Peptidoglycans isolated from two Fusobacterium species of anaerobic bacteri
a were analyzed for constituent amino acids. Hydrolysis conditions were var
ied to optimize the yield of diamino acids from peptidoglycan. The o-phthal
aldehyde derivatives of the diamino acid stereoisomers were separated by hi
gh-performance liquid chromatography (OPA-HPLC), and variations in the rela
tive areas of the two peaks noticed during analysis of solid samples were a
ttributed to sampling errors. Co-derivatization/injection experiments using
standards of the meso and rac forms separated from commercial mixtures dem
onstrated that meso-2,6-diaminopimelic acid and meso-lanthionine were pepti
doglyean components in Fusobacterium varium and Fusobacterium nucleatum, re
spectively. The protonated molecules of 2,6-diaminopimelic acid and lanthio
nine were detected in peptidoglycan hydrolyzates by off-line, flow-injectio
n electrospray mass spectrometry (ESI-MS). In ESI-MS-MS experiments under i
dentical collision-induced dissociation (CID) conditions, peptidoglycan-der
ived and standard diamino acids exhibited similar fragmentations. Fragmenta
tion pathways are proposed for each diamino acid. The results confirm that
the meso forms of two different diamino acids are utilized in the peptidogl
ycans of Fusobacterium species.