论文标题
通过磷酸骨架振动的激发探测的RNA融化上的水合模式的变化
Change of Hydration Patterns upon RNA Melting Probed by Excitations of Phosphate Backbone Vibrations
论文作者
论文摘要
水水合壳对RNA的结构和功能特性具有决定性的影响。 RNA结构在融化和生化过程中的变化伴随着水合模式的变化，这一过程几乎没有表征。为了辨别分子水平的RNA双螺旋的骨架磷酸基团周围的水合几何形状，我们将磷酸盐振动的二维红外光谱与理论模拟相结合。 RNA A-helix的三个独特的共存水合基序是水分子的有序链样排列，在邻近的磷酸基团之间具有链接，最多六个水分子的局部水合壳以及水合的磷酸盐/柜台接触对。熔化时的RNA无序与从主要有序的水结构到磷酸单元周围局部水合壳的过渡有关。结构波动以300 FS时间尺度发生的库水动作为主，而没有水合基序之间交换。
The water hydration shell has decisive impact on the structural and functional properties of RNA. Changes of RNA structure upon melting and in biochemical processes are accompanied by a change of hydration patterns, a process which is barely characterized. To discern hydration geometries around the backbone phosphate groups of an RNA double helix at the molecular level, we combine two-dimensional infrared spectroscopy of phosphate vibrations with theoretical simulations. There are three distinct coexisting hydration motifs of the RNA A-helix, an ordered chain-like arrangement of water molecules with links between neighboring phosphate groups, separate local hydration shells of up to six water molecules, and hydrated phosphate/counterion contact pairs. RNA disordering upon melting is connected with a transition from predominant ordered water structures to local hydration shells around phosphate units. Structural fluctuations are dominated by librational water motions occurring on a 300 fs time scale, without exchange between hydration motifs.
