The cycling of Escherichia coli DNA polymerase III holoenzyme in replication

J Biol Chem. 1983 Jun 25;258(12):7669-75.

Abstract

ATP-activated DNA polymerase III holoenzyme (holoenzyme) forms a stable initiation complex with primed DNA with concomitant hydrolysis of the ATP (Burgers, P. M. J., and Kornberg, A. (1982) J. Biol. Chem. 257, 11468-11478). Upon replication of primed single-stranded circular DNA to a duplex circle with a small gap (RFII), the holoenzyme remains stably bound. Dissociation requires binding by ATP or the generally nonhydrolyzable analog, adenosine 5'-(3-thiotriphosphate). Transfer of holoenzyme to another primed DNA absolutely requires ATP (or dATP) and takes about 2 min at 30 degrees C. The rate of cycling of holoenzyme is only slightly dependent on the concentration of primed DNA. However, the transfer time is reduced to only 2 to 5 s when it is intramolecular, as shown by movement to other primers on the same template chain. A rapid transfer of holoenzyme from a completed chain to another primer on the same template molecule is anticipated from the frequency of initiating nascent chains at the replicating fork of the cellular chromosome (about 1 per s at 37 degrees C) and the low cellular abundance of holoenzyme (about 10 to 20 molecules per cell).

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphate / analogs & derivatives
  • Adenosine Triphosphate / pharmacology
  • DNA Ligases / metabolism
  • DNA Polymerase I / metabolism
  • DNA Polymerase III / metabolism*
  • DNA Replication*
  • DNA-Directed DNA Polymerase / metabolism*
  • Escherichia coli / enzymology*
  • Escherichia coli / genetics
  • Kinetics

Substances

  • Adenosine Triphosphate
  • DNA Polymerase I
  • DNA Polymerase III
  • DNA-Directed DNA Polymerase
  • DNA Ligases