SIMULATIONS OF THE AQUEOUS SOLVATION OF TRILAURIN

Molecular dynamics and energy minimization computer modeling calculations have been used to study the conformational behavior of the prototypical triglyceride molecule trilaurin. The energy of an isolated molecule was minimized using both the Quanta/CHARMm force field and a newly developed CFF parametrization for comparisons. The crystal structure was found to be a locally stable geometry using CHARMm, but with the CFF potential the structure collapsed into a geometry with C-3 symmetry similar to the hypothesized bilayer structure with all three aliphatic chains on the same side of the glycerol backbone. A full molecular dynamics simulation of a trilaurin molecule in aqueous solution, starting in the crystal structure, was also performed. This ''tuning fork'' structure was found to undergo a slow drift in solution toward a more compact geometry, but it was not possible to simulate the system for a sufficient period to determine whether this process was completed or would continue until a geometry similar to the CFF structure was reached. The triglyceride-water interactions were found to be consistent with the behavior expected for a predominantly hydrophobic species containing a polar headgroup consisting of hydrogen-bond-accepting oxygen atoms.