Protein A based binding domains with desirable activities

摘要

Provided are Staphylococcal protein A (SpA) variants for binding immunoglobulin (Ig), comprising a polypeptide which varies by one or more amino acids from the amino acid sequence of a natural variable heavy chain III ("VH3") Ig-Fab binding region ("binding region") of SpA, wherein the polypeptide exhibits a different binding specificity for Ig-Fab than does SpA or exhibits a different binding specificity for a non-Ig target molecule than does SpA. Further provided are methods of making the variants and methods of using the variants for in purification of Ig as well as diagnostic and therapeutic intervention.