Elsaesser Thomas
Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, D-12489 Berlin, Germany.
Biol Chem. 2009 Nov;390(11):1125-32. doi: 10.1515/BC.2009.126.
Structural memory of aqueous systems, such as neat water and biomolecules, in an aqueous environment is strongly influenced by hydrogen bond dynamics. Vibrational spectroscopy in the femtosecond (fs) time domain is applied to map structural dynamics in real-time and identify underlying molecular interactions. Neat liquid water displays an ultrafast loss of structural memory with the fastest decay of structural correlations occurring in the sub-100 fs regime. Both OH stretching and bending excitations of water molecules decay on a subpicosecond time scale, followed by dissipation of excess energy in the hydrogen bond network within a few picoseconds. Water shells around fully hydrated DNA show similar although slightly slower dynamics. A detailed study of hydration shells around ionic phosphate groups in the DNA backbone demonstrates a strong phosphate-water coupling and a subpicosecond rearrangement of hydrogen bonds upon energy disposal. Hydration shells serve as primary heat sinks for excess energy.
在水性环境中，诸如纯水和生物分子等水性体系的结构记忆受到氢键动力学的强烈影响。飞秒（fs）时域的振动光谱被用于实时绘制结构动力学并识别潜在的分子相互作用。纯液态水显示出结构记忆的超快丧失，结构相关性的最快衰减发生在亚100 fs范围内。水分子的OH伸缩和弯曲激发都在亚皮秒时间尺度上衰减，随后在几皮秒内在氢键网络中耗散多余能量。完全水合DNA周围的水壳显示出类似但稍慢的动力学。对DNA主链中离子磷酸基团周围水合壳的详细研究表明，磷酸基团与水之间有很强的耦合作用，并且在能量释放时氢键会在亚皮秒内重新排列。水合壳作为多余能量的主要热阱。
