Mechanistic comparisons among base excision repair glycosylases.
The mechanisms by which various DNA glycosylases initiate the base excision repair pathways are discussed. Fundamental distinctions are made between "simple glycosylases," that do not form DNA single-strand breaks, and "glycosylases/abasic site lyases," that do form single-strand breaks. Several groupings of BER substrate sites are defined and some interactions between these groupings and glycosylase mechanisms discussed. Two characteristics are proposed to be common among all BER glycosylases: a nucleotide flipping step that serves to expose the scissile glycosyl bond to catalysis, and a glycosylase transition state characterized by substantial tetrahedral character at the base glycosyl atom.
Dodson
M L
ML
The Sealy Center for Molecular Science and Department of Human Biological Chemistry and Genetics, The University of Texas Medical Branch, Galveston, TX , USA.
Lloyd
R Stephen
RS
D002384:Catalysis; D004249:DNA Damage; D045647:DNA Glycosylases; D004260:DNA Repair / Q000502:physiology*; D005609:Free Radicals; D008958:Models, Molecular; D009699:N-Glycosyl Hydrolases / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*
D005609:Free Radicals; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases