hda (Escherichia coli K12):   ATPase regulatory factor involved in DnaA inactivation; Mediates the interactions of DNA replication initiator protein DnaA with DNA polymerase subunit beta sliding clamp (dnaN). Stimulates hydrolysis of ATP-DnaA to ADP-DnaA, rendering DnaA inactive for reinitiation, a process called regulatory inhibition of DnaA or RIDA. ADP-binding activates Hda to hydrolyze DnaA-ATP; Hda monomers bind to ADP with about 200-fold greater affinity than for ATP. RIDA function can be genetically separated from viability, suggesting this protein has another function as well.