Purification of interferon gamma-interferon gamma receptor complexes by preparative electrophoresis on native gels

Cytokine-receptor complexes are required for certain studies including crystallization, NMR spectra, and investigation of the biological response mechanism to the cytokine. The purity of the ligand-receptor complex is critical for most of these applications. We investigated the possibility of purifying protein-protein complexes by electrophoresis on native gels. Starting with partially purified mouse and highly purified human proteins, we prepared milligram amounts of interferon gamma-interferon gamma receptor complexes by preparative electrophoresis on nondenaturing polyacrylamide gels. In both cases, pure ligand-receptor complexes with the correct stoichiometry of binding were recovered. Electrophoresis on preparative native gels may prove to be of general interest for the preparation of protein-protein complexes to be used in diverse studies.