Coding of Class I and II Aminoacyl-tRNA Synthetases.

ABSTRACT: The aminoacyl-tRNA synthetases and their cognate transfer RNAs translate the universal genetic code. The twenty canonical amino acids are sufficiently diverse to create a selective advantage for dividing amino acid activation between two distinct, apparently unrelated superfamilies of synthetases, Class I amino acids being generally larger and less polar, Class II amino acids smaller and more polar. Biochemical, bioinformatic, and protein engineering experiments support the hypothesis that the two Classes descended from opposite strands of the same ancestral gene. Parallel experimental deconstructions of Class I and II synthetases reveal parallel losses in catalytic proficiency at two novel modular levels-protozymes and Urzymes-associated with the evolution of catalytic activity. Bi-direct

SUBMITTER: Carter CW 

PROVIDER: S-EPMC5927602 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature