NMR Analyses of the Conformations of L-Isoleucine and L-valine Bound to Escherichia coli Isoleucyl-tRNA Synthetase

Daisuke Kohda, Gota Kawai, Shigeyuki Yokoyama, Tatsuo Miyazawa, Daisuke Kohda, Makoto Kawakami, Shoji Mizushima

研究成果: Contribution to journalArticle査読

18 被引用数 (Scopus)

抄録

The 400-MHz 1 H NMR spectra of L-isoleucine and L-valine were measured in the presence of Escherichia coli isoleucyl-tRNA synthetase (IleRS). Because of chemical exchange of L-isoleucine or L-valine between the free state and the IleRS-bound state, a transferred nuclear Overhauser effect (TRNOE) was observed among proton resonances of L-isoleucine or L-valine. However, in the presence of isoleucyl adenylate tightly bound to the amino acid activation site of IleRS, no TRNOE for L-isoleucine or L-valine was observed. This indicates that the observed TRNOE is due to the interaction of L-isoleucine or L-valine with the amino acid activation site of IleRS. The conformations of these amino acids in the amino acid activation site of IleRS were determined by the analyses of time dependences of TRNOEs and TRNOE action spectra. The IleRS-bound L-isoleucine takes the gauche + form about the C α -C β bond and the trans form about the C β -C γ1 bond. The IleRS-bound L-valine takes the gauche - form about the C α -C β bond. Thus, the conformation of IleRS-bound L-valine is the same as that of IleRS-bound L-isoleucine except for the δ-methyl group. The side chain of L-isoleucine or L-valine lies in an aliphatic hydrophobic pocket of the active site of IleRS. Such hydrophobic interaction with IleRS is more significant for L-isoleucine than for L-valine. The TRNOE analysis is useful for studying the amino acid discrimination mechanism of aminoacyl-tRNA synthetases.

本文言語英語
ページ(範囲)6531-6538
ページ数8
ジャーナルBiochemistry
26
20
DOI
出版ステータス出版済み - 1 1 1987
外部発表はい

All Science Journal Classification (ASJC) codes

  • 生化学

フィンガープリント

「NMR Analyses of the Conformations of L-Isoleucine and L-valine Bound to Escherichia coli Isoleucyl-tRNA Synthetase」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

引用スタイル