Thermodynamic study of solvent effects on nanostructures: phosphatidylserine and phosphatidylinositol membranes

Abstract

At present, quantum chemistry is almost universally applicable to the interpretation of physical and chemical properties of various compounds. Phospholipids are an important part of biological lipids and are commonly used in biophysical studies. A quantum calculation for two phospholipids PS and PI was performed using the ab initio software. Geometry optimisation and thermodynamic data over the 304–340 K temperature range are included in the supporting information. The effect of the polarity of the environment on the conformation of the membrane lipid PS and PI head groups has been investigated with calculation at the Hartree-Fock level using the STO-3G, 3-21G, 6-31G and 6-31G* basis sets together with the Onsager continuum solvation model with the program GAUSSIAN 98. The different basis sets were used in order to understand the effects of environmental polarity on the conformation and geometry optimisation of PS and PI in various solvents by SCRF theory. Further, the solvent effect on the stability of PS and PI molecules were discussed using Onsager model.