オキシリピン生物合成酵素の進化経路に関する構造的洞察
Dong-Sun Lee1, Pierre Nioche, Mats Hamberg
1Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston, Texas 77030, USA.
Nature
|August 22, 2008
まとめ
研究者らは,アレン酸化合成酵素 (AOS) が植物から揮発性物質を生成するメカニズムを解明した. 構造的な洞察は,AOS活性部位を改変することで,緑葉の揮発性 (GLV) 酵素に変換され,オキシリピン進化に意味を持つことを明らかにしました.
科学分野:
- バイオケミストリー バイオケミストリー
- 構造生物学 構造生物学とは
- 植物科学 植物科学について
背景:
- オキシリピン経路は,ジャスモネートと緑葉の揮発性物質 (GLV) を合成し,植物防御と香りにとって不可欠です.
- アレーン酸化合成酵素 (AOS) とヒドロペロキシドライアゼは,この経路における重要な酵素であるが,それらの基板再配置機構は不明である.
研究 の 目的:
- アラビドプシス・サリアナ (AOS) の結晶構造を決定するために.
- ジャスモナートとGLVsの生産におけるAOSの触媒メカニズムを解明する.
- オキシリピン生物合成遺伝子の進化史を調査する.
主な方法:
- アラビドプシス・タリアナ (AOS) のX線結晶学 (自由と複合同類).
- AOS活性サイト残留物のサイト指向型変異.
- 種間の関連酵素のバイオ情報学および生化学分析.
主要な成果:
- AOSの結晶構造は,ラジカル/カチオン中間物質を制御する芳香性Piシステムを持つ異常な活性部位を明らかにした.
- 主要な活性部位残留物の変異により,AOSはGLV生物合成酵素に変換された.
- 進化論的分析は,細菌,サンゴ,およびアンフィオクサスで同類酵素を特定し,古代の起源を示唆しました.
結論:
- この研究は,AOSのメカニズム的理解と,オキシリピン生物合成におけるその二重の役割を提供します.
- 酵素工学では,ジャスモネートとGLVの生産の間にAOS機能を切り替えることができます.
- オキシリピン生物合成遺伝子は,植物と動物の共通の祖先に存在する,深い進化の歴史を持っています.
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