That DNA may react with reducing sugars in vitro has been shown long ago but it is a discovery of the last decade that reducing sugars may react with DNA in living organisms. In a chemical reaction, called the Maillard reaction (non-enzymatic glycation or glycation), the NH2 groups of primary amines react spontaneously (no catalysis) and reversibly with the carbonyl groups of glucose and other carbonyl compounds to form Schiff bases (aldimines). Then, at neutral pH, the Schiff bases undergo an intramolecular rearrangement to more stable Amadori products (APs) (ketoamines). In the late stage of the Maillard reaction, because of additional chemical transformations, APs give rise to the so-called advanced glycation end products (AGEs). In previous studies we have demonstrated that the chromosomal DNA of Escherichia coli K-12 accumulates both APs and AGEs under normal growth conditions and that these DNA adducts represent an important endogenous source of spontaneous mutations in E. coli. The repair of DNA modified with APs and AGEs is poorly studied. As far as APs are AGEs precursors, we supposed that E. coli may have mechanisms for repair of APs damaged DNA, because maturing of APs to AGEs results in DNA structural alterations and mutability. Indeed, we have observed that E. coli lyses are capable of catalyzing the removal of APs derived from the interaction of DNA with glucose 6-phospate. In this study, we report data from experiments designed to identify the carrier(s) of the observed DNA repair activity.
Acknowledgements: NSF Contract № DN 01/5/16.12.2016