ABSTRACT
Water is not only the most unique molecules known to mankind but also one of the most important molecules in biological systems. In fact, water might be the most crucial biological molecule, even though it is often ignored by biologists simply as background. Hydrophobicity, or simply water fearing, a much related physical property of molecule, is essential for sustainable life as we all know. It is associated with various unusual properties of aqueous solutions of polar or nonpolar solutes and contributes signicantly to a wide variety of biological phenomena such as protein folding, DNA/RNA folding, and self-assembly of lipid membranes [1-7]. Biological water, particularly those under nanoscale connement, plays a key role in so many important biological processes that
12.1 Introduction 329 12.2 Simple Macroscopic eory 331 12.3 Dehydration in Protein Folding 333
12.3.1 Hydration in TIM Barrel ILV Cluster 334 12.3.2 Experimental Spectra Conrm the eoretical Prediction 337 12.3.3 Interplay between ILV Cluster Drying and Protein Stability 337
12.4 Nanoscale Dewetting in Protein Complexes 339 12.4.1 Dewetting in Protein Folding 339 12.4.2 Dewetting in Protein-Ligand Binding 343 12.4.3 Dewetting in Ion-Channel Gating 345
12.5 Summary 347 References 348
considerable eort has been devoted to understanding it over the past decades [8-19]. Not long ago, Ball [13] presents an intriguing review and measured historical discussion of the contentious issues along with recent developments and how they correspond to other general questions about the role of water in biological systems. Although many of the controversies involve quantitative questions, they cannot be resolved by taking a rigid and simplistic view based on generally useful qualitative concepts, whether of broken hydrogen bonds, dry interfaces, or hydrogen bond networks. Since water is a subtle and exible medium with a uctuating and elusive balance between many nearly degenerate local congurations, it can respond to dierent perturbations in surprising ways. erefore, we must be equally exible in our attempts to understand its solvation properties with both experimental and theoretical approaches.
