Hydration of biologically relevant tetramethylammonium cation by neutron scattering and molecular dynamics.

0581785 - ÚOCHB 2025 RIV GB eng J - Článek v odborném periodiku
Mason, Philip E. - Martinek, Tomáš - Fábián, Balázs - Vazdar, M. - Jungwirth, Pavel - Ticháček, Ondřej - Duboué-Dijon, E. - Martinez-Seara, Hector
Hydration of biologically relevant tetramethylammonium cation by neutron scattering and molecular dynamics.
Physical Chemistry Chemical Physics. Roč. 26, č. 4 (2024), s. 3208-3218. ISSN 1463-9076. E-ISSN 1463-9084
Grant CEP: GA ČR(CZ) GA19-19561S
GRANT EU: European Commission(XE) 101095957 - Q-SCALING
Výzkumná infrastruktura: e-INFRA CZ II - 90254
Institucionální podpora: RVO:61388963
Klíčová slova: X-ray-scattering * aqueous-solutions * water-structure
Impakt faktor: 3.3, rok: 2022
Způsob publikování: Open access
https://doi.org/10.1039/D3CP05449G

Neutron scattering and molecular dynamics studies were performed on a concentrated aqueous tetramethylammonium (TMA) chloride solution to gain insight into the hydration shell structure of TMA, which is relevant for understanding its behavior in biological contexts of, e.g., properties of phospholipid membrane headgroups or interactions between DNA and histones. Specifically, neutron diffraction with isotopic substitution experiments were performed on TMA and water hydrogens to extract the specific correlation between hydrogens in TMA (HTMA) and hydrogens in water (HW). Classical molecular dynamics simulations were performed to help interpret the experimental neutron scattering data. Comparison of the hydration structure and simulated neutron signals obtained with various force field flavors (e.g. overall charge, charge distribution, polarity of the CH bonds and geometry) allowed us to gain insight into how sensitive the TMA hydration structure is to such changes and how much the neutron signal can capture them. We show that certain aspects of the hydration, such as the correlation of the hydrogen on TMA to hydrogen on water, showed little dependence on the force field. In contrast, other correlations, such as the ion-ion interactions, showed more marked changes. Strikingly, the neutron scattering signal cannot discriminate between different hydration patterns. Finally, ab initio molecular dynamics was used to examine the three-dimensional hydration structure and thus to benchmark force field simulations. Overall, while neutron scattering has been previously successfully used to improve force fields, in the particular case of TMA we show that it has only limited value to fully determine the hydration structure, with other techniques such as ab initio MD being of a significant help.
Trvalý link: https://hdl.handle.net/11104/0349920


Vědecká data: ILL