Tricarbocyclic core formation of tyrosine-decahydrofluorenes implies a three-enzyme cascade with XenF-mediated sigmatropic rearrangement as a prerequisite.

ABSTRACT: Tyrosine-decahydrofluorene derivatives feature a fused [6.5.6] tricarbocyclic core and a 13-membered para-cyclophane ether. Herein, we identified new xenoacremones A, B, and C (1-3) from the fungal strain Xenoacremonium sinensis ML-31 and elucidated their biosynthetic pathway using gene deletion in the native strain and heterologous expression in Aspergillus nidulans. The hybrid polyketide synthase-nonribosomal peptide synthetase (PKS-NRPS) XenE together with enoyl reductase XenG were confirmed to be responsible for the formation of the tyrosine-nonaketide skeleton. This skeleton was subsequently dehydrated by XenA to afford a pyrrolidinone moiety. XenF catalyzed a novel sigmatropic rearrangement to yield a key cyclohexane intermediate as a prerequisite f

SUBMITTER: Liu Z 

PROVIDER: S-EPMC8642415 | biostudies-literature | 2021 Nov

REPOSITORIES: biostudies-literature