Molecular insights into the binding selectivity of a synthetic ligand DAAG to Fc fragment of IgG.
Affinity chromatography with synthetic ligands has been focused as the potential alternative to protein A-based chromatography for antibody capture because of its comparable selectivity and efficiency. Better understanding on the molecular interactions between synthetic ligand and antibody is crucial for improving and designing novel ligands. In this work, the molecular interaction mechanism between Fc fragment of IgG and a synthetic ligand (DAAG) was studied with molecular docking and dynamics simulation. The docking results on the consensus binding site (CBS) indicated that DAAG could bind to the CBS with the favorable orientation like a tripod for the top-ranked binding complexes. The ligand-Fc fragment complexes were then tested by molecular dynamics simulation at neutral condition (pH 7.0) for 10 ns. The results indicated that the binding of DAAG on the CBS of Fc fragment was achieved by the multimodal interactions, combining the hydrophobic interaction, electrostatic interaction, hydrogen bond, and so on. It was also found that multiple secondary interactions endowed DAAG with an excellent selectivity to Fc fragment. In addition, molecular dynamics simulation conducted at acidic condition (pH 3.0) showed that the departure of DAAG ligand from the surface of Fc fragment was the result of reduced interaction energies. The binding modes between DAAG and CBS not only shed light on the molecular mechanisms of DAAG for antibody purification but also provide useful information for the improvement of ligand design.
Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.
Rong-Zhu
RZ
Wang
Dong-Qiang
DQ
Lin
Hong-Fei
HF
Tong
Shan-Jing
SJ
Yao
D001665:Binding Sites; D057927:Hydrophobic and Hydrophilic Interactions; D007141:Immunoglobulin Fc Fragments / Q000737:chemistry* / Q000378:metabolism*; D007074:Immunoglobulin G / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D011485:Protein Binding; D013816:Thermodynamics
D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D008024:Ligands
affinity chromatography; immunoglobulin G; molecular docking; molecular dynamics simulation; molecular interactions; peptide ligand