American Chemical Society
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Formation of the Fungal Indole Alkaloid Speradine F Implies Multiple Nonenzymatic Oxidation Steps

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journal contribution
posted on 2023-04-12, 21:29 authored by Zheng-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.