Adenosine triphosphatases of thermophilic archaeal double-stranded DNA viruses

Adenosine triphosphatases (ATPases) of double-stranded (ds) DNA archaeal viruses are structurally related to the AAA+ hexameric helicases and translocases. These ATPases have been implicated in viral life cycle functions such as DNA entry into the host, and viral genome packaging into preformed procapsids. We summarize bioinformatical analyses of a wide range of archaeal ATPases, and review the biochemical and structural properties of those archaeal ATPases that have measurable ATPase activity. We discuss their potential roles in genome delivery into the host, virus assembly and genome packaging in comparison to hexameric helicases and packaging motors from bacteriophages.