FIGURE 2.

The DEDD-Y active site of RRP6. (A) hR6^CAT D313N¹ mutant with Mg. Active-site residues D313N, E315, D371, D440, and Y436 are shown coordinating one of the magnesium ions Mg^B, depicted as a green sphere. Also shown are residues D404 and H316. (B) yR6^CAT Y361A-AMP bound structure. D238, E240, D296, D365, and Y361A are shown coordinating two manganese atoms Mn^A and Mn^B (purple spheres) and the end product AMP. Also shown are residues A329 and H241. (C) hR6^CAT D313N² mutant with Y. Active-site residues D313N, E315, D371, D440, and Y436 are shown. Residue D440 is depicted coordinating an yttrium (shown as a cyan sphere) with D404 and D440. (D) hR6^CAT Y436A mutant with two magnesiums. Active-site residues D313, E315, D371, D440, and Y436A are shown coordinating the two magnesium ions: Mg^A and Mg^B (green spheres). All waters are shown as red spheres.