Understanding the potency of fatty acids with the amino acid side chains of bovine β lactoglobulin-A quantum chemical approach.

The present study aims to spotlight on the strength of interaction between different fatty acids with the Bovine-lactoglobulin (LGB) protein side chains along with the crystal water molecules at M062X/def2-QZVP level of theory. To analyse the role of carboxylic acid and its interaction with side chains and to reveal the significance of carboxylic acid, it was replaced by Acyl chloride (COCl), Acyl Bromide (COBr) and Acyl-Fluorine (COF) group and COS group. The ligands are linear with a straight and branched chain of carbon atoms, but extended methyl group make the ligand bend resulting in non-planar geometry. The least and highest band gap energy reveals the conductivity properties of ligands. 3UEW, the Palmitic acid is well-built owing to the interaction with the amino acid side chains Lys 69 and Glu 62 resulting in interaction energy of -124.98kcal/mol. 3D-NCIplot isosurface map and 2D-NCIplot graph plays a key role to confirm and analyse the occurrence of various non covalent interactions. The overall analysis of the fatty acids implies the fact that depending on the aliphatic chain length, the carboxyl group was capable of positioning favourable binding site.