• 15 February 1989
    • journal article
    • research article
    • Vol. 264  (5) , 2469-2475
Abstract
The dnaC protein of Escherichia coli, by forming a complex with the dnaB protein, facilitates the interactions with single-stranded DNA that enable dnaB to perform its ATPase, helicase, and priming functions. Within the dnaB-dnaC complex, dnaB appears to be inactive but becomes active upon the ATP-dependent release of dnaC from the complex. With adenosine 5''-(.gamma.-thio)triphosphate substituted for ATP, the dnaB-dnaC complex does not direct dnaB to its targeted actions. Excess dnaC inhibits dna.beta. actions and augments the ATP.gamma.S effects. In the dnaA protein-driven initiation of duplex chromosome replication, dnaB is introduced for its essential helicase role via the dnaB-dnaC complex. Similarly, when the dnaA protein interacts nonspecifically with single-stranded DNA, the dnaB-dnaC complex is essential to introduce dnaB for its role in primer formation by primase.