Tetrapeptide ligands screening for antibody separation and purification by molecular simulation and experimental verification

Abstract

Short peptide resin has a great advantage in the separation and purification of antibodies due to its high selectivity and stable ligand binding ability. In this study, a peptide library containing 480 tetrapeptides was established with six critical residues (Phe, Tyr, Leu, Glu, Ile, Lys) of Protein A binding to Fc part of the antibody and one Histidine. Then the library was screened by LibDock and five tetrapeptide ligands with high LibDock scores were selected. Subsequently, the electrostatic interaction energies and van der Waals interaction energies between the screened ligands and the Fc-A fragment of IgG were further calculated by molecular dynamics simulation to research the binding ability between ligands and target proteins. The simulation results showed that YEHF was the optimal ligand with higher van der Waals interaction energies. Then, four tetrapeptides (YFLH, FYHI, FYKH and YEHF) were selected as ligands for preparing adsorption resins, and the resins were used to bind hIgG and BSA by static adsorption experiments. The results showed that Ac-YEHF-4FF resin had higher hIgG binding ability and lower BSA binding ability, also indicating that YEHF was the optimal screened ligand. Therefore, molecular simulation was verified as a well use technology for antibody separation and purification.