FIGURE 4.

Pb²⁺-induced cleavage sites mapped onto the structure of the specificity domain of RNase P RNA. Pb²⁺-induced cleavage sites Ia, Ib, IIa, and IIb were mapped onto the structure of the specificity domain of Thermus thermophilus RNase P RNA. The cleavage positions within the backbone are indicated in black (yellow arrows). (Inset) Distances in A° between the Pb²⁺ induced cleavage sites Ia, Ib, IIa, and IIb in the specificity domain (see Fig. 1 and text for details).