Figure 1.

NEIL1 can excise 5caC from DNA: The glycosylase activities of NEIL1 or the control P2T variant were tested using dsDNA substrates (200 nM enzyme, 20 nM dsDNA). The ³²P radiolabelled strand contained the indicated base in position 20, placed opposite a G base in the complementary strand. After the enzymatic reaction (37 °C, 60 min), samples were subjected to alkaline conditions to break DNA strands at AP-sites. DNA was analysed by denaturing gel electrophoresis and visualized by autoradiography. The 5′ cleavage product of NEIL1 glycosylase activity on the 5caC containing DNA is marked by an arrow. In this and the following figures, “-” designates the absence of enzyme.