Range, Magnitude, and Ultrafast Dynamics of Electric Fields at the Hydrated DNA Surface

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• 作者：Torsten Siebert ; Biswajit Guchhait ; Yingliang Liu ; Benjamin P. Fingerhut ; Thomas Elsaesser
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2016
• 出版时间：August 18, 2016
• 年：2016
• 卷：7
• 期：16
• 页码：3131-3136
• 全文大小：390K
• 年卷期：0
• ISSN：1948-7185

文摘

Range and magnitude of electric fields at biomolecular interfaces and their fluctuations in a time window down to the subpicosecond regime have remained controversial, calling for electric-field mapping in space and time. Here, we trace fluctuating electric fields at the surface of native salmon DNA via their interactions with backbone vibrations in a wide range of hydration levels by building the water shell layer by layer. Femtosecond two-dimensional infrared spectroscopy and ab initio based theory establish water molecules in the first two layers as the predominant source of interfacial electric fields, which fluctuate on a 300 fs time scale with an amplitude of 25 MV/cm due to thermally excited water motions. The observed subnanometer range of these electric interactions is decisive for biochemical structure and function.