Synthesis of cysteine-containing dipeptides by aminpacyl-tRNA synthetases

Hieronim Jakubowski

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20 Scopus citations


Arglnyl-tRNA synthetase (ArgRS) catalyses AMP- and PP1independent deacylation of Arg-tRNAArg9 in the presence of cysteine. A dipeptide, Arg-Cys, is a product of this deacylation reaction. Similar reaction with homocysteine yields Arg-Hcy. Arginine is a noncompetitive inhibitor of the cysteine-dependent deacylation which indicates that cysteine binds to the enzyme-Arg-tRNAArg.9 complex at a site separate from the arginine binding site. In the presence of arginine, [14C]Arg-tRNAArg is deacylated at a rate similar to the rate of its spontaneous deacylation in solution and [14C]arginine is a product. Experiments with cysteine derivatives indicate that the -SH group is essential for the reaction whereas -NH2 and -COOH groups are not. Thloesters of arginine are formed with 3-mercaptopropionic acid, N-acetyl-L-cysteine and dithiothreitol. These data suggest that formation of the dipeptide Arg-Cys involves a thioester intermediate, S->L-arginyl)- L-cysteine, which is not observed because of the rapid rearrangement to form a stable peptide bond. Facile intramolecular reaction results from the favorable geometric arrangement of the a-amino group of cysteine with respect to the thioester formed in the initial reaction. Similar reactions, yielding Ile-Cys and Val-Cys, are catalyzed by isoleucyl- and valyl-tRNA synthetases, respectively.

Original languageEnglish (US)
Pages (from-to)4608-4615
Number of pages8
JournalNucleic acids research
Issue number22
StatePublished - 1995
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Genetics


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