Spectral manifestations of nitrogen-containing amino acids intermolecular interaction with maleimide

Nitrogen-containing amino acids complexation when one of them is enriched with maleimide has been studied using quantum chemical modeling methods based on density functional theory. Nitrogen-containing amino acids that are part of protein capsules for drug delivery are considered as the studied objects: tryptophan, arginine, lysine and histidine, as well as the maleimide molecule. Based on molecular complexes structures and their infrared spectra calculation, followed by an analysis of the parameters of the hydrogen bonds formed for pairs of interacting amino acids modified with maleimide, it was found that maleimide enhances the intermolecular interaction of nitrogen- containing amino acids. This allows us to conclude that the mechanism of increasing the therapeutic activity of protein delivery capsule enriched with maleimide is due to increased intermolecular interaction of delivery capsule proteins and target proteins in the presence of maleimide.