A study on the biosynthesis of hygrophorone B(12) in the mushroom Hygrophorus abieticola reveals an unexpected labelling pattern in the cyclopentenone moiety.
The hitherto unknown natural formation of hygrophorones, antibacterial and antifungal cyclopentenone derivatives from mushrooms, was investigated for hygrophorone B(12) in Hygrophorus abieticola Krieglst. ex Gröger & Bresinsky by feeding experiments in the field using (13)C labelled samples of D-glucose and sodium acetate. The incorporation of (13)C isotopes was extensively studied using 1D and 2D NMR spectroscopy as well as ESI-HRMS analyses. In the experiment with [U-(13)C6]-glucose, six different (13)C2 labelled isotopomers were observed in the 2D INADEQUATE spectrum due to incorporation of [1,2-(13)C2]-acetyl-CoA. This labelling pattern demonstrated that hygrophorone B(12) is derived from a fatty acid-polyketide route instead of a 1,4-α-D-glucan derived anhydrofructose pathway. The experiment with [2-(13)C]-acetate revealed an unexpected incorporation pattern in the cyclopentenone functionality of hygrophorone B(12). Four single-labelled isotopomers, in particular [1-(13)C]-, [2-(13)C]-, [3-(13)C]-, and [4-(13)C]-hygrophorone B(12), were detected that showed only half enrichment in comparison to the respective labelled alkyl side chain carbons. This labelling pattern indicates the formation of a symmetrical intermediate during hygrophorone B(12) biosynthesis. Based on these observations, a biogenetic route via a 4-oxo fatty acid and a chrysotrione B homologue is discussed.
Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120 Halle/Saale, Germany.
Alexander
A
Otto
Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120 Halle/Saale, Germany.
Andrea
A
Porzel
Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120 Halle/Saale, Germany.
Jürgen
J
Schmidt
Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120 Halle/Saale, Germany.
Ludger
L
Wessjohann
Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120 Halle/Saale, Germany. Electronic address: Norbert.Arnold@ipb-halle.de.
Norbert
N
Arnold
D000105:Acetyl Coenzyme A / Q000378:metabolism; D000363:Agaricales / Q000737:chemistry*; D002247:Carbon Isotopes / Q000378:metabolism; D003517:Cyclopentanes / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism; D048690:Fruiting Bodies, Fungal / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D061065:Polyketides / Q000378:metabolism
D002247:Carbon Isotopes; D003517:Cyclopentanes; D005227:Fatty Acids; D061065:Polyketides; C000608060:hygrophorone B(12); C007201:cyclopentanone; D000105:Acetyl Coenzyme A; D005947:Glucose; C013905:cyclopentenone
(13)C labelled precursors; Acetyl-CoA; Basidiomycetes; Cyclopentenones; Feeding experiments; Hygrophorones; Hygrophorus abieticola; INADEQUATE; Oxidised fatty acids; Symmetrical intermediate