title: Does the TauD enzyme always hydroxylate alkanes, while an analogous synthetic non-heme reagent always desaturates them?
abstract: This theoretical work addresses the mechanistic switch between hydroxylase (alcohol formation) and desaturase (olefin formation) activities during alkane oxidation by two non-heme high-valent oxoiron reagents, the enzyme taurine:α-ketoglutarase dioxygenase (TauD) and the synthetic shape-selective catalyst (TpOBzFe), toward cyclohexadiene, cyclohexane, cyclopentane, and ethane. As we show, the desaturase/hydroxylase steps obey unique orbital selection rules, and the mechanistic switch is determined by intrinsic reactivity factors that depend on the ligand-sphere flexibility of the oxoiron species, the substrate, and the spin states of the reaction pathways. Testable predictions are outlined.
authors.affiliation: Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel.
authors.forename: Dandamudi
authors.initials: D
authors.lastname: Usharani
authors.forename: Deepa
authors.initials: D
authors.lastname: Janardanan
authors.forename: Sason
authors.initials: S
authors.lastname: Shaik
mesh_terms: D000473:Alkanes / Q000737:chemistry / Q000378:metabolism*; D006900:Hydroxylation; D058085:Iron Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D006899:Mixed Function Oxygenases / Q000737:chemistry / Q000378:metabolism*; D015394:Molecular Structure; D010084:Oxidation-Reduction
chemical_list: D000473:Alkanes; D058085:Iron Compounds; D006899:Mixed Function Oxygenases; C433064:taurine-alpha-ketoglutarate dioxygenase