title: Phenylalanyl-tRNA synthetase and isoleucyl-tRNA Phe : a possible verification mechanism for aminoacyl-tRNA.
abstract: The synthesis of isoleucyl-tRNA(Phe) (Escherichia coli) proceeds at an appreciable rate under normal in vitro conditions in the presence of isoleucyl-tRNA synthetase (EC 6.1.1.5) from E. coli. The misacylated product is shown here to be hydrolyzed by highly purified phenylalanyl-tRNA synthetase from E. coli, with release of isoleucine and active tRNA(Phe). Thus, phenylalanyl-tRNA synthetase possesses a previously unrecognized activity, which deacylates a mistakenly acylated tRNA(Phe); the enzyme is inactive toward correctly matched aminoacyl tRNAs. Such a mechanism could serve to verify aminoacyl-tRNAs, deacylating those that are misacylated. Thus, a common generalization needs to be modified: an amino acid is not necessarily committed to a given (incorrect) anticodon when it is incorporated into aminoacyl-tRNA. It may be possible to correct it thereafter.
mesh_terms: D000215:Acylation; D000249:Adenosine Monophosphate; D000255:Adenosine Triphosphate; D000596:Amino Acids; D000604:Amino Acyl-tRNA Synthetases / Q000302:isolation & purification; D002247:Carbon Isotopes; D002384:Catalysis; D002845:Chromatography; D002855:Chromatography, Thin Layer; D004926:Escherichia coli / Q000201:enzymology*; D006868:Hydrolysis; D006882:Hydroxyapatites; D007532:Isoleucine; D007700:Kinetics; D008433:Mathematics; D009573:Nitrites; D010649:Phenylalanine; D012343:RNA, Transfer; D046249:Transfer RNA Aminoacylation; D014316:Tritium
chemical_list: D000596:Amino Acids; D002247:Carbon Isotopes; D006882:Hydroxyapatites; D009573:Nitrites; D007532:Isoleucine; D014316:Tritium; D000249:Adenosine Monophosphate; D010649:Phenylalanine; D000255:Adenosine Triphosphate; D012343:RNA, Transfer; D000604:Amino Acyl-tRNA Synthetases