IDENTIFICATION AND DIRECTED BIOSYNTHESIS OF EFRAPEPTINS IN THE FUNGUS TOLYPOCLADIUM-GEODES GAMS (DEUTEROMYCOTINA, HYPHOMYCETES)

HPLC analysis of crude dichloromethane extracts of shaken liquid cultures of the hyphomycetous fungus Tolypocladium geodes Gams revealed the presence of efrapeptins. These peptides, which have mitochondrial ATPase inhibitory activity as well as antifungal and insecticidal properties, are previously known only from the cogeneric species, T. niveum Rostrup. The identity of efrapeptins was confirmed by fast atom bombardment mass spectrometry and by amino acid analysis. HPLC analyses of efrapeptins extracted from single isolates of both T. geodes and T. niveum indicated that both species produced the same efrapeptins but the profile of relative abundance of the compounds produced was diagnostic for the isolates examined. Efrapeptin F was the major component of the mixture from T. geodes with the order of abundance of the six efrapeptins detected being F > G > D approximately E > H > C. Efrapeptin D was the major component from T. niveum with the order of abundance of the six efrapeptins detected being D > E > F > C approximately G > H. Efrapeptin F differs from efrapeptin D by a single amino acid residue, efrapeptin F having an alanine where efrapeptin D has a glycine. Addition of alanine to the culture medium increased the relative abundance of efrapeptin F in the profile of both species. Conversely, addition of glycine increased the relative abundance of efrapeptin D in the profile of both species.