Tylopeptins A and B, new antibiotic peptides from Tylopilus neofelleus.

Two new peptides, tylopeptins A and B, were isolated from the methanol extract of the fruiting body of the mushroom, Tylopilus neofelleus. These peptides were identified as peptaibols possessing an acetylated N-terminal residue, fourteen amino acids, and leucinol as the C-terminal amino alcohol. Sequential determination and complete 1H and 13C resonance assignments were based on positive ion FAB mass spectroscopy and two dimensional NMR techniques. These peptides were subsequently shown to be active against some gram-positive bacteria, but inactive against pathogenic fungi and gram-negative bacteria.