Modified heme peptides as components of systems for solar energy conversion

Nature makes use of tetrapyrrole-based chromophores complexed with protein as light-harvesting agents in solar energy conversion. Inspired by nature\u27s approach, we are designing and preparing porphyrin-peptide conjugates for use in solar-energy conversion. Heme peptides are expressed in E. coli by making make use of the cytochrome c maturation apparatus that covalently attaches heme to Cys-X-X-Cys-His motifs. Heme iron is then replaced with zinc, resulting in photoexcitable electron donors. The peptides are designed to optimize binding to nanotubes, the intended electron acceptor for long-range charge separation. An ultimate goal is to utilize the porphyrin-peptides in devices for the photogeneration of hydrogen as a clean energy carrier