Structural elucidation by field desorption and electron-impact mass spectrometry of the C-mycosides isolated from Mycobacterium smegmatis.

C-mycosides are superficial type-specific glycopeptidolipids of mycobacterial origin. In the present work, we have shown that field desorption mass spectrometry using the cationization method is a useful method for the molecular weight determination of such compounds. Complementary structural information has been obtained by electron-impact mass spectrometry. Combination of both methods has permitted the elucidation of the structure of the C-mycosides of Mycobacterium smegmatis, ATCC 607. This structure is similar to those described elsewhere, but some minor differences are observed in the lipid portion, mainly in the double bond location.