Phylogenetic and computational structural analysis of VP7 gene of group a human rotavirus G1P[8] strains obtained in Sapporo, Japan from 1987 to 2000

Abstract

Many studies indicate that G1P[8] genotypes are the most prevalent rotavirus strains worldwide. Although two vaccines have been licensed and their value proven in many countries, continuous surveillance for genetic evolution of circulating rotavirus strains before and after the introduction of the vaccines is desirable. G and P typing were carried out on all field strains isolated during 1987-2000 in Sapporo, Japan. Phylogenetic analysis for the VP7 gene of rotavirus G1P[8] strains was performed. Amino acid substitutions were mapped on the predicted three-dimensional VP7 protein image. G1P[8] genotype predominated. One hundred thirteen strains with G1P[8] genotype were analyzed. Phylogenetic studies of the VP7 gene classified these strains into three lineages. The mean estimated substitution rate was 7.25 × 10(-4) nucleotide substitutions per site per year. One predominant lineage contained the mutant strains which had VP7 amino acid substitutions at residue 91 and 212 that is in the neutralization domains. They were estimated to locate in or near intersubunit boundary of VP7 trimer. It is suggested that the most prevalent G1P[8] lineage strains in Sapporo obtained some survival advantages by changing the neutralization domains of VP7.