Development of magnetic beads for rapid and efficient metal-chelate affinity purifications

Metal-chelate affinity chromatography offers multiple advantages for protein purification, yet existing resins make its applications to sparse, hydrophobic, or particularly labile proteins and peptides quite difficult. In this work, we have developed a simple method to covalently modify commercially available superparamagnetic beads with a six-carbon spacer and nitrilotriacetic acid to provide a novel resin for extremely rapid and efficient metal chelate affinity purifications. Further, the small size and surface chemistry of these beads provide clear improvement in applicability to small scale purifications with reduced nonspecific adsorption. These advantages have been demonstrated relative to a commercially available nickel resin.