ハイパー核性基質を用いたヘッジホッグタンパク質コレステロール解析における一般基質触媒の化学バイパス
Daniel A Ciulla1, Michael T Jorgensen2, José-Luis Giner2
1Chemistry Department, Binghamton University (SUNY) , Binghamton, New York 13902, United States.
Journal of the American Chemical Society
|September 21, 2017
まとめ
ヘッジホッグのタンパク質は コレステロールを使って自己分裂します 変異したタンパク質D303Aは,ヒドロペロキシド群で改変されたコレステロールを使用して再活性化され,アルファ効果を明らかにしました.
科学分野:
- 生物化学
- 分子生物学
- タンパク質化学
背景:
- ヘッジホッグのタンパク質は 重要なシグナル伝達分子です
- 自己触媒の内タンパク質分解によって 自動処理されます
- この過程でコレステロールは核愛体として作用し,D303は一般的な塩基触媒として識別される.
研究 の 目的:
- 保存されたアスパルテート残留物 (D303) のエッジホッグの自己処理における役割を調査する.
- D303によるコレステロール活性化のメカニズムを探求する.
- 異なった基質を用いたヘッジホッグ変異体の活動を特徴づける.
主な方法:
- エジホグのタンパク質におけるD303残基のサイト指向型変異.
- 新しい基質である3β-ヒドロペロキシコレステン (3HPC) の合成.
- コレステロールと3HPCを用いたヘッジホッグ変異性の測定
主要な成果:
- D303をアラニン (D303A) に変異させると,ヘッジホッグの自己処理活性が劇的に低下した (> 10^4倍).
- D303A変異体は,ヒドロペロキシド群の基質である3HPCと有意な活性回復を示した.
- 他のD303変異体 (D303N,D303R,D303E) も3HPCによって様々な程度に活性化している.
- 3HPCの反応性の向上はアルファ効果に起因する.
結論:
- エジホッグのタンパク質のD303残留は,コレステロール活性化のための一般的な塩基触媒として作用する.
- 3HPCの水酸化基から生じるアルファ効果は,核愛性を強化し,突然変異の活動を救う.
- この研究は,ヘッジホッグの自動処理のメカニズムと基板核愛性の役割についての洞察を提供します.
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