タクサジーン合成酵素の構造と,テルペン生物合成におけるモジュール構造の進化
Mustafa Köksal1, Yinghua Jin, Robert M Coates
1Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, USA.
Nature
|December 17, 2010
まとめ
タクサジネ合成酵素 (TXS) の結晶構造は,ハイブリッドサイクラス構造を示している. この発見は,タクソール生物合成に不可欠な異なるテルペノイドサイクラゼのクラス間の進化的リンクを明らかにしています.
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
- 自然製品バイオシンセシス 自然製品バイオシンセシス
背景:
- 抗がん剤タクソールを含むテルペノイドは,多様な種類の天然製品です.
- タクソール生物合成は,タクサジーン合成酵素 (TXS) によってゲラニルゲラニル二酸化酸 (GGPP) のサイクル化を含む.
- TXSの構造を理解することは,Taxolの複雑な生物合成経路を解明する鍵です.
研究 の 目的:
- 断片化されたタクサジエン合成酵素 (TXS) 変異体のX線結晶構造を決定する.
- GGPPサイクリングとTaxol前駆体形成の構造的基礎を調査する.
- テルペノイドサイクラゼの異なるクラス間の進化的関係を調査する.
主な方法:
- TXSの構造を決定するために,X線結晶学を用いた.
- TXSの構造は,基質の類似体である13-aza-13,14-dihydrocopalyl diphosphateと2-fluorogeranylgeranyl diphosphateで複合されている.
- 三次元構造の分析により,ドメインの組織と触媒機構が明らかになった.
主要な成果:
- TXSの構造は,3つのアルファ-ヘリクルスドメインのユニークなモジュールアセンブリを示しています.
- C端末ドメインは,GGPP活性化のために3金属イオンクラスタを使用するクラスIテルペノイドサイクラースとして機能します.
- N端末と"挿入"ドメインは,残留のクラスIIテルペノイドサイクラゼの特徴的な折りたたみを採用する.
結論:
- TXSのハイブリッド構造は,異なるサイクラスクラスの進化的合併の直接的な証拠を提供します.
- この発見は,テルペノイド生物合成におけるメカニズム的および進化的経路に光を当てています.
- 構造的な洞察は,Taxol.のような貴重な天然製品の生産を理解するのに役立ちます.
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