Brovchenko Ivan, Oleinikova Alla
Physical Chemistry, Dortmund University of Technology, Otto-Hahn-Str. 6, Dortmund, Germany.
Chemphyschem. 2008 Dec 22;9(18):2695-702. doi: 10.1002/cphc.200800662.
The central role of water in biological functions is well-recognized, but numerous questions concerning the physical mechanisms behind the importance of water for life remain unanswered. Water in biosystems exists mainly as hydration water. Analysis of the phase diagram of hydration water shows that biological functions are possible only when the surfaces of biomolecules are covered by spanning hydrogen-bonded networks of hydration water. The comparative studies of the various properties of hydrated biosystems in the presence and in the absence of a spanning water network should clarify its specific physical properties, which are crucial for biological functions. Herein, we summarize the recent progress in these studies. The biological activity of the living organisms is maximal in a narrow temperature interval, where the spanning network of hydration water breaks up with heating via a percolation transition. The entropy of the hydration water related to the diversity of cluster size diverges at this percolation threshold. The possible role of this phenomenon in life processes is discussed.
水在生物功能中的核心作用已得到充分认可，但关于水对生命重要性背后的物理机制仍存在许多未解答的问题。生物系统中的水主要以水化水的形式存在。对水化水相图的分析表明，只有当生物分子表面被跨越的水化水氢键网络覆盖时，生物功能才有可能实现。对存在和不存在跨越水网络的水合生物系统的各种特性进行比较研究，应能阐明其对生物功能至关重要的特定物理特性。在此，我们总结了这些研究的最新进展。生物体的生物活性在一个狭窄的温度区间内最大，在这个区间内，水化水的跨越网络会随着加热通过渗流转变而瓦解。与团簇尺寸多样性相关的水化水熵在这个渗流阈值处发散。讨论了这一现象在生命过程中的可能作用。
