Fast atom bombardment mass spectrometry and tandem mass spectrometry of biologically active peptidoglycan monomers from Neisseria gonorrhoeae

Abstract

Fast atom bombardment mass spectrometry (FABMS) and tandem mass spectrometry (MS/MS) were employed to define the structures of Neisseria gonorrhoeae peptidoglycan monomers that were of interest because of their abilities to mediate diverse biological reactions ranging from arthritogenicity to somogenicity. FABMS-determined molecular weights of individual components present in several different enzymatically derived classes of gonococcal monomers revealed that each of these classes was a complex mixture of up to 13 distinct peptidoglycan fragments. These ranged from the predominant disaccharide tetrapeptides possessing reducing or nonreducing 1,6-anhydro-N-acetylmuramic acid ends to relatively minor constituents containing glycine or asparagine in addition to traditional peptidoglycan amino acids, i.e. alanine, glutamic acid, and diaminopimelic acid. FABMS of high performance liquid chromatography-purified monomers yielded some sequence information; however, analysis even of unfractionated peptidoglycan mixtures using a JEOL HX110/HX110 tandem mass spectrometer operating at 10 kV provided unambiguous primary sequence data for the peptidoglycan monomers and defined the position of glycine in four compounds as well as the location of O-acetyl substituents (present on some compounds) on C-6 of the N-acetylmuramic acid residue.