Mutant enzymes and dissected tRNAs that elucidate motifs for protein-RNA recognition

Domains in RNAs and aminoacyl tRNA synthetases that mutually interact have been identified by structural, biochemical and genetic methods. Altered specificity has been demonstrated by amino acid substitutions in the domains of synthetases that interact with the distinct anticodon-helix-and acceptor-helix-containing domains of tRNA. Further clarification of the contribution of specific structural elements to overall recognition has been achieved using dissected tRNA molecules which recreate the acceptor helix subdomain. Unsolved problems include evaluating the relative contributions to overall recognition of the interactions of synthetases with individual domains of the tRNA structure, and distinguishing between essential and non-essential components.