Primase directs the release of DnaC from DnaB.
An AAA+ ATPase, DnaC, delivers DnaB helicase at the E. coli chromosomal origin by a poorly understood process. This report shows that mutant proteins bearing alanine substitutions for two conserved arginines in a motif named box VII are defective in DNA replication, but this deficiency does not arise from impaired interactions with ATP, DnaB, or single-stranded DNA. Despite their ability to deliver DnaB to the chromosomal origin to form the prepriming complex, this intermediate is inactive. Quantitative analysis of the prepriming complex suggests that the DnaB-DnaC complex contains three DnaC monomers per DnaB hexamer and that the interaction of primase with DnaB and primer formation triggers the release of DnaC, but not the mutants, from DnaB. The interaction of primase with DnaB and the release of DnaC mark discrete events in the transition from initiation to the elongation stage of DNA replication.
Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824-1319, USA.
Magdalena
M
Makowska-Grzyska
Jon M
JM
Kaguni
D000255:Adenosine Triphosphate / Q000378:metabolism; D020816:Amino Acid Motifs; D001120:Arginine / Q000737:chemistry / Q000502:physiology; D019915:DNA Primase / Q000502:physiology*; D004261:DNA Replication / Q000502:physiology*; D004277:DNA, Single-Stranded / Q000378:metabolism; D053488:DnaB Helicases / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D025941:Protein Interaction Mapping; D018741:Replication Origin
D004277:DNA, Single-Stranded; C071702:DnaC protein, E coli; D029968:Escherichia coli Proteins; D000255:Adenosine Triphosphate; D001120:Arginine; D019915:DNA Primase; C506730:dnaB protein, E coli; D053488:DnaB Helicases