Authors: L. Zamolo, V. Busini, D. Moiani, D. Moscatelli and C. Cavallotti
Affilation: Politecnico di Milano, Italy
Pages: 450 - 453
Keywords: monoclonal antibodies, IgG, molecular dynamics, spacer, agarose
Monoclonal antibodies are gaining an increasing importance in diagnostic and therapeutic treatment of grave diseases such as immunodeficiency, Alzheimer’s syndrome and cancer. The production of these pharmaceuticals and especially the purification step, however, are still too expensive to ensure their large scale consumption. Affinity chromatography is one of the most employed methods for IgG purification, based on the development of specific interactions between the antibody and a ligand. Protein A and protein G are among the most common affinity ligands used at present, thanks to their high binding capacity, but they present elevated costs for their isolation, leakage and contamination problems and low stability to sterilization. Thus, synthetic ligands are being searched to improve the purification process. Usually the computational design of new ligands for proteins is performed neglecting the effect of a support on which the target molecule might be adsorbed. In order to investigate the support and spacer influence, we performed MD simulations of the support-spacer-ligand-IgG system in explicit water. The results were compared with experimental data and revealed that the interaction of the ligand with spacer and support can affect the binding process. The energetic analysis of the simulations results helped to identify the origin of such specific interactions.