血小板活性化因子を不活性化する脳アセチルヒドロラーゼは,Gタンパク質のようなトリマーである
Y S Ho1, L Swenson, U Derewenda
1Department of Molecular Physiology and Biological Physics, University of Virginia Health Sciences Center, Charlottesville 22906-0011, USA.
Nature
|January 2, 1997
まとめ
血小板活性化因子 (PAF) は,細胞シグナル伝達において極めて重要です. 研究者らは,重要な酵素であるPAFアセチルヒドローラゼα1サブユニットの結晶構造を決定し,Gタンパク質のような構造と活性部位を明らかにした.
科学分野:
- バイオケミストリー バイオケミストリー
- 分子生物学は分子生物学である.
- 構造生物学 構造生物学とは
背景:
- 血小板活性化因子 (PAF) は,炎症とアポトーシスを含む多様な細胞プロセスに関与する強力な脂質媒介体です.
- PAFの正確な細胞内信号伝達経路は,まだ完全に理解されていません.
- 血小板活性化因子アセチルヒドロラーゼ (PAF-AHs) は,そのsn-2アセチル基を除去することによってPAFを無効化する.
研究 の 目的:
- 重要なPAF-AHイソフォームの結晶構造を決定することによって,PAF不活性化の構造的基礎を明らかにする.
- PAFのシグナル伝達と水解の基礎となる分子機構を理解する.
主な方法:
- 牛のPAF-AH ((Ib) alpha1サブユニットの結晶化.
- タンパク質の3次元構造を1.7 Åの解像度で決定するX線 difraktion分析.
- 構造分析のための反応産物であるアセテートとの複合形成.
主要な成果:
- 牛のPAF-AH ((Ib) alpha1サブユニットの結晶構造は,アセテートとの複合で決定されました.
- タンパク質の三次折り畳みは,p21 (ras) と他のGTPasesと非常に似ています.
- 活性部位にはトリプシンのような触媒三合体 (Ser47,His195,Asp192) が含まれています.
結論:
- GTPasesとの構造的類似性は,PAF-AH.で機能的なモチーフが保存されていることを示唆しています.
- 特定された活性部位は,PAF水解の触媒機構の洞察を提供します.
- 完ぺきなPAF-AH (Ib) 酵素は,珍しいGタンパク質のような (α1/α2) βトリマーである.
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