現代の (+) - ゲルマクリーンAシンタゼからα-ヒュームレンシンタゼの再構築による進化的および機械的洞察
Veronica Gonzalez1, Sabrina Touchet, Daniel J Grundy
1School of Chemistry and ‡Cardiff Catalysis Institute, School of Chemistry, Cardiff University , Main Building, Park Place, Cardiff CF10 3AT, United Kingdom.
Journal of the American Chemical Society
|September 18, 2014
まとめ
ゲルマクレンA合成酵素 (GAS) の活性については,活性部位の残基を変化させることで調査した. GASにおけるグリシン402の置換とGDSにおけるグリシン404は,セスクイテルペン合成酵素の進化経路を明らかにした.
科学分野:
- バイオケミストリー バイオケミストリー
- 酵素学 酵素学とは
- 有機化学 オーガニック・ケミストリー
背景:
- セスクイターペン合成酵素 (SPSs) は,植物二次代謝における重要な酵素である.
- ソリダゴ・カナデンシスのゲルマクレンA合成酵素 (GAS) は,通常,1,10-サイクル化によって (+) -ゲルマクレンAを生成する.
- 軽微な製品であるα-humuleneは1,11-cyclizationから発生し,二重活性の可能性を示唆しています.
研究 の 目的:
- GAS.における1,10-対1,11-サイクライゼーションの選択性の構造的およびメカニズム的基礎を調査する.
- 1,10-および1,11-セスクイターペンの合成酵素の間の進化的関係を調査する.
- 循環経路の制御における特定の活性部位残留物の役割を理解する.
主な方法:
- 1,10-および1,11-合成酵素のアミノ酸配列の並べ替え.
- GASのX線結晶学とホモロジーモデリング.
- GAS (Gly402) とGDS (Gly404) のサイト指向型変異.
- 同位体ラベル付きファルネシル二酸化物 (FDP) とデウテリウムラベルを使用したメカニズム研究.
主要な成果:
- GASにおけるThr401-Gly402-Gly403トライアードの特定は,1,10-サイクル化に潜在的に責任がある.
- GASにおけるGly402の変異は,徐々に1,11-サイクライゼーション活動を増加させました.
- GDSにおけるGly404の変異は,バイサイクロゲルマクレンを生成し,二重の1,10-1,11-サイクル化を示した.
- 機械学的研究は,経路を結びつけるゲルマクレン-ヒューミュレンの再配置を支持した.
結論:
- Gly402は,GASの1,10-対1,11-サイクルを制御する機能的なスイッチとして機能します.
- 厳格な機能を持つ酵素は,小さな置換を経て,より少ない特異性の祖先から進化することがあります.
- ゲルマクレネとヒューミュレネの反応経路は,共通の中間物質を通じて潜在的に結びついている.
- 現代の1,10-シンタゼは,乱交的な1,11-セスクイターペンのシンタゼから進化したのかもしれない.
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