Biosynthesis of Fungal Drimane‐Type Sesquiterpene Esters

Abstract

Drimane-type sesquiterpenes exhibit various biological activities and are widely present in eukaryotes.Here,we completely elucidated the biosynthetic pathway of the drimanetype sesquiterpene esters isolated from Aspergillus calidoustus and we discovered that it involves ad rimenol cyclase having the same catalytic function previously only reported in plants. Moreover,since many fungal drimenol derivatives possess a gbutyrolactone ring, we clarified the functions of the clusterassociated cytochrome P450 and FAD-binding oxidoreductase discovering that these two enzymes are solely responsible for the formation of those structures.Furthermore,swapping of the enoyl reductase domain in the identified polyketide synthase led to the production of metabolites containing various polyketide chains with different levels of saturation. These findings have deepened our understanding of howf ungi synthesize drimane-type sesquiterpenes and the corresponding esters.

The Biosynthetic Gene Cluster of Mushroom‐Derived Antrocin Encodes Two Dual‐Functional Haloacid Dehalogenase‐like Terpene Cyclases

“…Following cyclization, two dephosphorylation events catalyzed by the dephosphorylases, AstI and AstK, produce drim‐8‐ene‐11‐ol (with a Δ 8,9 double bond). The recently discovered DrtB, a homolog of AstC, produces drimenol (Δ 7,8 double bond) in vivo [18] . The above four enzymes are annotated as HAD‐like hydrolases.…”

“…To probe the catalytic motifs of AncC, mutagenesis, in vivo and in vitro experiments were performed. First, AncC was aligned with other HAD‐like TCs from Ascomycota (AstC [17] and DrtB [18] ), and the AstK and AstI phosphatases [17] and shown to contain conserved D 179 DxxD/E 183 (for ionization‐initiated/Class I mechanism) and D 285 DxD 288 TT motifs (for protonation‐initiated/Class II mechanism; Figure S12). Next, AncC was analyzed by AlphaFold 2 [21] to detect the catalytic residues, revealing that D285, D286 and D288 may be involved in protonation‐initiated cyclization of FPP and that four aspartates (D26, D29, D179 and D180) may participate in magnesium binding and pyrophosphatase (PPase) activity against 9 (Figure S13).…”