Figure 3.

Observed conformations of the U/U base pairs. In simulations, the cWW U13/U18 base pair possessed either two direct H-bonds (top, conformation 2a) or one direct and one water-mediated H-bond (top middle, conformation 1a). Both possible symmetry variants of the cWW U10/U21 base pair (conformations 2a and 2b, and their water-mediated variants 1a and 1b) were observed in simulations of the NSR in the absence of RIO. In the presence of RIO only conformations 2a and 1a were observed. The dashed black lines indicate H-bonds.