APPENDIX B Some Well-characterized DNA-repair Nucleases/Glycosylases

Abstract

The following table lists some of the well-characterized DNA-repair nucleases, DNA glycosylases, and combined DNA glycosylase/AP lyases. The DNA glycosylases and DNA glycosylase/AP lyases are categorized and presented relative to the type of modified bases on which they function.

This table does not attempt to cover comprehensively all of the DNA-repair enzymes that have appeared in the literature, but rather to serve as a general guide to the complexity that is associated with the maintenance of an organism’s genetic integrity. References were chosen to document the most salient features of the individual enzymes.

SOME WELL-CHARACTERIZED DNA-REPAIR NUCLEASES/GLYCOSYLASES

EnzymeGeneMolecular mass (kD)PropertiesReferencesI. GLYCOSYLASES, GLYCOSYLASE/AP LYASESA. Oxidized PyrimidinesE. coli endonuclease IIInth23.5DNA glycosylase/AP lyase specific for thymine glycols and other pyrimidine radiolysis products; crystal structure solved; a 4Fe-4S enzyme1–4Murine UV–43 (I)DNA glycosylase/AP lyases specific for thymine glycols and other pyrimidine radiolysis products5Endonucleases I, II–28 (II)B. Oxidized PurinesE. coli Fpg DNA glycosylase (or 8-oxoguanine DNA glycosylase, or mutM gene product)fpg30DNA glycosylase/AP lyase specific for Fapy-A, Fapy-G, their methylated derivatives and 8-oxodG; catalyzes δ-elimination; zinc finger motif6–11mutMC. Deaminated BasesE. coli uracil DNA glycosylaseudg26DNA glycosylase specific for the release of uracil from ssDNA and dsDNA; mammalian cells have both nuclear and mitochondrial forms12–14Mammalian G/T thymine DNA glycosylase–?thymine-specific DNA glycosylase with associated incision activities that leave a one-base gap; thymine/guanine15,165-Hydroxymethyl-uracil