Proofreading activity of DNA polymerase III responds like elongation activity to auxiliary subunits. Journal Article uri icon



  • A comparison of the 3'----5' proofreading properties between Escherichia coli DNA polymerase III holoenzyme and DNA polymerase III' was conducted. This study indicated that the influence of the holoenzyme auxiliary subunits on the proofreading exonuclease parallels their effect on the elongation reaction. At physiological ionic strengths the auxiliary subunits markedly stimulated the exonuclease rate in an ATP-dependent reaction, while the exonuclease rate of DNA polymerase III' was not affected by ATP. E. coli single-stranded DNA binding protein stimulated the 3'----5' exonuclease activity of holoenzyme and inhibited DNA polymerase III'. Similarly, the auxiliary subunits and ATP converted the proofreading activity to a highly processive exonuclease. Our observation, that the exonuclease activity of the DNA polymerase III holoenzyme responded to ATP, salt, and E. coli single-stranded DNA-binding protein like the elongation activity, is consistent with the polymerase and exonuclease subunits acting within the same complex in a coordinated reaction.

publication date

  • March 15, 1991

Date in CU Experts

  • October 1, 2013 12:09 PM

Full Author List

  • Reems JA; Griep MA; McHenry CS

author count

  • 3

Other Profiles

International Standard Serial Number (ISSN)

  • 0021-9258

Additional Document Info

start page

  • 4878

end page

  • 4882


  • 266


  • 8