バクテリアのTIMバレルプレニルトランスファーゼの2つの異なるメカニズム
Emma H Doud1, Deborah L Perlstein, Manuel Wolpert
1Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02139, United States.
Journal of the American Chemical Society
|January 11, 2011
まとめ
2つの細菌のプレニルトランスファーゼ (PT) は,異なる反応機構を示しています. MoeO5は前例のないイソメリゼーション経路を使用し,PcrBはグリセロール-1-ホスファート (G1P) をプレニラートする最初の細菌酵素である.
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
- 分子生物学は分子生物学である.
背景:
- プレニルトランスフェラーゼ (PT) は,様々なイソプレノイド化合物を合成する際に重要な酵素である.
- TIMバレルの折り畳みは,PTsを含む多くの酵素に見られる一般的な構造モチーフです.
- PT反応メカニズムの理解は,代謝経路と酵素進化の洞察を提供します.
研究 の 目的:
- バクテリアの2つのTIMバレルプレニルトランスフェラーゼ,MoeO5とPcrBの反応機構を調査する.
- これらの酵素の基板特異性と触媒経路を解明する.
- TIMバレルファミリー内の異なるPTによって採用される異なるメカニズムを比較する.
主な方法:
- MoeO5とPcrB.の活性を特徴付けるために,酵素動力学アッセイが行われました.
- 質量スペクトロメトリーおよびNMRスペクトロスコーピーを用いた製品分析により,反応中介物質および製品が特定されました.
- サイト・ディレクテッド・ミュータゲネシスは,触媒作用に関わる主要な残留物を探査するために使用されました.
主要な成果:
- MoeO5は,ネロリジルパイロフォスファート中間体への前例のない異体化を経由して,ファルネシルから3フォスフォグリセリック酸 (3PG) への転移を触媒化する.
- PcrBは,ゲラニルおよびゲラニルゲラニル基でグリセロール-1-フォスファート (G1P) をプレニラートする最初の細菌酵素として特定されています.
- PcrBの反応メカニズムは,異体化なしに直接のプレニル移転を含み,プレニルドナーのトランスアリル結合を保持します.
結論:
- バクテリアのTIMバレルプレニルトランスフェラーゼは,驚くべきメカニズム的多様性を表しています.
- MoeO5は,以前に知られているメカニズムとは異なる,プレニル転送のための新しい反応経路を採用しています.
- PcrBは,細菌のPTsの既知の基板範囲を拡大し,MoeO5.5と比較して異なる触媒戦略を使用しています.
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