Genome Mining and Total Synthesis of Viduamanide, A Non-canonical Prolineless Cycloamanide from Amanita vidua.

The MeOH extract of the newly described deadly mushroom Amanita vidua was dominated by an unknown peptide. Despite the limited fungal material available, the compound was isolated and characterized as a homodetic cyclic hexapeptide by NMR and MS/MS analyses, and its structure was confirmed by high-efficiency solid-phase peptide synthesis. Recently implemented genome mining further validated the structure and provided a broader insight into the cyclopeptide-producing capabilities of this rare mushroom. Named viduamanide, this compound is a non-canonical cycloamanide of the "prolineless" subtype and the first of its kind ever reported to not contain a proline residue.