Consideration of an artificial protein as a non-biological heteropolymer coupled with computational design can now lead to modules capable of incorporating synthetic non-biological cofactors, thereby creating peptide-based systems with novel properties not exhibited by Nature. For example, cofactors possessing extended pi-electron systems can now be designed and tailored, with appropriate donors, acceptors and constituents, to exhibit selected nonlinear optical (NLO) responses and light-induced electron transfer (LIET) over large distances.
Importantly, the interior of the artificial protein scaffold can be used to control the conformation, solubility, position, orientation, local environment, and indeed the properties of the cofactor within the peptide. However, an ensemble of such artificial protein modules with these designed novel properties cannot form a material unless they can be ordered in one, two or three dimensions on macroscopic length scales. Our lab is working on the design and synthesis of NLO chromophores and Donor-Bridge-Acceptor (D-B-A) supermolecules and the incorporation of these chromophores in designed amphiphilic protein bundles with directed assembly to orient these at air-water interfaces and transfer to the surface of a functionalized substrate.
These protein-chromophore complexes are computationally designed in collaboration with Jeff Saven, Bill DeGrado and Kent Blasie at the University of Pennsylvania. The computational design of protein exteriors is particularly suited for membrane insertion and self assembly to form oriented, periodic 2D and 3D macroscopic assemblies with noncentrosymmetric order.