Salentinig Research Group has recently published a new article in the Journal of Chemical Theory and Computation, JCTC, entitled "A Coarse-Grained SPICA Makeover for Solvated and Bare Sodium and Chloride Ions", in collaboration with Vanni Group from Department of Biology - University of Fribourg.

Congratulations to Mr. Janak Prabhu, Mr. Matteo Frigerio, Mr. Emanuele Petretto, PhD and Mr. Pablo Campomanes Ramos and congratulations to Prof. Stefan Salentinig and Prof. Stefano Vanni !

For more information and to read the article: https://pubs.acs.org/doi/full/10.1021/acs.jctc.4c00529

Abstract

Aqueous ionic solutions are pivotal in various scientific domains due to their natural prevalence and vital roles in biological and chemical processes. Molecular dynamics has emerged as an effective methodology for studying the dynamic behavior of these systems. While all-atomistic models have made significant strides in accurately representing and simulating these ions, the challenge persists in achieving precise models for coarse-grained (CG) simulations. Our study introduces two optimized models for sodium and chloride ions within the nonpolarizable surface property fitting coarse-grained force field (SPICA-FF) framework. The two models represent solvated ions, such as the original FF model, and unsolvated or bare ions. The nonbonded Lennard-Jones interactions were reparameterized to faithfully reproduce bulk properties, including density and surface tension, in sodium chloride solutions at varying concentrations. Notably, these optimized models replicate experimental surface tensions at high ionic strengths, a property not well-captured by the ions of the original model in the SPICA-FF. The optimized unsolvated model also proved successful in reproducing experimental osmotic pressure. Additionally, the newly reparameterized ion models capture hydrophobic interactions within sodium chloride solutions and show qualitative agreement when modeling structural changes in phospholipid bilayers, aligning with experimental observations. For aqueous solutions, these optimized models promise a more precise representation of the ion behavior.