2026-09-20T00:01:04Zhttps://ecommons.cornell.edu/server/oai/requestoai:ecommons.cornell.edu:1813/1145812026-05-15T19:50:57Zcom_1813_35col_1813_47
Bollmeyer, Melissa
Lancaster, Kyle
Crane, Brian
Ando, Nozomi
2024-04-05T18:46:12Z
2023-08
ProQuest Submission ID: 13939
ProQuest Publication ID: 30631062
https://hdl.handle.net/1813/114581
https://doi.org/10.7298/xm5b-jh16
16219203
247 pages
Ammonia oxidizing bacteria (AOB) have evolved a nitrogen-based metabolism in which they rely solely on the oxidation of ammonia as their energy for life. In contrast to carbon-based metabolisms, there is a large gap in our knowledge of nitrogen-based metabolisms. The primary energy producing step by AOB is performed by the enzyme hydroxylamine oxidoreductase, which oxidizes hydroxylamine (NH2OH) to nitric oxide (NO). Another enzyme expressed by AOB, cytochrome P460, can also oxidize NH2OH but produces nitrous oxide (N2O). The ability of these enzymes to oxidize NH2OH is attributed in part to their unique heme P460 cofactors, which feature additional cross-links to the porphyrin. While a proposed function of cytochrome P460 in vivo is the detoxification of NH2OH, this remains speculative. This thesis will address the reactivity of cytochrome P460 and put it into the context of AOB metabolism. Cytochrome P460 can catalyze a variety of reactions, both as the proenzyme and matured cross-linked enzyme. I will interrogate the mechanisms employed by cytochrome P460 using a combination of spectroscopy and mutagenesis. By doing so, I hope to expand our understanding of the function(s) of cytochrome P460, highlighting its ability to do chemistry that had not previously been considered. The results herein will have important implications for AOB metabolism.
en
Bioinorganic
Cytochrome P460
Hydroxylamine Oxidation
Nitrification
Spectroscopy
Elucidating the Reactivity of Cytochrome P460: Maturation, Product Selectivity, and Substrate Scope
dissertation or thesis
https://newcatalog.library.cornell.edu/catalog/16219203
application/pdf
Chemistry and Chemical Biology
Cornell University
Doctor of Philosophy
Ph. D., Chemistry and Chemical Biology
https://hdl.handle.net/1813/59810.2
Publication
Cornell Theses and Dissertations
Bollmeyer, Melissa
5893a6ea-7af3-41d7-abc6-04bcd26ab5df
open.access
open.access
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<Keyword>Bioinorganic</Keyword>
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<Keyword>Hydroxylamine Oxidation</Keyword>
<Keyword>Nitrification</Keyword>
<Keyword>Spectroscopy</Keyword>
<Abstract>Ammonia oxidizing bacteria (AOB) have evolved a nitrogen-based metabolism in which they rely solely on the oxidation of ammonia as their energy for life. In contrast to carbon-based metabolisms, there is a large gap in our knowledge of nitrogen-based metabolisms. The primary energy producing step by AOB is performed by the enzyme hydroxylamine oxidoreductase, which oxidizes hydroxylamine (NH2OH) to nitric oxide (NO). Another enzyme expressed by AOB, cytochrome P460, can also oxidize NH2OH but produces nitrous oxide (N2O). The ability of these enzymes to oxidize NH2OH is attributed in part to their unique heme P460 cofactors, which feature additional cross-links to the porphyrin. While a proposed function of cytochrome P460 in vivo is the detoxification of NH2OH, this remains speculative. This thesis will address the reactivity of cytochrome P460 and put it into the context of AOB metabolism. Cytochrome P460 can catalyze a variety of reactions, both as the proenzyme and matured cross-linked enzyme. I will interrogate the mechanisms employed by cytochrome P460 using a combination of spectroscopy and mutagenesis. By doing so, I hope to expand our understanding of the function(s) of cytochrome P460, highlighting its ability to do chemistry that had not previously been considered. The results herein will have important implications for AOB metabolism.</Abstract>
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