Conformational analyses of the polymorphism of triglycerides

Triglycerides, the major components of neutral lipids, are important biomaterials, as they take part in the edification of membranes. In this perspective, the consideration of biological membranes at a molecular level requires detailed knowledge of the preferred conformations of the triglycerides in their various polymorphic forms. In this context, we adapted a molecular modeling approach, which allows the simulation the three‐dimensional structure of the different polymorphic forms (α, β′, and β) valid for any triglyceride. Their conformational analysis is based on molecular mechanics calculations, as follows: First, a large number of isolated molecular structures were generated in a systematic structuretree analysis. For their generation, atomic charges within the Mulliken scheme, calculated at the ab initio RHF–LCAO–MO–SCF level (6‐31G), were considered. The lowest‐energy conformers were, next, correlated with experimental data (NMR, powder X‐ray diffraction) in order to select α, β′, or β structures. Then, in a second step, these selected conformers were assembled, in head‐to‐tail dimers in order to form a monolayer. For this step, the use of potential‐derived atomic charges is known to be more suitable. In this study, we consider triglycerides derived from the predominant fatty acids, i.e., stearic, elaidic, and oleic acids. © 1994 John Wiley & Sons, Inc. Copyright © 1994 John Wiley & Sons, Inc.