Biosynthesis of the trichothecene 3-acetyldeoxynivalenol. Identification of the oxygenation steps after isotrichodermin.

摘要: Upon feeding an excess of the substrate isotrichodermin, five tricyclic metabolites accumulated in Fusarium culmorum cultures. These compounds were also identified as transient intermediates trichothecene biosynthesis by kinetic pulse labeling. Their structures characterized spectroscopic techniques (1H NMR, 13C 2H and nuclear Overhauser effect difference experiments) as: 1, 15-deacylcalonectrin; 2, calonectrin; 3, 7-hydroxyisotrichodermin; 4, 8-hydroxyisotrichodermin; 5, 7, hydroxycalonectrin. Four these (1-4) rigorously proven to be biosynthetic precursors 3-acetyldeoxynivalenol. Indeed, their deuteriated derivatives shown incorporated very efficiently into 3-acetyldeoxynivalenol 2H-NMR. In addition, our experimental data suggests that first oxygenation step after isotrichodermin is at C-15, producing 15-deacylcalonectrin.