Influence of water models on water movement through AQP1

TL;DR

This study compares three water models in simulating water transport through AQP1, revealing significant differences and highlighting the importance of model choice for accurate biological water diffusion simulations.

Contribution

It provides a detailed numerical comparison of TIP3P, OPC, and TIP4P/2005 water models in AQP1, emphasizing the impact of model selection on simulation accuracy.

Findings

TIP3P shows significant deviations from experimental data.

OPC and TIP4P/2005 models align well with experimental observations.

Water model choice critically affects simulated water dynamics in AQP1.

Abstract

Water diffusion through membrane proteins is a key aspect of cellular function. Essential processes of cellular metabolism are driven by osmotic pressure, which depends on water channels. Membrane proteins such as aquaporins (AQPs) are responsible for enabling water transport through the cell membrane. AQPs are highly selective, allowing only water and relatively small polar molecules to cross the membrane. Experimentally, estimation of water flux through membrane proteins is still a challenge, and hence accurate simulations of water transport are of particular importance. We present a numerical study of water diffusion through AQP1 comparing three water models: TIP3P, OPC and TIP4P/2005. Bulk diffusion, diffusion permeability and osmotic permeability are computed and compared among all models. The results show that there are significant differences between TIP3P (a particularly widespread model for simulations of biological systems), and the more recently developed TIP4P/2005 and OPC models. We demonstrate that OPC and TIP4P/2005 reproduce protein-water interactions and dynamics in excellent agreement with experimental data. From this study, we find that the choice of the water model has a significant effect on the computed water dynamics as well as its molecular behaviour within a biological nanopore.