image: If one is good, two are better. Four main approaches are used to create bi-specific proteins. (A) Two protein domains are chemically conjugated directly with a bifunctional cross-linker. (B) Recombinant proteins that each bind to a distinct target are coexpressed in a variety of host expression systems and associate through noncovalent interactions, without chemical linkage. (C) A single protein is engineered with a single promiscuous site that binds to multiple targets, one at a time. (D) Multiple binding epitopes are introduced into a protein ligand so that it will bind two separate targets simultaneously. This image relates to an article that appeared in the February 3, 2010, issue of Science Translational Medicine. The study, by Dr. Cochran of Stanford University in Stanford, Calif., was titled, "Bi-specific Engineered Proteins Pull Double Duty." view more
Credit: Image by C. Bickel, © <i>Science</I>/AAAS