FEATURES

FAMILY

tryptophan dimethylallyltransferase family

DESCRIPTION

Also known as NOTF_ASPSM, notF. Deoxybrevianamide E synthase; part of the gene cluster that mediates the biosynthesis of notoamide, a fungal indole alkaloid that belongs to a family of natural products containing a characteristic bicyclo[2.2.2]diazaoctane core (PubMed:20722388). The first step of notoamide biosynthesis involves coupling of L-proline and L-tryptophan by the bimodular NRPS notE, to produce cyclo-L-tryptophan-L-proline called brevianamide F (PubMed:20722388). The reverse prenyltransferase notF then acts as a deoxybrevianamide E synthase and converts brevianamide F to deoxybrevianamide E via reverse prenylation at C-2 of the indole ring leading to the bicyclo[2.2.2]diazaoctane core (PubMed:20722388). Deoxybrevianamide E is further hydroxylated at C-6 of the indole ring, likely catalyzed by the cytochrome P450 monooxygenase notG, to yield 6-hydroxy-deoxybrevianamide E (Probable). 6-hydroxy-deoxybrevianamide E is a specific substrate of the prenyltransferase notC for normal prenylation at C-7 to produce 6-hydroxy-7-prenyl-deoxybrevianamide, also called notoamide S (PubMed:20722388). As the proposed pivotal branching point in notoamide biosynthesis, notoamide S can be diverted to notoamide E through an oxidative pyran ring closure putatively catalyzed by either notH cytochrome P450 monooxygenase or the notD FAD-linked oxidoreductase (Probable). This step would be followed by an indole 2, 3-epoxidation-initiated pinacol-like rearrangement catalyzed by the notB FAD-dependent monooxygenase leading to the formation of notoamide C and notoamide D (PubMed:22188465). On the other hand notoamide S is converted to notoamide T by notH (or notD), a bifunctional oxidase that also functions as the intramolecular Diels-Alderase responsible for generation of (+)-notoamide T (Probable). To generate antipodal (-)-notoaminide T, notH' (or notD') in Aspergillus versicolor is expected to catalyze a Diels-Alder reaction leading to the opposite stereochemistry (Probable). The remaining oxidoreductase notD (or notH) likely catalyzes the oxidative pyran ring formation to yield (+)-stephacidin A (Probable). The FAD-dependent monooxygenase notI is highly similar to notB and is predicted to catalyze a similar conversion from (+)-stephacidin A to (-)-notoamide B via the 2, 3-epoxidation of (+)-stephacidin A followed by a pinacol-type rearrangement (Probable). Finally, it remains unclear which enzyme could be responsible for the final hydroxylation steps leading to notoamide A and sclerotiamide (Probable). Monomer.

EXTERNAL LINKS

notF

Deoxybrevianamide E synthase notF

notF

Molecular Synopsis