Construction, Expression, and Purification of Chimeric Protein Reagents Based on Immunoglobulin Fc Regions

Recombinant fusion proteins incorporating experimental protein domains fused to immunoglobulin Fc regions have become widely utilized in studies of protein–ligand interactions. The advantages of these systems include an inherent increase in avidity provided by the multimerization of Fc regions, combined with robust detection methods based on numerous commercially available secondary reagents directed against the Fc tag. We describe a set of methods for subcloning, expression, and purification of chimeric protein reagents containing a protein domain (or domains) of interest fused to a C-terminal moiety derived from the Fc region of either IgG or IgM.