tau binds and organizes Escherichia coli replication proteins through distinct domains: domain III, shared by gamma and tau, oligomerizes DnaX. Journal Article uri icon



  • The tau and gamma proteins of the DNA polymerase III holoenzyme DnaX complex are products of the dnaX gene with gamma being a truncated version of tau arising from ribosomal frameshifting. tau is comprised of five structural domains, the first three of which are shared by gamma (Gao, D., and McHenry, C. (2001) J. Biol. Chem. 276, 4433-4453). In the absence of the other holoenzyme subunits, DnaX exists as a tetramer. Association of delta, delta', chi, and psi with domain III of DnaX(4) results in a DnaX complex with a stoichiometry of DnaX(3)deltadelta'chipsi. To identify which domain facilitates DnaX self-association, we examined the properties of purified biotin-tagged DnaX fusion proteins containing domains I-II or III-V. Unlike domain I-II, treatment of domain III-V, gamma, and tau with the chemical cross-linking reagent BS3 resulted in the appearance of high molecular weight intramolecular cross-linked protein. Gel filtration of domains I-II and III-V demonstrated that domain I-II was monomeric, and domain III-V was an oligomer. Biotin-tagged domain III-V, and not domain I-II, was able to form a mixed DnaX complex by recruiting tau, delta, delta', chi, and psi onto streptavidin-agarose beads. Thus, domain III not only contains the delta, delta', chi, and psi binding interface, but also the region that enables DnaX to oligomerize.

publication date

  • September 21, 2001

has subject area

has restriction

  • hybrid

Date in CU Experts

  • October 1, 2013 12:09 PM

Full Author List

  • Glover BP; Pritchard AE; McHenry CS

author count

  • 3

Other Profiles

International Standard Serial Number (ISSN)

  • 0021-9258

Additional Document Info

start page

  • 35842

end page

  • 35846


  • 276


  • 38