O-GlcNAcトランスファーゼは,テトラトリコペプチドリピート (TPR) スーパーヘリックスにおけるアスパラジン梯子を用いてタンパク質基質を認識する
Zebulon G Levine1, Chenguang Fan1, Michael S Melicher1
1Department of Microbiology and Immunobiology , Harvard Medical School , Boston , Massachusetts 02115 , United States.
Journal of the American Chemical Society
|February 28, 2018
まとめ
酵素O-GlcNAcトランスファーゼ (OGT) は,TPRドメインでアスパラジンの梯子を用いて,タンパク質基板を認識し,グリコシル化します. この発見は,OGTがO-GlcNAcylationのターゲットをどのように選択するかを明確にします.
科学分野:
- 生物化学
- 分子生物学
- グライコバイオロジー
背景:
- 酵素O-GlcNAcトランスファーゼ (OGT) は,多数の核および細胞質タンパク質を改変する.
- OGTの基板認識メカニズムは,コンセンサス配列がないため,ほとんど不明のままです.
研究 の 目的:
- OGTが様々なタンパク質の基質を認識する方法を研究する.
- 基質選択におけるOGTのテトラトリコペプチドリート (TPR) ドメインにおけるアスパラジンレダーの役割を決定する.
主な方法:
- 何千ものタンパク質のOGT活性を評価するための化学酵素タンパク質マイクロアレイの開発.
- OGT TPR領域内の5つのアスパラジン残基のサイト指向型変異.
主要な成果:
- アスパラジン・レッダの変異により,OGTがマイクロアレイ上のタンパク質基板をグリコシル化する能力が著しく低下した.
- 細胞抽出物におけるタンパク質基質のO- GlcNAcylationも著しく弱まった.
- OGTは短いペプチドに対する活性を維持しており,これはタンパク質の認識に不可欠であることを示唆しています.
結論:
- OGT TPR ドメイン内のアスパラジンの梯子は,その大半のタンパク質基板を認識するために不可欠です.
- この相互作用は,触媒領域に近接する TPR ルーメンで起こります.
- この研究は,OGTの基板特異性に関する重要なメカニズムを明らかにしている.
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