Direct Raman Measurement of an Elevated Base pK_a in the Active Site of a Small Ribozyme in a Precatalytic Conformation

摘要

Catalytic RNA molecules can be found at the heart of many essential biological reactions. It has been posited that such ribozymes can achieve rate acceleration by shifting base pK_a values, by providing functional groups for general acid/base catalysis, by coordinating water molecules for specific acid/base catalysis, and by providing electrostatic stabilization of high-energy intermediates. Although these chemical transformation strategies are similar to those utilized by protein enzymes, the limited chemical repertoire of RNA would appear to place it at a significant disadvantage. A major challenge to the field is to elucidate how ribozymes gain biological functionality by forging structure-function relationships.