Monitoring Insulin-Aggregated Structures in the Presence of Epigallocatechin-3-gallate and Melatonin by Molecular Dynamics Simulations.

In the present work we illustrate the results of classical molecular dynamics simulations of model systems composed of six insulin molecules in water in the presence and in the absence of either epigallocatechin-3-gallate or melatonin molecules. For each model system, we performed three independent simulations (replicas) to study the aggregate formation dynamics and insulin interaction with epigallocatechin-3-gallate and melatonin. We find that melatonin is less stably close to insulin with respect to epigallocatechin-3-gallate, which interacts more stably with insulin molecules and mainly with insulin's chain B hydrophobic residues. We observe that the shape of the insulin-aggregated structures in the three model systems is different and depends on whether epigallocatechin-3-gallate is present or not. Simulations show that in the absence of epigallocatechin-3-gallate, insulin molecules tend to form linear aggregates, while in the presence of epigallocatechin-3-gallate, aggregates display a globular shape, less prone to form fibril structures.