Figure 6.

Stereoviews comparing the structures of the analogous metal binding sites in the GAAA duplex and the hammerhead ribozyme. (a) Base pairs C11.1·G10.1, G12·A9, and A13·G8 of domain II in the DNA–RNA hybrid hammerhead ribozyme (15). (b) Base pairs C4·G9*, G5·A8*, and A6·A7* are shown for the GAAA duplex The positions of the Mn²⁺ ions are indicated by crosses. The carbon and nitrogen atoms in the C4·G9* and G5·A8* base pairs of the GAAA duplex were superimposed on the corresponding atoms in the hammerhead ribozyme to obtain this common orientation.