Figure 7.
Divalent metal ions are not essential for Trm10 catalytic activity. (A) ScTrm10 methylation activity on tRNAGly was measured in the presence of varied concentration of EDTA in the assay. The percent conversion of the labeled G9 to m1G9 catalyzed by 4 nM ScTrm10 was measured as described in methods and plotted versus [EDTA]. (B) Time courses of m1G9 methylation activity catalyzed by ScTrm10 purified under metal-free conditions on G9-tRNAPhe. Percent product formed under these single turnover conditions was plotted and fit to Equation (2) to yield the indicated kobs (shown in parentheses) for catalysis in the absence and presence of Mg2+ in the reactions; NE is no enzyme control.