Chemical characterization of two lipopolysaccharide species isolated from Rhizobium loti NZP2213.
Phenol-water extraction of Rhizobium loti NZP2213 cells allowed a simultaneous isolation of two structurally different lipopolysaccharides from the aqueous (LPS-W) and phenol (LPS-P) phase that differed in their sodium deoxycholate-PAGE pattern and composition. LPS-W showed a profile indicating an R-type LPS; LPS-P had a cluster of poorly resolved bands in the high-molecular-weight region. LPS-P contained large amounts of 6-deoxy-L-talose (6dTal), and a small amount of 2-O-methyl-6-deoxy-talose (molar ratio approximately 30:1), both of which were completely absent in LPS-W. Methylation analysis gave only one major product, 2,4-di-O-methyl-6dTal, indicating that the O-chain is composed of a homopolymer of 1,3-linked 6dTal, having the methylated 6dTal (2-O-Me-6dTal) probably localized at the non-reducing end of the O-chain. This homopolymeric O-chain was additionally O-acetylated, as evidenced by GC-MS and by 13C NMR analysis. The lipid A moieties of both LPS-W and LPS-P showed almost identical composition, with six different 3-OH fatty acids and with two, so far not described, long-chain 4-oxo-fatty acids, all being amide-linked, and with 27-OH-28:0 as the main ester-linked fatty acid. Lipid A was of the lipid ADAG-type, i.e., having a (phosphorylated) 2,3-diamino-2,3-dideoxy-D-glucose-containing lipid A backbone. Lipid ADAG is widespread among species of the alpha-2 group of Proteobacteria, but has so far not been encountered in any other rhizobial or agrobacterial species.
Russa
R
R
Max-Planck-Institut für Immunbiologie, Freiburg, Germany.
Urbanik-Sypniewska
T
T
Lindström
K
K
Mayer
H
H
D002241:Carbohydrates / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis; D008070:Lipopolysaccharides / Q000737:chemistry / Q000302:isolation & purification*; D010710:Phosphates / Q000032:analysis; D012231:Rhizobium / Q000737:chemistry*
D002241:Carbohydrates; D005227:Fatty Acids; D008070:Lipopolysaccharides; D010710:Phosphates