Design and simulation of an enzymatically modified phosphatidylcholine micelle with caprylic acid using a coarse-grained molecular dynamics approach

Computationally simulated micelle models provide useful information in molecular biological sciences. One perspective to investigate the mechanisms of micelle formation is through molecular dynamics (MD) simulations. In this study, we used the coarse-grained MD (CG-MD) simulation approach, and designed a model system of a micelle, formed by enzymatically modified phospholipids (PL). To perform the model simulation, we used a random mixture of PLs modified by phospholipase A1. This required enzymatic interesterification of soybean phosphatidylcholine (PC) with caprylic acid, along with purification and characterization by chromatographic techniques to determine the conformation of the esterified fatty acids and the corresponding phospholipid composition. The number of molecules used in the CG-MD simulation system was determined from the experimental critical micellar concentration (CMC) data. The simulation conditions, such as temperature, water and lipid concentration, were taken from the experimental settings. Our results showed that a micelle (elliptical vesicle structure) was formed within 150 ns. Moreover, the analysis confirmed that the stretched and elliptical structure was the best structure that could be formed. Our results confirmed that the modified PLs have a good tendency to form micelles depending on their geometric shapes and physicochemical properties. Finally, we propose that the simulated micellar structure as a simple model could be useful to design optimal and biocompatible nanoemulsions as possible vehicles for bioactive compounds.