FIGURE 6.

Positive-ion vMALDI-LIT mass spectra of HF-treated waaL O-LPS (dephosphorylated PS). After HF treatment, the sodiated monoisotopic mass corresponding to the major glycoform present in waaL was observed at m/z 1470.0 (supplemental Fig. S9). MALDI-MSⁿ analyses were subsequently performed on this dephosphorylated PS. The parent ion at m/z 1470 was fragmented to yield the product ion at m/z 951 (A). Product ions at m/z 951 (B), m/z 731 (C), and m/z 569 (D) were sequentially fragmented to determine the composition of the parent mass. These analyses showed that the glycoform corresponding to the ion at m/z 1470 is composed of 1 Kdo, 2 Hep, 2 Hex, and two sugars with a combined mass of 519 Da. Masses labeled with an asterisk designate major masses minus water or CO₂.