title: New insights into ergot alkaloid biosynthesis in Claviceps purpurea: an agroclavine synthase EasG catalyses, via a non-enzymatic adduct with reduced glutathione, the conversion of chanoclavine-I aldehyde to agroclavine.
abstract: Ergot alkaloids are indole derivatives with diverse structures and biological activities. They are produced by a wide range of fungi with Claviceps purpurea as the most important producer for medical use. Chanoclavine-I aldehyde is proposed as a branch point via festuclavine or pyroclavine to clavine-type alkaloids in Trichocomaceae and via agroclavine to ergoamides and ergopeptines in Clavicipitaceae. Here we report the conversion of chanoclavine-I aldehyde to agroclavine by EasG from Claviceps purpurea, a homologue of the festuclavine synthase FgaFS in Aspergillus fumigatus, in the presence of reduced glutathione and NADPH. EasG comprises 290 amino acids with a molecular mass of about 31.9 kDa. The soluble monomeric His(6)-EasG was purified after overproduction in E. coli by affinity chromatography and used for enzyme assays. The structure of agroclavine was unequivocally elucidated by NMR and MS analyses.
authors.affiliation: Philipps-Universität Marburg, Institut für Pharmazeutische Biologie und Biotechnologie, Deutschhausstrasse 17A, D-35037, Marburg, Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Matuschek
authors.forename: Christiane
authors.initials: C
authors.lastname: Wallwey
authors.forename: Xiulan
authors.initials: X
authors.lastname: Xie
authors.forename: Shu-Ming
authors.initials: SM
authors.lastname: Li
mesh_terms: D000447:Aldehydes / Q000737:chemistry / Q000378:metabolism*; D055162:Biocatalysis; D002967:Claviceps / Q000201:enzymology* / Q000378:metabolism; D004873:Ergolines / Q000737:chemistry / Q000378:metabolism*; D004876:Ergot Alkaloids / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D005978:Glutathione / Q000737:chemistry / Q000378:metabolism*; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000737:chemistry / Q000378:metabolism*; D013237:Stereoisomerism
chemical_list: D000447:Aldehydes; D004873:Ergolines; D004876:Ergot Alkaloids; D005656:Fungal Proteins; C004465:agroclavine; D000587:Oxidoreductases Acting on CH-NH Group Donors; C560846:agroclavine synthase, Claviceps purpurea; D005978:Glutathione