Dynamics of Protein and Peptide Hydration

摘要: Biological processes often involve the surfaces of proteins, where structural and dynamic properties aqueous solvent are modified. Information about dynamics protein hydration can be obtained by measuring magnetic relaxation dispersion (MRD) water 2 H 17 O nuclei or recording nuclear Overhauser effect (NOE) between protons. Here, we use MRD method to study cyclic peptide oxytocin globular BPTI in deeply supercooled solutions. The results provide a detailed characterization layer at surface these biomolecules. More than 95% molecules contact with biomolecular found no more two-fold motionally retarded as compared bulk water. In contrast small nonpolar molecules, retardation factor for showed little temperature dependence, suggesting that exposed residues do not induce clathrate-like hydrophobic structures. New NOE data published were analyzed, mutually consistent interpretation was achieved aid new theory intermolecular dipolar accounts explicitly perturbation surface. analysis indicates water-protein NOEs dominated long-range couplings water, unless monitored proton is near partly fully buried site molecule has long residence time. Most proteins other biomolecules have been adapted evolution function optimally environments. Protein-water interactions therefore play an essential role folding, stability, dynamics, proteins. Conceptually, problem may analyzed terms different orders. first-order on described solvent-averaged potentials, dielectric screening Coulomb interactions. To second order, must acknowledge modifies adjacent this modification reacts back protein. term usually refers such second-order effects, which range from highly specific entrapment internal cavities generic covering external present work, examine what extent differs This important question because primary events most biological processes, enzymatic catalysis, association, recognition, take place -water interface. Moreover, volume monolayer comparable dry protein, even large energetics dynamics.