Functional independence of microhelix aminoacylation from anticodon binding in a class I tRNA synthetase

S. Kim, P. Schimmel

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

The monomeric form of the class I Escherichia coli methionine tRNA synthetase has a distinct carboxyl-terminal domain with a segment that interacts with the anticodon of methionine tRNA. This interaction is a major determinant of the specificity and efficiency of aminoacylation. The end of this carboxyl-terminal domain interacts with the amino-terminal Rossman fold that forms the site for amino acid activation. Thus, the carboxyl-terminal end may have evolved in part to integrate anticodon recognition with amino acid activation. We show here that internal deletions that disrupt the anticodon interaction have no effect on the kinetic parameters for amino acid activation. Moreover, an internally deleted enzyme can aminoacylate an RNA microhelix, which is based on the acceptor stem of methionine tRNA, with the same efficiency as the native protein. These results suggest that, in this enzyme, amino acid activation and acceptor helix aminoacylation are functionally integrated and are independent of the anticodon-binding site.

Original languageEnglish
Pages (from-to)15563-15567
Number of pages5
JournalJournal of Biological Chemistry
Volume267
Issue number22
Publication statusPublished - 1992

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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