HppEによるラジカル媒介カタリシスの証拠:サイクロプロピルおよびメチレンサイクロプロピル基板類の類似体を用いた研究
Hui Huang1, Wei-chen Chang, Pei-Jing Pai
1Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712, USA.
Journal of the American Chemical Society
|September 26, 2012
まとめ
(S) - 2 - ヒドロキシプロピルフォスフォニック酸エポキシダゼ (HppE) は,フォスフォマイシン生物合成のためのラジカル中間物質を使用します. 研究では, (R) -HPP酸化におけるC2中心の基が明らかにされ,この異常な鉄酵素に関する重要な力学的な洞察が得られる.
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
- 有機化学 オーガニック・ケミストリー
背景:
- 酵素 (S) - 2 - ヒドロキシプロピルフォスフォン酸エポキシダース (HppE) は,フォスフォマイシン抗生物質の生物合成に不可欠です.
- 珍しい単核鉄酵素であるHppEは, (S) -2-ヒドロキシプロピルフォスフォン酸 ((S) -HPP) の酸化エポキシデーションを触媒化する.
- また,HppEは (R) -同位体である (R) - 2 - ヒドロキシプロピルフォスフォン酸 ((R) - HPP) を2 - オクソプロピルフォスフォン酸に処理する.
研究 の 目的:
- HppE触媒による酸化反応の反応機構を解明する.
- HppEの活動における急性中間物質の関与を調査する.
- HppEの基板特異性と触媒経路を調査する.
主な方法:
- 含有サイクロプロピルおよびメチレンサイクロプロピルのラジカルクロック基板類の合成.
- これらのアナログを用いた酵素分析は,HppEの活性を研究する.
- 酵素機構を決定するために反応産物の分析.
主要な成果:
- HppEは,サイクロプロピルを含むアナログをエポキシド ((S) -アイソマー) とケトン ((R) -アイソマー) 製品に効率的に変換しました.
- メチレンサイクロプロピルの類型はHppEを素早く不活性化させ,急激に激素が誘発したリング開きを示した.
- 実験的証拠は, (R) -HPP酸化におけるナノ秒寿命を持つC2中心の中間基を裏付けている.
結論:
- この研究は,HppE触媒 (R) -HPP酸化におけるC2中心の中間基の最初の実験的証拠を提供します.
- ラジカル・クロック・アナログは,HppEの異常な酵素反応のメカニズムを効果的に探究する.
- この発見により,単核鉄酵素の触媒とフォスフォマイシン生物合成の理解が進んでいます.
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