Please review the sequences from the two samples for validation of this finding.
PF11 background carries a quadruple set of amino acids crossing Hemagglutinin and Neuraminidase:
- HA 206T
- HA 226R
- NA 106I
- NA 248N
The QC2 changes, of course, are not fixed in the geography, as other sequences from the areas demonstrate considerable variation. Movement within and around the Receptor Binding Domain (RBD) continues to draw our focus.
A University of Wisconsin-Madison study in 2008 found that Glutamine (Q) at 226 mediates the Binding Affinity for SAα2,6Gal (Sialic Acid α2,6) and, in turn, lowers infectivity levels in primary epithelial cells for humans compared to Leucine at that position (226L). I am not aware of conclusive studies comparing 226Q to 226R in this regard. Please contact me if you have applicable studies.
226R on PF11 Background (9)
- Finland553 with HA:206T and NA:106I
At any rate, ΣPF11 in Eurasia and the Americas is now varying away from a stable, low infectivity position in the Receptor Binding Domain to an amino acid found in H5N1 at 226 (A/Anhui/2/2005/H5N1). And I remind you that Anhui2 carries 206T and 296H which we are seeing persistently emerge throughout the world including clustering in Italy and the Northeastern United States.
Scrutiny is required here.
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