Protein dynamics, solvent viscosity effects

Rector, K.D., Jiang, J., Berg, M.A., and Payer, M.D. (2001) Effect of solvent viscosity on protein dynamics infrared vibrational echo experiment and theory, J. Phys. Chem. 105, 1081-1082. 

The technique of BD models these dynamic effects in an implicit fashion by combining the use of a diffusion coefficient, suitably scaled for the molecules of interest, which accounts for solvent viscosity, with a random force component that models the effects of collisions with solvent molecules. The dynamics of the diffusional motion are described by the Langevin equation [for review see Madura et al. (1997)], which can be solved in a number of ways. The solution used for protein-protein association is that of Ermak and McCammon (1978),... 

Roche and co-workers studied the effect of high pressure on an intrinsically disordered protein, a-synuclein. Rip relaxation rates showed a modest and rather uniform increase at the pressure of 2500 bar, compared to 1 bar. This was explained in terms of the small increase of the solvent viscosity and the backbone dynamics unaffected by pressure. 

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