Table 3.

Amino acid replacements found in VP1 and 3D of the mutant spectrum of FMDV populations subjected to chemical mutagenesis

ProteinAmino acid replacementaStructural elementbPresence (+) or absence (−) of replacements in the following populationc:
FUAZCOther
VP1K-41 → Ed βB++
T-50 → AβC+
I-61 → VαA+
Y-72 → CβD+
P-94 → Ll+
H-108 → Rd βF+
G-142 → Wl+
T-148 → Kl++
T-149 → Kl+++
T-150 → Kl++
H-151 → Rl++
E-167 → Dl+
E-167 → Kd l+
3DA-116 → Tl+
V-181 → Il+
I-196 → Tl+
F-230 → Sl+
R-289 → Cl+
I-334 → Mβ2+
D-349 → El+
  • a The single-letter amino acid code is used; amino acids are numbered independently for each protein.

  • b 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.

  • c 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 1and 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).

  • d 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.