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).

Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.