The Adaptor hypothesis revisited

As originally postulated in Crick's Adaptor hypothesis, the faithful synthe sis of proteins from messenger RNA is dependent on the presence of perfectl y acylated tRNAs. The hypothesis also suggested that each aminoacyl-tRNA wo uld be made by a unique enzyme. Recent data have now forced a revision of t his latter point, with an increasingly diverse array of enzymes and pathway s being implicated in aminoacyl-tRNA synthesis. These unexpected findings h ave far-reaching implications for our understanding of protein synthesis an d its origins.