(C) (Left panel) 8-oxo-dG (green) preferentially adopts the pro-mutagenic syn-conformation. A simulated annealing Fo-Fc omit density map is shown for 8-oxo-dG (contoured at 3σ). (Right panel) 8-oxo-dG(anti) (black, modeled using 2PFO) was overlayed with the Fo-Fc omit density map. In the anti-conformation, the C8-carbonyl would directly clash with the 5′-phosphate (red-dotted line). 