Fungal metabolites. Part 5. Rapid structure elucidation of antibiotic peptides, minor components of Trichosporin Bs from Trichoderma polysporum. Application of linked-scan and continuous-flow fast-atom bombardment mass spectrometry

Abstract

From the minor-components mixture of Trichosporin Bs (TS-Bs) produced by Trichoderma polysporum, ten components could be elucidated by means of linked-scan and continuous-flow fastatom bombardment. The combination of their complementary results made the rapid structure elucidation of the minor components possible without isolation and purification. The identified compounds are antibiotic eicosapeptides and have very similar structures with relative molecular masses of ∼2000. Four new peptide groups were found. In their structures, the first group has Gly at the amino acid position 3 in contrast to the known TS-Bs, the second one has Vxx (valine or isovaline) at position 12, and the third and the fourth ones have Ala at position 13 or 17, respectively.