Engineering of Photosystem I Attachment to Titanium Oxide Nanostructures via Ferredoxin-Fusion Proteins
Date of Award
Master of Science
Biochemistry and Cellular and Molecular Biology
Barry D. Bruce
Brad Binder, Engin Serpersu
Ferredoxins (Fds) are iron-sulfur proteins that mediate electron transfer in a range of metabolic reactions. In the thylakoid membrane of photosynthetic organisms, Fd facilitates electron transfer from the stromal surface of photosystem I (PSI) to the ferredoxin Nicotinamide adenine dinucleotide phosphate oxidoreductase (FNR), which requires that Fd is capable of docking and transferring electrons between these two complexes. In applied photosynthesis, many efforts have been devoted towards re-directing these electrons into either a hydrogen-evolving catalyst or an electron-conducting semiconductor. In this study, the electrons from the PSI complex are directed to a titanium oxide (TiO2) electrode, and Fd is used to facilitate the electron transfer. In doing so, three different TiO2 binding peptides (TOBiP) were introduced to Fd in order to provide a specific affinity for TiO2. The TOBiP-Fd fusion proteins were characterized for their ability to transfer electrons, and optimized for its attachment to TiO2 nanoparticles. In addition, we have chemically crosslinked PSI to TOBiP-Fd and optimized the attachment of the PSI-Fd-TOBiP complex protein to TiO2. In the future, we will test and optimize the photocurrent generated by the PSI-Fd-TiO2 complex.
Zhu, Tuo, "Engineering of Photosystem I Attachment to Titanium Oxide Nanostructures via Ferredoxin-Fusion Proteins. " Master's Thesis, University of Tennessee, 2014.