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Substrate-induced conformational changes in Escherichia coli arginyl-tRNA synthetase observed by 19F NMR spectroscopy
Yong-Neng Yao1, Qing-Shuo Zhang, Xian-Zhong Yan
1State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences, 320 Yue Yang Road, 200031, Shanghai, PR China.
Abstract:
The 19F nuclear magnetic resonance (NMR) spectra of 4-fluorotryptophan (4-F-Trp)-labeled Escherichia coli arginyl-tRNA synthetase (ArgRS) show that there are distinct conformational changes in the catalytic core and tRNA anticodon stem and loop-binding domain of the enzyme, when arginine and tRNA(Arg) are added to the unliganded enzyme. We have assigned five fluorine resonances of 4-F-Trp residues (162, 172, 228, 349 and 446) in the spectrum of the fluorinated enzyme by site-directed mutagenesis. The local conformational changes of E. coli ArgRS induced by its substrates observed herein by 19F NMR are similar to those of crystalline yeast homologous enzyme.