Protein Engineered Triblock Polymers Composed of Two SADs: Enhanced Mechanical Properties and Binding Abilities.

Recombinant methods have been used to engineer artificial protein triblock polymers composed of two different self-assembling domains (SADs) bearing one elastin (E) flanked by two cartilage oligomeric matrix protein coiled-coil (C) domains to generate CEC. To understand how the two C domains improve small molecule recognition and the mechanical integrity of CEC, we have constructed CEC, which bears an impaired C domain that is unstructured as a negative control. The CEC triblock polymer demonstrates increased small molecule binding and ideal elastic behavior for hydrogel formation. The negative control CEC does not exhibit binding to small molecule and is inelastic at lower temperatures, affirming the favorable role of C domain and its helical conformation. While both CEC and CEC assemble into micelles, CEC is more densely packed with C domains on the surface enabling the development of networks leading to hydrogel formation. Such protein engineered triblock copolymers capable of forming robust hydrogels hold tremendous promise for biomedical applications in drug delivery and tissue engineering.