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Nematodes were found to synthesize phosphorylcholine-containing molecules not present in higher organisms, i.e. phosphorylcholine-substituted glycosphingolipids and (glyco)proteins. Investigations on the biosynthesis of these structures provided first biochemical evidence for the presence of the Kennedy and Bremer-Greenberg pathways in the model organism Caenorhabditis elegans. 相似文献
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Paschinger K Rendic D Lochnit G Jantsch V Wilson IB 《The Journal of biological chemistry》2004,279(48):49588-49598
Cross-reactivity with anti-horseradish peroxidase antiserum is a feature of many glycoproteins from plants and invertebrates; indeed staining with this reagent has been used to track neurons in Drosophila melanogaster and Caenorhabditis elegans. Although in insects the evidence indicates that the cross-reaction results from the presence of core alpha1,3-fucosylated N-glycans, the molecular basis for anti-horseradish peroxidase staining in nematodes has been unresolved to date. By using Western blots of wild-type and mutant C. elegans extracts in conjunction with specific inhibitors, we show that the cross-reaction is due to core alpha1,3-fucosylation. Of the various mutants examined, one with a deletion of the fut-1 (K08F8.3) gene showed no reaction to anti-horseradish peroxidase; the molecular phenotype was rescued by injection of either the K08F8 cosmid or the fut-1 open reading frame under control of the let-858 promoter. Furthermore, expression of fut-1 cDNA in Pichia and insect cells in conjunction with antibody staining, high pressure liquid chromatography, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry analyses showed that FUT-1 is a core alpha1,3-fucosyltransferase with an unusual substrate specificity. It is the only core fucosyltransferase in plants and animals described to date that does not require the prior action of N-acetylglucosaminyltransferase I. 相似文献
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Gunter Lochnit Roger D Dennis Ulrich Zahringer Rudolf Geyer 《Glycoconjugate journal》1997,14(3):389-399
The neutral glycosphingolipid fraction from adults of the pig parasitic nematode, Ascaris suum, was resolved into four components
on thin-layer chromatography. The high-performance liquid chromatography-isolated components were structurally analysed by:
methylation analysis; exoglycosidase cleavage; gas-liquid chromatography/mass spectrometry; liquid secondary-ion mass spectrometry;
and, in particular, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Their chemical structures
were determined as: Glc(β1-1)ceramide, Man(β1-4)Glc(β1-1)ceramide, GlcNAc(β1-3)Man(β1-4)Glc(β1-1)ceramide and Gal(α1-3)GalNAc(β1-4)GlcNAc(β1-3)Man(β1-4)Glc(β1-1)ceramide;
and were characterized as belonging to the arthro-series of protostomial glycosphingolipids. No glycosphingolipid component
corresponding to ceramide tetrasaccharide was detected during these analyses. The ceramide composition of the parent glycosphingolipids
was dominated by the 2-(R)-hydroxy C24:0 fatty acid, cerebronic acid, and C17 sphingoid-bases: 15-methylhexadecasphing-4-enine
and 15-methylhexadecaphinganine in approximately equal proportions. The component ceramide monohexoside was characterized
by an additional 15-methylhexadecaphytosphingosine. Abbreviations: CDH, ceramide dihexoside; Cer, ceramide; CMH, ceramide
monohexoside; CPH, ceramide pentahexoside; CTH, ceramide trihexoside; CTetH, ceramide tetrahexoside; Hex, hexose; HexNAc,
N-acetylhexosamine; HPTLC, high-performance thin-layer chromatography; LSIMS, liquid secondary-ion mass spectrometry; MALDI-TOF-MS,
matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; N-, Nz- and A-glyco(sphingo)lipids, neutral,
neutralzwitterionic and acidic glyco(sphingo)lipids, respectively
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
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Isolation and structural analysis of three neutral glycosphingolipids from a mixed population of Caenorhabditis elegans (Nematoda: Rhabditida) 总被引:1,自引:0,他引:1
The free-living nematode, Caenorhabditis elegans, has been proposedand analyzed as a prototypic model for parasitic nematodes.In order to study whether there is a structural basis for theproposed analogy with respect to nematode glycoconjugates, wehave analyzed Caenorhabditis elegans glycosphingolipids. Three,simple neutral glycosphingo-lipid components of the neutralglycolipid fraction were isolated by high-performance liquidchromatography. Structural analysis was performed by methylationanalysis, exoglycosidase cleavage, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and ceramide analysis.The chemical structures have been determined as Glcß1Cer,Manß4Glcß1Cer and GlcNAcß3Manp4Glcß1Cer;that are characterized as belonging to the arthro-series ofprotostomial glycosphingolipids. The ceramide moiety of theparent glycosphingolipid-ceramide mono-hexoside was dominatedby 2-hydroxy fatty acids, and a d17:1 sphingoid-base with aniso- or anteiso-branched chain. The chemical composition ofthe three glycosphingolipids from Caenorhabditis elegans displayedclose structural coincidence with the equivalent structuresfrom the porcine parasitic nematode, Ascaris suum (G.Lochnit,R.D. Dennis, U.Zähringer, and R.Geyer, Glycoconjugate J.,1997), in support of this organism as a prototypic glyco-sphingolipidmodel for parasitic nematodes. Arthro-series glycosphingolipids Caenorhabditis elegans d17:1 branched sphingoid-bases MALDI-TOF-MS nematode neutral glycosphingolipids 相似文献
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Hahn J Strauss HM Landgraf FT Gimenèz HF Lochnit G Schmieder P Hughes J 《The FEBS journal》2006,273(7):1415-1429
We have investigated mutants of phytochrome Cph1 from the cyanobacterium Synechocystis PCC6803 in order to study chromophore-protein interactions. Cph1Delta2, the 514-residue N-terminal sensor module produced as a recombinant His6-tagged apoprotein in Escherichia coli, autoassembles in vitro to form a holoprotein photochemically indistinguishable from the full-length product. We generated 12 site-directed mutants of Cph1Delta2, focusing on conserved residues which might be involved in chromophore-protein autoassembly and photoconversion. Folding, phycocyanobilin-binding and Pr-->Pfr photoconversion were analysed using CD and UV-visible spectroscopy. MALDI-TOF-MS confirmed C259 as the chromophore attachment site. C259L is unable to attach the chromophore covalently but still autoassembles to form a red-shifted photochromic holoprotein. H260Q shows UV-visible properties similar to the wild-type at pH 7.0 but both Pr and Pfr (reversibly) bleach at pH 9.0, indicating that the imidazole side chain buffers chromophore protonation. Mutations at E189 disturbed folding but the residue is not essential for chromophore-protein autoassembly. In D207A, whereas red irradiation of the ground state leads to bleaching of the red Pr band as in the wild-type, a Pfr-like peak does not arise, implicating D207 as a proton donor for a deprotonated intermediate prior to Pfr. UV-Vis spectra of both H260Q under alkaline conditions and D207A point to a particular significance of protonation in the Pfr state, possibly implying proton migration (release and re-uptake) during Pr-->Pfr photoconversion. The findings are discussed in relation to the recently published 3D structure of a bacteriophytochrome fragment. 相似文献
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Schistosoma mansoni cercarial glycolipids are dominated by Lewis X and pseudo-Lewis Y structures 总被引:1,自引:0,他引:1
The oligosaccharide structures of glycolipids from cercariaeof the human blood fluke, Schistosoma mansoni, were analyzedin the form of their corresponding, pyridylaminated oligosaccharidesby methylation analysis, partial hydrolysis, exoglycosidasetreatment, on-target exoglycosidase cleavage and matrix-assistedlaser desorption/ionization time-of-flight mass spectrometry.The six, dominant chemical structures present have been determinedas: GalNAc(ß14)Glc1-ceramide; GlcNAc(ß13)GalNAc(ß14)Glc1-ceramide;Gal(ß14)GlcNAc(ß13)GalNAc(ß14)Glc1-ceramide;Gal(ß14)[Fuc( 相似文献
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Beermann C Lochnit G Geyer R Groscurth P Filgueira L 《Biochemical and biophysical research communications》2000,267(3):897-905
The spirochaetal bacteria Borrelia burgdorferi (Bb) is the tick-borne causative agent of lyme disease. The major membrane immunogens of Bb are outer surface proteins. The lipid component of these lipoproteins is relevant for the immunogenicity of Bb-lipoproteins. To characterize the antigenic properties, the native lipid component of lipoproteins was isolated and the detailed molecular structure was analyzed. The molecular structure of the lipoprotein-lipid component turned out to be S(propane-2',-3'diol)-3-thio-2-aminopropanic acid (S-glyceryl-cysteine) with one ester-linked fatty acid, one acetyl group, and one N-terminal amide-bound fatty acid. Fatty acid analysis of the lipid component indicated a heterogeneous composition comprising C16:0, C18:0, C18:1, C18:2, and C 20:0. The antigenicity was tested with in vitro bioassays using human blood-derived dendritic cells (DCs) as antigen-presenting cells and autologous Bb-specific T-cells. We found that human DCs present the lipid component of Bb-lipoproteins via MHC class II inducing an antigen-specific T-cell immune response in vitro. 相似文献
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Tomofumi Kurokawa Manfred Wuhrer Günter Lochnit Hildegard Geyer Jürgen Markl Rudolf Geyer 《European journal of biochemistry》2002,269(22):5459-5473
Keyhole limpet (Megathura crenulata) hemocyanin (KLH), an extracellular respiratory protein, is widely used as hapten carrier and immune stimulant. Although it is generally accepted that the sugar constituents of this glycoprotein are likely to be implicated in the antigenicity and biomedical properties of KLH, knowledge of its carbohydrate structure is still limited. Therefore, we have investigated the N-linked oligosaccharides of KLH. Glycan chains were enzymatically liberated from tryptic glycopeptides, pyridylaminated and separated by two-dimensional HPLC. Only neutral oligosaccharides were obtained and characterized by carbohydrate constituent and methylation analyses, MALDI-TOF-MS, ESI-ion trap-MS and sequential exoglycosidase digestion. The results revealed that KLH is carrying high mannose-type glycans and truncated sugar chains derived thereof. As a characteristic feature, a number of the studied N-glycans contained a Gal(beta1-6)Man-unit which has not been found in glycoprotein-N-glycans so far. Hence, our studies demonstrate that this marine mollusk glycoprotein is characterized by a unique oligosaccharide pattern comprising, in part, novel structural elements. 相似文献