title: Characterisation of the ArmA adenylation domain implies a more diverse secondary metabolism in the genus Armillaria.
abstract: The armA-gene, encoding a tridomain enzyme reminiscent of nonribosomal peptide synthetases, was identified in the genome of the basidiomycete Armillaria mellea. Heterologously expressed enzyme and the ATP-pyrophosphate exchange assay were used for the in vitro biochemical characterisation of the ArmA adenylation domain. l-leucine was the preferred substrate, while l-threonine, l-valine, l-alanine, and l-isoleucine were turned over at lower rates (83 %, 62 %, 56 %, and 44 %, respectively). Other proteinogenic amino acids, 2-oxo acids, and benzoic acid derivatives were not accepted. As the substrate range of ArmA is incompatible with the secondary metabolites known from the genus Armillaria, our results imply greater natural product diversity in this genus. This is the first biochemical characterisation of a basidiomycete amino acid-adenylating domain, and our results may help refine computer algorithms to predict substrate specificities for basidiomycete nonribosomal peptide synthetases whose genes are discovered through genome sequencing.
authors.affiliation: Friedrich-Schiller-Universität Jena, Department Pharmaceutical Biology at the Hans-Knöll-Institute, Beutenbergstrasse 11a, 07745 Jena, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Misiek
authors.forename: Jana
authors.initials: J
authors.lastname: Braesel
authors.forename: Dirk
authors.initials: D
authors.lastname: Hoffmeister
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism; D055392:Armillaria / Q000737:chemistry / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010453:Peptide Synthases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity
chemical_list: D000596:Amino Acids; D005656:Fungal Proteins; D010453:Peptide Synthases