Fig. 5.

DME and ROS1 process 5-meC by a DNA glycosylase/lyase mechanism proceeding through a transient imine intermediate. Double-stranded oligonucleotide substrates containing a C·G, 5-meC·G, or 8-oxoG·C pair in a CpG context were incubated with purified DME (lanes 1, 4, and 7), ROS1 (lanes 2, 5, and 8), or AtOGG1 (lanes 3, 6, and 9) in the presence of NaBH₄. After incubation, the reaction mixture was subjected to SDS/PAGE, and products were visualized by autoradiography. Free substrates and crosslinked enzyme–substrate complexes are indicated by arrows. M, 5-meC; O, 8-oxoG.