Cicadapeptins I and II: new Aib-containing peptides from the entomopathogenic fungus Cordyceps heteropoda.
Fermentation extracts of Cordyceps heteropoda (ARSEF #1880), an entomopathogenic fungus isolated from an Australian cicada, yielded a known antifungal compound, myriocin, and a complex microheterogeneous family of novel nonribosomal peptides, each containing two residues of alpha-aminoisobutyric acid (Aib). Structure elucidation of two major components of the peptide mixture, cicadapeptins I and II (1 and 2), was accomplished by amino acid analysis and various MS, 1-D NMR, and 2-D NMR experiments. Both compounds are acylated at the N-terminus by n-decanoic acid and amidated at the C-terminus by 1,2-diamino-4-methylpentane. The amino acid sequence of cicadapeptin I is N-terminus-Hyp-Hyp-Val-Aib-Gln-Aib-Leu-C-terminus. Ile substitutes for Leu in cicadapeptin II. To our knowledge, this is the first report from fungi of consecutive Hyp or Pro residues in a nonribosomal linear peptide. ROESY data indicated that the cicadapeptins adopt a helical conformation. Cicadapeptins I and II displayed antibacterial activity and limited antifungal activity.
Krasnoff
Stuart B
SB
Department of Plant Pathology, Cornell University, Ithaca, New York 14853, USA. sbk1@cornell.edu
Reátegui
Ricardo F
RF
Wagenaar
Melissa M
MM
Gloer
James B
JB
Gibson
Donna M
DM
D000596:Amino Acids / Q000032:analysis / Q000737:chemistry; D000818:Animals; D001315:Australia; D032661:Cordyceps / Q000737:chemistry*; D005229:Fatty Acids, Monounsaturated / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D006430:Hemiptera; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology
D000596:Amino Acids; D005229:Fatty Acids, Monounsaturated; D010455:Peptides; C497865:cicadapeptin I; C497866:cicadapeptin II; C001996:thermozymocidin