Biosynthesis of a Periodic Protein Containing 3-Thienylalanine: A Step Toward Genetically Engineered Conducting Polymers

Abstract

Protein engineering provides an approach to materials synthesis in which macromolecular architecture is subject to precise control. Proteins synthesized biologically from a genetic template by the protein synthesis machinery are monodisperse with respect to molecular weight, and they are stereochemically pure, as only L-amino acids are used. Chemical composition and sequence are controlled, as the covalent structure of the chain is encoded by the template messenger RNA. We reasoned that genetic engineering technology could be used to create conducting materials by incorporation of electroactive amino acids, which could subsequently be cross-linked (or grafted) to produce extended conjugated systems. The role of the protein backbone in such materials would be to control the spatial organization of the conducting layers or domains. We report here the successful synthesis of a recombinant protein containing 3-thienylalanine (3-TA, 1) in place of phenylalanine (2).