Elongation factor G is a critical target during oxidative damage to the translation system of Escherichia coli

Takanori Nagano, Kouji Kojima, Toru Hisabori, Hidenori Hayashi, Eugene Hayato Morita, Takashi Kanamori, Tomoko Miyagi, Takuya Ueda, Yoshitaka Nishiyama

研究成果: Article

14 被引用数 (Scopus)

抄録

Elongation factor G (EF-G), a key protein in translational elongation, is known to be particularly susceptible to oxidation in Escherichia coli. However, neither the mechanism of the oxidation of EF-G nor the influence of its oxidation on translation is fully understood. In the present study, we investigated the effects of oxidants on the chemical properties and function of EF-G using a translation system in vitro derived from E. coli. Treatment of EF-G with 0.5 mM H 2O 2 resulted in the complete loss of translational activity. The inactivation of EF-G by H 2O 2 was attributable to the oxidation of two specific cysteine residues, namely, Cys 114 and Cys 266, and subsequent formation of an intramolecular disulfide bond. Replacement of Cys 114 by serine rendered EF-G insensitive to oxidation and inactivation by H 2O 2. Furthermore, generation of the translation system in vitro with the mutated EF-G protected the entire translation system from oxidation, suggesting that EF-G might be a primary target of oxidation within the translation system. Oxidized EF-G was reactivated via reduction of the disulfide bond by thioredoxin, a ubiquitous protein that mediates dithiol-disulfide exchange. Our observations indicate that the translational machinery in E. coli is regulated, in part, by the redox state of EF-G, which might depend on the balance between the supply of reducing power and the degree of oxidative stress.

本文言語English
ページ(範囲)28697-28704
ページ数8
ジャーナルJournal of Biological Chemistry
287
34
DOI
出版ステータスPublished - 2012 8 17

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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