Figure 2. Calculated free energy profiles for TT or CPD damage flipping performed in the absence of the repair enzyme.
(A) Free energy of the flipping process for simulations on DNA duplexes without additional restraints on DNA. The regions with the central CPD damage in intra-helical conformation (near 30° along the reaction coordinate) and extra-helical (looped out) conformations are illustrated (stick representation, strands in different colors, central damage atom-color coded). (B) Calculated free energy for the flipping process with the terminal segments of the DNA restrained to B-DNA form. (C) Free energy for flipping process including restraints on terminal segments of the DNA to the repair enzyme bound form (but in the absence of the repair enzyme).