FIG. 4.

vMALDI-LTQ-MS spectra of O-deacylated LOS isolated from 35000HP-RSM2 (A) and 35000HP-RSM2(pLBGA) (B). Samples were run in the negative ion mode. A loss of 98 indicates the neutral loss of phosphoric acid, H₃PO₄, presumably by β-elimination. All of the deprotonated molecular ions, [M-H]⁻, corresponding to the major O-LOS glycoforms are shown in boldface in each spectrum. Peaks labeled with an asterisk indicate glycoforms that contain salt adducts (potassium) resulting in an increase of 38 Da.