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ポリケチド合成酵素モジュールの触媒サイクル中の構造的再配置

Jonathan R Whicher¹, Somnath Dutta², Douglas A Hansen³

¹1] Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, USA [2] Chemical Biology Graduate Program, University of Michigan, Ann Arbor, Michigan 48109, USA [3].

|June 27, 2014

まとめ

ポリケチド合成酶 (PKS) 酵素は,薬物を生成するためにモジュール式設計を使用します. PKS酵素の構造を視覚化して,アシルキャリアタンパク質 (ACP) が触媒サイクルを通して基質をどのように移動させるか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
自然製品合成自然製品の合成

背景:

ポリケチド合成酵素 (PKS) は,生物活性天然製品の広範囲の生産を担当する大規模な酵素複合体です.
これらの天然製品は,多くの医薬品にとって重要な支架です.
PKS酵素は,各モジュールが特定の改変を触媒するモジュール構造を備えています.

研究の目的:

触媒サイクル中の全長PKSモジュールの構造ダイナミクスを解明する.
基板の移転と処理におけるアシルキャリアタンパク質 (ACP) ドメインの役割を理解する.
触媒ドメインの構成変化,特にケトリデクタゼ (KRED) の構成変化についての洞察を提供するためです.

主な方法:

電子冷凍顕微鏡 (cryo-EM) を使用したピクロミシン PKS モジュールの3次元構造の決定.
液体染色学/フーリエ変換イオンサイクロトロン共振質量スペクトロメトリ (LC-FTICR-MS) による生化学状態の確認.
酵素サイクル全体を通してACPドメインと触媒ドメインの位置と動態を分析した.

主要な成果:

基板の負荷,β-ケトの中間物質の形成,およびβ-ヒドロキシ製品生成のキー段階で,PKSモジュールの明確な構造のスナップショットをキャプチャしました.
ケトシンタゼ (KS),アシルトランスファーゼ (AT),ケトリデクタゼ (KRED) ドメインとの連続相互作用のためのACPドメインの正確な位置づけが実証されました.
KRED領域で重要な形状的再配置が観察され,ACP限定の中間物質の削減のために最適化されました.

結論:

この研究は,PKSモジュール内の基板処理と転送のダイナミックなメカニズムを明らかにしています.
ACPと触媒領域の動きに関する構造的洞察は,PKSの機能を理解するために重要である.
発見は,新しいPKSモジュールの合理的な設計と,医薬品開発のためのエンジニアリングの経路を促進します.

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