Related Experiment Video
Updated: Jan 18, 2026
13:12
Quantitative Analyses of all Influenza Type A Viral Hemagglutinins and Neuraminidases using Universal Antibodies in Simple Slot Blot Assays
Published on: April 4, 2011
18.7K
Influenza hemagglutinin subtypes have different sequence constraints despite sharing extremely similar structures
Jenny J Ahn1,2, Timothy C Yu1,3, Bernadeta Dadonaite1
1Division of Basic Sciences and Computational Biology Program, Fred Hutchinson Cancer Center, Seattle, WA.
Biorxiv : the Preprint Server for Biology
|January 16, 2026
Summary
Influenza hemagglutinin (HA) sequences diverge, but structure and function remain. Different subtypes show distinct amino acid preferences at about 50% of HA sites, revealing varied evolutionary constraints.
Area of Science:
- Virology
- Structural Biology
- Evolutionary Biology
Background:
- Influenza A virus hemagglutinins (HA) exhibit low sequence identity across subtypes.
- Despite sequence divergence, HA protein structure and cell entry function are highly conserved.
Purpose of the Study:
- To investigate how sequence constraints on HA differ across influenza A virus subtypes.
- To compare site-specific amino acid preferences for H7 HA with previously studied H3 and H5 HAs.
Main Methods:
- Utilized pseudovirus deep mutational scanning to assess the impact of all amino-acid mutations on H7 HA cell entry.
- Compared H7 HA mutational data with existing data for H3 and H5 HA subtypes.
Main Results:
- Approximately 50% of HA sites showed significantly different amino acid preferences between subtypes.
- Divergent amino acid preferences were most pronounced at buried sites with biochemically distinct wildtype residues.
- Rewiring of residue interactions explained shifts in amino acid tolerance at specific sites.
Conclusions:
- Influenza HA subtypes experience distinct site-specific evolutionary constraints despite conserved structure and function.
- Sequence divergence leads to varied evolutionary pressures on different HA sites.
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