Figure 2.

The proposed base pairs between a deprotonated modified U and a G proposed in the present study (a and b) and the conventional wobble U–G pair (c). (a) The proposed xnm⁵U*^-–G pair with the Watson–Crick configuration; (b) the alternative xnm⁵U*^-–G pair with the xnm⁵U*^- displaced toward the minor groove side from the Watson–Crick configuration; (c) the conventional wobble U-G pair. The sulfur atom in (a) and (b) could be substituted with an oxygen atom, and the negative charge could be delocalized within the π-electron system.