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Hydroxylation of Longiborneol by a Clm2-Encoded CYP450 Monooxygenase to Produce Culmorin in Fusarium graminearum
- Bahadoor, Adilah, Schneiderman, Danielle, Gemmill, Larissa, Bosnich, Whynn, Blackwell, Barbara, Melanson, Jeremy E., McRae, Garnet, Harris, Linda J.
- Journal of natural products 2016 v.79 no.1 pp. 81-88
- Fusarium graminearum, X-ray diffraction, biosynthesis, cytochrome P-450, hydroxylation, light scattering, mutants, nuclear magnetic resonance spectroscopy, plant pathogens, secondary metabolites, stereochemistry, structural genes
- A second structural gene required for culmorin biosynthesis in the plant pathogen Fusarium graminearum is described. Clm2 encodes a regio- and stereoselective cytochrome P450 monooxygenase for C-11 of longiborneol (1). Clm2 gene disruptants were grown in liquid culture and assessed for culmorin production via HPLC-evaporative light scattering detection. The analysis indicated a complete loss of culmorin (2) from the liquid culture of the ΔClm2 mutants. Culmorin production resumed in a ΔClm2 complementation experiment. A detailed analysis of the secondary metabolites extracted from the large-scale liquid culture of disruptant ΔClm2D20 revealed five new natural products: 3-hydroxylongiborneol (3), 5-hydroxylongiborneol (4), 12-hydroxylongiborneol (5), 15-hydroxylongiborneol (6), and 11-epi-acetylculmorin (7). The structures of the new compounds were elucidated by a combination of HRMS, 1D and 2D NMR, and X-ray crystallography.