Astellifadiene: Structure Determination by NMR Spectroscopy and Crystalline Sponge Method, and Elucidation of its Biosynthesis

Abstract

Genome mining of at erpene synthase gene from Emericella variecolor NBRC 32302 and its functional expression in Aspergillus oryzae led to the production of the new sesterterpene hydrocarbon, astellifadiene (1), having a6-8-6-5fused ring system. The structure of 1 was initially investigated by extensive NMR analyses,and was further confirmed by the crystalline sponge method, whiche stablished the absolute structure of 1 and demonstrated the usefulness of the method in the structure determination of complex hydrocarbon natural products.Furthermore,the biosynthesis of 1 was proposed on the basis of isotope-incorporation experiments performed both in vivo and in vitro.T he cyclization of GFPP involves ap rotonation-initiated second cyclization sequence,1 ,2-alkyl migration, and 1,5-hydride shift to generate the novel scaffold of 1.

Multi-domain terpenoid cyclase architecture and prospects for proximity in bifunctional catalysis

“…Fusicoccadiene is a precursor of the diterpene glucoside fusicoccin A, a phytotoxin that also exhibits promising antitumor properties [38,39], and PaFS was the first bifunctional diterpene synthase with αα domain architecture to be discovered [40]. A second bifunctional synthase was later discovered in the same organism [41], and more recent reports describe additional bifunctional diterpene and sesterterpene synthases with presumed αα domain architecture [42-45]. The C-terminal α domain of PaFS catalyzes the condensation of dimethylallyl diphosphate (DMAPP) and three isopentenyl diphosphate (IPP) molecules to generate GGPP, and the N-terminal α domain catalyzes the cyclization of GGPP to form fusicoccadiene (Figure 3a) [40,46].…”

The Biosynthetic Gene Cluster for Sestermobaraenes—Discovery of a Geranylfarnesyl Diphosphate Synthase and a Multiproduct Sesterterpene Synthase from Streptomyces mobaraensis

“…[13] The only type I TS from bacteria with StTS side activity that catalyzes the conversion of GFPP into prenylspata-13,17-diene (4) is spata-13,17-diene synthase (SpS) from Streptomyces xinghaiensis, but this enzyme functions naturally as a diterpene synthase. [14] Starting from the ophiobolin F (5) synthase from Aspergillus clavatus, a few StTSs from fungi [15][16][17][18][19][20][21][22][23] and plants [24][25][26] were discovered recently. In fungi sesterterpene biosynthesis is always promoted by bifunctional enzymes with a GFPPS and a StTS domain, [27,28] while in plants clustered genes for two discrete enzymes are found.…”

Biosynthesegencluster für Sestermobaraene – Entdeckung einer Geranylfarnesyldiphosphatsynthase und einer Multiprodukt‐Sesterterpensynthase aus Streptomyces mobaraensis

“…[13] Die einzige TS des Typs I aus Bakterien mit Nebenaktivität als StTS, die die Umsetzung von GFPP zu Prenylspata-13,17-dien (4) katalysiert, ist Spata-13,17-dien-Synthase (SpS) aus Streptomyces xinghaiensis, aber dieses Enzym besitzt eine natürliche Funktion als Diterpensynthase. [14] Beginnend bei der Synthase für Ophiobolin F (5) aus Aspergillus clavatus wurden in letzter Zeit einige StTSn aus Pilzen [15][16][17][18][19][20][21][22][23] und Pflanzen [24][25][26] entdeckt. In Pilzen wird die Biosynthese von Sesterterpenen immer durch bifunktionale Enzyme mit einer GFPPS-und einer StTS-Domäne katalysiert, [27,28] während in Pflanzen geclusterte Gene für zwei diskrete Enzyme aufgefunden werden.…”