Compositions and methods are provided for producing materials having increased immunoglobulin binding capacities, the materials including full-length or truncated forms of protein A, protein G, protein A/G, protein L and other immunoglobulin-binding proteins or peptides, which moieties contain polypeptide domains, or polypeptide-oligopeptide combinations. Also provided are separation matrices containing the moieties and methods of using the separation matrices for separation of immunoglobulins or immunoglobulin containing proteins.