Talaropeptins A and B, Tripeptides with an --Cinnamoyl Moiety from the Marine-Derived Fungus CX11.

We report the discovery of talaropeptins A () and B (), tripeptides with an unusual 5/6/5 heterocyclic scaffold and an --cinnamoyl moiety, which were identified from the marine-derived fungus CX11. A bioinformatic analysis of the genome of CX11 and gene inactivation revealed that the biosynthesis of talaropeptins involves a nonribosomal peptide synthase gene cluster. Their chemical structures were elucidated using a combination of 1D and 2D NMR spectroscopy and mass spectrometry. The absolute configurations of and were established by electronic circular dichroism calculations and Marfey's method. The plausible biosynthesis of and is also proposed on the basis of gene deletion, substrate feeding, and heterologous expression. Compounds and showed moderate antifungal activity against phytopathogenic fungus with MIC values of 12.5 and 25 μg/mL, respectively.