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Int. J. Mol. Sci. 2008, 9(9), 1717-1729; doi:10.3390/ijms9091717
Article

Are the Genes nadA and norB Involved in Formation of Aflatoxin G1?

* , Jr.
,
 and *
Received: 6 August 2008; in revised form: 26 August 2008 / Accepted: 4 September 2008 / Published: 9 September 2008
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Abstract: Aflatoxins, the most toxic and carcinogenic family of fungal secondary metabolites, are frequent contaminants of foods intended for human consumption. Previous studies showed that formation of G-group aflatoxins (AFs) from Omethylsterigmatocystin (OMST) by certain Aspergillus species involves oxidation by the cytochrome P450 monooxygenases, OrdA (AflQ) and CypA (AflU). However, some of the steps in the conversion have not yet been fully defined. Extracts of Aspergillus parasiticus disruption mutants of the OYE-FMN binding domain reductase-encoding gene nadA (aflY) contained a 386 Da AFG1 precursor. A compound with this mass was predicted as the product of sequential OrdA and CypA oxidation of OMST. Increased amounts of a 362 Da alcohol, the presumptive product of NadA reduction, accumulate in extracts of fungi with disrupted aryl alcohol dehydrogenase-encoding gene norB. These results show that biosynthesis of AFG1 involves NadA reduction and NorB oxidation.
Keywords: Aspergillus parasiticus; aflatoxin biosynthesis; aryl alcohol dehydrogenase; gene disruption; OYE-flavin mononucleotide reductase Aspergillus parasiticus; aflatoxin biosynthesis; aryl alcohol dehydrogenase; gene disruption; OYE-flavin mononucleotide reductase
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Ehrlich, K.C.; Scharfenstein, L.L., Jr.; Montalbano, B.G.; Chang, P.-K. Are the Genes nadA and norB Involved in Formation of Aflatoxin G1? Int. J. Mol. Sci. 2008, 9, 1717-1729.

AMA Style

Ehrlich KC, Scharfenstein LL, Jr, Montalbano BG, Chang P-K. Are the Genes nadA and norB Involved in Formation of Aflatoxin G1? International Journal of Molecular Sciences. 2008; 9(9):1717-1729.

Chicago/Turabian Style

Ehrlich, Kenneth C.; Scharfenstein, Leslie L., Jr.; Montalbano, Beverly G.; Chang, Perng-Kuang. 2008. "Are the Genes nadA and norB Involved in Formation of Aflatoxin G1?" Int. J. Mol. Sci. 9, no. 9: 1717-1729.


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