Structural characterization of lichenysin A components by fast atom bombardment tandem mass spectrometry

The structural characterization of the cyclic lipoheptapeptide surfactant l ichenysin A components, produced by Bacillus licheniformis strains via the non-ribosomal pathway on a corresponding peptide synthetase, was carried ou t using a tandem mass spectrometry (MS/MS) under fast atom bombardment (FAB ) conditions. Based on the analysis of the collision-induced fragment-ion s pectrum of the single charged molecular ions of both native and partially h ydrolyzed forms of lipopeptide, a new general structure of lichenysin A com ponents was elucidated. It varies from previously proposed structure by hav ing in the peptide portion of lipopeptide the r-Gln-1 and r-Asp-5 residues instead of L-Glu-1 and L-Asn-5. The verified chemical structure of lichenys in A was found to be reflected in the structural organization of the corres ponding lichenysin A synthetase, LchA, described recently. (C) 1999 Publish ed by Elsevier Science B.V. All rights reserved.