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

Org Biomol Chem. 2011 Jun 7;9(11):4328-35. doi: 10.1039/c0ob01215g. Epub 2011 Apr 15.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aldehydes / chemistry
  • Aldehydes / metabolism*
  • Biocatalysis
  • Claviceps / enzymology*
  • Claviceps / metabolism
  • Ergolines / chemistry
  • Ergolines / metabolism*
  • Ergot Alkaloids / biosynthesis*
  • Ergot Alkaloids / chemistry
  • Ergot Alkaloids / genetics
  • Fungal Proteins / chemistry
  • Fungal Proteins / metabolism*
  • Glutathione / chemistry
  • Glutathione / metabolism*
  • Molecular Conformation
  • Molecular Sequence Data
  • Oxidoreductases Acting on CH-NH Group Donors / chemistry
  • Oxidoreductases Acting on CH-NH Group Donors / metabolism*
  • Stereoisomerism


  • Aldehydes
  • Ergolines
  • Ergot Alkaloids
  • Fungal Proteins
  • agroclavine
  • Oxidoreductases Acting on CH-NH Group Donors
  • agroclavine synthase, Claviceps purpurea
  • Glutathione

Associated data

  • GENBANK/AJ703809
  • GENBANK/AY836771