Since 2013, H7N9 avian influenza viruses (AIVs) have caused more than 1,600 human infections, posing a threat to public health. An emerging concern is whether H7N9 AIVs will cause pandemics among humans. Molecular analysis of hemagglutinin (HA), which is a critical determinant of interspecies transmission, shows that the current H7N9 AIVs are still dual-receptor tropic, indicating limited human-to-human transmission potency. Mutagenesis and structural studies reveal that a G186V substitution is sufficient for H7N9 AIVs to acquire human receptor-binding capacity, and a Q226L substitution would favor binding to both avian and human receptors only when paired with A138/V186/P221 hydrophobic residues. These data suggest a different evolutionary route of H7N9 viruses compared to other AIV-subtype HAs.
H7N9hemagglutinininfluenza A virusinterspecies transmissionreceptor-binding propertystructural basisAnimalsBirdsHemagglutinin Glycoproteins, Influenza VirusHemagglutininsHumansInfluenza A Virus, H7N9 SubtypeInfluenza in BirdsInfluenza, HumanOrthomyxoviridae InfectionsProtein BindingViral Proteins
Structured evidence records
Evidence records
3 total
Genomic Evolution1 records
Genomic EvolutionExtraction confidence 0.80
Key finding
Genomic and structural analysis of the H7N9 hemagglutinin identified G186V and Q226L substitutions as key mutations driving avian-to-human receptor-binding evolution, indicating a distinct evolutionary pathway from other avian influenza subtypes.
Molecular analysis of hemagglutinin (HA) shows that the current H7N9 AIVs are dual-receptor tropic, and mutagenesis and structural studies reveal that G186V and Q226L substitutions influence avian-to-human receptor binding capacity, suggesting a different evolutionary route of H7N9 viruses compared to other AIV-subtype HAs.
The G186V mutation in H7N9 hemagglutinin enables human receptor-binding adaptation, while Q226L in combination with hydrophobic residues A138/V186/P221 enhances dual avian and human receptor binding.
Mutagenesis and structural studies reveal that a G186V substitution is sufficient for H7N9 AIVs to acquire human receptor-binding capacity, and a Q226L substitution would favor binding to both avian and human receptors only when paired with A138/V186/P221 hydrophobic residues.
A G186V mutation in H7N9 influenza virus hemagglutinin enables human-type receptor binding, while Q226L together with A138/V186/P221 residues enhances dual avian and human receptor recognition.
Mutagenesis and structural studies reveal that a G186V substitution is sufficient for H7N9 AIVs to acquire human receptor-binding capacity, and a Q226L substitution would favor binding to both avian and human receptors only when paired with A138/V186/P221 hydrophobic residues.
