Metal ion requirements in artificial ribozymes that catalyze aminoacylation and redox reactions.

The means of in vitro selection has yielded a number of artificial ribozymes with functions that have not been discovered as yet in modern biological systems. Like naturally occurring ribozymes, most artificial ribozymes also use metal ions for the support of catalysis. Here we choose two such ribozymes, flexizyme and ribox, that exhibit specific activities of tRNA aminoacylation and redox chemistry, respectively, and comprehensively summarize the roles of metal ions in conjunction with their structure and function.