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

A 13C NMR spectrum of O-specific polysaccharide isolated from Yersinia pseudotuberculosis III serovar lipopolysaccharide has been interpreted. This allowed to define more precisely the configuration of glycosidic bonds and to confirm the structure of the repeating unit of the specific polysaccharide which was earlier established by other methods.
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PMID:[13C-NMR spectrum of O-specific polysaccharide from the lipopolysaccharide of Yersinia pseudotuberculosis of serotype III]. 620 40

Using methylation studies, partial hydrolysis and 13C NMR spectroscopy data, the following structure of O-specific polysaccharide from lipopolysaccharide of Yersinia pseudotuberculosis VI serovar has been proposed: (Formula: see text).
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PMID:[Structure of O-specific polysaccharide from Yersinia pseudotuberculosis of serotype VI lipopolysaccharide]. 621 95

An enzyme-linked immunosorbent assay (ELISA) for the detection and quantitation of human immunoglobulin M (IgM), IgG, and IgA antibodies against Yersinia enterocolitica by using lipopolysaccharides as antigens is described. The results obtained with the lipopolysaccharide ELISA were compared with the results of the whole bacterium ELISA. The correlations observed were good for each immunoglobulin class. Cross-reactions between Y. enterocolitica serotypes O:3 and O:9, Yersinia pseudotuberculosis IA, and Brucella abortus were studied by human and rabbit antisera in the whole bacterium and lipopolysaccharide ELISAs and by rabbit antisera using ELISA inhibition. The greatest cross-reactivity observed was that of the anti-Brucella serum with Y. enterocolitica O:9 in the whole bacterium ELISA. In the lipopolysaccharide ELISA this cross-reaction was not demonstrable with the rabbit antiserum, but it was strong with the human antiserum. However, differential diagnosis was possible with ELISA inhibition. On the basis of our experience, we are now routinely using whole bacterium ELISA for the determination of class-specific Yersinia antibodies, and potential cross-reactions are controlled by the ELISA inhibition.
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PMID:Measurement of immunoglobulin M, immunoglobulin G, and immunoglobulin A antibodies against Yersinia enterocolitica by enzyme-linked immunosorbent assay: comparison of lipopolysaccharide and whole bacterium as antigen. 679 May 70

The polysaccharide of the O-specific side chain of the lipopolysaccharide from the Yersinia pseudotuberculosis VA serovar has been isolated and studied. The structural pattern of the chemical repeating unit of the specific polysaccharide has been proposed as follows: (formula; see text).
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PMID:Structural studies on the O-specific side-chain polysaccharide of lipopolysaccharide from the Yersinia pseudotuberculosis VA serovar. 683 55

The use of 13C-NMR spectroscopy in the establishment of lipid A backbone structure from lipopolysaccharide of Yersinia pseudotuberculosis has been described. The 13C-NMR spectra of degraded lipid A and its N-acetate were obtained. The assignment of signals was made by comparison with the chemical shifts for 13C-NMR spectra of glucosaminitol, N-acetyl-glucosaminitol and their beta-1,4 and beta-1,6 disaccharides. It was shown that lipid A backbone of the lipopolysaccharide in question consists of beta-1,6-linked glucosamine disaccharide.
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PMID:The application of 13C-NMR spectroscopy to study lipid A from Yersinia pseudotuberculosis lipopolysaccharide. 712 94

CDP-6-deoxy-delta 3,4-glucoseen reductase (E3), which catalyzes the reduction of the C-3 deoxygenation step during the formation of CDP-ascarylose, a 3,6-dideoxyhexose found in the lipopolysaccharide of Yersinia pseudotuberculosis, has been expressed at high level in Escherichia coli (670 times over the wild-type strain). This flavoenzyme, which also contains one plant ferredoxin type [2Fe-2S] cluster, was inactivated by 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) and N-ethylmaleimide. In both cases the inactivation followed a pseudo first order kinetics. The second order rate constant for the reaction of DTNB with E3 was 0.25 mM-1 min-1 at 20 degrees C, pH 8.0. Detailed characterization of the inactivated enzyme showed that neither the flavin nor the [2Fe-2S] cluster was altered during inactivation. Since this inactivation was reversible by treating the inactivated enzyme with 1 mM D,L-dithiothreitol (DTT), it was concluded that only cysteine residues were modified during inactivation. Analysis of the inactivation using the method developed by Tsou revealed that two cysteines react with DTNB at similar rates and modification of either one is enough to impair E3's activity. Tryptic digestion of E3 labeled with N-ethyl[2,3-14C]maleimide, followed by fractionation of the digest by high performance liquid chromatography, gave two labeled peptides, both of which were separately isolated as a pair of interconvertible diastereoisomers. Sequence analysis of these labeled peptides allowed the identification of Cys-75 and Cys-296 as the reactive cysteine residues. Interestingly, the C75S and C296S mutant proteins exhibit identical physical and comparable catalytic properties as the wild-type enzyme. Since Cys-296 is a conserved residue in the NAD(P) binding domain of enzymes belonging to the same class, this residue may be involved in stabilizing the charge-transfer complex between E3 and NADH, thus facilitating hydride transfer from the nicotinamide nucleotide to flavin. A chemically modified Cys-75 which is immediately adjacent to the [2Fe-2S] center in E3 may prevent the proper juxtaposition of the redox centers and thus impede electron transfer leading to enzyme inactivation. These results may be useful for placing constraints on the peptide folding comprising the active site of E3 for electron transfer between NADH, FAD, and the [2Fe-2S] center.
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PMID:Mechanistic studies on CDP-6-deoxy-delta 3,4-glucoseen reductase: the role of cysteine residues in catalysis as probed by chemical modification and site-directed mutagenesis. 770 27

Samples of Y.pseudotuberculosis (serovar I) antigens, represent a high-molecular lipopolysaccharide (LPS) fraction with a mol. wt. of 22.5 kD and fractions of outer membrane proteins isolated by the method of M. Osborn and R. Munson (1974), were tested in comparison with the activity with live cells of Y. pseudotuberculosis I attenuated mutant KV 9/2, having lost its Cad plasmid of virulence with a mol. wt. of 47 MD and carrying 2 attenuating markers: resistance to crystal violet and nalidixic acid. In experiments on guinea pigs pathomorphological studies demonstrated high protective activity of Y.pseudotuberculosis I attenuated mutant KV 9/2 and a pronounced protective effect achieved after the immunization of the animals with complex biopolymers, including a high-molecular LPS fraction and outer membrane proteins.
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PMID:[The protective activity of Yersinia pseudotuberculosis antigens]. 799 35

The CDP-6-deoxy-delta 3,4-glucoseen reductase (E3) is a NADH-dependent enzyme which catalyzes the key reduction of the C-3 deoxygenation step during the formation of CDP-ascarylose, a 3,6-dideoxyhexose found in the lipopolysaccharide of Yersinia pseudotuberculosis. This highly purified enzyme is also a NADH oxidase capable of mediating the direct electron transfer from NADH to O2, forming H2O2. While previous work showed that E3 contains no common cofactor, one FAD and one plant ferredoxin type [2Fe-2S] center were found in this study to be associated with each molecule of E3. The iron-sulfur center is essential for E3 activity since bleaching of the [2Fe-2S] center leads to inactive enzyme. These results suggest that E3 employs a short electron-transport chain composed of both FAD and the iron-sulfur center to shuttle electrons from NADH to its acceptor. The order of electron flow, as indicated by EPR measurement with partially reduced E3, starts with hydride reduction of FAD by NADH. The iron-sulfur cluster, receiving electrons one at a time from the reduced flavin, relays the reducing equivalents via another iron-sulfur center in the active site of E1 to its final acceptor, the E1-bound PMP-glucoseen adduct. The participation of a one-electron-carrying iron-sulfur center in this reduction is advantageous since both electrons are dispatched from the same redox state of the prosthetic group, allowing electrons of equal energy to be delivered to the final acceptor.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cofactor characterization and mechanistic studies of CDP-6-deoxy-delta 3,4-glucoseen reductase: exploration into a novel enzymatic C-O bond cleavage event. 821 67

The 3,6-dideoxyhexoses, usually confined to the cell wall lipopolysaccharide of gram-negative bacteria, are essential to serological specificity and are formed via a complex biosynthetic pathway beginning with CDP-D-hexoses. In particular, the biosynthesis of CDP-ascarylose, one of the naturally occurring 3,6-dideoxyhexoses, consists of five enzymatic steps, with CDP-6-deoxy-delta 3,4-glucoseen reductase (E3) participating as the key enzyme in this catalysis. This enzyme has been previously purified from Yersinia pseudotuberculosis by an unusual procedure (protocol I) including a trypsin digestion step (O. Han, V.P. Miller, and H.-W. Liu, J. Biol. Chem. 265:8033-8041, 1990). However, the cloned gene showed disparity with the expected gene characteristics, and upon expression, the resulting gene product exhibited no E3 activity. These findings strongly suggested that the protein isolated by protocol I may have been misidentified as E3. A reinvestigation of the purification protocol produced a new and improved procedure (protocol II) consisting of DEAE-Sephacel, phenyl-Sepharose, Cibacron blue A, and Sephadex G-100 chromatography, which efficiently yielded a new homogeneous enzyme composed of a single polypeptide with a molecular weight of 39,000. This highly purified protein had a specific activity nearly 8,000-fold higher than that of cell lysates, and more importantly, the corresponding gene (ascD) was found to be part of the ascarylose biosynthetic cluster. Presented are the identification and confirmation of the E3 gene through cloning and overexpression and the culminating purification and unambiguous assignment of homogeneous E3. The nucleotide and translated amino acid sequences of the genuine E3 are also presented.
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PMID:CDP-6-deoxy-delta 3,4-glucoseen reductase from Yersinia pseudotuberculosis: enzyme purification and characterization of the cloned gene. 828 41

The efficiency of serological identification of Yersinia pestis strains which contain different plasmids was assessed with polyclonal and monoclonal immunoglobulin preparations in the direct fluorescent antibody method. Plague polyclonal luminescent immunoglobulins recognize only those Y. pestis strains which contain pPst, pFra plasmids or both. Anticapsular plague monoclonal antibodies interact only with capsule-forming plague agent strains (pFra+) grown at 37 degrees C. With plague monoclonal lipopolysaccharide antibodies one can identify all Y. pestis strains irrespective of their plasmid content and cultivation temperature. However, these antibodies cross-react with Yersinia pseudotuberculosis bacteria in 60% of cases. The problem of laboratory diagnosis of the plague organism, whatever its plasmid profile, can be solved through the development of a test kit involving two preparations such as plague lipopolysaccharide monoclonal luminescent antibodies and pseudotuberculosis specific luminescent adsorbed immunoglobulins.
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PMID:Identification of Yersinia pestis with varied plasmid composition using monoclonal and polyclonal fluorescent immunoglobulins. 847 14


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