The NH2-terminal php domain of the alpha subunit of the Escherichia coli replicase binds the epsilon proofreading subunit. Journal Article uri icon

Overview

abstract

  • The alpha subunit of the replicase of all bacteria contains a php domain, initially identified by its similarity to histidinol phosphatase but of otherwise unknown function (Aravind, L., and Koonin, E. V. (1998) Nucleic Acids Res. 26, 3746-3752). Deletion of 60 residues from the NH2 terminus of the alpha php domain destroys epsilon binding. The minimal 255-residue php domain, estimated by sequence alignment with homolog YcdX, is insufficient for epsilon binding. However, a 320-residue segment including sequences that immediately precede the polymerase domain binds epsilon with the same affinity as the 1160-residue full-length alpha subunit. A subset of mutations of a conserved acidic residue (Asp43 in Escherichia coli alpha) present in the php domain of all bacterial replicases resulted in defects in epsilon binding. Using sequence alignments, we show that the prototypical gram+ Pol C, which contains the polymerase and proofreading activities within the same polypeptide chain, has an epsilon-like sequence inserted in a surface loop near the center of the homologous YcdX protein. These findings suggest that the php domain serves as a platform to enable coordination of proofreading and polymerase activities during chromosomal replication.

publication date

  • May 1, 2006

has subject area

Date in CU Experts

  • October 1, 2013 12:09 PM

Full Author List

  • Wieczorek A; McHenry CS

author count

  • 2

citation count

  • 22

Other Profiles

International Standard Serial Number (ISSN)

  • 0021-9258

Electronic International Standard Serial Number (EISSN)

  • 1083-351X

Additional Document Info

start page

  • 12561

end page

  • 12567

volume

  • 281

issue

  • 18