Theoretical and experimental considerations on the hammerhead ribozyme reactions: divalent magnesium ion mediated cleavage of phosphorus-oxygen bonds

Theoretical studies using ab initio calculations and kinetic experiments demonstrate the ability of magnesium ion to cleave a phosphorus-oxygen bond by directly coordinating with the translating oxygen. This direct coordination favors the second step of the hammerhead ribozyme reactions. A comparative study of the stabilities of oxyphosphoranes with different ionic valences reveals that stability is increased by the protonation of a dianionic species.