Thermodynamic study of glyphosate insertion into pure and binary lipid bilayers

PORASSO, RODOLFO D.; FRIGINI, EZEQUIEL N.; FRIGINI, EZEQUIEL N.; PORASSO, RODOLFO D.

San Luis

Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Biofísica; 2019

Glyphosate is the most used herbicide for the control of weed growth, allowing to reduce the use of fertilizers. In this work, simulations of molecular dynamics (MD) were carried out to study the influence of glyphosate (in its charged state, GLYP²⁻ ) on different models of pure (1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphoserine (DPPS)) and binary (DPPC/DPPS) lipid bilayers completely hydrated. In this sense, the profiles of free energy, entropy and enthalpy were obtained by means of umbrella sampling calculations at three different temperatures (350, 355, and 360 K). For the systems (i) DPPC/DPPS for the temperatures of 350 and 355 K, and (ii) DPPS for the three temperatures, water defect and Na⁺ ions were observed together with the GLYP²⁻ inside the lipid bilayers. In addition, different properties of the different lipid bilayer model at different temperatures were analyzed. Both the mean area per lipid, the thickness of the lipid bilayer and the orientation of the lipid head groups were not observed noticeable changes (less than 5 %) when comparing the system in presence and absence of GLYP²⁻. Translational diffusion coefficient value for the systems in presence and in absence of the GLYP²⁻ was obtained a considerable change (greater than 6 % until 59.6 % ). In the process of GLYP²⁻ insertion into the membrane for the DPPC and DPPS system, they are driven by a favorable enthalpic change. For binary lipid bilayer systems it is driven by favorable entropic change.