Designing artificial electron transfer pathways in dioxygen-activating metalloenzymes

Date created: 
2016-07-26
Identifier: 
etd9722
Keywords: 
Redox enzymes
Oxygen activation
Electron transfer
Enzyme design
Biofuels
Oxygen activation
Ruthenium-modified enzymes
Cyanobacterial aldehyde deformylating oxygenases
Cytochrome c peroxidase
Abstract: 

This thesis describes efforts to introduce new redox reactivity into two classes of dioxygen-activating enzymes. First, I investigated modified cytochrome c peroxidase (CcP). Here, a series of Trp residues were introduced between the heme active site and the surface of the enzyme to serve as a hole transfer wire. The addition of two mutations (A193W and Y229W) introduced new oxidation chemistry to CcP, as evaluated using aromatic substrate oxidation assays. This enzyme is a functional model for lignin peroxidase enzymes and provides a strong foundation for the development of new protein-based oxidation catalysts. Second, we investigated cyanobacterial aldehyde deformylating oxygenase (cAdo) enzymes. Here, we characterized and investigated three Ru-cAdo models. To provide the four electrons required for catalysis, we introduced a Ru-tris(diimine) photosensitizer to solvent exposed cysteine residues. Through NMR and GC-MS, we gained an insight into the catalytic activity of Ru-cAdo. This work highlights the nature of protein based electron transfer and points toward other underlying factors that dictate catalytic efficiency.

Document type: 
Thesis
Rights: 
This thesis may be printed or downloaded for non-commercial research and scholarly purposes. Copyright remains with the author.
File(s): 
Supervisor(s): 
Dr. Jeffrey J. Warren
Department: 
Science: Department of Chemistry
Thesis type: 
(Thesis) M.Sc.
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