Characterization of lipid A Cronobacter sakazakii.

We have characterized the structure of lipid A in food-borne pathogen Cronobacter sakazakii BAA-894. Lipid A molecules were purified by mild acid hydrolysis, DEAE-cellulose anion exchange chromatography and preparative thin-layer chromatography. Its structure was analyzed by electrospray ionization/mass spectrometry. Two lipid A species have been found in C. sakazakii BAA-894. The majority has a structure of disaccharide of glucosamine, phosphorylated at 1- and 4'-positions, and acylated with primary 3-hydroxymyristoyl chains at 2-, 3-, 2'- and 3'-positions and secondary myristoyl residues at 2'- and 3'- positions. The other contains a secondary lauroyl chain at 2'-position in place of the myristoyl residue.