The spatial range of protein hydration.

摘要: Proteins interact with their aqueous surroundings, thereby modifying the physical properties of solvent. The extent this perturbation has been investigated by numerous methods in past half-century, but a consensus still not emerged regarding spatial range perturbation. To large extent, disparate views found current literature can be traced to lack rigorous definition range. Stating that particular solvent property differs from its bulk value at certain distance protein is particularly helpful since such findings depend on sensitivity and precision technique used probe system. What needed well-defined decay length, an intrinsic dilute solution, specifies length scale which given approaches bulk-water value. Based molecular dynamics simulations four small globular proteins, we present analysis structural dynamic hydrogen-bonded network. results demonstrate unequivocally short-ranged, all having exponential lengths less than one hydration shell. short consequence high energy density water, rendering highly resistant perturbations. electric field protein, under conditions long-ranged, induces weak alignment water dipoles, which, however, merely linear dielectric response and, therefore, should thought as By decomposing first shell into polarity-based subsets, find structure nonpolar parts surface similar solutes. For examined mean number water-water hydrogen bonds subset within 1% suggesting fragmentation topography protein-water interface evolved minimize propensity for aggregation reducing unfavorable free hydrophobic hydration.