Purification and characterization of a DNA-dependent ATPase from Escherichia coli.

A DNA-dependent ATPase has been isolated and purified from an Escherichia coli cell-free extract. The ATPase has the following characteristics: preferential dependence on single-stranded DNA, specificity for ATP hydrolysis, Km value of 1.4 X 10-4 M for ATP, and molecular weight of approximately 69,000. The ATPase can be shown to bind to single stranded DNA. The resemblance between this ATPase and that isolated from vaccinia cores is discussed.