BLUETONGUE VIRUS VP6 PROTEIN BINDS ATP AND EXHIBITS AN RNA-DEPENDENT ATPASE FUNCTION AND A HELICASE ACTIVITY THAT CATALYZE THE UNWINDING OFDOUBLE-STRANDED-RNA SUBSTRATES

RNA-dependent ATPase and helicase activities have been identified asso ciated with the purified VP6 protein of bluetongue virus, a member of the Orbivirus genus of double-stranded RNA (dsRNA; Reoviridae family) viruses. In addition, the protein has an ATP binding activity. RNA unw inding of duplexes occurred with both 3' and 5' overhang templates, as well as with blunt-ended dsRNA, an activity not previously identified in other viral helicases. Although little sequence similarity to othe r helicases was detected, certain similarities to motifs commonly attr ibuted to such proteins were identified.