Abstract
Base excision repair (BER) constitutes a ubiquitous excision repair mechanism, which is responsible for the removal of multiple types of damaged and inappropriate bases in DNA. We have employed a yeast cell-free system to examine the biochemical mechanism of the BER pathway in lower eukaryotes. Using uracil-containing DNA as a model substrate, we demonstrate that yeast BER requires Apn1 protein, an Escherichia coli endonuclease IV homolog. In extracts of an apn1 deletion mutant, the 5'-incision at AP (apurinic/apyrimidinic) sites is not detectable, supporting the notion that yeast contains only one major 5'-AP endonuclease. The processing of the 5'- deoxyribose phosphate moieties was found to be a rate-limiting step. During BER of uracil-containing DNA, repair patch sizes of 1-5 nucleotides were detected, with single nucleotide repair patches predominant.
Original language | English |
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Pages (from-to) | 24064-24071 |
Number of pages | 8 |
Journal | Journal of Biological Chemistry |
Volume | 272 |
Issue number | 38 |
DOIs | |
State | Published - Sep 19 1997 |
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology