Escherichia coli tRNA4Arg(UCU) induces a constrained conformation of the crucial Ω-loop of arginyl-tRNA synthetase

Yong Neng Yao, Qing Shuo Zhang, Xian Zhong Yan, Guang Zhu, En Duo Wang

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

Previous investigations show that tRNAArg-induced conformational changes of arginyl-tRNA synthetase (ArgRS) Ω-loop region (Escherichia coli (E. coli), Ala451-Ala457) may contribute to the productive conformation of the enzyme catalytic core, and E. coli tRNA2 Arg(ICG)-bound and -free conformations of the Ω-loop exchange at an intermediate rate on NMR timescale. Herein, we report that E. coli ArgRS catalyzes tRNA2Arg(ICG) and tRNA4 Arg(UCU) with similar efficiencies. However, 19F NMR spectroscopy of 4-fluorotryptophan-labeled E. coli ArgRS reveals that the tRNA4Arg(UCU)-bound and -free conformations of the Ω-loop region interconvert very slowly and the lifetime of bound conformation is much longer than 0.33ms. Therefore, tRNA4 Arg(UCU) differs from tRNA2Arg(ICG) in the conformation-exchanging rate of the Ω-loop. Comparative structure model of E. coli ArgRS is presented to rationalize these 19F NMR data. Our 19F NMR and catalytic assay results suggest that the tRNA Arg-induced conformational changes of Ω-loop little contribute to the productive conformation of ArgRS catalytic core.

Original languageEnglish (US)
Pages (from-to)129-134
Number of pages6
JournalBiochemical and Biophysical Research Communications
Volume313
Issue number1
DOIs
StatePublished - Jan 2 2004

Keywords

  • Aminoacyl-tRNA synthetase
  • ArgRS
  • Arginine
  • Comparative modeling
  • argU
  • tRNA

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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