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Publication Abstract from PubMed

Cytochrome P450s are amongst nature's most powerful catalysts. Their ability to activate molecular dioxygen to form high-valent ferryl intermediates (Compounds I and II) enables a wide array of chemistries ranging from simple epoxidations to more complicated C-H bond oxidation. Oxygen activation is achieved by reduction of the ferrous dioxygen complex, which requires electron transfer from a redox partner and subsequent double protonation to yield a water molecule and a ferryl porphyrin pi-cation radical (Compound I). Previous studies on the CYP101 family of cytochrome P450s demonstrated the importance of the conserved active site Asp25X residue in this protonation event, although its precise role is still yet to be unraveled. To further explore the origin of protons in oxygen activation, we analyzed the effects of an Asp to Glu mutation at the 25X position in P450cam and in CYP101D1. This mutation inactivates P450cam but not CYP101D1. A series of mutagenic, crystallographic, kinetic and molecular dynamics studies indicate that this mutation locks P450cam into a closed inactive conformation. In CYP101D1 the D259E mutant changes the rate limiting step to reduction of the P450-oxy complex thus opening a window into the critical proton coupled electron step in P450 catalysis.

The Proton Relay Network in the Bacterial P450s: CYP101A1 and CYP101D1.,Amaya JA, Batabyal D, Poulos TL Biochemistry. 2020 Jun 23. doi: 10.1021/acs.biochem.0c00329. PMID:32574066^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.