Gene A32 product of vaccinia virus may be an ATPase involved in viral DNA packaging as indicated by sequence comparisons with other putative viral ATPases.

Statistically significant sequence similarity was revealed between the gene A32 product of vaccinia virus (VV), gene I products (gpI) of filamentous single-stranded DNA bacteriophages, and IVa2 gene products of adenoviruses. Four conserved sequence motifs were delineated, the two N-proximal of which correspond to the A and B motifs of the purine NTP-binding pattern. Based on the role of gpI and IVa2 proteins in virion morphogenesis, and on the conservation of the NTP-binding pattern in these proteins, we hypothesize that the A32 gene product might be involved in an ATP-consuming function in VV virion formation, e.g., packaging of the DNA in the virus particle.