Roseabol A, a New Peptaibol from the Fungus Clonostachys rosea

• Published in: Molecules (Basel, Switzerland) Vol. 26; no. 12; p. 3594
• Main Authors: Kim, Chang-Kwon, Krumpe, Lauren R. H., Smith, Emily, Henrich, Curtis J., Brownell, Isaac, Wendt, Karen L., Cichewicz, Robert H., O’Keefe, Barry R., Gustafson, Kirk R.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 11.06.2021; MDPI
• Subjects: Alzheimer's disease; Amino acid sequence; Amino acids; Carbon; Clonostachys rosea; Fungi; Hydroxyproline; Merkel cell carcinoma; Metabolites; Nucleotide sequence; peptaibol; Peptides; Skin cancer
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules26123594

A new 11 amino acid linear peptide named roseabol A (1) and the known compound 13-oxo-trans-9,10-epoxy-11(E)-octadecenoic acid (2) were isolated from the fungus Clonostachys rosea. Combined NMR and MS analysis revealed that roseabol A (1) contained amino acid residues characteristic of the peptaibol family of peptides such as isovaline, α-aminoisobutyric acid, hydroxyproline, leucinol, and an N-terminal isovaleric acid moiety. The amino acid sequence was established by a combination of NMR studies and tandem MS fragmentation analyses, and the absolute configurations of the constituent amino acids of 1 were determined by the advanced Marfey’s method. Compound 2 showed inhibitory activity against Merkel cell carcinoma, a rare and difficult-to-treat type of skin cancer, with an IC50 value of 16.5 μM.