Effect of frictional force on urea and thiourea during an intramembrane transport: an explicit solvent Langevin dynamics simulation method

Abstract

An explicit solvent Langevin dynamics (LD) simulation method is employed to investigate the effect of frictional force on the solute–solvent interactions in urea and thiourea, which are subjected to varied degree of frictional forces akin to diffusional transport across the membrane system. Utilizing the frictional force concept in LD method, the effect of increasing frictional coefficient is studied on the microscopic properties such as single-point energy and N–C–N bond angle of urea and thiourea in aqueous solutions. The present work follows a self-conscious approach by explicitly including the solvent molecules in the LD simulations. The results are further compared with the standard Langevin approach without explicitly specifying solvent molecules. An analysis of the results reveals that the two cases differ strongly in the intermediate (Brownian) regime of frictional coefficient.