An evolved artificial radical cyclase enables the construction of bicyclic terpenoid scaffolds via an H-atom transfer pathway.

Autor: Chen D; Department of Chemistry, University of Basel, Basel, Switzerland.; National Center of Competence in Research 'Catalysis', ETH Zurich, Zurich, Switzerland.; National Center of Competence in Research 'Molecular Systems Engineering', Basel, Switzerland., Zhang X; Department of Chemistry, University of Basel, Basel, Switzerland.; National Center of Competence in Research 'Catalysis', ETH Zurich, Zurich, Switzerland.; National Center of Competence in Research 'Molecular Systems Engineering', Basel, Switzerland., Vorobieva AA; Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.; VIB-VUB Center for Structural Biology, Brussels, Belgium., Tachibana R; Department of Chemistry, University of Basel, Basel, Switzerland.; National Center of Competence in Research 'Catalysis', ETH Zurich, Zurich, Switzerland., Stein A; National Center of Competence in Research 'Molecular Systems Engineering', Basel, Switzerland., Jakob RP; Biozentrum, University of Basel, Basel, Switzerland., Zou Z; Department of Chemistry, University of Basel, Basel, Switzerland.; National Center of Competence in Research 'Molecular Systems Engineering', Basel, Switzerland., Graf DA; Department of Chemistry, University of Basel, Basel, Switzerland.; National Center of Competence in Research 'Molecular Systems Engineering', Basel, Switzerland., Li A; State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China., Maier T; Biozentrum, University of Basel, Basel, Switzerland., Correia BE; Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland. bruno.correia@epfl.ch., Ward TR; Department of Chemistry, University of Basel, Basel, Switzerland. thomas.ward@unibas.ch.; National Center of Competence in Research 'Catalysis', ETH Zurich, Zurich, Switzerland. thomas.ward@unibas.ch.; National Center of Competence in Research 'Molecular Systems Engineering', Basel, Switzerland. thomas.ward@unibas.ch.
Jazyk: angličtina
Zdroj: Nature chemistry [Nat Chem] 2024 Oct; Vol. 16 (10), pp. 1656-1664. Date of Electronic Publication: 2024 Jul 19.
DOI: 10.1038/s41557-024-01562-5
Abstrakt: While natural terpenoid cyclases generate complex terpenoid structures via cationic mechanisms, alternative radical cyclization pathways are underexplored. The metal-catalysed H-atom transfer reaction (M-HAT) offers an attractive means for hydrofunctionalizing olefins, providing access to terpenoid-like structures. Artificial metalloenzymes offer a promising strategy for introducing M-HAT reactivity into a protein scaffold. Here we report our efforts towards engineering an artificial radical cyclase (ARCase), resulting from anchoring a biotinylated [Co(Schiff-base)] cofactor within an engineered chimeric streptavidin. After two rounds of directed evolution, a double mutant catalyses a radical cyclization to afford bicyclic products with a cis-5-6-fused ring structure and up to 97% enantiomeric excess. The involvement of a histidine ligation to the Co cofactor is confirmed by crystallography. A time course experiment reveals a cascade reaction catalysed by the ARCase, combining a radical cyclization with a conjugate reduction. The ARCase exhibits tolerance towards variations in the dienone substrate, highlighting its potential to access terpenoid scaffolds.
(© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)
Databáze: MEDLINE
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