Multifunctional protein which displays endonuclease and helicase activities required for initiating and directing viral DNA replication. Also plays a role in viral packaging and transactivation of several promoters. Binds site-specifically to 2-3 approximate tandem copies within the origins of replication (Ori), unwinds this hairpin region and nicks one DNA strand thereby initiating the rolling circle replication (RCR). ATP + H2O = ADP + H(+) + phosphate The endonuclease active site can probably bind other divalent cations. Homooligomer. In the N-terminus, the endonuclease region is involved in binding to the origin of replication. In the middle, there are the ATPase and helicase activities (By similarity). The C-terminus probably contains a transactivation domain (By similarity). Belongs to the parvoviruses initiator protein NS1 family.