Conformational analysis of the Sda determinant-containing tetrasaccharide and two mimics in aqueous solution by using 1H NMR ROESY spectroscopy in combination with MD simulations

The conformational behaviour of the spacer-linked synthetic Sd^a tetrasaccharide -d-GalpNAc-(14)-[-Neu5Ac-(23)]--d-Galp-(14)--d-GlcpNAc-(1O)(CH₂)₅NH₂ (1) and the two mimics -d-Galp-(14)-[-Neu5Ac-(23)]--d-Galp-(14)--d-GlcpNAc-(1O)(CH₂)₅NH₂ (2) and -d-GlcpNAc-(14)-[-Neu5Ac-(23)]--d-Galp-(14)--d-GlcpNAc-(1O)(CH₂)₅NH₂ (3) were investigated by ¹H NMR spectroscopy in combination with molecular dynamics (MD) simulations in water. Experimental 2D ¹H ROESY cross-peak intensities (ROEs) of the tetrasaccharides were compared with calculated ROEs derived from MD trajectories using the CROSREL program. Analysis of these data indicated that the oligosaccharidic skeletons of the compounds 1–3 are rather rigid, especially the -d-Hex(NAc)-(14)-[-Neu5Ac-(23)]--d-Galp fragments. The - Neu5-Ac-(23)--d-Galp linkage occurred in two different energy minima in the three-dimensional structure of the compounds 1–3 in aqueous solution. Experimental data and dynamics simulations supported the finding that the higher energy rotamer (CHEAT forcefield) was abundant in compounds 1 and 3 due to the existence of a hydrogen bond between the carboxyl group of the sialic acid and the acetamido group of the terminal monosaccharide (GalNAc or GlcNAc) unit. The conformational similarity between 1 and 3 leads to the suggestion that also their activities will be alike.     

Monoclonal antibody specific for α2→8-linked oligo deaminated neuraminic acid (KDN) sequences in glycoproteins. Preparation and characterization of a monoclonal antibody and its application in immunohistochemistry

Two particular types of sialoglycoproteins have been detected in fish: polysialoglycoproteins containing 28-linked polysialic acid (8Neu5Gc2) _n present in unfertilized Salmonidae fish eggs, and glycoproteins bearing oligo/polymers of deaminated neuraminic acids (KDN) found in the vitelline envelope of the eggs and ovarian fluid. We report the preparation and characterization of a monoclonal antibody specifically recognizing oligo/polymers of KDN sequences in glycoproteins and its application in immunohistochemistry. Fusion of spleen cells from a BALB/c mouse immunized with a KDN-rich glycoprotein (KDN-gp) containing (8KDN2) _n 6(KDN23Gal13GlNAc13) GalNAc1 residues, with mouse myeloma cells yielded a hybrid cell line producing a monoclonal antibody that bound to KDN-gp, but not to KDN-gp depleted of KDN residues. The specificity of the monoclonal antibody, designated mAb.kdn8kdn, was determined by an enzyme-linked immunosorbent assay using KDN-gp samples that varied in KDN content. These antigens were prepared by the selective removal of KDN residues from the native KDN-gp. The mAb.kdn8kdn reacted most strongly with the intact KDN-gp and less strongly with KDN-gp samples containing decreased numbers of KDN residues. The mAb.kdn8kdn was shown specifically to recognize the 28-linked oligo/polyKDN sequences, (8KDN2) _n , and to be able to distinguish specifically (8KDN2) _n chains from (8Neu5Ac2) _n and (8Neu5Gc2) _n chains. The antibody was used successfully for the immunohistochemical detection of reactive KDN epitopes in sections of paraffin embedded rat pancreas. Several controls verified the specificity of the immunohistochemical staining, thus providing the first demonstration of (8KDN2) _n sequences in a mammalian tissue. The mAb.kdn8kdn can now be used to search further for glycoconjugates containing (8KDN2) _n chains and will facilitate studies on their biosynthesis, intracellular localization and function.     

Cytochrome P-450-dependent catabolism of triethanolamine in Rhodotorula mucilaginosa

The yeast Rhodotorula mucilaginosa was able to grow in media containing triethanolamine or diethanolamine as the sole nitrogen source. During growth in the presence of triethanolamine, extracts of yeast cells contained increased levels of cytochrome P-450 dependent monooxygenase which catalyzed the oxidative N-dealkylation of aminoalcohols. Formation of diethanolamine, ethanolamine and glyoxylate from triethanolamine was demonstrated, and the identity of the products was verified by thin layer chromatography. These observations suggested the following scheme of triethanolamine catabolism: triethanolamine diethanolamine + glycolaldehyde, diethanolamine ethanolamine + glycolaldehyde, ethanolamine NH₃ + glycolaldehyde glycolate glyoxylate glycerate pathway.     

Differential expression of enzyme activities initiating anoxic metabolism of various aromatic compounds via benzoyl-CoA

The regulation of the expression of enzyme activities catalyzing initial reactions in the anoxic metabolism of various aromatic compounds was studied at the whole cell level in the denitrifying Pseudomonas strain K 172. The specific enzyme activities were determined after growth on six different aromatic substrates (phenol, 4-hydroxybenzoate, benzoate, p-cresol, phenylacetate, 4-hydroxyphenylacetate) all being proposed to be metabolized anaerobically via benzoyl-CoA. As a control cells were grown on acetate, or aerobically on benzoate. The expression of the following enzyme activities was determined.Phenol carboxylase, as studied by the isotope exchange between ¹⁴CO₂ and the carboxyl group of 4-hydroxybenzoate; 4-hydroxybenzoyl-CoA reductase (dehydroxylating); p-cresol methylhydroxylase; 4-hydroxybenzyl alcohol dehydrogenase; 4-hydroxybenzaldehyde dehydrogenase; coenzymeA ligases for the aromatic acids benzoate, 4-hydroxybenzoate, phenylacetate, and 4-hydroxyphenylacetate; phenylglyoxylate: acceptor oxidoreductase and 4-hydroxyphenylglyoxylate: acceptor oxidoreductase; aromatic alcohol and aldehyde dehydrogenases.The formation of most active enzymes is strictly regulated; they were only induced when required, the basic activities being almost zero. The observed whole cell regulation pattern supports the postulate that the enzyme activities play a role in anoxic aromatic metabolism and that the compounds are degraded via the following intermediates: Phenol 4-hydroxybenzoate 4-hydroxybenzoyl-CoA benzoyl-CoA; 4-hydroxybenzoate 4-hydroxybenzoyl-CoA benzoyl-CoA; benzoate benzoyl-CoA; p-cresol 4-hydroxybenzaldehyde 4-hydroxybenzoate 4-hydroxybenzoyl-CoA benzoyl-CoA; phenylacetate phenylacetyl-CoA phenylglyoxylate benzoyl-CoA plus CO₂; 4-hydroxyphenylacetate 4-hydroxyphenylacetyl-CoA 4-hydroxyphenylglyoxylate 4-hydroxybenzoyl-CoA plus CO₂ benzoyl-CoA.     

Occurrence of reducing terminal N-acetylglucosamine 3-sulfate and fucosylated outer chains in acidic N-glycans of porcine zona pellucida glycoproteins

Structures of acidic N-glycans released from porcine zona pellucida glycoproteins by hydrazinolysis were studied. The results indicated that the acidic glycans are of mono- to tetraantennary complex-type with and without N-acetyllactosamine repeating units. Sulfated residues are not only located at the C-6 position of GlcNAc included in the N-acetyllactosamine repeating units, but also at the C-6 position of GlcNAc in the non-repeated antennae and at the C-3 position of reducing terminal GlcNAc residue. Analysis of the oligosaccharide fragments released by endo--galactosidase digestion and by hydrazine/nitrous acid treatment also revealed that various sulfated and non-sulfated forms of fucosylated structures such as Fuc12Gal14(±SO–36)GlcNAc (type 2H), Gal14(Fuc13)(±SO–36)GlcNAc(Lex) and Fuc13 or 4(±SO–36)GlcNAc, are expressed in the repeated outer chain moieties.     

Expression sites and developmental regulation of genes encoding (1→3,1→4)-β-glucanases in germinated barley

Expression sites of genes encoding (13,14)--glucan 4-glucanohydrolase (EC 3.2.1.73) have been mapped in germinated barley grains (Hordeum vulgare L.) by hybridization histochemistry. A³²P-labelled cDNA (copy DNA) probe was hybridized to cryosections of intact barley grains to localize complementary mRNAs. No mRNA encoding (13,14)--glucanase is detected in ungerminated grain. Expression of (13,14)--glucanase genes is first detected in the scutellum after 1 d and is confined to the epithelial layer. At this stage, no expression is apparent in the aleurone. After 2 d, levels of (13,14)--glucanase mRNA decrease in the scutellar epithelium but increase in the aleurone. In the aleurone layer, induction of (13,14)--glucanase gene expression, as measured by mRNA accumulation, progresses from the proximal to distal end of the grain as a front moving away from, and parallel to, the face of the scutellum.Abbreviations cDNA copy DNA - RNase ribonuclease     

Curdlan and other bacterial (1→3)-β-d-glucans

Three structural classes of (13)--d-glucans are encountered in some important soil-dwelling, plant-associated or human pathogenic bacteria. Linear (13)--glucans and side-chain-branched (13,12)--glucans are major constituents of capsular materials, with roles in bacterial aggregation, virulence and carbohydrate storage. Cyclic (13,16)--glucans are predominantly periplasmic, serving in osmotic adaptation. Curdlan, the linear (13)--glucan from Agrobacterium, has unique rheological and thermal gelling properties, with applications in the food industry and other sectors. This review includes information on the structure, properties and molecular genetics of the bacterial (13)--glucans, together with an overview of the physiology and biotechnology of curdlan production and applications of this biopolymer and its derivatives.     

Ganglioside-cholera toxin interactions: a binding and lipid monolayer study

Summary On t.l.c. plates ¹²⁵I-cholera toxin binds to a disialoganglioside tentatively identified as GD_lb with about 10 times less capacity than to ganglioside GM₁. Binding of labeled toxin to both gangliosides was abolished in presence of excess amounts of unlabeled B subunit. Ganglioside extracts from human or pig intestinal mucosa showed toxin binding to gangliosides GM₁ and GD_1b. In ganglioside-containing lipid monolayers the penetration of the toxin was independent of the ganglioside binding capacity.Abbreviations GM₂ Gal-NAc14Gal(3-2NeuAc)14G1c1Cer - GM₁ Gal3Ga1-NAc14Gal(32NeuAc)14G1c11Cer - GD_1a NeuAc23Ga113Gal-NAc14Gal(32NeuAc)14G1c11Cer - GD1b Gall3Gal-NAcl4Gal(32NeuAc82NeuAc)14Glc11Cer - GT_1b NeuAc23Ga113Ga1-NAcal4Gal(3-2NeuAc82NeuAc)14G1c11Cer - dpPC 1,2-hexadecanoyl-sn-glycero-3-phosphocholine - dpPE 1,2-hexadecanoyl-sn-glycero-3-phosphoethanolamine     

Synthesis of the acceptor analog αFuc(1→2)αGal-O(CH2)7 CH3: A probe for the kinetic mechanism of recombinant human blood group B glycosyltransferase

We report the chemical synthesis of Fuc(12)Gal-O(CH₂)₇CH₃ (1) an analog of the natural blood group (O)H disaccharide Fuc(12)Gal-OR. Compound 1 was a good substrate for recombinant blood group B glycosyltransferase (GTB) and was used as a precursor for the enzymatic synthesis of the blood group B analog Gal(3)[Fuc(12)]Gal-O(CH₂)₇CH₃ (2). To probe the mechanism of the GTB reaction, kinetic evaluations were carried out employing compound 1 or the natural acceptor disaccharide Fuc(12)Gal-O(CH₂)₇CH₃ (3) with UDP-Gal and UDP-GalNAc donors. Comparisons of the kinetic constants for alternative donor and acceptor pairs suggest that the GTB mechanism is Theorell-Chance where donor binding precedes acceptor binding. GTB operates with retention of configuration at the anomeric center of the donor. Retaining reactions are thought to occur via a double-displacement mechanism with formation of a glycosyl-enzyme intermediate consistent with the proposed Theorell-Chance mechanism.     

Purification of (1→3)-β-glucan endohydrolase isoenzyme II from germinated barley and determination of its primary structure from a cDNA clone

A (13)--D-glucan 3-glucanonydrolase (EC 3.2.1.39) of apparent M _r 32 000, designated GII, has been purified from germinated barley grain and characterized. The isoenzyme is resolved from a previously purified isoenzyme (GI) on the basis of differences in their isoelectric points; (13)--glucanases GI and GII have pI values of 8.6 and 10.0, respectively. Comparison of the sequences of their 40 NH₂-terminal amino acids reveals 68% positional identity. A 1265 nucleotide pair cDNA encoding (13)--glucanase isoenzyme GII has been isolated from a library prepared with mRNA of 2-day germinated barley scutella. Nucleotide sequence analysis of the cDNA has enabled the complete primary structure of the 306 amino acid (13)--glucanase to be deduced, together with that of a putative NH₂-terminal signal peptide of 28 amino acid residues. The (13)--glucanase cDNA is characterized by a high (G+C) content, which reflects a strong bias for the use of G or C in the wobble base position of codons. The amino acid sequence of the (13)--glucanase shows highly conserved internal domains and 52% overall positional identity with barley (13, 14)--glucanase isoenzyme EII, an enzyme of related but quite distinct substrate specificity. Thus, the (13)--glucanases, which may provide a degree of protection against microbial invasion of germinated barley grain through their ability to degrade fungal cell wall polysaccharides, appear to share a common evolutionary origin with the (13, 14)--glucanases, which function to depolymerize endosperm cell walls in the germinated grain.     

Proton translocation during denitrification in Rhodopseudomonas sphaeroides f. denitrificans

Proton translocation during the reduction of NO ₃ ^- , NO ₂ ^- , N₂O and O₂, with endogenous substrates, in washed cells of Rhodopseudomonas sphaeroides f. denitrificans was investigated by an oxidant pulse method. On adding NO ₂ ^- to washed cells, anaerobically in the dark, an alkalinization occurred in the reaction mixture followed by acidification. When NO ₃ ^- , N₂O or O₂ was added to cells in the dark or with these compounds and NO ₂ ^- in light an acidification only was observed. Proton translocation was inhibited by carbonyl cyanide-m-chlorophenyl hydrazone.Valinomycin treated cells produced acid in response to the addition of either NO ₃ ^- , NO ₂ ^- , N₂O or O₂. The proton extrusion stoichiometry ( ratios) in illuminated cells were as follows: NO ₃ ^- 0.5N₂, 4.82; NO ₂ ^- 0.5N₂, 5.43; N₂ON₂, 6.20; and O₂H₂O, 6.43. In the dark the comparable values were 3.99, 4.10, 4.17 and 3.95. Thus, illuminated cells produced higher values than those in the dark, indicating a close link between photosynthesis and denitrification in the generation of proton gradients across the bacterial cell membranes.When reduced benzyl viologen was the electron donor in the presence of 1 mM N-ethylmaleimide and 0.5 mM 2-n-heptyl-4-hydroxyquinoline-N-oxide in the dark, the addition of either NO ₃ ^- , NO ₂ ^- or N₂O to washed cells resulted in a rapid alkalinization of the reaction mixture. The stoichiometries for proton consumption, ratios without a permeant ion were NO ₃ ^- NO ₂ ^- ,-1.95; NO ₂ ^- 0.5 N₂O,-3.03 and N₂ON₂,-2.02. The data indicate that these reductions occur on the periplasmic side of the cytoplasmic membrane.Abbreviations BVH reduced benzyl viologen - CCCP carbonyl cyanide m-chlorophenyl hydrazone - DIECA N, N-diethyl-dithiocarbamate - HOQNO 2-n-heptyl-4-hydroxyquinoline-N-oxide - NEM N-ethylmaleimide     

Effects of Biogenic Amines and Polypeptide Hormones on Protein Kinase A and Adenylyl Cyclase Activities in Muscles of the Mollusc Anodonta cygnea

The effects of biogenic amines, glucagon, and insulin on the cAMP-dependent protein kinase A (PKA) activity have been studied in the muscle tissue of the freshwater bivalve mollusc Anodonta cygnea. It was shown that serotonin, glucagon, and insulin both in vivo and in vitro stimulated PKA activity, whereas isoproterenol inhibited it. The stimulating effect of serotonin and inhibiting effect of isoproterenol was blocked by serotoninergic (cyproheptadine) and adrenergic (propranolol) inhibitors, which confirms specificity of the effect of biogenic amines on the PKA activity. Taking into account participation of adenylyl cyclase system in action of the above hormones, the revealed hormonal effects on the PKA activity produce metabolic effects via the following chain reaction. In the case of serotonin and glucagon: receptor G_s-protein AC cAMP PKA phosphorylation of glycogen synthase (GS) and glucose-6-phosphate dehydrogenase (G6PDH) and inhibition of their activity; in the case of isoproterenol: -adrenoreceptor G_i-protein AC inhibition decreasing PKA inhibition of phosphorylase and stimulation of GSI and G6PDH. A participation is suggested of the insulin-stimulated AC signaling system in the mechanism of the mitogenic insulin effect mediated, as shown in this work, via the PKA activation, but not of the metabolic effect of insulin.     

Direct evidence of structural changes in reaction centers of Rb. sphaeroides containing suppressor mutations for Asp L213 → Asn: A FTIR study of QB photoreduction

In bacterial reaction centers (RCs), changes of protonation state of carboxylic groups, of quinone-protein interactions as well as backbone rearrangements occuring upon Q_B photoreduction can be revealed by FTIR difference spectroscopy. The influence of compensatory mutations to the detrimental Asp L213 Asn replacement on Q_B ^–/Q_B FTIR spectra of Rb. sphaeroides RCs was studied in three double mutants carrying a Asn M44 Asp, Arg M233 Cys, or Arg H177 His suppressor mutation. The proton uptake by Glu L212 upon Q_B ^– formation, as reflected by the positive band at 1728 cm^–1, is increased in the Asn M44 Asp and Arg H177 His suppressor RCs with respect to native RCs, and remains comparable to that observed in Asp L213 Asn mutant RCs. Only the Arg M233 Cys suppressor mutation affected the 1728 cm^–1 band, reducing its amplitude to near native level. Thus, there is no clear correlation between the apparent extent of proton uptake by Glu L212 and the recovery of the proton transfer RC function. In all of the mutant spectra, several protein (amide I and amide II) and quinone anion (C...O/C...C) modes are perturbed compared to the spectrum of native RCs. These IR data show that all of the compensatory mutations alter the semiquinone-protein interactions and the backbone providing direct evidence of structural changes accompanying the restoration of efficient proton transfer in RCs containing the Asp L213 Asn lesion.     

Synthesis of Aminoethyl Glycosides of the Carbohydrate Chains of Glycolipids Gb3, Gb4, and Gb5

4-O-Glycosylation of 2-azidoethyl 2,3,6-tri-O-benzoyl-4-O-(2,3,6-tri-O-benzoyl--D-galactopyranosyl)--D-glucopyranoside with ethyl 2,3,4,6-tetra-O-benzyl- and ethyl 3-O-acetyl-2,4,6-tri-O-benzyl-1-thio--D-galactopyranoside in the presence of methyl trifluoromethanesulfonate led to trisaccharide 2-azidoethyl (2,3,4,6-tetra-O-benzyl--D-galactopyranosyl)-(14)-(2,3,6-tri-O-benzoyl--D-galactopyranosyl)-(14)-2,3,6-tri-O-benzoyl--D-glucopyranoside and its 3"-O-acetylated analogue, 2-azidoethyl (3-O-acetyl-2,4,6-tri-O-benzyl--D-galactopyranosyl)-(14)-(2,3,6-tri-O-benzoyl--D-galactopyranosyl)-(14)-2,3,6-tri-O-benzoyl--D-glucopyranoside in yields of 85 and 83%, respectively. Deacetylation of the latter compound and subsequent glycosylation with 4-trichloroacetamidophenyl 3,4,6-tri-O-acetyl-2-deoxy-1-thio-2-trichloroacetamido--D-galactopyranoside and 4-trichloroacetamidophenyl 4,6-di-O-acetyl-2-deoxy-3-O-(2,3,4,6-tetra-O-acetyl--D-galactopyranosyl)-1-thio-2-trichloroacetamido--D-galactopyranoside in dichloromethane in the presence of N-iodosuccinimide and trifluoromethanesulfonic acid resulted in the corresponding selectively protected derivatives of the tetrasaccharide GalNAc(13)Gl(14)Gal(14)Glc-OH₂CH₂N₃ and the pentasaccharide Gal(13)GalNAc(13)Gl(14)Gal(14)Glc-OH₂CH₂N₃ in 88 and 73% yields, respectively. Removal of O-protecting groups, substitution of acetyl group for the N-trichloroacetyl group, and reduction of the aglycone azide group resulted in the target 2-aminoethyl globo-tri-, -tetra-, and -pentasaccharide, respectively.     

Novel promoter and splice junction defects add to the genetic,clinical or geographic heterogeneity of β-thalassaemia in the Portuguese population

Summary In order to delineate the spectrum and the relative abundance of -globin gene defects causing thalassaemia in the Portuguese population, a representative sample was analysed including 51 -thalassaemia carriers along with 26 patients representing different clinical phenotypes. Seven mutations were identified, four of which [codon 39 (CT), 39%; intervening sequence (IVS)1 nucleotide (nt) 1 (GA), 26%; IVS1 nt 110 (GA), 17%; IVS1 nt6 (TC), 15%] account for 97% of 93 -thalassaemia chromosomes. Two previously undescribed mutations, namely a CT substitution at position — 90 in the proximal CACCC box, and the deletion of nucleotides 4 and 5 (AG) in IVS 2 were identified. The uncommon, though ubiquitous, GT transversion at codon 121 was found once upon haplotype V. Direct prenatal diagnosis can be offered to 95% of couples at risk of bearing a thalassaemic child.     

Production of a novel syrup containing neofructo-oligosaccharides by the cells of Penicillium citrinum

A novel syrup containing neofructo-oligosaccharides was produced from sucrose (Brix 70) by whole cells of Penicillium citrinum. The efficiency of fructo-oligosaccharides production was more than 55% and those of the main carbohydrate components, 1-kestose (Fruf 21Fruf 21 Glc), nystose (Fruf 21Fruf 21 Fruf 21 Glc) and neokestose (Fruf 26 Glc12 Fruf), were 22, 14 and 11%, respectively.     

The coagulation factor VII regulator is located on 8p23.1

Summary Cytogenetic and coagulation studies have been performed on two patients with different abnormalities of chromosome 8, i.e. del(8p23.1pter) and dup(8q23.1qter). Results confirm the existence of a regulatory mechanism for clotting factor VII on chromosome 8 and define its location to the p23.1p23.2 region.     

Pyrimidine dimers as pre-mutational lesions in Escherichia coli WP2 Hcr

Summary Mutation to prototrophy in E. coli WP2 Hcr^- induced by far-UV radiation (F-UV) in an intermediate dose range follows dose-squared kinetics. In a comparable dose-range with near-UV radiation in the presence of acetophenone (N-UV+Acph) mutation induction follows kinetics which are linearly related to dose. The difference in response to the two types of irradiation is a more general one in that it is the same for true revertants, for suppressor mutants, and for several markers.Double-irradiation experiments together with treatment by photoreactivating light (PR) after the first irradiation (i.e. F-UVPRF-UV; N-UV+AcphPRN-UV+Acph; N-UV+AcphF-UV; N-UV+AcphPRF-UV) seem to indicate the following: a) the dose-squared kinetics for F-UV are due to the necessary co-operation of at least two types of pre-mutational lesions, only one of which is photoreversible; b) N-UV+Acph also produces these photoreversible lesions in addition to such photoreversible ones which do not require the co-operation of other types; the production of the former is not indicated by the appearance of visible mutants because the non-photoreversible type, whose co-operation is required to give rise to such mutants, is not produced.     

Structural diversity of O-polysaccharides and serological classification of <Emphasis Type="Italic">Pseudomonas syringae</Emphasis> pv. <Emphasis Type="Italic">garcae</Emphasis> and other strains of genomospecies 4

Novel O-serotypes were revealed among Pseudomonas syringae pv. garcae strains by using a set of mouse monoclonal antibodies specific to the lipopolysaccharide O-polysaccharide. Structural studies showed that the O-polysaccharide of P. syringae pv. garcae NCPPB 2708 is a hitherto unknown linear L-rhamnan lacking strict regularity and having two oligosaccharide repeating units I and II, which differ in the position of substitution in one of the rhamnose residues and have the following structures: I:3)--L Rha (12)-- L Rha (12)--L-Rha-(13)--L Rha (1;II: 2)--L-Rha-(13) -L-Rha-(12)--L-Rha-(13)--L Rha (1.The branched O-polysaccharides of P. syringae pv. garcae ICMP 8047 and NCPPB 588^T have the same L-rhamnan backbone with repeating units I and II and a lateral chain of 14)- or 13)-linked residues of 3-acetamido-3,6-dideoxy-D-galactose (D-Fuc3NAc). Several monoclonal antibody epitopes associated with the L-rhamnan backbone or the lateral -D-Fuc3NAc residues were characterized.Translated from Mikrobiologiya, Vol. 73, No. 6, 2004, pp. 777–789.Original Russian Text Copyright © 2004 by Ovod, Zdorovenko, Shashkov, Kocharova, Knirel.     

Synthesis of Gal-β-(1→4)-GlcNAc-β-(1→6)-[Gal-β- (1→3)]-GalNAc-α-OBn oligosaccharides bearing O-methyl or O-sulfo groups at C-3 of the Gal residue: specific acceptors for Gal: 3-O-sulfotransferases

Our recent studies have revealed the existence of two distinct Gal: 3-O-sulfotransferases capable of acting on the C-3 position of galactose in a Core 2 branched structure, e.g., Gal14GlcNAc16(Gal13)GalNac1OBenzyl as acceptor to give 3-O-sulfoGal14GlcNAc13(Gal13)GalNAc1OB 20 and Gal14GlcNAc16(3-O-sulfoGal13)GalNAc1OB 23. We herein report the synthesis of these two compounds and also that of other modified analogs that are highly specific acceptors for the two sulfotransferases. Appropriately protected 1-thio-glycosides 7, 8, and 10 were employed as glycosyl donors for the synthesis of our target compounds.