Fast atom bombardment mass spectrometry of mycobacterial phenolic glycolipids

Fast atom bombardment mass spectra were successfully recorded for intact glycosylphenolphthiocerol dimycocerosates (phenolic glycolipids, PGLs) from Mycobacterium kansasii, M. leprae, M. tuberculosis, M. marinum, M. bovis and M. haemophilum. Characteristic fragment ions from the loss of the oligosaccharide moiety and one of the long-chain multimethyl-branched mycocerosic acids were observed in most cases. A tandem mass spectrometric experiment was carried out on the PGL from M. tuberculosis, revealing the type of mycocerosic acids esterified to individual homologues. Mass spectra of homologues separated by reversed-phase high-performance liquid chromatography gave information on the substitution pattern in certain cases. The potential of matrix-assisted laser desorption ionization spectroscopy was demonstrated by a successful analysis of the PGL from M. tuberculosis.