Degree Type
Honors Capstone Project
Date of Submission
Spring 5-1-2018
Capstone Advisor
Olga Makhlynets
Honors Reader
Ivan Korendovych
Capstone Major
Biology
Capstone College
Arts and Science
Audio/Visual Component
no
Capstone Prize Winner
no
Won Capstone Funding
no
Honors Categories
Sciences and Engineering
Subject Categories
Biochemistry | Biochemistry, Biophysics, and Structural Biology | Life Sciences
Abstract
Natural enzymes are complex systems with intricate folds and binding pockets, which recognize specific substrates and position them ideally for catalysis. Large size and complexity of enzymes prevent their study and use as industrial catalysts. On the other hand, de novo designed models of enzymes often use simple and stable protein scaffold, which streamlines mechanistic studies and allows industrial applications. In this work, we use previously designed four-helix bundle as a protein framework to incorporate 2-His-1- carboxylate motif often found in non-heme enzymes. Such coordination environment provides ligands to bind iron(II) and leaves three additional coordination sites to accommodate substrate and oxidant. The resulting protein named MFsc is folded, thermally stable and binds a single Fe(II) ion. MFsc protein loaded with Fe(II) catalyzes oxidation of phenols by dioxygen, thus mimicking function of catechol dioxygenases, natural enzymes that have 2-His-1-carboxylate motif. One of the intermediates in the catechol dioxygenase mechanistic pathway is Fe(II)-semiquinone radical (SQ•) adduct. This intermediate has been observed in the Fe(II)- MFsc model system and characterized by UV-vis spectroscopy and EPR. We recently discovered that even apo protein can stabilize SQ• radical for weeks. A combination of NMR studies and docking showed that the substrate sits in the hydrophobic pocket with hydroxyl groups facing the negatively charged interior of the protein.
Recommended Citation
Rempillo, Joel John, "Design of mononuclear nonheme enzyme for oxygen activation" (2018). Renée Crown University Honors Thesis Projects - All. 1170.
https://surface.syr.edu/honors_capstone/1170
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
