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At least 19 recordsLinked to original sources

PubMed1992

Linkage position determination in a novel set of permethylated neutral trisaccharides by collisional-induced dissociation and tandem mass spectrometry.

A set of neutral permethylated trisaccharides identical in the non-reducing (A----B) disaccharide and linkage isomeric in the reducing terminal (B----C) disaccharide has been synthesized. Collision-activated tandem mass spectrometry was used for analysis of the B----C linkage position. The trisaccharides, gal(beta 1----4)glc(beta 1----X)glc, where X = 3, 4 and 6, were synthesized and examined using fast atom bombardment collision-induced dissociation tandem mass spectrometry. Results were rationalized using molecular modeling. We have previously reported results for determination of the A----B linkage position with isomeric sets of synthetic trisaccharides containing internal amino sugars. The neutral trisaccharides were synthesized to isolate electronic effects of the amino group. An approach of relating daughter ion to parent ion ratios and collision energy offset was used to generate slopes that predict linkage position in glc beta 1----X glc reducing end glycoside form of terminal trisaccharides.

Magnetic Resonance Spectroscopy↗

PubMed1991

Interactions of five D-mannose-specific lectins with a series of synthetic branched trisaccharides.

The interaction of a series of synthetic, branched trisaccharides with five D-mannose-specific lectins was studied by precipitation-inhibition assay. The branched methyl alpha-D-mannotrioside, alpha-D-Manp-(1----3)-[alpha-D-Manp-(1----6)]-alpha-D-Man pOMe, the best inhibitor of the Con A-Dextran interaction, was 42 times more potent than alpha-D-ManpOMe, and 3-6 times more potent than the two trisaccharides substituted with D-glucosyl groups, and 8-15 times those with D-galactosyl groups. Surprisingly, methyl O-alpha-D-mannopyranosyl-(1----3)-alpha-D-mannopyranoside was bound to Con A 8-fold more avidly than methyl alpha-D-mannopyranoside. However, the related pea lectin (PSA) was singularly different from Con A in its carbohydrate-binding activity, showing no significantly enhanced binding to any of the sugars examined. The trisacchrides containing terminal, nonreducing, (1----3)-linked alpha-D-mannopyranosyl groups, i.e., alpha-D-Manp-(1----3)-[alpha-D-Glep-(1----6)]alpha-D-Manp OMe, alpha-D-Manp-(1----3)]-alpha-D-Galp-(1----6)]-alpha-D-ManpOMe++ +, and alpha-D-Manp-(1----3)-[alpha-D-Manp-(1----6)]-alpha-D-Man pOMe, were the best inhibitors of the snowdrop lectin (GNA)-D-mannan precipitation system. On the other hand, all branched trisaccharides exhibited very similar inhibitory potencies toward the daffodil lectin (NPA)-D-mannan interaction, whereas alpha-D-Manp-(1----3)-[alpha-D-Galp-(1----6)]-alpha-D-ManpOMe++ + and alpha-D-Manp-(1----3)-[alpha-D-Manp-(1----6)]-alpha-D-Man pOMe were somewhat better inhibitors than the other branched trisaccharides of the amaryllis lectin (HHA)-D-mannan precipitation reaction. (ABSTRACT TRUNCATED AT 250 WORDS)

Carbohydrate Conformation↗

PubMed1992

[Synthesis of spaced trisaccharides with blood group A and B specificity, their fragments, and structural analogs].

Trisaccharides GalNAc alpha 1----3(Fuc alpha 1----2)Gal and Gal alpha 1----3(Fuc alpha 1----2)Gal, which are the determinant fragments of the human blood group specific antigens A and B, respectively, were synthesized as R-glycosides (R = beta-OCH2CH2CH2NHCOCF3). 4,6-BdGal-R was acetylated selectively at 3-OH, the 3-O-acetate was alpha-fucosylated and then deacetylated to give a protected H-disaccharide bearing a free 3-OH. The disaccharide was alpha-glycosylated with 2-azido-3,4,6-tri-O-acetyl-2-deoxy-beta-D-galactopyranosyl chloride (GCl) or 2,3,4,6-tetra-O-benzyl-alpha-D-galactopyranosyl bromide (GBr) to give protected spacered trisaccharides A and B, respectively. Disaccharides GalNAc alpha 1----3Gal-R and Gal alpha 1----3Gal-R were synthesized in two ways. 1. Hydrogenolysis followed by benzylidenation of Bzl3-2-O-Ac-Gal-R gave 4,6-Bd-2-O-Ac-Gal-R, which was alpha-glycosylated with GCl and GBr. 2. The required disaccharides were isolated from the mixture of di- and trisaccharides which was obtained by selective glycosylation of 4,6-Bd-Gal-R with GCl and GBr. Synthesis of GalNAc alpha 1----3(GalNAc alpha 1----2)Gal and Gal alpha 1----3(Gal alpha 1----2)Gal, non-natural analogues of A and B trisaccharides, is also described. Deprotected R-glycosides were converted to OCH2CH2CH2NH2 (R1) derivatives, N-biotinyl derivatives were synthesized from GalNAc alpha 1----3(Fuc alpha 1----2)Gal-R1 and Gal alpha 1----3(Fuc alpha 1----2)Gal-R1 glycosides. The oligosaccharides, their macromolecular forms, and affinity sorbents obtained from them were used in the epitope specificity studies of the monoclonal antibodies and blood group typing.

ABO Blood-Group System↗

PubMed1978

[Gas chromatographic determination of di- and trisaccharides (author's transl)].

Three new methods are reported for the gas chromatographic analysis of di- and trisaccharides. Method I: Sugars are converted into their methoximes by reaction with methoxylamine hydrochloride in pyridine, followed by esterification with acetic anhydride. The separation is performed on OV 225 at 260 degrees C. Method II: Disaccharides are reduced to the alditols with sodium borohydride in aqueous solution, followed by acetylation with acetic anhydride in pyridine. In this method, only one peak is observed for each sugar. The derivatives are separated on OV 225 at 260 degrees C. Method III: Sugars are converted into their methoximes by reaction with methoxylamine hydrochloride in pyridine, followed by trifluoroacetylation with N-methyl-bis (trifluoroacetamide). The trisaccharide derivatives still show sufficient volatility. The separation is performed on OV 101 at 130 degrees C for disaccharides, and at 160 degrees C for trisaccharides. The retention times for biologically occurring di- and trisaccharides such as maltose, maltotriose, lactose, and sucrose are reported. The reliability criteria for method I are reported for the analysis of lactose, maltose and sucrose.

Chromatography, Gas↗

PubMed1991

Characterization of nematode glycoproteins: the major O-glycans of Toxocara excretory-secretory antigens are O-methylated trisaccharides.

Toxocara excretory-secretory antigens (TES) were isolated from the culture media of T.canis and T.cati larvae and their O-glycan content was investigated using fast atom bombardment-mass spectrometry (FAB-MS), gas chromatography and electron impact mass spectrometry. The major oligosaccharides released by reductive elimination of T.canis TES glycoproteins were shown to be two, approximately equi-abundant, trisaccharides: 2-O-Me-Fucp(alpha 1----2)-4-O-Me-Galp(beta 1----3)GalNAcitol and 2-O-Me-Fucp(alpha 1----2)-Galp(beta 1----3)GalNAcitol. In contrast T.cati TES O-glycans are predominantly one component, shown by FAB-MS to be a di-O-methylated trisaccharide, which is probably identical to the di-O-methylated trisaccharide from T.canis. The O-methylated trisaccharides are strong candidates for the carbohydrate epitopes recognized by a panel of monoclonal antibodies which exhibit multiple reactivity against TES antigens. This study constitutes the first rigorous characterization of glycans from a parasitic nematode.

Animals↗

PubMedDate not supplied

Studies of the binding activity of phage G13 to synthetic trisaccharides analogous to binding structures in Salmonella typhimurium and Escherichia coli C core saccharide. Correlation between conformation and binding activity.

Phage G13 binds to the carbohydrate part of lipopolysaccharides from rough mutants of Salmonella and Escherichia coli as the first event of infection. Equilibrium dialysis inhibition studies with native and synthetic trisaccharides as inhibitors suggested that phage G13 recognizes branched oligosaccharides having 6-O-alpha- or 7-O-alpha-glycosyl groups with alpha-Man(1----3) [alpha-Man(1----6)]Man (Man[Man]Man) and alpha-Glc(1----3)-[alpha-Hep(1----7)] alpha-Hep(1----3) alpha-Hep(1----5)Kdo as the smallest saccharides with inhibitory activity (Wollin et al., 1989). Of four synthetic analogues to Man[Man]Man only Man(1----3)[alpha-Gal(1----6)]alpha-Man-OMe (Man[Gal]-Man) and alpha-Glc(1----3)[alpha-Hep(1----7)]alpha-Hep-OMe (Glc[Hep]Hep) inhibited the binding of labelled E. coli C core nonasaccharide ligand to G13 with activities which were 10- and 15-fold lower than Man[Man]Man. The trisaccharides alpha-Man(1----3)[alpha-Glc(1----6)[alpha-Man-OMe (Man[Glc]Mann) and alpha-Man(1---3)[alpha-Tal(1----6)]alpha-Man-OMe (Man[Tal]Man) showed no inhibition at concentrations 75-fold higher than Man[Man]Man. Minimum energy conformation calculations of the saccharides using the GESA method showed that the 6-O-alpha-Man group in Man[Man]Man and the 7-O-alpha-Hep group SL805 pentasaccharide expose their OH-2 and OH-3 groups in a similar way and these are postulated to be key structural features for binding activity. The importance of hydroxy groups at certain positions is implied from the fact that both manno- and galacto-isomers are active. We also conclude that the O6-C6-C5-O5-C1 region of the 3-O-alpha-glycosyl group in the Man[Man]Man trisaccharide, or part of it, is important for the G13 binding activity.

Bacteriophages↗

PubMed1990

Synthesis of a peripheral trisaccharide sequence of lutropin, a pituitary glycoprotein hormone; use of chitobiose as a key starting material.

A chitobiose derivative, methyl O-(3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-beta-D-glucopyranosyl)-(1--- -4)-3,6 - di-O-acetyl-2-deoxy-2-phthalimido-beta-D-glucopyranoside, was derived from the corresponding N-acetyl derivative and this was converted into the glycosyl bromide (5). Glycosidation reaction between 5 and methyl 3,4,6-tri-O-benzyl-alpha-D-mannopyranoside in the presence of silver trifluoromethanesulfonate gave a beta-D-linked trisaccharide derivative. Replacement of the N,N-phthaloyl group by acetyl groups resulted in a product that was converted into methyl O-(2-acetamido-3,6-di-O-benzyl-2-deoxy-beta-D-glucopyranosyl)-(1----4)-O -(2- acetamido-3,6-di-O-benzyl-2-deoxy-beta-D-glucopyranosyl)-(1----2)-3,4,6- tri-O- benzyl-alpha-D-mannopyranoside (11) by use of a few reaction steps. The 4(3)-hydroxyl group of 11 was methanesulfonylated, and the product subjected to SN2 replacement with acetate anion, to give the D-galactosamine-containing trisaccharide derivative (12). After basic hydrolysis of 12, the 4(3)-hydroxyl group was sulfated, and all benzyl groups were removed by hydrogenolysis, giving methyl O-(2-acetamido-2-deoxy-4-O-sulfo-beta-D-galactopyranosyl)-(1----4)-O-(2- acetamido-2-deoxy-beta-D-glucopyranosyl)-(1----2)-alpha-D-mannopyranosid e monosodium salt, the methyl alpha-glycoside derivative of the peripheral trisaccharide sequence of the pituitary glycoprotein hormone lutropin.

Carbohydrate Sequence↗

PubMed1991

Synthesis and n.m.r. analysis of branched trisaccharide and pentasaccharide haptens of the beta-hemolytic streptococci group A and the preparation of synthetic antigens.

The synthesis of branched trisaccharide and pentasaccharide portions of the cell-wall polysaccharide of the beta-hemolytic Streptococci Group A is described. The key dissaccharide acceptors, allyl or 8-(methoxycarbonyl)ocytol 3-O-(3,4,6-tri-O-benzyl-2-deoxy-2-phthalimido-beta-D-glucopyranosyl)-4-O -benzyl - alpha-L-rhamnopyranoside, in conjunction with a selectively blocked alpha-L-rhamnopyranosyl chloride under Koenigs-Knorr conditions, afforded the branched trisaccharides in 81 and 62% yield, respectively. Analogously, glycosylation of the 8-(methoxycarbonyl)octyl disaccharide with a protected beta-D-GlcpNAc-(1----3)-alpha-L-Rhap-(1----3)-alpha-L-Rhap chloride gave the pentasaccharide in 43% yield. The key disaccharide acceptors were obtained, in turn, from the allyl or 8-(methoxycarbonyl)octyl rhamnoside acceptors and 3,4,6-tri-O-benzyl-2-deoxy-2-phthalimido-beta-D-glucopyranosyl chloride under Koenigs-Knorr conditions. The latter glycosyl donor has not been described previously. Removal of the protecting groups afforded the trisaccharide haptens as their 1-propyl and 8-(methoxycarbonyl)octyl glycosides and the pentasaccharide as its 8-(methoxycarbonyl)octyl glycoside. The compounds have been subjected to detailed analysis by two-dimensional n.m.r. methods. Preparation of the synthetic antigens followed coupling of the 8-(methoxycarbonyl)octyl glycosides to bovine serum albumin via the acyl azide intermediates.

Carbohydrate Sequence↗

PubMed1992

Synthesis of four novel trisaccharides by induction of loose acceptor specificity in Gal beta 1----4 transferase (EC 2.4.1.22): Galp(beta 1----4)Glcp(X)Glc where X = beta 1----3: beta 1----4: beta 1----6: alpha 1----4.

Development of tandem mass spectral methods for direct linkage determination in oligosaccharides requires sets of trisaccharides differing only in one structural parameter. In this case, we chose the position of linkage to the reducing-end hexose. These sets of compounds would also be useful for the development of high-resolution separation techniques geared to resolve linkage types. Conventional organic synthesis of such a set could take as long as 2-5 months for each member of the set. Each trisaccharide would require 10-20 steps of synthesis. Instead, we utilized low pH to induce a loose acceptor specificity for bovine milk galactosyltransferase (lactose synthase: EC 2.4.1.22) and by this method, within 2 weeks, generated four novel oligosaccharides for NMR and mass spectral studies. The disaccharides cellobiose (beta 1----4), laminaribiose (beta 1----3), gentiobiose (beta 1----6) and maltose (alpha 1----4) acted as acceptors for EC 2.4.1.22 under these conditions. The beta 1----2-linked disaccharide, sophorose, was not commercially available and is not included in this study. The alpha-linked disaccharides were also examined, but except for the alpha 1----4 disaccharide maltose, were very poor acceptors under a variety of conditions. From these four acceptors, the following four novel trisaccharides were synthesized in micromole amounts, suitable for studies of linkage position using low-energy collision-induced-dissociation tandem mass spectrometry (FAB-MS-CID-MS), and for NMR: Galp(beta 1----4)Glcp(beta 1----3)-Glc, Galp(beta 1----4)Glcp(beta 1----4)Glc, Galp(beta 1----4)Glcp(beta 1----6)-Glc and Galp(beta 1----4)Glcp(alpha 1----4)Glc.

Carbohydrate Conformation↗

PubMed1977

GLC analysis of the hydroxy and oxo compounds produced by the Smith degradation of reducing Di- and trisaccharides.

Reducing di- and trisaccharides were oxidized with periodate under conditions minimizing overoxidation, and the hydroxy and oxo compounds produced by subsequent reduction and hydrolysis were analyzed by GLC after trimethylsilylation. The present study has demonstrated that GLC analysis of the hydroxy and oxo compounds produced by Smith degradation is useful for linkage analysis of reducing di- and trisaccharides. In addition, it is suggested that the rate of periodate oxidation of the internal hexopyranose residue of trisaccharides depends markedly upon their structures.

Aldehydes↗

PubMed1991

Access to fluorescent probes via allyl glycosides: the synthesis of a Brucella trisaccharide epitope linked to a coumarin.

Oligosaccharide allyl glycosides are demonstrated to provide a route to fluorescent probes and simple inhibitors. Ethyl 2-O-acetyl-4-azido-3-O-benzoyl-4,6-dideoxy-1-thio-alpha-D-mannopyranosid e (6) was used as glycosyl donor in the preparation of the trisaccharide [alpha-D-Rha p4NFo-(1----2)-]2-alpha-D-Rha p4NFo-O-allyl (16). Thioglycoside 6 was activated with N-iodosuccinimide and triflic acid or by bromine in the glycosylations and the inhibitor 16 was obtained after deprotection by transesterification, reduction of the azido groups with hydrogen sulfide, and N-formylation with ethyl formate. Ozonolysis of the allyl glycoside in 16 and reductive amination with 7-amino-4-methylcoumarin then gave the target fluorescent trisaccharide conjugate.

Allyl Compounds↗

PubMed1991

Structure and solution conformations of a cyclic trisaccharide from high-resolution n.m.r. spectroscopy and molecular modelling.

The conformational properties of a cyclic trisaccharide: [O-beta-D-glucopyranosyl-(1----6)]3 1,6"-anhydride nonacetate (C36H48O24, 1) have been established by high-resolution 1H- and 13C-n.m.r. spectroscopy in conjunction with potential-energy and molecular-mechanics calculations. The n.m.r. parameters used were nuclear Overhauser enhancements (n.O.e.) and coupling constants. From theoretical models of the trisaccharide, a statistical-mechanics approach was used to compute an ensemble average-relaxation matrix from which the n.O.e. were calculated. The observed nuclear Overhauser enhancements as measured by n.m.r. spectroscopy may be satisfactorily modelled if averaging over two conformational states is considered. In solution, both conformations of the molecule exhibit three-fold symmetry; the beta-linked glucopyranose rings have the 4C1 conformation. In one conformer, the orientation about the (1----6) linkage is characterized by torsion angles phi = 79.5 degrees, psi = 143.5, and omega = -64.3. For the other conformer, these values are phi = -137.7, psi = 68.2, and omega = 45.6. The existence of such a conformer shows that solution behaviour is not dominated by the stabilizing influence of the exoanomeric effect.

Carbohydrate Conformation↗

PubMed1991

Approaches to the C-B-A trisaccharide of dihydroaclacinomycin by extending the chain from either side.

Selective benzylation of L-fucal (1) under phase-transfer conditions gave the 3- and 4-monoethers 2 and 3, respectively. Two routes, the "tail" or the "head" addition are presented, both leading to the target molecule 9, a mimic of the C-B-A trisaccharide component of dihydroaclacinomycin. Addition of glycals 2 and 3 respectively, to the acetylated glycal (7) of amicetose used as glycosyl donor gave the disaccharide glycals 6 and 8. Alternatively, glucosylation of the 4-acetate (4) of 2 with the benzyl hex-2-enopyranoside derivative 10 gave the disaccharide derivative 11. In the first case, the final glycosylation step involves the addition of 10 to disaccharide glycal 8. In the second procedure, the disaccharide alcohol 12 is obtained by O-deacetylation of 11, and serves as the glycosyl acceptor for glycal derivative 7 to give the C-B-a precursor trisaccharide derivative.

Aclarubicin↗

PubMed1992

Human glucosamine-6-sulphatase deficiency. Diagnostic enzymology towards heparin-derived trisaccharide substrates.

Glucosamine-6-sulphatase (6S) activity towards a series of radiolabelled heparin-derived trisaccharide substrates was determined in cultured human skin fibroblast and leucocyte homogenates, and in urine supernatants of normal individuals and patients affected with 6S deficiency [Sanfilippo D syndrome; mucopolysaccharidosis (MPS) type IIID]. The N-sulphated and N-acetylated derivatives of the trisaccharide substrate O-(alpha-glucosamine 6-sulphate)-(1----4)-L-O-(alpha-iduronic acid 2-sulphate)-(1----4)-D-O-2,5-anhydro[1-3H]mannitol 6-sulphate (GlcNH6S-IdoA2S-anM6S) were prepared by enzymic digestion of a pentasulphated tetrasaccharide isolated following the HNO2 deamination of heparin. Purified lysosomal enzymes and MPS-patient skin fibroblasts were used along with chemical degradation to confirm the structure of each of the substrates that were utilized to study the interaction of the enzyme activities required to degrade the highly sulphated regions of heparan sulphate. Human liver, skin fibroblast and urine 6S activities were separated by chromatofocusing into at least four and possibly up to six individual activities. 6S activities present in each of the tissues generally had similar catalytic properties, including Km values, pH optima and inhibition with NaCl, Na2SO4 and NaH2PO4. Leucocyte and skin fibroblast 6S activities towards GlcNAc6S-IdoA2S-anM6S were maximal at pH 4.1 and 3.9 respectively, with Km values of 2.8 microM and 0.9-1.7 microM respectively. Urine 6S activity towards GlcNAc6S-IdoA2S-anM6S was stimulated 30-fold by BSA at pH 3.9, which shifted the pH optimum from 5.1 to 4.2 and decreased the Km value at pH 4.2 from 4.0 microM to 0.5 microM. Residual 6S activity present in the skin fibroblast homogenates from MPS IIID patients was characterized for activity towards GlcNAc6S-IdoA2S-anM6S and observed to have similar pH optima and Km values to normal skin fibroblast 6S activities, although the residual 6S activity was less than 1% of the normal control range.

Chromatography, Gel↗

PubMed1978

Increased excretion of two sialic acid-containing trisaccharides in the urine of patients with rheumatoid arthritis.

The urinary excretion of sialic acid-containing trisaccharides in patients with active rheumatoid arthritis was studied. Sialyl-lactose and sialyl-N-acetyllactosamine were identified and their excretion patterns studied by thin layer and gas chromatography. The urinary output of sialyl-lactose was greater in patients with active rheumatoid arthritis (48.2 +/- 6.1 mg/24 h, SEM, n = 6) than in healthy subjects (19.8 +/- 3.7 mg/24 h, SEM, n = 5; P less than 0.01). The excretion of sialyl-N-acetyllactosamine was also higher in the rheumatoid group (18.5 +/- 2.1 mg/24 h, SEM, n = 6) than in the controls (11.1 +/- 1.2 mg/24 h, SEM, n = 5; P less than 0.05). The qualitative excretion patterns of the sialyl-oligosaccharide fraction were similar for the two groups as judged from the thin layer chromatograms. Correlating the results with the clinical state of the patients with rheumatoid arthritis suggests that the urinary level of the sialyl-oligosaccharides reflects the activity of the disease. A proposed mechanism for the increased excretion of sialic acid-containing trisaccharides in rheumatoid arthritis is presented.

Adult↗

PubMed1990

Structure determination of five sialylated trisaccharides with core types 1, 3 or 5 isolated from bovine submaxillary mucin.

In this study we have investigated the structures of five sialylated trisaccharides released from bovine submaxillary mucin by alkaline borohydride treatment and isolated by high-performance liquid chromatography. Three of the trisaccharides contained NeuAc while two contained NeuGc. One oligosaccharide contained core-type 1, two contained core-type 3 and two contained core-type 5. The structures, determined by a combination of one- and two-dimensional 1H-NMR spectroscopy at 270 MHz and methylation analysis involving gas-liquid chromatography/mass spectrometry, were as follows: A4b, GalNAc alpha(1----3) [NeuAc alpha(2----6)]GalNAcol; A4c, GlcNAc beta(1----3)[NeuAc alpha(2----6)]GalNAcol; A4d, Gal beta(1----3)[NeuAc alpha(2----6)]GalNAcol; A4e, GalNAc alpha(1----3)-[NeuGc alpha(2----6)]GalNAcol; A4f, GlcNAc beta(1----3)[NeuGc alpha (2----6)]GalNAcol. The oligosaccharides occurred in the approximate molar ratios 1.0:12.0:0.3:0.2:2.0. This is the first report of oligosaccharides containing core-type 5 and of the occurrence of oligosaccharides A4b, A4e, and A4f in bovine submaxillary mucin. 1H-NMR data for structure A4e, which is a novel structure, are presented for the first time.

Animals↗

PubMed1992

Structural analysis of a novel sialic-acid-containing trisaccharide from Rhodobacter capsulatus 37b4 lipopolysaccharide.

Sialic-acid-containing lipopolysaccharides from Rhodobacter capsulatus 37b4 (S-form lipopolysaccharide), KB-1 (R-type lipopolysaccharide) and Sp 18 (deep R-type lipopolysaccharide) were investigated for the linkage and substitution of sialic acids. Methylation analysis and behaviour towards acid and enzymic hydrolysis indicated a non-reducing terminal location of sialic acids in the R-type lipopolysaccharide of strain Sp 18, whereas an internal, chain-linked location of sialic acids was found in the lipopolysaccharides of strains 37b4 and KB-1. For these latter strains, methylation analysis revealed a substitution of sialic acids by other sugars at position 7 for strain 37b4 and positions 4 and 7 for strain KB-1. In accordance with the chain-linked position of sialic acids, mild hydrolysis of R. capsulatus 37b4 lipopolysaccharide with acetic acid released a trisaccharide with sialic acid at the reducing terminus. Structural investigation of this trisaccharide by methylation analysis, 1H- and 13C-NMR spectroscopy revealed the presence of the disaccharide Gal1-6Glc at the non-reducing end, probably with an alpha-anomeric configuration of the galactose residue, i.e. melibiose, beta-glycosidically linked to position 7 of sialic acid. Therefore the structure Gal alpha 1-6Glc beta 1-7Neu5Ac is proposed for this core oligosaccharide from R. capsulatus 37b4 lipopolysaccharide.

Carbohydrate Sequence↗

PubMed1992

Specificity analysis of antibodies formed in rabbits to a mannosyl trisaccharide: similarity with lectin binding activity. Para-aminophenyl O-alpha-D-mannopyranosyl-(1-->2)-alpha-D-mannopyranosyl- (1-->6)-alpha-D-mannopyranoside linked to bovine serum albumin as an antigen.

The para-aminophenyl derivative of Man alpha 1-->2Man alpha 1-->6Man alpha 1-->was coupled via a diazotization reaction to bovine serum albumin, and the resulting glycoconjugate was used to immunize two rabbits. The resultant antisera were tested for reactivity with a number of related mono, di- and trisaccharides to determine the immunodominant portion of this trisaccharide. Two populations of antibody resulted, one of which required the reducing end mannose, and could react with either an N-acetylglucosamine or a mannose as the penultimate sugar. The other population reacted with the Man alpha 1-->2Man alpha 1-->6Man alpha 1-->. The aglycone moiety and its configurations play an important role in determining the specificity of antibodies to this synthetic antigen. The similarity of this reactivity to the reactivity of mannose binding lectins is discussed.

Animals↗