Escherichia coli single-stranded DNA binding protein stimulates the DNA deoxyribophosphodiesterase activity of exonuclease I.
The E. coli single-stranded binding protein (SSB) has been demonstrated in vitro to be involved in a number of replicative, DNA renaturation, and protective functions. It was shown previously that SSB can interact with exonuclease I to stimulate the hydrolysis of single-stranded DNA. We demonstrate here that E. coli SSB can also enhance the DNA deoxyribophosphodiesterase (dRpase) activity of exonuclease I by stimulating the release of 2-deoxyribose-5-phosphate from a DNA substrate containing AP endonuclease-incised AP sites, and the release of 4-hydroxy-2-pentenal-5-phosphate from a DNA substrate containing AP lyase-incised AP sites. E. coli SSB and exonuclease I form a protein complex as demonstrated by Superose 12 gel filtration chromatography. These results suggest that SSB may have an important role in the DNA base excision repair pathway.
Sandigursky
M
M
Department of Radiology, Albert Einstein College of Medicine, Bronx, NY 10461.
Franklin
W A
WA
D001426:Bacterial Proteins / Q000502:physiology*; D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000502:physiology*; D004926:Escherichia coli / Q000378:metabolism*; D005090:Exodeoxyribonucleases / Q000378:metabolism*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D011485:Protein Binding; D012267:Ribosemonophosphates / Q000378:metabolism
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D012267:Ribosemonophosphates; C058245:2-deoxyribose 5-phosphate; D005090:Exodeoxyribonucleases; C028450:exodeoxyribonuclease I; C058246:DNA deoxyribophosphodiesterase; D010727:Phosphoric Diester Hydrolases