E. coli Ada regulatory protein repairs the Sp diastereoisomer of alkylated DNA

Abstract
Using HPLC and 31 P NMR spectroscopy on a chemically synthesized asymmetric mixture of the diastereoisomers of thymidyl(3' → 5')thymidyl- O -methyl phosphate absolute configuration has been correlated with Chromatographic mobility. The methyl phosphotriester system in alkylated DNA which is repaired by the Ada regulatory protein of E. coli has consequently been established to possess the S p configuration.