New tetrapeptide ligands designed for antibody purification with biomimetic chromatography: Molecular simulation and experimental validation

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 7⿿8 and low at pH 4⿿5. 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.