PKA RIIβテトラメリックホロ酵素の構造とアロステリー
Ping Zhang1, Eric V Smith-Nguyen, Malik M Keshwani
1Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093-0654, USA.
Science (New York, N.Y.)
|February 11, 2012
まとめ
サイクルアデノシンモノホスファート (cAMP) 依存タンパク質キナーゼ (PKA) RIIβ(2):C(2) ホロ酵素構造は,cAMP結合がアロステリックにPKAを活性化する方法を示しています. この構造は,PKAについての洞察を提供します.
科学分野:
- バイオケミストリー バイオケミストリー
- 構造生物学 構造生物学とは
- 分子生物学は分子生物学である.
背景:
- 循環性アデノシンモノホスファート (cAMP) 依存タンパク質キナーゼ (PKA) は,細胞プロセスを調節する重要な酵素です.
- PKAは,生理学的に,調節 (R) と触媒 (C) のサブユニットを含むテトラメアとして存在します.
研究 の 目的:
- 全長テトラメリックRIIβ(2):C(2) PKAホロ酵素の2.3アングストーム構造を決定する.
- 構造分析を通じて,cAMPによるアロステル活性化のメカニズムを解明する.
主な方法:
- 2.3アングストームの解像度のX線結晶学.
- RIIβ(2):C(2) ホロ酵素構造と核酸結合状態の分析.
主要な成果:
- RIIβ(2):C(2) ホロ酵素は,ダイマーのダイマーを形成し,RIIβとCサブユニット間のアンカリングインターフェースを明らかにします.
- RIIβサブユニットのβ4-β5ループの相互作用は,Cサブユニットを核酸のない閉じた形状に強制する.
- 結晶はATPの代わりに反応産物 (ADPとリン酸化RIIβ) を明らかにし,PKAサイクルへの影響を示唆した.
結論:
- 決定された構造は,PKAのcAMP媒介アロステリック活性化のためのメカニズム的基礎を提供します.
- RIIβテトレメアの四次構造はRIαテトレメアとは異なっており,PKAイソフォームの構造的な配置が異なることを示している.
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