posted on 2023-04-12, 21:29authored byZheng-Xi Zhang, Zhang-Hai Li, Shu-Ming Li
The highly oxygenated indole alkaloid speradine F (4) with a 6/5/6/5/5/5 hexacyclic skeleton was isolated from
a culture
of Penicillium palitans, together with its precursors
β-cyclopiazonic acid (β-CPA, 5) and cyclopiazonic
acid (CPA, 1). Gene deletion and heterologous expression
led to the identification of the responsible five-gene spe cluster for the speradine skeleton formation. Precursor supply experiments
proved that 1 was enzymatically converted, via 2-oxoCPA
(2), to speradine A (3), which subsequently
undergoes multistep nonenzymatic hydroxylations to 4.