Fragmentation-Adducts-Xyl-N-Fragments-Adducts-Fragments-j

The fragmentation of the sodium adducts of acidic oligosaccharides (Xyl(n)meGlcA, Xyl(n)GlcA) resulted in the loss of the substituting residue (GlcA or meGlcA) as the predominant fragment, while the corresponding ammonium adducts yielded B-type fragments.N-Linked glycoprotein assembly. Oligosaccharides that oligosaccharide attachment occurs within the lumen of the endoplasmic reticulum.The transbilayer orientation of the oligosaccharide chain transferred from oligosaccharide-lipid to endogenous protein acceptors in sealed hen oviduct microsomes has been examined using endo-beta-N-acetylglucosaminidase H as a topological probe. The oligosaccharide moiety of these acceptors was released by the enzyme only under conditions where the microsomes were made permeable to macromolecules. The release of the oligosaccharide chain by endo-beta-N-acetylglucosaminidase H was not increased by removal of ribosomes or by mild trypsinization of the sealed microsomes.

The endogenous acceptors were shown to be membrane-associated proteins that are not a part of the mRNA . ribosome . tRNA . nascent chain complex. From these results we conclude that the transfer of oligosaccharide from oligosaccharide-lipid occurs at the luminal face of the rough endoplasmic reticulum.Structure of the major O-glycosidic oligosaccharide of monkey erythrocyte Sialic acids and the major O-glycosidic oligosaccharide of glycophorin MK from monkey (Japanese monkey, Macaca fuscata) erythrocyte membranes were characterized. Get it now -Glycolylneuraminic acid (Neu5Gc) was found as the major sialic acid, which was confirmed by gas-liquid chromatography-mass spectrometry as the trimethylsilyl methyl ester.

Three O-glycosidic oligosaccharide units were obtained from a tryptic glycopeptide that contained all of the carbohydrate units in glycophorin MK by mild alkaline borohydrideborotritide treatment. Carbohydrate analyses of the oligosaccharides revealed that they were composed of Neu5Gc, galactose and N-acetylgalactosaminitol in the molar ratios of 111 content of oligosaccharide units was estimated to be 1125 for penta-, tetra- and trisaccharide, respectively, based on the yields, the molecular weight, and the number of oligosaccharide attachment sites in the amino-acid sequence. The tetrasaccharide was the major oligosaccharide and its structure was proposed to Oligosaccharide beta-glucans with unusual linkages from Sarcina ventriculi.The structure of a family of unusual glucans from Sarcina ventriculi has been characterized by NMR spectroscopy, methylation analysis, and mass spectrometry. One is a trisaccharide containing a beta-(1--3) and a beta-(1--4)-linkage. The other is a hexasaccharide that is simply a 1,4-linkage dimer of the trisaccharide unit. This is the first report of beta-glucan biosynthesis in a Gram-positive organism.

Their occurrence in these organisms supports an even more general link between their synthesis and the adaptability of bacteria.The influence of the O-antigen and the capsular polysaccharide on the establishment of PlCmts lysogeny in Klebsiella pneumoniae.The O-antigen of the lipopolysaccharide in Klebsiella pneumoniae caused a significant reduction in the frequency of establishment of PlCmts lysogeny, while the capsular polysaccharide showed no effect on this frequency. The bacterial receptor for PlCmts are the lipopolysaccharide-core oligosaccharides, the results suggest that K. pneumoniae strains with an O-antigen in their lipopolysaccharide have a poorly accessible lipopolysaccharide-core (the PlCmts bacterial receptor), while K. pneumoniae strains lacking the O-antigen have a highly accessible lipopolysaccharide-core. The accessibility of the receptor is independent of the K antigen (capsular polysaccharide).

Synthesis of a photoreactive, radiolabelled derivative of the oligosaccharide of A photoreactive, radioiodinatable derivative of the oligosaccharide (GM1OS) of ganglioside GM1 was synthesized as follows GM1OS was generated from GM1 by ozonolysis and alkaline fragmentation, and reductively aminated to GM1OSNH2 with N-hydroxysuccinimidyl-4-azidosalicylic acid (NHS-ASA) to form GM1OSNH-ASA [1-(4-azidosalicoylamido)-1-deoxymonosialogangliotetraitol], which was radioiodinated and further purified. To test the [125I]GM1OSNH-IASA [1-(4-iodoazidosalicoylamido)-1-deoxymonosialogangliotetraitol+ ++] as a probe for ganglioside-binding proteins, the derivative was incubated with cholera toxin, which specifically binds GM1, followed by photolysis and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The probe only labelled the B or binding subunit of cholera toxin, but not the A or adenylyl cyclase activating subunit. Labelling was inhibited by excess GM1OS, but not by the oligosaccharides from gangliosides GD1a and GD1b.