ophiobolin F 生成 (Z)-(1R,6aS,7R,9aR,10aS)-7-((S)-1,5-Dimethyl-hexyl)-1,4,9a-trimethyl-1,2,3,5,6,6a,7,8,9,9a,10,10a-dodecahydro-dicyclopenta[a,d]cycloocten-1-ol
Heterologous expression of four candidate genes found in ophiobolin gene clusters from three fungal strains was employed to elucidate the late-stage biosynthetic pathway of phytotoxin ophiobolin. Expression of oblB(Ac), (cytochrome P450) from the cryptic gene cluster gave unexpected products, and that of oblB(Bm)/oblB(Ev) from the gene cluster of ophiobolin producers, with oblD(Bm) as the transporter, yielded intermediate ophiobolin C through an unusual four-step oxidation process. The observation made in this study may provide a useful guideline for the elucidation of genuine biosynthetic pathways of natural products.
Enzymic formation of a tricyclic sesterterpene alcohol from mevalonic acid and all-trans-geranylfarnesyl pyrophosphate
作者:Shigeo Nozoe、Masuo Morisaki
DOI:10.1039/c29690001319
日期:——
Mevalonicacid lactone and the chemically synthesized all-trans-geranylfarnesylpyrophosphate are converted into a tricyclicsesterterpenealcohol, ophiobolin F, by incubation with 100,000 ×g supernatant fraction from cell-free system of Chochlibolus heterostrophus.
During a screening of putative diterpene synthase genes found in public databases using the Aspergillus oryzae expression system, it was found that a single transformant with the ACLA_76850 gene from A. clavatus produced a sesterterpene alcohol, ophiobolin F, and three minor sesterterpene hydrocarbons. The sesterterpene synthase has two catalytically independent domains (prenyltransferase/terpene cyclase)