Multispectroscopic and Computational Analysis Insight into the Interaction of Cationic Diester-Bonded Gemini Surfactants with Serine Protease α-Chymotrypsin

Abstract

Accumulation of different protein–surfactant mixtures affords further knowledge about the structure–property interactions of biomacromolecules. They will help design suitable surfactants, which, in turn, can enhance the utilization of protein–surfactant complexes in biotechnologies, cosmetics, and food industry realms. Owing to their adaptable and remarkably notable properties, we are describing herein the interaction of Cm-E2O-Cm gemini surfactants (m = 12, 14, and 16) with α-CHT by employing various spectroscopic techniques including with molecular docking and density functional theory (DFT) method. Results have revealed complex formation, unfolding, and a static quenching mechanism in the interaction of gemini surfactants with α-CHT. The Stern–Volmer constant (KSV), quenching constant (kq), the number of binding sites (n), and binding constant (Kb) were interrogated by utilizing the fluorescence quenching method, UV–vis, synchronous, 3-D, and resonance Rayleigh scattering fluorescence studies. The data perceive the α-CHT–Cm-E2O-Cm complex formation along with conformational alterations induced in α-CHT. The contribution of aromatic residues to a nonpolar environment is illustrated by pyrene fluorescence. Fourier transform infrared spectroscopy and circular dichroism outcomes reveal conformational modifications in the secondary structure of α-CHT with the permutation of gemini surfactants. The computational calculations (molecular docking and DFT) further corroborate the complex formation between α-CHT and Cm-E2O-Cm gemini surfactants and the contribution of electrostatic/hydrophobic interaction forces therein.