Why are Vibrational Lines Narrow in Proteins?
Why are Vibrational Lines Narrow in Proteins?
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DOI：
10.1021/acs.jpclett.0c01760
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发表时间：
2020-08-06
影响因子：
5.7
通讯作者：
Matyushov, Dmitry, V
中科院分区：
文献类型：
--
作者：
Martin, Daniel R.;Matyushov, Dmitry, V
蛋白质中的振动斯塔克效应产生了线移，表明强大的内部电场高达每埃几伏。这些数值得到了蛋白质数值模拟的支持。模拟结果还显示，极大范围的场起伏会导致振动线的不均匀展宽。根据涨落耗散的观点，强大的内场应该导致宽线。然而，实验报告的蛋白质中的振动线非常窄。这种脱节在这里用振动探头寿命中蛋白质构型的不充分(非遍历)采样来解释。蛋白质中电场起伏的慢分量在几十纳秒的时间尺度上松弛，在振动寿命上动态冻结。
The vibrational Stark effect in proteins yields line shifts indicative of strong internal electric fields up to a few volts per angstrom. These values are supported by numerical simulations of proteins. The simulations also show a significant breadth of field fluctuations translating to inhomogeneous broadening of vibrational lines. According to fluctuation-dissipation arguments, strong internal fields should lead to broad lines. Experimentally reported vibrational lines in proteins are, however, very narrow. This disconnect is explained here in terms of the insufficient (nonergodic) sampling of the protein's configurations on the lifetime of the vibrational probe. The slow component of the electric field fluctuations in proteins relaxes on the time scale of tens of nanoseconds and is dynamically frozen on the vibrational lifetime.