scholarly journals Analysis of carbohydrate-protein interactions with synthetic N-linked neoglycoconjugate probes

1993 ◽  
Vol 296 (3) ◽  
pp. 817-825 ◽  
Author(s):  
S Y C Wong ◽  
I D Manger ◽  
G R Guile ◽  
T W Rademacher ◽  
R A Dwek

Recently we have describe a simple efficient chemical method of generating an asparagine side-chain linker with beta-stereochemistry at the anomeric position of neutral oligosaccharides. We now report the 1-N-glycyl beta-derivatization of sialylated saccharides. Several neoglycoconjugates formed using these N-linked inter-mediates were investigated for their usefulness in probing carbohydrate-protein interactions. First, biotinyl derivatives of two xylose/fucose class plant-type oligosaccharides purified from horseradish peroxidase were effective in demonstrating the carbohydrate specificity of polyclonal anti-(horseradish peroxidase) antibodies. Secondly, a fluorescein-labelled asialo- and digalactosylated biantennary complex sugar was synthesized and shown to bind to a Ricinus communis agglutinin column. This galactose-specific recognition was abolished by treating this fluorescein-labelled oligosaccharide with jack bean beta-galactosidase. Finally, two 1-N-glycyl beta-saccharide derivatives were modified with thiophosgene to form their corresponding isothiocyanate derivatives. Coupling of these isothiocyanate derivatives of sugars to BSA, amino-derivatized polystyrene plates and glass-fibre discs resulted in multiple sugar presentation. The binding of an anti-N-acetylglucosamine monoclonal antibody to N,N′-diacetylchitobiose residues presented on BSA and solid supports was shown by e.l.i.s.a. Similarly the binding of concanavalin A to asialo-, agalactosylated biantennary complex oligosaccharide residues attached to BSA was demonstrated by a competitive e.l.i.s.a. Our results demonstrate that N-linked neoglycoconjugates could be made readily available and they are valuable tools for the detailed analyses of carbohydrates and carbohydrate-binding proteins.

1998 ◽  
Vol 333 (3) ◽  
pp. 539-542 ◽  
Author(s):  
Shalini SHARMA ◽  
Satish BHARADWAJ ◽  
Avadhesha SUROLIA ◽  
Sunil Kumar PODDER

High-sensitivity isothermal titration calorimetry has been used to investigate the thermodynamics of binding of Ricinus communis agglutinin to galactose, lactose and their derivatives in the temperature range 280.5–298 K. The present study unequivocally establishes the carbohydrate-binding stoichiometry of the tetrameric agglutinin from castor bean as two, i.e. the (As–sB)2-type tetramer of the agglutinin has two equivalent sites that are non-interacting and independent. The site binding constants range from 2.2×103 M-1 at 282 K for galactose to 4.84×104 M-1 at 281 K for N-acetyl-lactosamine. The binding enthalpies range from -21.9 kJ·mol-1 at 293 K for 4-methylumbelliferyl-β-galactoside to -50.2 kJ·mol-1 at 292.9 K for thiodigalactoside. The observation of limited entropy–enthalpy compensation for binding of the sugars to the lectin indicates that reorganization of water molecules plays an important role in binding. As the slope of the compensation plot is greater than unity, the reactions are largely enthalpically driven. These studies show that the stronger binding of N-acetyl-lactosamine than lactose is due to a favourable interaction between the acetamido group of the reducing-end N-acetylglucosamine of the former and the corresponding loci in the agglutinin molecule. Preferential binding of methyl-β-galactoside over methyl-α-galactoside also indicates the apolar nature of the interaction with the methyl group of the former sugar.


2003 ◽  
Vol 56 (6) ◽  
pp. 567 ◽  
Author(s):  
Noriko Nagahori ◽  
Kenichi Niikura ◽  
Reiko Sadamoto ◽  
Kenji Monde ◽  
Shin-Ichiro Nishimura

Photopolymerizable glycolipids incorporating ceramide- or amido-type linkers and able to form stable monolayers were efficiently synthesized by chemical and enzymatic methods. Glycolipid polymer films served as platforms for the immobilization of proteins through specific carbohydrate–protein interactions at the air–water interface. Carbohydrate-binding proteins deposited on the glycolipid film were observed by atomic force microscopy, which showed varying submicron-sized protein patterns such as dendrites, dots, and networks, depending on the lipid structure, membrane preparation process, and sugar density of the membrane. Surface plasmon resonance measurement confirmed that the subunit-type lectins immobilized on the glycolipid membranes exhibited the ability to interact specifically with carbohydrate ligands by using unoccupied binding sites.


2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Galina Pazynina ◽  
Vitaly Nasonov ◽  
Ivan Belyanchikov ◽  
Reinchard Brossmer ◽  
Maxim Maisel ◽  
...  

Earlier we reported a convenient and efficient method of preparing α2-6 sialooligosaccharides in conditions of Koenigs-Knorr reaction. The use of Ag2CO3 allowed carrying out α2-6 sialylation of galacto-4,6-diol of mono- and disaccharides with chloride of acetylated N-acetylneuraminic acid methyl ester as glycosyl donor. In this study we applied this approach to other derivatives of neuraminic acid, namely, Neu5Gc, 9-deoxy-9-NAc-Neu5Ac, Neu5Acα2-8Neu5Ac, and Neu5Acα2-8Neu5Acα2-8Neu5Ac as glycosyl donors; eight compounds were synthesized: Neu5Gcα-O(CH2)3NH2 (8), Neu5Gcα2-6Galβ1-4GlcNAcβ-O(CH2)3NH2 (10), 9-deoxy-9-NAc-Neu5Ac-O(CH2)3NH2 (15), 9-deoxy-9-NAc-Neu5Acα2-6Galβ1-4GlcNAcβ-O(CH2)3NH2 (17), Neu5Acα2-8Neu5Acα-O(CH2)3NH2(23) Neu5Acα2-8Neu5Acα-OCH3 (24), Neu5Acα2-8Neu5Acα-OCH2(p-C6H4)NHCOCH2NH2 (25), and Neu5Acα2-8Neu5Acα2-8Neu5Acα-O(CH2)3NH2 (32). These sialosides were used for characterization of siglecs and other carbohydrate-binding proteins.


1991 ◽  
Vol 39 (6) ◽  
pp. 793-800 ◽  
Author(s):  
M A Vannier-Santos ◽  
E M Saraiva ◽  
W de Souza

We demonstrated the presence of intracellular lectin binding sites in promastigotes of Leishmania mexicana amazonensis. Direct and indirect lectin-gold techniques were used on Lowicryl K4M-embedded cells. The nuclear compartment was labeled by most lectins. Nucleoli were mainly labeled by WFH (Wistaria floribunda hemagglutinin) and LFA (Limax flavus agglutinin) specific for D-galactose/N-acetyl-D-galactosamine (D-Gal/D-GalNAc) and sialic acid, respectively. Sections treated with the fetuin-gold complex without previous lectin incubation also exhibited labeled nucleoli, although less intensely, suggesting the presence not only of sialic acid but also of a sialic acid-specific endogenous carbohydrate binding molecule in Leishmania nuclei. Surprisingly, the Golgi complex was never labeled, whereas the endoplasmic reticulum was frequently labeled, especially by RCA (Ricinus communis agglutinin; D-GalNAc/D-Gal) and WGA (wheat germ agglutinin; D-GlcNAc). The kinetoplast, a DNA-containing structure located within the mitochondrion, was generally labeled towards its extremities, where previous studies have shown the presence of ribonucleoproteins. Some possible biological roles for these intracellular glycoconjugates are discussed.


1988 ◽  
Vol 60 (02) ◽  
pp. 182-187 ◽  
Author(s):  
Morio Aihara ◽  
Ken Tamura ◽  
Ryuko Kawarada ◽  
Keizou Okawa ◽  
Yutaka Yoshida

SummaryThe adhesion of human fixed washed platelets (FWP) to collagen was decreased after treatment with Serratia marcescens protease (SP), which removed 95% of the glycocalicin from platelet membrane glycoprotein (GP) lb. However, the diminished adhesion of SP treated FWP to collagen could still be increased in the presence of purified von Willebrand factor (vWF). This ability of vWF to increase FWP adhesion to collagen is defined as collagen cofactor (CCo). The adhesion of FWP to collagen was not affected by a monoclonal antibody (MAb) to GP Ilb/IIIa (10E5), that inhibits ADP and collagen induced platelet aggregation. On the other hand, it was decreased by 50% by a MAb to GP lb (6D1), that inhibits ristocetin induced platelet aggregation. Adhesion of FWP in buffer to collagen was completely inhibited by Ricinus communis agglutinin I or concanavalin A, while Lens culinalis agglutinin and wheat germ agglutinin showed 50% inhibition. The FWP adhesion to collagen in the presence of vWF (normal plasma) was unaffected by MAbs to GP Ilb/IIIa (10E5, P2, HPL1) but was decreased to 32-38% by MAbs to GP lb (6D1, AN51, HPL11). A MAb to vWF (CLB-RAg 35), that inhibits ristocetin induced binding of vWF to platelets, decreased the CCo of normal plasma by 70%. The MAb, CLB-RAg 201, that inhibits the binding of vWF to collagen, completely inhibited the CCo of normal plasma. In conclusion, our data suggest that (1) GP lb has a partial role in FWP adhesion to collagen; (2) the binding of vWF to collagen is required for the expression of CCo; (3) CCo is partly mediated through GP lb; but (4) other platelet membrane protein(s) besides GP lb or GP Ilb/IIIa must also be involved in FWP-vWF-collagen interactions.


1986 ◽  
Vol 55 (03) ◽  
pp. 338-341 ◽  
Author(s):  
H Takahashi ◽  
W Tatewaki ◽  
M Hanano ◽  
R Nagayama ◽  
A Shibata

SummaryPlatelet-type von Willebrand’s disease (vWD) is a bleeding disorder characterized by a heightened interaction between platelets and von Willebrand factor (vWF) as the result of an intrinsic platelet abnormality (probably in GPIb). Platelet aggregability was nearly normal in response to thrombin, wheat germ agglutinin and Ricinus communis agglutinin in this disorder. Unmodified platelets showed no aggregation upon the addition of peanut agglutinin. Partially purified human vWF induced little aggregation of washed patient platelets, but the aggregation was greatly enhanced in the presence of plasma devoid of vWF. Monoclonal antibodies directed against GPIb and GPIIb/IIIa as well as EDTA completely inhibited vWF-induced aggregation. These results indicate that human vWF induces aggregation of platelet-type vWD platelets in the presence of divalent cations and some plasma cofactor(s), and that both GPIb and GPIIb/IIIa are involved in this aggregation.


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