Fluorine‐19 NMR studies of the thermal unfolding of 5‐fluorouracil‐substituted Escherichia coli valine transfer RNA

FEBS Letters

Chu, Wen-Chy¹  Horowitz, Jack¹ 

[1] Department of Biochemistry and Biophysics, Iowa State University, Ames, Iowa 50011, USA

关键词: 19F NMR;    Fluorouracil;    Transfer RNA;    Thermal unfolding;    Escherichia coli;    NMR;    nuclear magnetic resonance;    FUra;    5-fluorouracil;    (FUra)tRNAVal;    5-fluorouracil-substituted E. coli tRNAVal;   

DOI  :  10.1016/0014-5793(91)81408-Z

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

¹⁹F NMR spectroscopy was used to monitor the thermal unfolding of E. coli tRNA^Val labeled by incorporation of 5-fluorouracil (FUra). With rising temperatures, resonances in the ¹⁹F NMR spectrum of (FUra)tRNA^Val gradually shift towards the central region of the spectrum and merge into a single broad peak above 85°C. FU55 and FU12 are the first to shift, beginning at temperatures below 40°C, which suggests that the initial steps of thermal denaturation of tRNA^Val involve disruption of the tertiary interactions between the D- and T-arms. The acceptor stem and the FU64-G50 wobble base pair in the T-stem are particularly stable to thermal denaturation. A temperature-dependent splitting of the ¹⁹F resonance assigned to FU64, at temperatures above 40°C, suggests that the T-arm of (FUra)tRNA^Val exists in two conformations in slow exchange on the NMR time scale.

【 授权许可】

Unknown