TABLE 3.
Amino acid replacements found in VP1 and 3D of the mutant spectrum of FMDV populations subjected to chemical mutagenesis
| Protein | Amino acid replacementa | Structural elementb | Presence (+) or absence (−) of replacements in the following populationc:
|
||
|---|---|---|---|---|---|
| FU | AZC | Other | |||
| VP1 | K-41 → Ed | βB | − | + | + |
| T-50 → A | βC | + | − | − | |
| I-61 → V | αA | + | − | − | |
| Y-72 → C | βD | + | − | − | |
| P-94 → L | l | + | − | − | |
| H-108 → Rd | βF | − | + | − | |
| G-142 → W | l | + | − | − | |
| T-148 → K | l | + | − | + | |
| T-149 → K | l | + | + | + | |
| T-150 → K | l | − | + | + | |
| H-151 → R | l | − | + | + | |
| E-167 → D | l | + | − | − | |
| E-167 → Kd | l | − | + | − | |
| 3D | A-116 → T | l | + | − | − |
| V-181 → I | l | + | − | − | |
| I-196 → T | l | + | − | − | |
| F-230 → S | l | + | − | − | |
| R-289 → C | l | − | + | − | |
| I-334 → M | β2 | − | + | − | |
| D-349 → E | l | − | + | − | |
The single-letter amino acid code is used; amino acids are numbered independently for each protein.
Structural elements (α, α helix; β, β strand; l, loop) of VP1 are assigned according to the three-dimensional structure of FMDV C-S8c1 (30, 39); structural elements of 3D are based on the three-dimensional structure of poliovirus 3D (25), assuming that the equivalent positions in FMDV 3D in an alignment of the two sequences (37) have the same structure.
FU and AZC, FMDV populations derived from C-S8c1 after one or multiple passages in the presence of FU and AZC, respectively; they correspond to the populations described in Tables 1 and 2. Other, possible presence of the replacements in populations of FMDV type C natural isolates (35, 36, 39) or laboratory variants of FMDV C-S8c1 (3, 19, 20, 27, 40, 59).
These three replacements have been found in the mutant spectrum of some populations and are dominant in some consensus sequences: K-41 → E and H-108 → R in three out of five clones of C-S8c1FUp25 and E-167 → K in two out of five clones of C-S8c1FUp25. Minority amino acids which coincide with the amino acid in the corresponding position of C-S8c1 are not included.