FIGURE 4.

Metal-binding sites in the catalytic core of the RNase P RNA. (A) Stereo view of the distribution of the core metal-binding sites in the context of the RNase P RNA structure. Highly conserved elements of the structure are highlighted: P4 (blue), J3/4 (orange), J5/15 (yellow), J15/15.1 (teal), CR IV (purple), and J19/4 (green). (B) Stereo view of cation binding at the major groove of helix P4 in the full-size RNase P RNA structure. Anomalous scattering by Pb²⁺ (contoured at 7σ, blue mesh) and Os(III) hexamine (5σ, red mesh) are shown. Highly conserved elements of the structure: (light blue) P4, (orange) J3/4, (light purple) CR IV, (light green) J19/4. (C) Stereo view of cation binding at the major groove of helix P4 in the Bst P7Δ structure. Anomalous scattering by Pb²⁺ (contoured at 8 σ, blue mesh) and Os(III) hexamine (7σ, red mesh), Sm³⁺ (8σ, teal), Gd³⁺ (4σ, purple), and Yb³⁺ (5σ, yellow) are shown. Conserved RNA structure elements are colored as above.