イソブタノールによる酵母の生育阻害メカニズムを解明～次世代バイオ燃料の高効率生産につながる新たな知見～

2026-06-30 京都工芸繊維大学

本研究成果の概要

＜関連情報＞

• https://www.kit.ac.jp/2026/06/news260630/
• https://www.kit.ac.jp/wp/wp-content/uploads/2026/06/news260630.pdf
• https://www.jbc.org/article/S0021-9258(26)02100-9/fulltext

サッカロミセス・セレビシエにおけるイソブタノールによる増殖阻害の分子標的としてのロイシルtRNA合成酵素 Leucyl-tRNA Synthetase as a Molecular Target of Isobutanol-Mediated Growth Inhibition in Saccharomyces cerevisiae

Mano Hasegawa ∙ Nodoka Oshimura ∙ Kaho Hitomi ∙ Ayako Furukawa ∙ Kenji Sugase ∙ Kouichi Kuroda
Journal of Biological Chemistry  Published:June 4, 2026
DOI:https://doi.org/10.1016/j.jbc.2026.113228

Abstract

Our dependence on fossil fuels and ongoing environmental degradation urgently require sustainable energy solutions. Biofuels that do not rely on fossil resources have attracted significant scientific interest. Among these, isobutanol produced by yeast is a promising next-generation biofuel owing to its high energy density and compatibility with existing fuel infrastructure. However, the inherent intolerance of yeast to isobutanol constrains its production, posing a major barrier to the large-scale implementation of bio-based isobutanol. Here, we provide compelling evidence that supplementation with excess branched-chain amino acids (BCAAs), particularly leucine, alleviates isobutanol-induced growth inhibition in yeast. Using saturation transfer difference nuclear magnetic resonance (STD-NMR) spectroscopy and structural modeling, we showed that isobutanol directly interacts with cytoplasmic leucyl-tRNA synthetase (LeuRS), acting as a competitive inhibitor of leucine binding. Collectively, these findings reveal the mechanistic basis by which isobutanol inhibits yeast growth, offering new insights into enhancing isobutanol tolerance and increasing isobutanol biosynthesis in yeast.