Nanowiring of a redox enzyme by metallized peptides.

A molecular assembly consisting of a redox enzyme, NADH peroxidase, a metallized double-helical peptide, and a gold nanoparticle immobilized onto a gold wire derivatized with a benzenedithiol compound, initiated and conducted redox signals in the presence of H(2)O(2) and NADH. The current generated by the binding of NADH, the electron donor, was transduced through the molecular assembly with apparently little loss of signal to the solution. The currents measured correlate to an electron transfer rate constant on the order of 3,000 s(-1) within each assembly. This electron transfer rate is two orders of magnitude higher than the endogenous electron transfer rate from NADH to the native enzyme, 27 s(-1). This rate indicates that the metallized peptide is in a conformation conducive for electron transfer and, in conjunction with the redox enzyme, can form effective conduits of electrical signals. This work demonstrates the feasibility of utilizing designed and highly efficient biomolecular assemblies for the production of ultra-sensitive, in-situ biosensors.