Skip to main content
PMC home page
Applied and Environmental Microbiology logoLink to Applied and Environmental Microbiology
. 1993 Aug;59(8):2486–2492. doi: 10.1128/aem.59.8.2486-2492.1993

Stereochemistry during aflatoxin biosynthesis: conversion of norsolorinic acid to averufin.

K Yabe 1, Y Matsuyama 1, Y Ando 1, H Nakajima 1, T Hamasaki 1
PMCID: PMC182310  PMID: 8368836

Abstract

A reaction sequence, norsolorinic acid (NA)-->averantin (AVN)-->5'-hydroxyaverantin (HAVN)-->averufin (AVR), is the early part of a biosynthetic pathway for aflatoxins. In this study, we determined the stereochemical relationship among these metabolites by using chiral high-performance liquid chromatography. In cell-free experiments using the cytosol fraction of Aspergillus parasiticus NIAH-26, (1'S)-AVN was exclusively produced from NA in the presence of NADPH. Also, only (1'S)-AVN, and not (1'R)-AVN, served as a substrate for the reverse reaction from AVN to NA. When the microsome fraction of NIAH-26 was incubated with (1'S)-AVN in the presence of NADPH, two HAVN diastereomers and one AVR enantiomer were formed, whereas these substances were never produced from (1'R)-AVN. Moreover, (1'S,5'R)-AVR was exclusively formed from both HAVN diastereomers by the cytosol fraction in the presence of NAD. The feeding experiments using this mutant showed that aflatoxins were produced from (1'S,5'R)-AVR but not from (1'R,5'S)-AVR. These results indicate that the enzymes involved in this pathway show strict stereospecificity to their substrates and that the configuration of (1'S,5'R)-AVR leading to the formation of aflatoxins is due to the stereospecificity of NA dehydrogenase which catalyzes the reaction between (1'S)-AVN and NA.

Full text

PDF
2486

Images in this article

2490Image
on p.2490

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Anderson J. A., Chung C. H. Conversion of versiconal acetate to versiconal and versicolorin C in extracts from Aspergillus parasiticus. Mycopathologia. 1990 Apr;110(1):31–35. doi: 10.1007/BF00442767. [DOI] [PubMed] [Google Scholar]
  2. Bennett J. W., Christensen S. B. New perspectives on aflatoxin biosynthesis. Adv Appl Microbiol. 1983;29:53–92. doi: 10.1016/s0065-2164(08)70354-x. [DOI] [PubMed] [Google Scholar]
  3. Bennett J. W., Lee L. S., Shoss S. M., Boudreaux G. H. Identification of averantin as an aflatoxin B1 precursor: placement in the biosynthetic pathway. Appl Environ Microbiol. 1980 Apr;39(4):835–839. doi: 10.1128/aem.39.4.835-839.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Bhatnagar D., Cleveland T. E., Kingston D. G. Enzymological evidence for separate pathways for aflatoxin B1 and B2 biosynthesis. Biochemistry. 1991 Apr 30;30(17):4343–4350. doi: 10.1021/bi00231a033. [DOI] [PubMed] [Google Scholar]
  5. Bhatnagar D., McCormick S. P., Lee L. S., Hill R. A. Identification of O-methylsterigmatocystin as an aflatoxin B1 and G1 precursor in Aspergillus parasiticus. Appl Environ Microbiol. 1987 May;53(5):1028–1033. doi: 10.1128/aem.53.5.1028-1033.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Birkinshaw J. H., Roberts J. C., Roffey P. Studies in mycological chemistry. XIX. "Product B" (averantin) [1,3,6,8-tetrahydroxy-2-(1-hydroxyhexyl)anthraquinone], a pigment from Aspergillus versicolor (Vuillemin) Tiraboschi. J Chem Soc Perkin 1. 1966;9:855–857. doi: 10.1039/j39660000855. [DOI] [PubMed] [Google Scholar]
  7. Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1006/abio.1976.9999. [DOI] [PubMed] [Google Scholar]
  8. Chuturgoon A. A., Dutton M. F. The affinity purification and characterization of a dehydrogenase from Aspergillus parasiticus involved in aflatoxin B1 biosynthesis. Prep Biochem. 1991;21(2-3):125–140. doi: 10.1080/10826069108018008. [DOI] [PubMed] [Google Scholar]
  9. Dutton M. F. Enzymes and aflatoxin biosynthesis. Microbiol Rev. 1988 Jun;52(2):274–295. doi: 10.1128/mr.52.2.274-295.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Hsieh D. P., Wan C. C., Billington J. A. A versiconal hemiacetal acetate converting enzyme in aflatoxin biosynthesis. Mycopathologia. 1989 Sep;107(2-3):121–126. doi: 10.1007/BF00707548. [DOI] [PubMed] [Google Scholar]
  11. ROBERTS J. C., ROFFEY P. STUDIES IN MYCOLOGICAL CHEMISTRY. XVII. AVERYTHRIN, AN ANTHRAQUINONOID PIGMENT FROM ASPERGILLUS VERSICOLOR (VUILLEMIN) TIRABOSCHI. J Chem Soc. 1965 Jun;33:3666–3672. doi: 10.1039/jr9650003666. [DOI] [PubMed] [Google Scholar]
  12. Yabe K., Ando Y., Hamasaki T. Biosynthetic relationship among aflatoxins B1, B2, G1, and G2. Appl Environ Microbiol. 1988 Aug;54(8):2101–2106. doi: 10.1128/aem.54.8.2101-2106.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Yabe K., Ando Y., Hashimoto J., Hamasaki T. Two distinct O-methyltransferases in aflatoxin biosynthesis. Appl Environ Microbiol. 1989 Sep;55(9):2172–2177. doi: 10.1128/aem.55.9.2172-2177.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Yabe K., Hamasaki T. Stereochemistry during aflatoxin biosynthesis: cyclase reaction in the conversion of versiconal to versicolorin B and racemization of versiconal hemiacetal acetate. Appl Environ Microbiol. 1993 Aug;59(8):2493–2500. doi: 10.1128/aem.59.8.2493-2500.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Yabe K., Nakamura H., Ando Y., Terakado N., Nakajima H., Hamasaki T. Isolation and characterization of Aspergillus parasiticus mutants with impaired aflatoxin production by a novel tip culture method. Appl Environ Microbiol. 1988 Aug;54(8):2096–2100. doi: 10.1128/aem.54.8.2096-2100.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Yabe K., Nakamura Y., Nakajima H., Ando Y., Hamasaki T. Enzymatic conversion of norsolorinic acid to averufin in aflatoxin biosynthesis. Appl Environ Microbiol. 1991 May;57(5):1340–1345. doi: 10.1128/aem.57.5.1340-1345.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Applied and Environmental Microbiology are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES