Elucidation of cladofulvin biosynthesis reveals a cytochrome P450 monooxygenase required for anthraquinone dimerization.
Anthraquinones are a large family of secondary metabolites (SMs) that are extensively studied for their diverse biological activities. These activities are determined by functional group decorations and the formation of dimers from anthraquinone monomers. Despite their numerous medicinal qualities, very few anthraquinone biosynthetic pathways have been elucidated so far, including the enzymatic dimerization steps. In this study, we report the elucidation of the biosynthesis of cladofulvin, an asymmetrical homodimer of nataloe-emodin produced by the fungus Cladosporium fulvum A gene cluster of 10 genes controls cladofulvin biosynthesis, which begins with the production of atrochrysone carboxylic acid by the polyketide synthase ClaG and the β-lactamase ClaF. This compound is decarboxylated by ClaH to yield emodin, which is then converted to chrysophanol hydroquinone by the reductase ClaC and the dehydratase ClaB. We show that the predicted cytochrome P450 ClaM catalyzes the dimerization of nataloe-emodin to cladofulvin. Remarkably, such dimerization dramatically increases nataloe-emodin cytotoxicity against mammalian cell lines. These findings shed light on the enzymatic mechanisms involved in anthraquinone dimerization. Future characterization of the ClaM enzyme should facilitate engineering the biosynthesis of novel, potent, dimeric anthraquinones and structurally related compound families.
Laboratory of Phytopathology, Wageningen University, 6708 PB Wageningen, The Netherlands;
Scott
S
Griffiths
Laboratory of Phytopathology, Wageningen University, 6708 PB Wageningen, The Netherlands; Laboratory of Molecular Plant Pathology, Institute of Agriculture and Environment, Massey University, Palmerston North 4442, New Zealand;
Carl H
CH
Mesarich
Laboratory of Phytopathology, Wageningen University, 6708 PB Wageningen, The Netherlands;
Benedetta
B
Saccomanno
Facultad de Ciencias y Filosofía, Departamento de Ciencias Celulares y Moleculares y Laboratorios de Investigación y Desarrollo, Avenida Honorio Delgado 430, Urbanización Ingeniería-San Martin de Porras, Universidad Peruana Cayetano Heredia, Lima 31, Peru;
Abraham
A
Vaisberg
Laboratory of Phytopathology, Wageningen University, 6708 PB Wageningen, The Netherlands; pierre.dewit@wur.nl j.collemare@gmail.com.
Pierre J G M
PJ
De Wit
Institut für Organische Chemie, Leibniz Universität Hannover, 30167 Hannover, Germany; School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom;
Russell
R
Cox
Laboratory of Phytopathology, Wageningen University, 6708 PB Wageningen, The Netherlands; UMR1345 Institut de Recherche en Horticulture et Semences (IRHS)-INRA, ACO, Université d'Angers, 49071 Beaucouzé Cedex, France pierre.dewit@wur.nl j.collemare@gmail.com.
Jérôme
J
Collemare
D000880:Anthraquinones / Q000737:chemistry / Q000378:metabolism*; D002963:Cladosporium / Q000201:enzymology / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D019281:Dimerization
D000880:Anthraquinones; D003577:Cytochrome P-450 Enzyme System
cytoxicity; emodin; gene cluster; nataloe-emodin; secondary metabolism