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Flavoenzyme CrmK-mediated substrate recycling in caerulomycin biosynthesis

Substrate salvage or recycling is common and important for primary metabolism in cells but is rare in secondary metabolism. Herein we report flavoenzyme CrmK-mediated shunt product recycling in the biosynthesis of caerulomycin A (CRM A 1), a 2,2′-bipyridine-containing natural product that is under d...

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Detalles Bibliográficos
Autores principales: Zhu, Yiguang, Picard, Marie-Ève, Zhang, Qingbo, Barma, Julie, Després, Xavier Murphy, Mei, Xiangui, Zhang, Liping, Duvignaud, Jean-Baptiste, Couture, Manon, Zhu, Weiming, Shi, Rong, Zhang, Changsheng
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Royal Society of Chemistry 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6016722/
https://www.ncbi.nlm.nih.gov/pubmed/30155134
http://dx.doi.org/10.1039/c6sc00771f
Descripción
Sumario:Substrate salvage or recycling is common and important for primary metabolism in cells but is rare in secondary metabolism. Herein we report flavoenzyme CrmK-mediated shunt product recycling in the biosynthesis of caerulomycin A (CRM A 1), a 2,2′-bipyridine-containing natural product that is under development as a potent novel immunosuppressive agent. We demonstrated that the alcohol oxidase CrmK, belonging to the family of bicovalent FAD-binding flavoproteins, catalyzed the conversion of an alcohol into a carboxylate via an aldehyde. The CrmK-mediated reactions were not en route to 1 biosynthesis but played an unexpectedly important role by recycling shunt products back to the main pathway of 1. Crystal structures and site-directed mutagenesis studies uncovered key residues for FAD-binding, substrate binding and catalytic activities, enabling the proposal for the CrmK catalytic mechanism. This study provides the first biochemical and structural evidence for flavoenzyme-mediated substrate recycling in secondary metabolism.