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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

O-specific polysaccharide was isolated by mild acid degradation of the lipopolysaccharide of Pseudoalteromonas tetraodonis type strain IAM 14160(T) and studied by sugar and methylation analyses along with 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, 1H,(13)C HMQC and HMBC experiments. The polysaccharide was found to consist of hexasaccharide repeating units containing one residue each of D-Gal, D-GlcA, D-GalNAc and D-GlcNAc and two residues of 3,6-dideoxy-L-xylo-hexose (colitose, Col) and having the following structure:In common with the polysaccharides of some other bacteria, the polysaccharide studied contains a tetrasaccharide fragment alpha-Colp-(1-->2)-beta-D-Galp-(1-->3)-[alpha-Colp-(1-->4)]-beta-D-GlcpNAc, which is a colitose ('3-deoxy-L-fucose') analogue of the Lewis(b) blood group antigenic determinant.
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PMID:Structure of a colitose-containing O-specific polysaccharide of the marine bacterium Pseudoalteromonas tetraodonis IAM 14160(T). 1142 9

The structure of the core region of the lipopolysaccharide (LPS) from the nontypable Haemophilus influenzae strain SB 33 was elucidated. The LPS was subjected to a variety of degradative procedures. The structures of the derived oligosaccharide products were established by monosaccharide and methylation analyses, NMR spectroscopy and mass spectrometry. These analyses revealed a series of related phosphocholine (PCho) containing structures differing in the number of hexose residues. The results pointed to each species containing a conserved phosphoethanolamine (PEtn) substituted heptose-containing trisaccharide inner-core moiety. The major LPS glycoforms were identified as 2-Hex, 3-Hex and 4-Hex species according to the number of hexose residues present.
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PMID:Structural analysis of the lipopolysaccharide from the nontypable Haemophilus influenzae strain SB 33. 1160 89

The O-specific polysaccharide of Citrobacter braakii PCM 1531 (serogroup O6) was isolated by mild acid hydrolysis of the lipopolysaccharide (LPS) and found to contain d-fucose, l-rhamnose, 4-deoxy-d-arabino-hexose and O-acetyl groups in molar ratios 2 : 1 : 1 : 1. On the basis of methylation analysis and 1H and 13C NMR spectroscopy data, the structure of the branched tetrasaccharide repeating unit of the O-specific polysaccharide was established. Using various serological assays, it was demonstrated that the LPS of strain PCM 1531 is not related serologically to other known 4-deoxy-d-arabino-hexose-containing LPS from Citrobacter PCM 1487 (serogroup O5) or C. youngae PCM 1488 (serogroup O36). Two other strains of Citrobacter, PCM 1504 and PCM 1505, which, together with strain PCM 1531, have been classified in serogroup O6, were shown to be serologically distinct from strain PCM 1531 and should be reclassified into another serogroup.
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PMID:Structural and serological studies on a new 4-deoxy-d-arabino-hexose-containing O-specific polysaccharide from the lipopolysaccharide of Citrobacter braakii PCM 1531 (serogroup O6). 1282 43

Cellular glucose uptake is mediated by a family of facilitative glucose transporters (GLUT) exhibiting differences in kinetics, substrate specificity, and tissue-specific expression. GLUT isoform expression has not been comprehensively studied in human leukocytes, which participate in immune and inflammatory responses and are critical for host defense. Therefore, we studied the regulated expression of GLUT 1-5 mRNA and protein in isolated human lymphocytes and monocytes and in human THP-1 macrophages and foam cells. Lymphocytes expressed GLUT 1 and GLUT 3 proteins, and cellular levels of both isoforms were augmented 3.5- to 6-fold following activation by phytohemagglutinin (PHA). Monocytes expressed 8.4-fold more GLUT 3 protein and 88% less GLUT 1 than lymphocytes, and activation by lipopolysaccharide (LPS) led to a 1.9-fold increase in GLUT 1. At the level of mRNA expression, GLUT 3 mRNA was the most prevalent GLUT mRNA species in monocytes, while lymphocytes expressed equal numbers of GLUT 1 and GLUT 3 transcripts. Differentiation of THP-1 monocytes into macrophages was associated with marked induction of GLUT 3 and GLUT 5 protein expression, and high levels of GLUT 1, GLUT 3, and GLUT 5 were maintained after transformation to foam cells. GLUT 5 mRNA was expressed in 2-fold greater abundance in macrophages and foam cells than that observed for GLUT 1 mRNA, while the level of GLUT 3 mRNA was intermediate. This facilitative glucose transporters are differentially expressed and regulated in human leukocytes in a pattern that could facilitate cellular functions. Speculatively, high GLUT 1 and GLUT 3 expression could provide cellular fuel for the immune response, and high levels of high-affinity GLUT 3 in macrophages might allow the cell to compete with pathogens for hexoses, even in the presence of low interstitial glucose concentrations. Ample expression of GLUT 1 and GLUT 3 in foam cells could also provide hexose substrates and promote lipid loading. The role for high levels of the fructose transporter GLUT 5 in macrophages and foam cells is unknown since interstitial and circulating fructose concentrations are low in these cells.
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PMID:Facilitative glucose transporter gene expression in human lymphocytes, monocytes, and macrophages: a role for GLUT isoforms 1, 3, and 5 in the immune response and foam cell formation. 1475 34

Nontypeable Haemophilus influenzae (NTHi) is a common commensal of the human upper respiratory tract and is associated with otitis media in children. The structures of the oligosaccharide portions of NTHi lipopolysaccharide (LPS) from several otitis media isolates are now well characterized but it is not known whether there are structural differences in LPS from colonizing, nondisease associated strains. Structural analysis of LPS from nondisease associated NTHi strains 11 and 16 has been achieved by the application of high-field NMR techniques, ESI-MS, ESI-MSn, capillary electrophoresis coupled to ESI-MS, composition and linkage analyses on O-deacylated LPS and core oligosaccharide material. This is the first study to report structural details on LPS from strains taken from the nasopharynx from healthy individuals. Both strains express identical structures and contain the common element of H. influenzae LPS, L-alpha-D-Hepp-(1-->2)-[PEtn-->6]-L-alpha-D-Hepp-(1-->3)-[beta-D-Glcp-(1-->4)]-L-alpha-D-Hepp-(1-->5)-[PPEtn-->4]-alpha-Kdop-(2-->6)-lipid A, in which each heptose is elongated by a single hexose residue with no further oligosaccharide extensions. In the major Hex3 glycoform, the terminal Hepp residue (HepIII) is substituted at the O-2 position by a beta-D-Galp residue and the central Hepp residue (HepII) is substituted at O-3 by a alpha-D-Glcp residue. Notably, the strains express two phosphocholine (PCho) substituents, one at the O-6 position of alpha-D-Glcp and the other at the O-6 position of beta-D-Galp. Major acetylation sites were identified at O-4 of Gal and O-3 of HepIII. Additionally, both strains express glycine, and strain 11 also expresses detectable amounts of N-acetylneuraminic acid.
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PMID:Characterization of novel structural features in the lipopolysaccharide of nondisease associated nontypeable Haemophilus influenzae. 1500 6

The O antigen of lipopolysaccharide in Gram-negative bacteria plays a critical role in bacterium-host interactions, and for pathogenic bacteria it is a major virulence factor. In Pseudomonas aeruginosa serotype O6 one of the initial steps in O-antigen biosynthesis is catalyzed by a saccharide epimerase, WbpP. WbpP is a member of the UDP-hexose 4-epimerase family of enzymes and exists as a homo-dimer. This enzyme preferentially catalyzes the conversion between UDP-GlcNAc and UDPGalNAc above UDP-Glc and UDP-Gal, using NAD(+) as a cofactor. The crystal structures of WbpP in complex with cofactor and either UDP-Glc or UDP-GalNAc were determined at 2.5 and 2.1 A, respectively, which represents the first structural studies of a genuine UDP-GlcNAc 4-epimerase. These structures in combination with complementary mutagenesis studies suggest that the basis for the differential substrate specificity of WbpP is a consequence of the presence of a pliable solvent network in the active site. This information allows for a comprehensive analysis of the relationship between sequence and substrate specificity for UDP-hexose 4-epimerases and enables the formulation of consensus sequences that predict substrate specificity of UDP-hexose 4-epimerases yet to be biochemically characterized. Furthermore, the examination indicates that as little as one residue can dictate substrate specificity. Nonetheless, phylogenetic analysis suggests that this substrate specificity is an evolutionary and highly conserved property within UDP-hexose 4-epimerases.
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PMID:Crystal structure of WbpP, a genuine UDP-N-acetylglucosamine 4-epimerase from Pseudomonas aeruginosa: substrate specificity in udp-hexose 4-epimerases. 1501 16

Reactive oxygen metabolites (ROMs) may contribute to several eye diseases, such as age-related macular degeneration, although the underlying mechanisms are unclear. The present study shows that human photoreceptor outer segments (POS) prime human retinal pigment epithelial (RPE) cells for massive ROM release in response to lipopolysaccharide (LPS) and interferon-gamma. However, no ROM priming of human RPE cells is observed for bovine POS. ROM production appears to be linked with underlying metabolic oscillations involving the hexose monophosphate shunt.
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PMID:Human, but not bovine, photoreceptor outer segments prime human retinal pigment epithelial cells for metabolic activation and massive oxidant release in response to lipopolysaccharide and interferon-gamma. 1533 7

Burkholderia brasiliensis, a Gram-negative diazotrophic endophytic bacterium, was first isolated from roots, stems, and leaves of rice plant in Brazil. The polysaccharide moiety was released by ammonolysis from the B. brasiliensis lipopolysaccharide (LPS), allowing the unambiguous characterization of a 3,6-dideoxy-4-C-(1-hydroxyethyl)-D-xylo-hexose (yersiniose A), an uncommon feature for Burkholderia LPS. The complete structure of the yersiniose A-containing O-antigen was identified by sugar and methylation analyses and NMR spectroscopy. Our results show that the repeating oligosaccharide motif of LPS O-chain consists of a branched tetrasaccharide with the following structure:-->2-alpha-d-Rhap-(1-->3)-[alpha-YerAp-(1-->2)]-alpha-D-Rhap-(1-->3)-alpha-D-Rhap-(1-->.
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PMID:Nitrogen-fixing bacterium Burkholderia brasiliensis produces a novel yersiniose A-containing O-polysaccharide. 1550 23

The O-chain polysaccharide of the lipopolysaccharide from the halophilic marine bacterium Pseudoalteromonas carrageenovora IAM 12662T was characterized. The structure was studied by means of chemical analysis and 2D NMR spectroscopy of the de-O-acylated lipopolysaccharide and shown to be the following:Col is colitose, 3,6-di-deoxy-L-xylo-hexose.
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PMID:The O-chain structure from the LPS of marine halophilic bacterium Pseudoalteromonas carrageenovora-type strain IAM 12662T. 1619 23

Variations in the outer membrane proteins (OMPs) and lipopolysaccharides (LPSs) of 54 isolates belonging to 16 different pathovars of Xanthomonas campestris were characterized. OMP samples prepared by sarcosyl extraction of cell walls and LPS samples prepared by proteinase K treatment of sonicated cells were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the presence of 4 M urea. In general, the OMP and LPS profiles within each pathovar were very similar but different from the profiles of other pathovars. Heterogeneity in OMP and LPS profiles was observed within X. campestris pv. campestris, X. campestris pv. translucens, and X. campestris pv. vesicatoria. LPSs were isolated from six X. campestris pathovars, which fell into two major groups on the basis of O antigenicity. The O antigens of X. campestris pv. begoniae, X. campestris pv. graminis, and X. campestris pv. translucens cross-reacted with each other; the other group consisted of X. campestris pv. campestris, X. campestris pv. pelargonii, and X. campestris pv. vesicatoria. A chemical analysis revealed a significant difference between the compositions of the neutral sugars of the LPSs of those two groups; the LPSs of the first group contained xylose and a 6-deoxy-3-O-methyl hexose, whereas the LPSs of the other group lacked both sugars.
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PMID:Outer Membrane Proteins and Lipopolysaccharides in Pathovars of Xanthomonas campestris. 1634 14


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