PEPTAIBOL METABOLITES OF TOLYPOCLADIUM GEODES

Three antibiotic peptides, LP237-F8 (1), F5 (2), and F7 (3), were isol ated from the liquid culture of the fungus Tolypocladium geodes. Chemi cal shift assignments of the H-1 and C-13 NMR resonances and sequencin g of these metabolites were achieved by extensive high-field 2D NMR sp ectroscopy. The N-terminal of peptides 1 and 2 is protected with an oc tanoyl (Oc) fatty acid unit, whereas that of peptide 3 is protected wi th a decanoyl (Dec) unit. The C-terminal of all three peptides is prot ected with the amino alcohol leucinol (Lol). All three metabolites con tain the common amino acids Ala, Phe or Tyr, Pro, and Gln, as well as the unusual amino acid alpha-aminoisobutyric acid (Aib). In addition, peptides 1 and 2 contain the amino acid alpha-amino-alpha-ethyl-n-pent anoic acid (alpha-ethylnorvaline, EtNor), which has not been previousl y reported as a constituent of a natural product. Metabolites 1, 2, an d 3 are new members of the class of natural products known as peptaibo ls.