Molecular materials for solar energy harvesting, molecular electronics and nanoscale devices require systems capable of facilitating long-range electron transfer (ET) with high quantum yield. Fe–S clusters are some of the most common cofactors held at specific distances within complex proteins allowing medium and long distance electron transfer. However, designing multi-center Fe–S proteins remains a challenge.
This study has demonstrated the potential of Consensus tetratricopeptide repeat (CTPR) proteins as a scaffold for [4Fe–4S] clusters, enabling to coordinate a desired number of redox active clusters in a single assembly, with the cluster count controlled solely through the size of the protein.
Arrays of one, two and four electron-transfer active [4Fe–4S] clusters were constructed on modular tetratricopeptide repeat protein scaffolds, with the number of clusters determined solely by the size of the scaffold. The constructs show reversible redox activity and transient charge stabilization necessary to facilitate charge transfer. Overall, this communication serves to further demonstrate the versatility of CTPR proteins as a protein scaffold for nanotechnological systems, including potential artificial photosystems.