膜蛋白中的脊柱键能量对局部水度的大变化不敏感
Henry J Lessen1, Ananya Majumdar2, Karen G Fleming1
1T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States.
Journal of the American Chemical Society
|March 6, 2020
概括
膜蛋白骨干的键在不同水度中表现出惊人的稳定性. 这些键提供了适度的热力学稳定性,许多胺在脂质双层内不受脱水的影响.
科学领域:
- 结构生物学
- 生物物理
- 膜蛋白的生物物理
背景情况:
- 由于水度的变化,生物脂质双层呈现深度依赖的极性梯度.
- 膜接口的水度急剧下降被认为会影响蛋白质的稳定性,但其对骨干键的影响尚不清楚.
研究的目的:
- 研究水诱导的极性梯度对跨膜蛋白的骨干键强度的影响.
- 在一系列水度的跨膜蛋白OmpW中量化骨干键的自由能量变化.
主要方法:
- 核磁共振 (NMR) 光谱使用/分离因子测量自由能量变化.
- 分析超离心和分子动力学模拟以确定OmpW-micelle复合物的水力动力学和溶解性质.
主要成果:
- 对于两层界面区域的特征,OmpW骨干键能量在广泛的水度中保持一致.
- 测量的键自由能量变化与水溶性蛋白质和界面的变化相当.
- 经过调整后,结果与以前对跨膜α螺旋蛋白的研究一致.
结论:
- 脊柱键为膜蛋白结构提供了适度的热力学稳定性.
- 跨膜蛋白中的许多氨基基团在脂质双层环境中对脱水效应具有弹性.
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