Mechanistic Study of Halogenation by Iron(II) and 2-Oxoglutarate-Dependent Oxygenases
Open Access
- Author:
- Katch, Bryce
- Area of Honors:
- Biochemistry and Molecular Biology
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Amie Kathleen Boal, Thesis Supervisor
Timothy Charles Meredith, Thesis Honors Advisor - Keywords:
- Enzymology
Structural Biology
C-H Activation
SadA
BesD - Abstract:
- Enzymes are responsible for catalyzing chemical reactions in living systems, making life as we know it possible. Many of the most challenging chemical reactions - reactions that involve breaking very stable bonds - are performed by enzymes that contain transition metals. The aliphatic carbon-hydrogen bond is an example of a bond that is typically considered inert; however, many enzymes in nature can make use of iron cofactors to activate this unreactive bond. One class of iron-dependent enzymes achieves C-H activation by coupling its chemistry to the oxidative decarboxylation of the small molecule 2-oxo-glutarate. This class of enzymes is known as the iron(II) and 2-oxo-glutarate-dependent (Fe/2OG) oxygenase superfamily. Here, we detail the study of two Fe/2OG enzymes- SadA and BesD- that perform halogenation of unactivated carbon-hydrogen bonds. SadA is a hydroxylase enzyme that we engineered to install a halide on an amino-acid derivative substrate, while BesD is natively a halogenase of a lysine substrate. Our work demonstrates that the reactivity of these enzymes can be expanded beyond their primary activity through mutagenesis or reaction with alternative substrates. We also show that these enzymes display creative strategies to favor the halogenation reaction over the canonical hydroxylation reaction. This work furthers our understanding of enzymatic C-H activation and showcases the potential biocatalytic value of this enzyme superfamily.