基于量子的建模表明,双酸89基质结合增强了氨酸/氨酸蛋白酸酶-2A (PPP2R5D/PPP2R1A/PPP2CA) 介导的脱化
E Alan Salter1, Andrzej Wierzbicki1, Richard E Honkanen2
1Department of Chemistry, University of South Alabama, Mobile, AL, United States.
Frontiers in cell and developmental biology
|June 28, 2023
概括
氨酸-89与基质的双酸结合对于最佳的蛋白质酸酶2A (PP2A) 催化功能至关重要. 计算显示,当Arg89直接与基质结合时,激活能量较低,这表明它在调节PP2A活动中的作用.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 酶学 是一种酶学.
背景情况:
- 蛋白质酸酶2A (PP2A) 全酶对于调节蛋白质酸化至关重要.
- PP2A包括支架 (A),催化 (C) 和调节 (B) 的子单位.
- 催化机制涉及一个双金属系统和一个保存的核心序列.
研究的目的:
- 调查阿尔金宁-89 (Arg89) 在PP2A的催化水解中的作用.
- 确定Arg89在水解过程中是否直接与基质的酸盐组结合.
- 了解Arg89与PP2A功能和疾病的调节子单元的相互作用的影响.
主要方法:
- 进行了基于量子的混合[ONIOM ((UB3LYP/6-31G ((d):UPM7) ]计算.
- 使用了PP2A ((PPP2R5D) /phosphoserine系统的39个残留模型.
- 估计了具有和没有直接结合Arg89基质的水解激活障碍.
主要成果:
- 溶解校正的激活障碍被计算出来: ΔH‡ ≈ ΔE‡ = +15.5 kcal/mol (直接结合) 与 +18.8 kcal/mol (间接结合).
- 直接与双酸89基质结合显著降低了水解的激活屏障.
- 在PP2A (PPP2R5D) 中,Arg89与B:Glu198的相互作用可能会封锁其催化功能.
结论:
- 双酸与Arg89基质的结合对于最佳的PP2A催化活性至关重要.
- B56δ的致病性E198K变体可能通过改变这个接口上的电荷来改变PP2A的功能.
- PP2A ((PPP2R5D) 的活性可能在本地条件下被B:Glu198与C:Arg89.9的相互作用抑制.
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