Figure 10.

Base pair stacking interactions determined from structural refinements using rMD calculations restrained by NMR-derived distance and torsion angles for the cis-5R,6S-Tg-adducted duplex containing the Tg⁶·G¹⁹ mismatch pair. The left panel shows stacking interactions when Tg⁶ CH₃ is in the axial conformation (PDB ID 2KH7). The right panel shows stacking interactions when Tg⁶ CH₃ is in the equatorial conformation (PDB ID 2KH8). In both instances, the Tg⁶ base shifts toward the major groove, into a wobble orientation with G¹⁹ in the complementary strand, but both Tg⁶ and G¹⁹ remain stacked into the duplex.