Biosynthesis of illudosin, a fomannosane-type sesquiterpene, by the Basidiomycete Omphalotus nidiformis

Abstract

Sites of incorporation of ¹³C-labelled acetates and [1-¹³C,2-²H₃]acetate into illudosin 1, a fomannosane type sesquiterpene produced by Omphalotus nidiformis, have been determined by ¹³C NMR spectroscopy. The biosynthesis of illudosin was as expected, apart from the presence of some labelled species with two deuteriums attached to C-6 in illudosin which is also labelled at C-5 with ¹³C. This unusual rearrangement was also observed in the co-metabolite illudin M. A mechanism is proposed which involves the formation of a series of carbocations at the active site of the cyclase enzyme that can be reprotonated (or deuterated) non-stereospecifically.

References

1. T. C. McMorris and M. Anchel, J. Am. Chem. Soc., 1963, 85, 831; M. Anchel, T. C. McMorris and P. Singh, Phytochemistry, 1970, 9, 2339.
2. W. A. Ayer and L. M. Browne, Tetrahedron, 1981, 37, 2199.
3. T. C. McMorris and M. J. Anchel, J. Am. Chem. Soc., 1965, 87, 1594; K. Nakanishi, M. Ohashi, M. Tada and Y. Yamada, Tetrahedron, 1965, 21, 1231.
4. C. L. Steele, J. Crock, J. Bohlmann and R. Croteau, J. Biol. Chem., 1998, 273, 2078.
5. J. R. Hanson and T. Marten, J. Chem. Soc., Chem. Commun., 1973, 171.
6. J. R. Hanson, T. Marten and R. Nyfeler, J. Chem. Soc., Perkin Trans. 1, 1976, 876.
7. P. W. Bradshaw, J. R. Hanson and M. Siverns, J. Chem. Soc., Chem. Commun., 1978, 303.
8. A. P. W. Bradshaw, J. R. Hanson and I. H. Sadler, J. Chem. Soc., Perkin Trans. 1, 1982, 2445.
9. D. E. Cane and R. B. Nachbar, J. Am. Chem. Soc., 1978, 100, 3208.
10. D. M. X. Donelly, J. O'Rielly, J. Polonsky and M. H. Sheridan, J. Chem. Soc., Chem. Commun., 1983, 615.
11. S. Nozoe, H. Kobayashi, S. Urano and J. Furukawa, Tetrahedron Lett., 1977, 16, 1381.
12. N. Morisaki, J. Furukawa, H. Kobayashi, S. Iwasaki, S. Nozoe and S. Okuda, Tetrahedron Lett., 1985, 26, 4755.
13. M. L. Burgess, PhD Thesis, University of New South Wales, 1998.
14. A. Arnone, R. Cardillo, G. Nasini and O. J. de Pava, J. Chem. Soc., Perkin Trans. 1, 1991, 1787.
15. C. Abell and J. Staunton, J. Chem. Soc., Chem. Commun., 1981, 16, 856.
16. W. Kemp, NMR in Chemistry; a Multinuclear Introduction, MacMillan, New York, 1986.
17. C. M. Starks, K. Back, J. Chappell and J. Noel, Science, 1997, 277, 1815.
18. C. A. Lesburg, G. Zhai, D. E. Cane and D. W. Christianson, Science, 1997, 277, 1820.
19. K. Back and J. Chappell, J. Biol. Chem., 1995, 270, 7375.
20. K. Back and J. Chappell, Proc. Natl. Acad. Sci., 1996, 93, 6841.
21. J. R. Mathis, K. Back, C. Starks, J. Noel, C. D. Poulter and J. Chappell, Biochemistry, 1997, 36, 8340.