CARLO CAVALLOTTI*, MATTEO SALVALAGLIO
*Corresponding author
Politecnico di Milano , Dept. Chimica, Materiali e Ingegneria Chimica, G. Natta, Via Mancinelli 7, Milano, 20131, Italy

Abstract

Affinity chromatography is among the most widely used methodologies for the purification of proteins. Despite of this, a molecular understanding of its working principles is essentially still missing, mostly because of the difficulty of disentangling the contribution of the different components responsible for the affinity interaction. Molecular modelling, which has greatly progressed in the last years, offers a chance to improve greatly our understanding of this complex process. In this perspective it will be discussed how this is possible and what are the most likely rewards from this effort. Several examples of recent progress in the field will be given as well as a list of open problems and challenges.

AFFINITY CHROMATOGRAPHY: A COMPLEX PROCESS

The affinity chromatography of proteins is a process through which biomolecules dispersed in a liquid (the mobile phase) are selectively purified. This is usually accomplished flowing the mobile phase through a porous solid (the stationary phase) on which are covalently bound molecules (affinity ligands) that are able to bind selectively the desired protein. The purified protein is then desorbed flowing through the stationary phase a solvent that displaces the adsorbed protein. The stationary phase of an affinity material is composed of three parts: the affinity ligand, the support on which it is bound, and, if present, the spacer arm through which ligand and support are connected. Affinity chromatography is a complex process in the sense that many interdependent components contribute to determine the material performances, such as the molecular structure of each constituent of the affinity material as well as its mesoscopic parameters (pore diameter and length, ligand density, grain size), the composition of the mobile phase, and the process operating conditions. From an experimental standpoint, it is difficult ...