In vivo DNA damage impacts the genetic stability of an organism; therefore, multiple pathways utilizing a large number of enzymes have evolved to repair DNA damage. This unit focuses on enzymes involved in base excision repair (BER). The BER enzymes possessing N-glycosylase activity can find and remove a wide variety of damaged bases in a sea of normal bases. The combination of unique substrate specificity, accuracy, and robust in vitro activity of many of these enzymes has led to their use in various experimental techniques, including site-specific DNA cleavage. The enzymes described in this unit are active on many substrates including oxidized purines and pyrimidines, alkylated bases, abasic sites, pyrimidine dimers, deaminated cytosines, and deaminated adenines.
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