Escherichia coli DNA polymerase V subunit exchange: a post-SOS mechanism to curtail error-prone DNA synthesis

J Biol Chem. 2003 Dec 26;278(52):52546-50. doi: 10.1074/jbc.M310127200. Epub 2003 Oct 22.


DNA polymerase V consisting of a heterotrimer composed of one molecule of UmuC and two molecules of UmuD' (UmuD'2C) is responsible for SOS damage-induced mutagenesis in Escherichia coli. Here we show that although the UmuD'2C complex remains intact through multiple chromatographic steps, excess UmuD, the precursor to UmuD', displaces UmuD' from UmuD'2C by forming a UmuDD' heterodimer, while UmuC concomitantly aggregates as an insoluble precipitate. Although soluble UmuD'2C is readily detected when the two genes are co-transcribed and translated in vitro, soluble UmuD2C or UmuDD'C are not detected. The subunit exchange between UmuD'2C and UmuD offers a biological means to inactivate error-prone polymerase V following translesion synthesis, thus preventing mutations from occurring on undamaged DNA.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cross-Linking Reagents / pharmacology
  • DNA / biosynthesis
  • DNA Damage
  • DNA-Directed DNA Polymerase / chemistry*
  • Dimerization
  • Dose-Response Relationship, Drug
  • Electrophoresis, Polyacrylamide Gel
  • Escherichia coli / enzymology*
  • Escherichia coli Proteins / chemistry*
  • Models, Biological
  • Mutagenesis
  • Plasmids / metabolism
  • Protein Binding
  • Protein Biosynthesis
  • Protein Structure, Tertiary
  • Serine Endopeptidases / chemistry*
  • Transcription, Genetic


  • Cross-Linking Reagents
  • Escherichia coli Proteins
  • DNA
  • UmuC protein, E coli
  • DNA polymerase V, E coli
  • DNA-Directed DNA Polymerase
  • UmuD protein, E coli
  • Serine Endopeptidases
  • UmuD protease, E coli