WATER-MEDIATED INTERACTIONS OF BIOSOLUTES - ASPECTS OF DYNAMICS, STRUCTURE, AND CONFIGURATION LIFETIME OF THE SOLVENT

Data from experiments performed at our laboratory (including static and dynamic light scattering, optical rotation, low-shear viscosity and thermal expansivity measurements) are combined with data available from the literature, to the purpose of shedding light on some basic aspects of solute-perturbed inherent structures and of relaxation times and statistical relevance of configurational states of the solvent. Non-additivity of solute perturbations and its role in establishing generalized forces between solutes or parts of a solute are discussed. Generalized forces are considered in two respects. The first of them concerns the Flory-Huggins interaction parameter, its modulation by co-solutes and its role in functional encounters of biosolutes. The second aspect concerns the microscopic, if statistical, view of the purely hydrophobic contribution of the solvent to biomolecular conformation and function. The (moderately) longer lifetime of some of the solute-perturbed configurational states of the solvent is scrutinized in what concerns its origin, its size and its effects on solvent-mediated forces among solutes. Experimental data (even apparently contradictory ones) fit very consistently the overall picture.