Confirmation of the structure of lipid A fromEnterobacter agglomerans by electrospray ionization tandem mass spectrometry

Publisher Website
Google Scholar
Abstract
Electrospray ionization (ESI) combined with tandem mass spectrometry (MS/MS) was utilized for the structural confirmation of lipid A derived from Enterobacter agglomerans, a Gram‐negative bacterium commonly found in field cotton. Previous ESI‐MS studies conducted in our laboratory found that similarities exist between the fatty acid side‐chains in the lipid A of E. agglomerans and that of Salmonella minnesota. It was noted that heterogeneity at the fatty acyl chain at position 3′ of the diglucosamine backbone of E. agglomerans can take the form of either a myristyloxymyristyl group or, less commonly, a hydroxymyristyloxymyristyl moiety. In this work, tandem mass spectra obtained from heptaacyl and hexaacyl lipid A precursors derived from E. agglomerans and a known standard S. minnesota were compared to assist in structural elucidation. These ESI‐MS/MS experiments confirmed the previously reported structure for lipid A derived from E. agglomerans. Moreover, MS/MS data indicated that the additional hydroxyl group of the 3′‐position hydroxymyristyloxymyristyl moiety is present as the α‐isomer. Copyright © 2000 John Wiley & Sons, Ltd.