Recombinational bypass of pyrimidine dimers promoted by the recA protein of Escherichia coli

Proc Natl Acad Sci U S A. 1982 May;79(10):3171-5. doi: 10.1073/pnas.79.10.3171.


recA protein, in the presence of single-stranded DNA binding protein and ATP, promotes the complete exchange of strands between circular single-stranded DNA containing pyrimidine dimers and a homologous linear duplex, converting the pyrimidine dimer-containing single-stranded DNA to a circular duplex. Bypass of a pyrimidine dimer during the branch-migration phase of the reaction requires approximately 20 seconds, a rate 1/50th of that in the absence of the dimer. The circular duplex product is specifically incised by the pyrimidine dimer-specific T4 endonuclease V, and the resulting 3' hydroxyl termini can serve as primers for deoxynucleotide polymerization by DNA polymerase I. These findings indicate that recA protein serves a direct role in recombinational repair and demonstrate that the pyrimidine dimers that have been bypassed can be processed by enzymes of the excision-repair pathway.

Publication types

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

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Bacterial Proteins / physiology*
  • Carrier Proteins / metabolism
  • DNA Repair*
  • DNA, Single-Stranded / genetics
  • Pyrimidine Dimers / genetics*
  • Rec A Recombinases
  • Recombination, Genetic*


  • Bacterial Proteins
  • Carrier Proteins
  • DNA, Single-Stranded
  • Pyrimidine Dimers
  • Adenosine Triphosphate
  • Rec A Recombinases