UTILIZATION OF COFACTORS EXPANDS METABOLISM IN A NEW RNA WORLD

RNA has been hypothesized to have preceded proteins as the major catal ysts of the biosphere, yet there are only a very limited number of che mical reactions that are known to be catalyzed by modern RNA. Cofactor s are used by the majority of protein enzymes to supply additional fun ctional groups to the active site. RNA should also be able to utilize some of these same cofactors to extend its own catalytic potential. We describe here how it could be possible to use selection - amplificati on from a population of random RNA to obtain a coenzyme A mediated RNA transacylase. Exploitation of some of the sulphur chemistry mediated by coenzyme A could have significantly expanded a prebiotic RNA direct ed metabolism.