TABLE 6.
Affinity of H9 escape mutants for sialyl substratesa
| Virus (amino acid change) |
Kd for substrate:
|
|||
|---|---|---|---|---|
| Fetuin | p3′SL | p6′SL | p6′SLN | |
| Sw/HK/9/98 | 2.43 ± 0.18 | >20 | 0.16 ± 0.03 | 0.18 ± 0.04 |
| Sw/HK/9/98-MA | 2.51 ± 0.12 | >20 | 0.19 ± 0.03 | 0.19 ± 0.03 |
| Sw/HK/9/98-MP (S133N) | 2.38 ± 0.12 | >20 | 0.19 ± 0.03 | 0.19 ± 0.01 |
| mG9-27 (S133N) | 2.47 ± 0.28 | >20 | 0.18 ± 0.02 | 0.19 ± 0.02 |
| m18G4 (S133N) | 2.35 ± 0.20 | >20 | 0.19 ± 0.03 | 0.23 ± 0.02 |
| mG1-29 (K157T) | 2.43 ± 0.16 | >20 | 0.23 ± 0.05 | 0.21 ± 0.03 |
| m18B1 (D145E) | 2.38 ± 0.35 | >20 | 0.19 ± 0.02 | 0.18 ± 0.01 |
| m7B10 (N193D) | 2.34 ± 0.30 | >20 | 0.63 ± 0.07 | 0.18 ± 0.02 |
| m3D11 (N193D) | 2.29 ± 0.15 | >20 | 0.65 ± 0.02 | 0.19 ± 0.02 |
| m15F1 (P162L) | 2.43 ± 0.19 | >20 | 0.51 ± 0.06 | 0.46 ± 0.06 |
| m19A10 (L226Q) | 2.58 ± 0.41 | 1.60 ± 0.22 | 0.86 ± 0.08 | 0.81 ± 0.06 |
| m18B10 (T198N) | 5.56 ± 0.13 | >20 | 2.09 ± 0.33 | 2.49 ± 0.27 |
| m8C4 (T198N) | 5.74 ± 0.52 | >20 | 1.90 ± 0.29 | 2.60 ± 0.32 |
| m18G4-18B1 (S133N, L226Q) | 2.31 ± 0.21 | 1.75 ± 0.14 | 0.87 ± 0.11 | 0.84 ± 0.07 |
| m7B10-18G4 (S116I, T135K, N193D) | 2.42 ± 0.24 | >20 | 0.68 ± 0.03 | 0.22 ± 0.05 |
| m7B10-18G4′ (T135K, N193D) | 2.55 ± 0.17 | >20 | 0.65 ± 0.07 | 0.22 ± 0.04 |
| m7B10-18B10 (N193D, T189A) | 2.50 ± 0.44 | >20 | 2.46 ± 0.34 | 2.87 ± 0.46 |
| m15F1-3D11 (P162L, F147L, T135A) | 2.23 ± 0.43 | >20 | 1.37 ± 0.22 | 1.16 ± 0.11 |
| m15F1-18B10 (P162L, N193T) | 2.22 ± 0.30 | >20 | 0.25 ± 0.04 | 0.25 ± 0.04 |
| mG1-29-18G4 (S133N, K157T) | 2.40 ± 0.26 | >20 | 0.45 ± 0.04 | 0.29 ± 0.02 |
| m3D11-18G4 (S133N, N193D) | 5.31 ± 0.53 | >20 | 1.15 ± 0.10 | 0.56 ± 0.05 |
a
In each case, Kd = mean ± SE × tα,n−1, where tα is Student's coefficient with probability α (α = 0.90) (micromolar sialic acid). Kd was calculated from results obtained in four independent experiments. p3′SL, 3′-sialyllactose on a polyacrylic carrier; p6′SL, 6′-sialyllactose on a polyacrylic carrier; p6′SLN, 6′-sialyllactosamine on a polyacrylic carrier. Amino acids are numbered according to the HA of the H3 subtype.