The temperature-dependent structure, hydrogen bonding and other related dynamic properties of the standard TIP3P and CHARMM-modified TIP3P water models

It was found in the literature that the use of CHARMM-modified TIP3P (mTIP3P) water model in molecular dynamics (MD) simulations resulted in a less realistic peptide folding, as compared to the standard TIP3P (sTIP3P) water model. It is hypothesised that the hydrogen bonding (HB) network in both sTIP3P and mTIP3P could play a role in the discrepancy of the MD simulation results obtained. The lack of direct comparison between the structure, HB and other dynamic properties of sTIP3P and mTIP3P in the existing literature is likely due to the perception that these two water models should share similar structural and dynamic properties, despite a slight difference in their force-field potentials. In the results obtained from our MD simulations that were run from 10 degrees C to 100 degrees C at 1 atm, distinct differences are observed in their equilibrated densities, O center dot center dot center dot O radial pair distribution function, HB and other dynamic properties, such as dynamic viscosity and self-diffusion coefficient. The mTIP3P water model shows a more extensive HB network than sTIP3P by having a higher number of HB per molecule, higher dynamic viscosity and higher latent heat of vaporization. (C) 2018 Elsevier B.V. All rights reserved.