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Mechanistic analysis of carbon–carbon bond formation by deoxypodophyllotoxin synthase
Deoxypodophyllotoxin contains a core of four fused rings (A to D) with three consecutive chiral centers, the last being created by the attachment of a peripheral trimethoxyphenyl ring (E) to ring C. Previous studies have suggested that the iron(II)- and 2-oxoglutarate–dependent (Fe/2OG) oxygenase, d...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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National Academy of Sciences
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8740726/ https://www.ncbi.nlm.nih.gov/pubmed/34969844 http://dx.doi.org/10.1073/pnas.2113770119 |
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author | Tang, Haoyu Wu, Min-Hao Lin, Hsiao-Yu Han, Meng-Ru Tu, Yueh-Hua Yang, Zhi-Jie Chien, Tun-Cheng Chan, Nei-Li Chang, Wei-chen |
author_facet | Tang, Haoyu Wu, Min-Hao Lin, Hsiao-Yu Han, Meng-Ru Tu, Yueh-Hua Yang, Zhi-Jie Chien, Tun-Cheng Chan, Nei-Li Chang, Wei-chen |
author_sort | Tang, Haoyu |
collection | PubMed |
description | Deoxypodophyllotoxin contains a core of four fused rings (A to D) with three consecutive chiral centers, the last being created by the attachment of a peripheral trimethoxyphenyl ring (E) to ring C. Previous studies have suggested that the iron(II)- and 2-oxoglutarate–dependent (Fe/2OG) oxygenase, deoxypodophyllotoxin synthase (DPS), catalyzes the oxidative coupling of ring B and ring E to form ring C and complete the tetracyclic core. Despite recent efforts to deploy DPS in the preparation of deoxypodophyllotoxin analogs, the mechanism underlying the regio- and stereoselectivity of this cyclization event has not been elucidated. Herein, we report 1) two structures of DPS in complex with 2OG and (±)-yatein, 2) in vitro analysis of enzymatic reactivity with substrate analogs, and 3) model reactions addressing DPS’s catalytic mechanism. The results disfavor a prior proposal of on-pathway benzylic hydroxylation. Rather, the DPS-catalyzed cyclization likely proceeds by hydrogen atom abstraction from C7', oxidation of the benzylic radical to a carbocation, Friedel–Crafts-like ring closure, and rearomatization of ring B by C6 deprotonation. This mechanism adds to the known pathways for transformation of the carbon-centered radical in Fe/2OG enzymes and suggests what types of substrate modification are likely tolerable in DPS-catalyzed production of deoxypodophyllotoxin analogs. |
format | Online Article Text |
id | pubmed-8740726 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | National Academy of Sciences |
record_format | MEDLINE/PubMed |
spelling | pubmed-87407262022-01-25 Mechanistic analysis of carbon–carbon bond formation by deoxypodophyllotoxin synthase Tang, Haoyu Wu, Min-Hao Lin, Hsiao-Yu Han, Meng-Ru Tu, Yueh-Hua Yang, Zhi-Jie Chien, Tun-Cheng Chan, Nei-Li Chang, Wei-chen Proc Natl Acad Sci U S A Biological Sciences Deoxypodophyllotoxin contains a core of four fused rings (A to D) with three consecutive chiral centers, the last being created by the attachment of a peripheral trimethoxyphenyl ring (E) to ring C. Previous studies have suggested that the iron(II)- and 2-oxoglutarate–dependent (Fe/2OG) oxygenase, deoxypodophyllotoxin synthase (DPS), catalyzes the oxidative coupling of ring B and ring E to form ring C and complete the tetracyclic core. Despite recent efforts to deploy DPS in the preparation of deoxypodophyllotoxin analogs, the mechanism underlying the regio- and stereoselectivity of this cyclization event has not been elucidated. Herein, we report 1) two structures of DPS in complex with 2OG and (±)-yatein, 2) in vitro analysis of enzymatic reactivity with substrate analogs, and 3) model reactions addressing DPS’s catalytic mechanism. The results disfavor a prior proposal of on-pathway benzylic hydroxylation. Rather, the DPS-catalyzed cyclization likely proceeds by hydrogen atom abstraction from C7', oxidation of the benzylic radical to a carbocation, Friedel–Crafts-like ring closure, and rearomatization of ring B by C6 deprotonation. This mechanism adds to the known pathways for transformation of the carbon-centered radical in Fe/2OG enzymes and suggests what types of substrate modification are likely tolerable in DPS-catalyzed production of deoxypodophyllotoxin analogs. National Academy of Sciences 2021-12-28 2022-01-04 /pmc/articles/PMC8740726/ /pubmed/34969844 http://dx.doi.org/10.1073/pnas.2113770119 Text en Copyright © 2021 the Author(s). Published by PNAS. https://creativecommons.org/licenses/by-nc-nd/4.0/This open access article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND) (https://creativecommons.org/licenses/by-nc-nd/4.0/) . |
spellingShingle | Biological Sciences Tang, Haoyu Wu, Min-Hao Lin, Hsiao-Yu Han, Meng-Ru Tu, Yueh-Hua Yang, Zhi-Jie Chien, Tun-Cheng Chan, Nei-Li Chang, Wei-chen Mechanistic analysis of carbon–carbon bond formation by deoxypodophyllotoxin synthase |
title | Mechanistic analysis of carbon–carbon bond formation by deoxypodophyllotoxin synthase |
title_full | Mechanistic analysis of carbon–carbon bond formation by deoxypodophyllotoxin synthase |
title_fullStr | Mechanistic analysis of carbon–carbon bond formation by deoxypodophyllotoxin synthase |
title_full_unstemmed | Mechanistic analysis of carbon–carbon bond formation by deoxypodophyllotoxin synthase |
title_short | Mechanistic analysis of carbon–carbon bond formation by deoxypodophyllotoxin synthase |
title_sort | mechanistic analysis of carbon–carbon bond formation by deoxypodophyllotoxin synthase |
topic | Biological Sciences |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8740726/ https://www.ncbi.nlm.nih.gov/pubmed/34969844 http://dx.doi.org/10.1073/pnas.2113770119 |
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