Structure of a highly phosphorylated lipopolysaccharide core in the DELTAalgC mutants derived from Pseudomonas aeruginosa wild-type strains PAO1 (serogroup O5) and PAC1R (serogroup O3)

摘要

Lipopolysaccharides (LPS) were isolated from rought-type mutant strains of Pseudomonas aeruginosa (DELTAalgC) derived from wild-type strains PAO1 (serogroup O5) and PAC1R (serogroup O3).Structural studies of the LPS core region with a special focus on the phosphoryaltion pattern were performed by 2D NMR spectroscopy,including a ~1H,~(31)P HMQC-TOCSY experiment,MALDI-TOF MS,and Fourier-transform ion cyclotron resonance ESIMS using the capillary skimmer dissociation technique.Both LPS were found to contain two residues each of 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo)and L-glycero-D-manno-heptose (Hpe),one residue of N-(L-alanyl)-D-galactosamine and one O-carbamoyl group (Cm) on the distal Hep residue.The following structures of a tetrasaccharide triphosphate from strain PAC1R DELTAalgC and that carrying an additional ethanolamine phosphate group (PEtN) from strain PAO1 DELTAalgC were elucidated:where R=P in PAC1R DELTAalgC and PPEtN in PaO1 deltaalgC.To our knowledge,in this work the presence of ethanolamine diphosphate is unambiguously confirmed and its position established for the first time in the LPS core of a rough-type strain of P.aeruginosa.In addition,the structure of the complete LPS core of wild-type strain P.aeruginosa PAO1 was reinvestigated and the position of the phosphorylation sites was revised.