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Protein isolation through impact desolvation of electrosprayed microdroplets (IDEM): Molecular dynamics simulation

Abstract:

Using molecular dynamics simulation, we investigate the collision of an echistatin molecule embedded in a 3330 molecule water droplet with a repulsive wall, such as it is relevant in the impact desolvation of electrosprayed microdroplets (IDEM) process. Protein denaturation and conformation stability are studied by monitoring the time evolution of the radius of gyration, the root mean squared deviation of the protein backbone, the solvent accessible and excluding surface areas, the secondary structure and by an analysis of the hydrogen bond network. The resulting dehydration process of the protein occurs on a time scale spanning at least tens of ps, and depends sensitively on the collision speed. We find that at the lowest impact velocities of 1.6-2.9 km/s the protein remains covered by a water shell and exhibits only little distortions. At the highest impact velocities (3.7-4.1 km/s) the protein is entirely dehydrated and strongly distorted. The minimum thickness of the hydration shell which is needed to preserve the non-denatured conformation of the protein, one monolayer of water, can be obtained by carefully tuning the impact velocity. © 2009 Elsevier B.V. All rights reserved.