Ergot cluster-encoded catalase is required for synthesis of chanoclavine-I in Aspergillus fumigatus

Goetz, Kerry E., Coyle, Christine M., Cheng, Johnathan Z., O'Connor, Sarah E. and Panaccione, Daniel G. (2011) Ergot cluster-encoded catalase is required for synthesis of chanoclavine-I in Aspergillus fumigatus. Current Genetics, 57 (3). pp. 201-211. ISSN 0172-8083

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Abstract

Genes required for ergot alkaloid biosynthesis are clustered in the genomes of several fungi. Several conserved ergot cluster genes have been hypothesized, and in some cases demonstrated, to encode early steps of the pathway shared among fungi that ultimately make different ergot alkaloid end products. The deduced amino acid sequence of one of these conserved genes (easC) indicates a catalase as the product, but a role for a catalase in the ergot alkaloid pathway has not been established. We disrupted easC of Aspergillus fumigatus by homologous recombination with a truncated copy of that gene. The resulting mutant (?easC) failed to produce the ergot alkaloids typically observed in A. fumigatus, including chanoclavine-I, festuclavine, and fumigaclavines B, A, and C. The ?easC mutant instead accumulated N-methyl-4-dimethylallyltryptophan (N-Me-DMAT), an intermediate recently shown to accumulate in Claviceps purpurea strains mutated at ccsA (called easE in A. fumigatus) (Lorenz et al. Appl Environ Microbiol 76:1822–1830, 2010). A ?easE disruption mutant of A. fumigatus also failed to accumulate chanoclavine-I and downstream ergot alkaloids and, instead, accumulated N-Me-DMAT. Feeding chanoclavine-I to the ?easC mutant restored ergot alkaloid production. Complementation of either ?easC or ?easE mutants with the respective wild-type allele also restored ergot alkaloid production. The easC gene was expressed in Escherichia coli, and the protein product displayed in vitro catalase activity with H2O2 but did not act, in isolation, on N-Me-DMAT as substrate. The data indicate that the products of both easC (catalase) and easE (FAD-dependent oxidoreductase) are required for conversion of N-Me-DMAT to chanoclavine-I.

Item Type:	Article
Faculty \ School:	Faculty of Science > School of Chemistry
UEA Research Groups:	Faculty of Science > Research Groups > Synthetic Chemistry (former - to 2017)
Depositing User:	Rhiannon Harvey
Date Deposited:	21 Mar 2012 13:23
Last Modified:	10 Mar 2024 00:45
URI:	https://ueaeprints.uea.ac.uk/id/eprint/38392
DOI:	10.1007/s00294-011-0336-4

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