Engineering solid-state metalloproteins

Abstract

The ability to harness the functional properties of metalloproteins within a solid-state material affords a number of commercial advantages such as stability and recyclability in heterogeneous biocatalysts and biosensors. Our strategy is to employ a recombinant coiled coil silk protein from honeybees as a de novo engineering scaffold. This recombinant protein can be produced at commercially viable levels, the protein sequence can be precisely manipulated using molecular biology, allowing very fine control over the properties of the heme-binding sites, and the protein can be fabricated in a variety of solid-state material forms such as films and sponges. We introduce heme cofactors to the silk materials and they interact through specific binding and coordination sites akin to naturally occurring metalloproteins. To date, we have developed a recoverable heme-silk sponge with peroxidase activity, a nitric oxide-sensing protein film and new metalloprotein materials for use in biofuel cells.