The Enigmatic P450 Decarboxylase OleT Is Capable of, but Evolved to Frustrate, Oxygen Rebound Chemistry

Chun H. Hsieh, Xiongyi Huang, José A. Amaya, Cooper D. Rutland, Carson L. Keys, John Taylor Groves, Rachel N. Austin, Thomas M. Makris

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

OleT is a cytochrome P450 enzyme that catalyzes the removal of carbon dioxide from variable chain length fatty acids to form 1-alkenes. In this work, we examine the binding and metabolic profile of OleT with shorter chain length (n ≤ 12) fatty acids that can form liquid transportation fuels. Transient kinetics and product analyses confirm that OleT capably activates hydrogen peroxide with shorter substrates to form the high-valent intermediate Compound I and largely performs C-C bond scission. However, the enzyme also produces fatty alcohol side products using the high-valent iron oxo chemistry commonly associated with insertion of oxygen into hydrocarbons. When presented with a short chain fatty acid that can initiate the formation of Compound I, OleT oxidizes the diagnostic probe molecules norcarane and methylcyclopropane in a manner that is reminiscent of reactions of many CYP hydroxylases with radical clock substrates. These data are consistent with a decarboxylation mechanism in which Compound I abstracts a substrate hydrogen atom in the initial step. Positioning of the incipient substrate radical is a crucial element in controlling the efficiency of activated OH rebound.

Original languageEnglish (US)
Pages (from-to)3347-3357
Number of pages11
JournalBiochemistry
Volume56
Issue number26
DOIs
StatePublished - Jul 5 2017

All Science Journal Classification (ASJC) codes

  • Biochemistry

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    Hsieh, C. H., Huang, X., Amaya, J. A., Rutland, C. D., Keys, C. L., Groves, J. T., Austin, R. N., & Makris, T. M. (2017). The Enigmatic P450 Decarboxylase OleT Is Capable of, but Evolved to Frustrate, Oxygen Rebound Chemistry. Biochemistry, 56(26), 3347-3357. https://doi.org/10.1021/acs.biochem.7b00338