Dual factors required for cytochrome-P450-mediated hydrocarbon ring contraction in bacterial gibberellin phytohormone biosynthesis

dc.contributor.author Nagel, Raimund
dc.contributor.author Alexander, Liza E.
dc.contributor.author Stewart, Charles
dc.contributor.author Peters, Reuben
dc.contributor.department Biochemistry, Biophysics and Molecular Biology
dc.date.accessioned 2023-06-29T13:22:12Z
dc.date.available 2023-06-29T13:22:12Z
dc.date.issued 2023-06-20
dc.description.abstract Cytochromes P450 (CYPs) are heme-thiolate monooxygenases that prototypically catalyze the insertion of oxygen into unactivated C–H bonds but are capable of mediating more complex reactions. One of the most remarked-upon alternative reactions occurs during biosynthesis of the gibberellin A (GA) phytohormones, involving hydrocarbon ring contraction with coupled aldehyde extrusion of ent-kaurenoic acid to form the first gibberellin intermediate. While the unusual nature of this reaction has long been noted, its mechanistic basis has remained opaque. Building on identification of the relevant CYP114 from bacterial GA biosynthesis, detailed structure–function studies are reported here, including development of in vitro assays as well as crystallographic analyses both in the absence and presence of substrate. These structures provided insight into enzymatic catalysis of this unusual reaction, as exemplified by identification of a key role for the “missing” acid from an otherwise highly conserved acid–alcohol pair of residues. Notably, the results demonstrate that ring contraction requires dual factors, both the use of a dedicated ferredoxin and absence of the otherwise conserved acidic residue, with exclusion of either limiting turnover to just the initiating and more straightforward hydroxylation. The results provide detailed insight into the enzymatic structure–function relationships underlying this fascinating reaction and support the use of a semipinacol mechanism for the unusual ring contraction reaction.
dc.description.comments This article is published as Nagel, Raimund, Liza E. Alexander, Charles E. Stewart Jr, and Reuben J. Peters. "Dual factors required for cytochrome-P450-mediated hydrocarbon ring contraction in bacterial gibberellin phytohormone biosynthesis." Proceedings of the National Academy of Sciences 120, no. 26 (2023): e2221549120. Posted with permission.<br/><br/>This article is distributed under <a href="https://creativecommons.org/licenses/by-nc-nd/4.0/" target="_blank">Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND)</a>.
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/3wxaeVgv
dc.language.iso en
dc.publisher The Proceedings of the National Academy of Sciences
dc.source.uri https://doi.org/10.1073/pnas.2221549120 *
dc.subject.disciplines DegreeDisciplines::Life Sciences::Biochemistry, Biophysics, and Structural Biology
dc.subject.keywords enzymatic structure–function
dc.subject.keywords monooxygenase
dc.subject.keywords reaction mechanism
dc.title Dual factors required for cytochrome-P450-mediated hydrocarbon ring contraction in bacterial gibberellin phytohormone biosynthesis
dc.type Article
dspace.entity.type Publication
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relation.isAuthorOfPublication 498a24ec-81d7-4bee-b145-323d38e7a392
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