New tetrapeptide ligands designed for antibody purification with biomimetic chromatography: Molecular simulation and experimental validation
Abstract Peptide ligands have been developed as powerful alternatives to Protein A for antibody purification. In this study, a tetrapeptide library with two aromatic residues, one arginine and one aromatic/aliphatic residue (Aro Aro R Aro/Ali) was constructed considering molecular interactions and applications. The library had 128 peptide ligands and was screened by flexible docking and molecular dynamics simulation. The results indicated that Ac YFRH was the best ligand, and then was coupled onto an aminated argarose matrix. The results of isotherm adsorption showed that the binding capacity of human immunoglobulin G (IgG) was high at pH 78 and low at pH 45. The IgG adsorption also showed obvious salt independence, and the addition of salt could reduce unspecific adsorption caused by electrostatic interaction. After the optimization of pH and salt addition, high IgG purity of 98.4% could be obtained with the recovery of 89.4% from BSA containing feedstock. The purification of monoclonal antibody from CHO cell culture supernatant was tested, and the purity and recovery reached 98.0% and 79.5% respectively. The results demonstrated that the new resin with the tetrapeptide YFRH ligand had high affinity and flexible operation window for IgG purification.