ATPase probably involved in chromosome partitioning. Cooperatively binds dsDNA, forming nucleoprotein filaments in a strictly ATP-dependent fashion. Can also bind ssDNA with lower affinity. ATP + H2O = ADP + H(+) + phosphate ATPase activity is stimulated 10-fold in the presence of Spo0J and DNA (parS, a plasmid centromere-like site or plasmid DNA itself). The first 20 residues of Spo0J stimulate ATPase by 8%. Monomer in the absence of nucleotides or presence of ADP, in the presence of ATP is found in a monomer-dimer equilibrium. ATP-binding is required for DNA-binding. Probably interacts with Spo0J. Belongs to the ParA family.