Initiation of base excision repair: Glycosylase mechanisms and structures

Research output: Contribution to journalReview articlepeer-review

333 Scopus citations


The base excision repair pathway is an organism's primary defense against mutations induced by oxidative, alkylating, and other DNA-damaging agents. This pathway is initiated by DNA glycosylases that excise the damaged base by cleavage of the glycosidic bond between the base and the DNA sugar- phosphate backbone. A subset of glycosylases has an associated apurinic/apyrimidinic (AP) lyase activity that further processes the AP site to generate cleavage of the DNA phosphate backbone. Chemical mechanisms that are supported by biochemical and structural data have been proposed for several glycosylases and glycosylase/AP lyases. This review focuses on the chemical mechanisms of catalysis in the context of recent structural information, with emphasis on the catalytic residues and the active site conformations of several cocrystal structures of glycosylases with their substrate DNAs. Common structural motifs for DNA binding and damage specificity as well as conservation of acidic residues and amino groups for catalysis are discussed.

Original languageEnglish (US)
Pages (from-to)255-285
Number of pages31
JournalAnnual Review of Biochemistry
StatePublished - Oct 4 1999
Externally publishedYes


  • AP lyase
  • Alkylation DNA damage
  • Base flipping
  • Oxidative DNA damage
  • Ultraviolet light DNA damage

ASJC Scopus subject areas

  • Biochemistry


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