ニトロソシンタゼが誘発した酸化性炭素-炭素結合の裂け方は,バウミシン生物合成における
Ahmad Al-Mestarihi1, Anthony Romo, Hung-wen Liu
1Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, USA.
Journal of the American Chemical Society
|July 27, 2013
まとめ
抗癌薬であるダウノルビシンとドクソルビシンと関連しているバウミシンには,異常な糖分が含まれています. DnmZ酵素は,新しいレトロオキシム-アルドール反応を通じて,それらのユニークな生物合成を開始します.
科学分野:
- バイオケミストリー バイオケミストリー
- 微生物学 微生物学とは
- 自然製品合成 自然製品合成
背景:
- バウミシンは,ダウノルビシンとドクソルビシンと共に共同生産され, *Streptomyces peucetius* の重要な抗がんアントラサイクリンである.
- バウミシンはダウノサミンの砂糖に独特のアセタル群を有しており,標準抽出で失われます.
- このアセタルは,異常な枝分かれのデオキシ糖から派生することを示唆しています.
研究 の 目的:
- バウミシンに含まれる異常な糖分の生物合成経路を解明する.
- バウミシン/ダウノルビシン生物合成遺伝子群内の*dnmZ*遺伝子の機能を特徴付ける.
- 新糖改変を開始する酵素メカニズムを調査する.
主な方法:
- *dnmZ*を中心とした*dox*遺伝子群のバイオ情報分析.
- DnmZと既知の酵素,特にニトロソシンタゼのシーケンス類似性の比較.
- 糖質基板におけるDnmZの酵素活性を決定する生化学的測定法.
主要な成果:
- *dnmZ*遺伝子は,ニトロソシンタゼと非常に類似したタンパク質をコードする.
- DnmZは,アミノ糖ニトロソシンタゼであることが実証されました.
- DnmZは,チミジン-5'-二酸化塩酸-l-epi-バンコサミンの初期変換を環開いた製品に触媒化します.
- この反応は,以前に説明されていない逆オキシム-アルドールメカニズムを経由して進行する.
結論:
- DnmZは,ユニークなバウミシン糖分の生物合成における重要な酵素です.
- DnmZによって触媒化されたレトロオキシム-アルドール反応は,新しい生化学的変換を表しています.
- この経路を理解することで,複雑なグリコシル化天然製品の生物合成の洞察が得られます.
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