RESUMO
Three encoding sequence genes (Lab, 3C, 3D) from 19 isolates of O-serotype of foot and mouth disease virus(FMDV) were down-loaded from GenBank. And the coding and amino acid sequences of 3 FMDV proteases (Lpro, 3Cpro, 3Dpol) were compared with the FMDV OA/58 serotype Lab, 3C, 3D sequences abstracted in our laboratory and qualified by variance analysis and multiple analysis(Duncan method). The experimental results revealed that the Lab, 3C and 3D genes had similar nucleotide mutation rates(P>0.05). However, overall analysis of the amino acid substitutions revealed that the Lpro- coding region was more prone to amino acid alterations than 3Cpro and 3Dpol- coding regions(P<0.01), but via multiple comparison, at the amino acid mutation, both 3Cpro and 3Dpol showed no significant difference. Depending on Swiss--pdb-Viewer sofe to simulate amino acid alterations at mutation hotspots, the findings showed that these alterations at hotspots failed to ruin the spatial structures of these 3 proteases. This result presents that the nucleotide mutation just acts on dynamics related to FMDV mutation, but the real evolutionary power must depend on the infected host cells to select functions with each viral proteases.