Shifted positioning of the anticodon nucleotide residues of amber suppressor tRNA species by Escherichia coli arginyl-tRNA synthetase

Daisuke Kiga, Kensaku Sakamoto, Saori Sato, Ichiro Hirao, Shigeyuki Yokoyama

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Cytidine in the anticodon second position (position 35) and G or U in position 36 of tRNA Arg are required for amino-acylation by arginyl-tRNA synthetase (ArgRS) from Escherichia coli. Nevertheless, an arginine-accepting amber suppressor tRNA with a CUA anticodon (FTOR1Δ26) exhibits suppression activity in vivo [McClain, W.H. & Foss, K. (1988) Science, 241, 1804-1807]. By an in vitro kinetic study with mutagenized tRNAs, we showed that the arginylation of FTOR1Δ26 involves C34 and U35, and that U35 can be replaced by G without affecting the activity. Thus, the positioning of the essential nucleotides for the arginylation is shifted to the 5′ side, by one residue, in the suppressor tRNAArg. We found that the shifted positioning does not depend on the tRNA sequence outside the anticodon. Furthermore, by a genetic method, we isolated a mutant ArgRS that aminoacylates FTOR1Δ26 more efficiently than the wild-type ArgRS. The isolated mutant has mutations at two nonsurface amino-acid residues that interact with each other near the anticodon-binding site.

Original languageEnglish
Pages (from-to)6207-6213
Number of pages7
JournalEuropean Journal of Biochemistry
Volume268
Issue number23
DOIs
Publication statusPublished - 2001 Dec 22
Externally publishedYes

Keywords

  • Aminoacyl-tRNA synthetase
  • Anticodon
  • Genetic screen
  • Kinetic analysis
  • tRNA identity

ASJC Scopus subject areas

  • Biochemistry

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