Carboxyl-terminal domain III of the delta' subunit of DNA polymerase III holoenzyme binds DnaX and supports cooperative DnaX complex assembly. Journal Article uri icon



  • The delta' subunit of the DNA polymerase-III holoenzyme is a key component of the DnaX complex; it is required for loading the beta(2) processivity factor onto a primed template. The x-ray crystal structure of delta' indicates a three domain C-shaped structure (Guenther, B., Onrust, R., Sali, A., O'Donnell, M., and Kuriyan, J. (1997) Cell 91, 335-345). In this study, we localized the DnaX-binding domain of delta' to its carboxyl-terminal domain III by quantifying protein-protein interactions using a series of delta' fusion proteins lacking specific domains. The fusion protein corresponding to domain III of delta' bound to DnaX with an affinity approaching that of full-length delta'. In contrast, a construct bearing delta' domains I-II did not bind DnaX at detectable levels. The presence of delta and chi psi strengthened the interaction of DnaX with full-length delta' and delta' domain III. Thus, domain III of delta' not only contains the DnaX-binding site, but also contains the elements required for positive cooperative assembly of the DnaX complex. A domain III-specific anti-delta' monoclonal antibody interfered with DnaX complex formation and abolished the replication activity of DNA polymerase III holoenzyme.

publication date

  • December 28, 2001

has restriction

  • closed

Date in CU Experts

  • October 1, 2013 12:09 PM

Full Author List

  • Song MS; McHenry CS

author count

  • 2

Other Profiles

International Standard Serial Number (ISSN)

  • 0021-9258

Additional Document Info

start page

  • 48709

end page

  • 48715


  • 276


  • 52