Biosynthesis of Fusarium culmorum trichothecenes. The roles of isotrichodermin and 12,13-epoxytrichothec-9-ene
- Universite du Quebec, Laval (Canada)
Two different approaches enabled us to unambiguously establish the intermediacy of isotrichodermin and 12,13-epoxytrichothec-9-ene in the biosynthesis of the trichothecenes 3-acetyldeoxynivalenol and sambucinol, respectively. The kinetic pulse-labeling method enabled us to detect a plausible precursor to 3-acetyldeoxynivalenol biosynthesis. Feeding experiments using the pure 14C-labeled intermediate established that it was incorporated 27% into 3-acetyldeoxynivalenol but not to sambucinol. The 14C-precursor was subsequently used as a marker to purify the unlabeled intermediate which was shown to be isotrichodermin by spectroscopic techniques. In order to trace the enriched carbons incorporated into 3-acetylde-oxynivalenol, specifically deuteriated isotrichodermin was synthesized and fed to Fusarium culmorum. The 2H NMR spectrum of the derived 3-acetyldeoxynivalenol proved conclusively the position of the deuteriums and that isotrichodermin is a major biosynthetic precursor. The proof that isotrichodermin is converted in vivo to 3-acetyldeoxynivalenol but not to sambucinol led us to postulate that 12,13-epoxytrichothec-9-ene might have an important role in the biosynthesis of trichothecenes. We synthesized 12,13-epoxytrichothec-9-ene with tritium at C-15 or with two deuteriums at C-4 and two deuteriums at C-15. These labeled compounds enabled us to prove that 12,13-epoxytrichothec-9-ene is a major precursor to sambucinol biosynthesis but is neither converted to isotrichodermin nor to 3-acetyldeoxynivalenol. We also succeeded in isolating a biosynthetic intermediate between 12,13-epoxytrichothec-9-ene and sambucinol and characterized its structure as 3-deoxysambucinol by spectroscopic techniques (1H NMR, 2H NMR, 13C NMR, correlation spectroscopy, two-dimensional heteronuclear correlation experiments, and mass spectroscopy).
- OSTI ID:
- 6897082
- Journal Information:
- Journal of Biological Chemistry; (USA), Journal Name: Journal of Biological Chemistry; (USA) Vol. 265:12; ISSN JBCHA; ISSN 0021-9258
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ANTIGENS
BARYONS
BIOSYNTHESIS
CARBON 13
CARBON 14 COMPOUNDS
CARBON ISOTOPES
CHROMATOGRAPHY
DEUTERIUM
ELEMENTARY PARTICLES
EUMYCOTA
EVEN-ODD NUCLEI
FERMIONS
FUNGI
FUSARIUM
HADRONS
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPE DILUTION
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
LIQUID COLUMN CHROMATOGRAPHY
MAGNETIC RESONANCE
MASS SPECTROSCOPY
MATERIALS
MOLECULAR STRUCTURE
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUCLEONS
ODD-ODD NUCLEI
PARASITES
PLANTS
PRECURSOR
PROTONS
RESONANCE
SEPARATION PROCESSES
SPECTROSCOPY
STABLE ISOTOPES
SYNTHESIS
TOXIC MATERIALS
TOXINS
TRACER TECHNIQUES
TRITIUM COMPOUNDS