A Molecular Tandem-Repeat Strategy For Elucidating Mechanical Properties of High Strength Proteins

We propose a new approach for the design and production of structural proteins that comprise one or more tandem copies of a single unit with distinct amorphous and crystalline regions. Our designed sequences are based on a structural protein produced in squid tentacles. This protein complex has a segmented copolymer structure with amorphous and crystalline domains. We designed block copolymers made from proteins with varying repeat number while keeping the lengths and compositions of the amorphous and crystalline regions fixed. We demonstrate that mechanical properties of synthetic proteins can be tuned by modulating their molecular weights. Specifically, the toughness and extensibility of synthetic polypeptides increases as a function of protein molecular weight.