Selective α-Hydroxyketone Formation and Subsequent C–C Bond Cleavage by Cytochrome P450 Monooxygenase Enzymes
Date
2024
Authors
Lee, J.H.Z.
Coleman, T.
Mclean, M.A.
Podgorski, M.N.
Hayball, E.F.
Stone, I.S.J.
Bruning, J.B.
Whelan, F.
De Voss, J.J.
Sligar, S.G.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
ACS Catalysis, 2024; 14(11):8958-8971
Statement of Responsibility
Joel H. Z. Lee, Tom Coleman, Mark A. Mclean, Matthew N. Podgorski, Eva F. Hayball, Isobella S. J. Stone, John B. Bruning, Fiona Whelan, James J. De Voss, Stephen G. Sligar, and Stephen G. Bell
Conference Name
Abstract
The heme enzymes of the cytochrome P450 superfamily (CYPs) catalyze oxidation reactions with a high level of selectivity. Here, the CYP199A4 enzyme from the bacterium Rhodopseudomonas palustris HaA2 is used to catalyze the hydroxylation of carbonyl-containing compounds to generate α-hydroxyketones. Both 4-propionyl- and 4-(2-oxopropyl)-benzoic acids were regioselectively hydroxylated by this enzyme to generate α-hydroxyketone metabolites, 4-(2- hydroxypropanoyl) benzoic acid and 4-(1-hydroxy-2-oxopropyl )benzoic acid, respectively, with high stereoselectivity. Co-crystallization of CYP199A4 with each substrate allowed high-resolution X-ray crystal structures of the enzyme bound with both to be determined. These provide a rationale for biochemical observations related to substrate binding and activity. As these versatile enzymes have a demonstrated ability to support carbon−carbon (C−C) bond cleavage (lyase) reactions on α- hydroxyketones, we assessed if this activity would be catalyzed by wild-type (WT) CYP199A4. Molecular dynamics (MD) simulations predicted the regioselective hydroxylation of each substrate but indicated that the WT enzyme would not be a good catalyst for lyase activity, in agreement with the experimental observations. The MD simulations also suggested the F182L mutant of CYP199A4 would permit closer approach of the substrate to the ferric-peroxo intermediate, enabling the formation of the lyase transition state. Indeed, this variant was observed to catalyze the cleavage reaction. Furthermore, the F182A variant of CYP199A4 was used to catalyze both the hydroxylation and C−C bond cleavage reactions with both 4-propionyl- and 4-(2-oxopropyl)-benzoic acids using hydrogen peroxide as the oxidant. This dual CYP activity is analogous to that supported by the mammalian CYP17A1 enzyme in steroid biosynthesis.
School/Discipline
Dissertation Note
Provenance
Description
Access Status
Rights
© 2024 American Chemical Society