Oxygen Activation by Mononuclear Non-heme Iron Enzymes

Download or read book Oxygen Activation by Mononuclear Non-heme Iron Enzymes written by Jeffrey T Babicz and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-heme iron (NHFe) enzymes are in critical in Nature, playing significant roles in bioremediation, the biosynthesis of natural products, DNA repair and human health. These metalloenzymes utilize an Fe cofactor to activate dioxygen for reaction with organic substrates in a wide variety of chemical transformations including: H-atom abstraction, hydroxylation, halogentation, aromatic ring cleavage, aliphatic ring expansion/formation, electrophilic aromatic substitution and sulfur oxygenation/oxidation. Elucidating the mechanisms of these diverse catalysts requires defining the geometric and electronic structure of key Fe-O2 intermediates along the reaction cycle. An ideal tool for the interrogation of these Fe-O2 intermediates is nuclear resonance vibrational spectroscopy (NRVS), a synchrotron-based technique that observes the vibrational side-bands of the Fe-57 Mossbauer transition, making it a site-selective probe of all normal modes containing Fe displacement. Interpretation and analysis of NRVS spectra by correlation to quantum mechanical simulations (via density functional theory), allows for assignment of Fe vibrations and crucially geometric structure. In this thesis, NRVS is applied to the Fe-O2 intermediates in the extradiol dioxygenase, homoprotocatechuate 2,3-dioxygenase (HPCD-HPCA-Int-1) and the intradiol dioxygenase, protocatechuate 3,4-dioxygenase (PCD-4FC-Int-1), the pre-Fe(IV)=O intermediate in the pterin-dependent hydroxylase, tryptophan hydroxylase, and intermediate Q in methane monooxygenase (included in the appendix), while the ETHE1 sulfur oxidase versus oxygenase and the alpha-KG-dependent DAOCS concerted versus sequential DAOCS mechanistic studies utilize a combination of spectroscopic methods.