Complete sequence of neutralization protein VP2 of the recent US isolate bluetongue virus serotype 2: its relationship with VP2 species of other US serotypes.

In order to determine the relationship between the most recently isolated bluetongue virus serotype (BTV-2), and other US serotypes, the complete nucleotide sequence was determined from cDNA clones representing the L2 dsRNA of BTV-2, the gene that codes for the outer capsid neutralization antigen (VP2). The predicted amino acid sequence of the protein was compared with the VP2 sequences of the US serotypes BTV-10, BTV-11, BTV-13 and BTV-17. The VP2 protein of BTV-2 was found to exhibit 47% homology with the VP2 species of BTV-13, but only 40-41% homology with the VP2 species of earlier US isolates, BTV-10-, and -17. However, Diagon comparisons and hydropathic plots of all five VP2 species indicated that all of them are structurally very similar.