在脂质头部区域埋藏的功能性重要水分子的惊人刚性
Rongfu Zhang1,2, Timothy A Cross1,2, Xinhua Peng3
1National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States.
Journal of the American Chemical Society
|April 19, 2022
概括
这项研究使用新型的固态NMR在脂质接口上发现了不同的"受限"和"受限"水物种. 这些发现挑战了高度移动的界面水的观点,在毫秒时间尺度上显示了稳定的水群.
科学领域:
- 生物物理化学
- 结构生物学
- 水动力学
背景情况:
- 生物系统中的界面水对于功能至关重要.
- 之前的研究表明,界面和散装水之间的交换速度很快 (femtosecond-nanosecond).
- 直接研究界面水是很有挑战性的,因为大量水的信号占主导地位.
研究的目的:
- 在化脂中直接探测功能重要的界面水.
- 描述脂质-水界面上的水的动态和结构.
- 挑战人们对水界移动性的普遍认识.
主要方法:
- 开发一种新的固态核磁共振 (NMR) 技术.
- 使用超高场磁铁 (35.2 T) 提高灵敏度.
- 选择性抑制散装水信号以隔离接口水.
主要成果:
- 观察到两种不同的界面水种:"封闭"和"绑定"水.
- 与散装水相比",受限"水表现出下场化学转移和改变的放松时间.
- "受限"水表现出严重限制的运动和明显的上升化学转移.
- 由于与弱相互作用的脂质群交换,即使是散装水也表现出较慢的动态.
结论:
- 在NMR时间表 (毫秒) 上证明了相对稳定的界面水群的存在.
- 提供了一个新的机会来研究生物大分子中的毫秒或更慢的时间尺度.
- 挑战了长期以来仅限于快速交换的界面水的观点.
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