Identification of the Cytochrome P450 Monooxygenase that Bridges the Clavine and Ergoline Alkaloid Pathways

Abstract

Clavines and D-lysergic acid-derived alkaloid amides and alkaloid peptides are two different families of compounds that have the indole-derived tetracyclic metergoline ring system in common. Previous work has shown that D-lysergic acid is biosynthetically derived from clavine alkaloids. Recent cloning and analysis of the ergot alkaloid biosynthesis gene cluster from the D-lysergic acid peptide (ergopeptines)-producing Claviceps purpurea, has shown that it most probably contains all genes necessary for D-lysergic acid synthesis as well as those that encode the assembly of D-lysergic acid peptides, such as ergotamine. To address the role of the oxygenase genes of alkaloid-gene clusters, the only cytochrome P450 monooxygenase gene of this cluster was inactivated by disruption. The resultant mutant accumulated agroclavine, elymoclavine, and chanoclavine in substantial amounts but not ergopeptines. Feeding the mutant with D-lysergic acid restored ergopeptine synthesis; this suggests a block in the conversion of elymoclavine to D-lysergic acid. The gene was designated cloA (for encoding a clavine oxidase, CLOA). Retransformation of the mutant with the intact cloA gene also restored ergopeptine synthesis. These data show that CLOA catalyses the conversion of clavines to D-lysergic acid, it acts as a critical enzyme in the ergot alkaloid gene cluster, and bridges the biosynthesis of the two different families of alkaloids.

Biosynthesis and Accumulation of Ergoline Alkaloids in a Mutualistic Association between Ipomoea asarifolia (Convolvulaceae) and a Clavicipitalean Fungus

“…1, A and B). Because the dmaW gene was found to be part of a cluster responsible for ergoline alkaloid biosynthesis in clavicipitalean fungi (compare Haarmann et al, 2005Haarmann et al, , 2006Fleetwood et al, 2007), the genetic material on the chromosome adjacent to this gene was also analyzed. We have previously demonstrated (Kucht et al, 2004) that alkaloids and the clavicipitalean fungi can be removed from I. asarifolia and T. corymbosa by treatment of the plant with systemic azole fungicides.…”

“…This cluster has been extended by Haarmann et al (2005). Assignment of individual genes in this cluster is under way (Haarmann et al, 2006;Fleetwood et al, 2007).…”

Microbial cytochromes P450: biodiversity and biotechnology. Where do cytochromes P450 come from, what do they do and what can they do for us?

“…The pathway includes a CYP required for the conversion of clavines to D-lysergic acid among a cluster of ergot alkaloid genes [101]. Mindful of Paracelsus' famous quote, these 'poisons' have also been turned to pharmaceutical use in migraine treatment and in inducing contractions in the uterus to stop bleeding after childbirth.…”

Endophytes: exploiting biodiversity for the improvement of natural product-based drug discovery

“…Fuelled by the conviction of secondary metabolite pathway genes clustering in fungal genomes (Keller and Hohn 1997), large-scale studies have been taken up, resulting in the identification of gene clusters for ergot alkaloid biosynthesis in C. purpurea (Tudzynski et al 1999;Correia et al 2003;Haarmann et al 2005Haarmann et al , 2006 and A. fumigatus (Coyle and Panaccione 2005;Unso¨ld and Li 2005;Li and Unso¨ld 2006); they contain 13 and 14 genes, respectively. It has been recently hypothesized that the fundamental ability to synthesize some type of ergot alkaloid was present in the most recent common ancestor of these Ascomycetes, accounting for the current phylogenetically discontinuous distribution of these secondary metabolites (Panaccione 2005).…”