Different efficiencies of the Tag and AlkA DNA glycosylases from Escherichia coli in the removal of 3-methyladenine from single-stranded DNA.
Escherichia coli possesses two different DNA repair glycosylases, Tag and AlkA, which have similar ability to remove the alkylation product 3-methyladenine from double-stranded DNA. In this study we show that these enzymes have quite different activities for the excision of 3-methyladenine from single-stranded DNA, AlkA being 10-20 times more efficient than Tag. We propose that AlkA and perhaps other glycosylases as well may have an important role in the excision of base damage from single-stranded regions transiently formed in DNA during transcription and replication.
Bjelland
S
S
Norwegian Defence Research Establishment, Division for Environmental Toxicology, Kjeller. svein.bjelland@tn.his.no.
Seeberg
E
E
D000225:Adenine / Q000031:analogs & derivatives* / Q000378:metabolism; D000478:Alkylation; D045647:DNA Glycosylases; D004260:DNA Repair; D004277:DNA, Single-Stranded / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D008745:Methylation; D009699:N-Glycosyl Hydrolases / Q000378:metabolism*; D011061:Poly A / Q000378:metabolism; D011067:Poly dA-dT / Q000378:metabolism
D004277:DNA, Single-Stranded; D011061:Poly A; C015465:poly(dA); D011067:Poly dA-dT; C025946:3-methyladenine; C021565:3-methyladenine-DNA glycosylase; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; C076131:DNA-3-methyladenine glycosidase II; D000225:Adenine