesting that this is one factor contributing to influenza's antigenic evolution.

| S-EPMC4109307 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data