Ribozymes

Abstract

Ribozymes are RNA molecules that can function to catalyze specific intracellular chemical reactions without the obligatory participation of proteins. Until recently, all biochemical reactions were believed to be catalyzed by protein enzymes. Since 1982, a number of RNA molecules have been found to be endowed with catalytic activity. For example, group I ribozymes take the form of introns, which can mediate their own excision from a self-splicing precursor RNA. Other ribozymes are derived from self-cleaving RNA structures that are essential for the replication of viral RNA molecules. Like protein enzymes, ribozymes can fold into complex three-dimensional structures that provide specific binding sites for substrates as well as cofactors, such as metal ions. Ribozymes have been developed into highly specific enzymes that are capable of recognizing and catalytically cleaving targeted RNA molecules. A wide variety of activities can be elicited from ribozymes by selection, and targeted ribozymes have been used scientifically and therapeutically to cleave viral RNAs and messenger RNAs associated with disease.