Figure 3: SB100X structure explains previous hyperactive mutations.

(a) The TCC model with catalytic domain residues mutated for the generation of SB100X shown in yellow. The localization of the interactions shown in (b,c) is indicated by red and orange rectangles, respectively. (b) H243 stabilizes the catalytic core (red) via π-stacking with H249 (indicated with dashed lines). (c) Residues 214DAVQ217 stabilize a flexible loop (including I212) and tether it to the tDNA-binding surface. Dashed lines indicate hydrogen bonds.