Antisera generated against each of the nine known chemotypes of Salmonella lipopolysaccharide (LPS) core were characterized in order to delineate cross-reactive epitopes and define the bases for their accessibility. Strongly cross-reactive epitopes were associated with three chemotypes: Ra and Rb4, which recognized α-GlcNAc 1→2 αGlc, and Rd1, which recognized L-α-D-heptose-(1→7)-L-α-D-heptose. Both these disaccharides and the more weakly cross-reactive α-Gal-1→6-α-Glc terminal in Rb3 LPS represent branch points along the core oligosaccharide. Therefore, branch points in endotoxin core oligosaccharides may generally be cross-reactive.
Lipopolysaccharide, core, epitope, lipopolysaccharide core, epitopes, Salmonella, Salmonella lipopolysaccharide
The publication contains the following compound(s):|
Show legend Show as text |
|
Show legend Show as text |
The O-antigenic repeating units of the Salmonella cell surface lipopolysaccharides (serotypes A, B and D1) serve as receptors for phage P22. This initial binding step is mediated by the tailspike protein (TSP), which is present in six copies on the base plate of the phage. In addition to the binding activity, TSP also displays a low endoglycolytic activity, cleaving the α(1,3)-O-glycosidic bond between rhamnose and galactose of the O-antigenic repeats. The crystal structure of TSP in complex with receptor fragments allowed to identify the receptor binding site for the octasaccharide product of the enzymatic action of TSP on delipidated LPS and the active site consisting of Asp392, Asp395 and Glu359. The structure comprises a large right-handed parallel beta-helix of 13 turns. These fold independently in the trimer, whereas the N-terminus forms a cap-like structure and the C-terminal parts of the three polypeptide strands merge to a single common domain. In addition, TSP has served as model system for the folding of large, multisubunit proteins. Its folding pathway is influenced by a large number of point mutations, classified as lethal, temperature sensitive or general suppressor mutations, which influence the partitioning between aggregation and the productive folding pathway.
O-antigen, Salmonella, crystal structure, endoglycosidase, X-ray crystallography, phage mutants, protein folding, receptor binding, β-helix, virus proyein
The publication contains the following compound(s):|
Show legend Show as text |
|
Show legend Show as text |
|
Show legend Show as text |
The chemical structure of a lipid A, which was obtained as a minor component from lipopolysaccharide of Helicobacter pylori strain 206-1, was determined to be a glucosamine β-(1-6) disaccharide 1-(2-aminoethyl)phosphate acylated by (R)-3-hydroxyoctadecanoic acid, (R)-3- hydroxyhexadecanoic acid, and (R)-3-(octadecanoyloxy)octadecanoic acid at the 2-, 3- and 2'-positions, respectively. Compared with the other major lipid A from the same strain, which was previously reported [Suda Y, Ogawa T, Kashihara W et al. Chemical structure of lipid A from Helicobacter pylori strain 206-1 lipopolysaccharide. J Biochem 1997; 121: 1129--1133], the structure was very similar with one exception. An (R)-3-hydroxyhexadecanoic acid was present at the 3-position of the novel lipid A component. The structure is apparently identical to one of the proposals by Moran et al. [Moran AP, Lindner B, Walsh EJ. Structural characterization of the lipid A component of Helicobacter pylori rough- and smooth-form lipopolysaccharides. J Bacteriol 1997; 179: 6453--6463], who concluded the same structure as the so-called major lipid A from the H. pylori strain NCTC 11637 but without isolating a homogeneous component. The endotoxic properties and pro-inflammatory cytokine-inducing activities of this novel tetra-acyl type lipid A were lower than those of previously reported major tri-acyl type lipid A.
structure, lipid A, chemical structure, biological activity, Helicobacter pylori, Helicobacter
The publication contains the following compound(s):|
Show legend Show as text |
The chemical structure of a novel lipid A, which was obtained as a major component from lipopolysaccharide of Helicobacter pylori strain 206-1, was determined to be a glucosamine β(1-6) disaccharide 1-(2-aminoethyl)phosphate acylated by (R)-3-hydroxyoctadecanoic acid and (R)-3-(octadecanoyloxy)octadecanoic acid at the 2- and 2'-position, respectively. The absence of a phosphoryl group at the 4'-position and fatty acyl groups at the 3- and 3'-position, and the stoichiometric presence of 2-aminoethyl phosphate at the 1-position are unique features, distinguishing it from the lipid A of enterobacteria.
Lipopolysaccharide, structure, lipid A, Helicobacter pylori, MS
The publication contains the following compound(s):|
Show legend Show as text |
| New query | Export IDs | Home | Help |
Execution: 2 sec
Found 
netscape.net