Nonenzymatic Template-Directed RNA Synthesis Inside Model Protocells

Abstract

Protecting Self-Replicating RNA? The potential for self-replication makes RNA an attractive candidate as a primordial catalysis in the origin of life. Catalysis may have occurred in some kind of compartment, possibly a fatty acid vesicle. However, RNA catalysis generally requires high levels of magnesium, which are incompatible with fatty acid vesicle integrity. Adamala and Szostak (p. 1098 ) screened magnesium chelators and found that several—including citrate, isocitrate, and oxalate—could maintain the membrane stability of fatty acid vesicles in the presence of Mg 2+ . Citrate also allowed Mg 2+ -dependent RNA synthesis within protocell-like vesicles, while at the same time protecting RNA from Mg 2+ -catalyzed degradation.