Viral-encoded ATPase can act as a part ofmolecular motor in genome packaging of DNA viruses,such as vaccinia virus and adenovirus, by TP hydrolysisand interaction with DNA. Poxviral ATPase (also calledA32) is involved in genomic ouble-stranded DNA(dsDNA) encapsidation, and inhibition of the expression ofA32 causes formation of immature virions lacking viralDNA. However, the role of A32 in goatpoxvirus genomepackaging and its dsDNA binding property are not known.In this study, purified recombinant goatpoxvirus A32 protein(rA32) was examined for its dsDNA binding propertyas well as the effect of dsDNA on ATP ydrolysis. Wefound that rA32 could bind dsDNA, and its ATPaseactivity was significant increased with dsDNA binding.Effects of magnesium and calcium ions on ATP hydrolysiswere investigated also. The ATPase activity was dramaticallyenhanced by dsDNA in the presence of Mg2?; incontrast, ATPase function was not altered by Ca2?. Furthermore,the enzyme activity of rA32 was completelyblocked by Zn2?. Regarding DNA–protein interaction, therA32-ATP-Mg2? showed lower dsDNA binding affinity
