TABLE 2.
Binding of Neu5Ac and of 3′-SL (Neu5Ac2-3Gal-4Glc) to influenza viruses
| Virus | Association constant (mM−1)a
|
|
|---|---|---|
| Neu5Acb | 3′-SL | |
| Chicken H5N1 | ||
| Ck/HK/220/97 (CHO158) | 1.2 | 40 |
| Ck/HK/258/97 (CHO158) | 1.3 | 30 |
| Human H5N1 HK/156/97 | 0.5 | 30 |
| Duck viruses | ||
| Dk/HK/205/77 (H5N2) | 0.3 | 15 |
| Dk/HK/698/79 (H5N2) | 0.5 | 15 |
| Dk/Bavaria/1/77 (H1N1) | 0.5 | 10 |
| Mallard/MT/61 (H2N2) | 0.3 | 10 |
| Dk/Hokkaido/7/82 (H3N8) | 0.8 | 10 |
| Human pandemic strain Aichi/2/68 (H3N2) | 0.2 | 0.2 |
a
The association constants of virus complexes with Neu5Ac and 3′SL were determined in a competitive binding assay as described in Materials and Methods.
b
Free Neu5Ac in solution is a mixture of α- and β-anomers. The β-anomer is not present in the natural sialylglycoconjugates and does not bind to influenza virus (26). Represented here are the values for the α-anomer, which were calculated from the binding data (assuming a 5% content of α-anomer in the mixture).