Isotope effect analyses provide evidence for an altered transition state for RNA 2'-O-transphosphorylation catalyzed by Zn(2+).

Solvent D2O and (18)O kinetic isotope effects on RNA 2'-O-transphosphorylation catalyzed by Zn(2+) demonstrate an altered transition state relative to specific base catalysis. A recent model from DFT calculations involving inner sphere coordination to the non-bridging and leaving group oxygens is consistent with the data.