Design of artificial proteins to incorporate non-biological cofactors

The design of artificial proteins with synthetic non-biological cofactors could lead to peptide based~systems with novel properties not exhibited by biological systems. Extended pi-electron~systems were designed~to exhibit selected NLO responses and light-induced electron transport. Amphiphilic 4-helix bundle peptides have been designed to selectively incorporate electron donor-acceptor prosthetic groups within both the hydrophilic and hydrophobic domains. The binding between a series of non-biological metalloporphyrin cofactors and the designed amphiphilic 4-helix bundles was studied. Incorporation of the non-biological cofactors into the 4-helix bundle did not change the secondary structure of the proteins. The binding selectivity depends on hydrophobicity and steric hindrance of the cofactors. Artificial proteins monolayer, both the apo- and holo-form, can be oriented vectorially at the air/water interface. This development may potentially lead to `bio-inspired' materials with novel electron transfer properties.