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The dnaB-dnaC replication protein complex of Escherichia coli

1989; Elsevier BV; Volume: 264; Issue: 5 Linguagem: Inglês

10.1016/s0021-9258(19)81637-x

1083-351X

Elmar Wahle, Roger S. Lasken, A Kornberg,

Bacterial Genetics and Biotechnology

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.