Release of chloroethyl ethyl sulfide-modified DNA bases by bacterial 3-methyladenine-DNA glycosylases I and II

Publisher Website
Google Scholar
Abstract
Treatment with chloroethyl ethyl sulfide introduces the following modified bases into DNA: 7-ethylthioethylguanine, 3-ethyithioethyladenine, and O6-ethylthioethylguanine. Using the ethylthioethylated bases as models for DNA modifications involving relatively bulky alkyl groups, we have investigated the release of these bases by Escherichia coli 3-methyladenine-DNA glycosylases I and II. 3-Methyladenine-DNA glycosylase I releases only 3-ethylthioethyladenine from chloroethyl ethyl sulfide-modified DNA, but does so at a rate which exceeds the rate of release of 3-methyladenine (m3A) from methyl nitrosourea-modified DNA under these conditions. 3-Methyladenine-DNA glycosylase II releases both 3-ethylthioethyl-adenine and 7-ethylthioethylguanine at rates approximating or exceeding the rate of release of m3A from methylnitrosourea-modified DNA. We conclude that these glycosylases may offer some protection against the toxicity of agents which introduce bulky groups into E.coli DNA.

This publication has 1 reference indexed in Scilit: