Ab Initio Studies of Rotation and Solvent Effects for two important membrane molecules: DPPC and DMPC

Document Type : Research Paper




DPPC (dipalmitoylphosphatidylcholine) and DMPC (dimyristoylphosphatidylcholine) are taken as
phospholipids with an equal polar heads and with the difference in the length of hydrocarbon
chains. Results obtain from the structural optimization of the isolated DPPC and DMPC in the gas
phase, at the Hartree-Fock level of theory by means of STO-3g,3-21G, 6-31G and 6-31G* basis
sets. the most important dihedral angle of these molecules (DPPC and DMPC) is chosen and the
energy of 14 important atoms were scanned within 180 degrees rotation and sites that have most
changes are determined and any rotated molecule separately placed in the 19 solvents (The method
is HF/6-31G* model) and then dielectric effect of surrounding were analyzed. The solvent effect
on the stability of DPPC & DMPC molecules were discussed using Onsager model.