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Lectin Interactions (lectin + interaction)
Selected AbstractsUsage of Aplysia lectin interactions with T antigen and poly- N -acetyllactosamine for screening of E. coli strains which bear glycoforms cross-reacting with cancer-associated antigensFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2001Nechama Gilboa-Garber Abstract Aplysia gonad lectin (AGL), which strongly agglutinates cancer cells, was found, in the present study, to bind to erythrocyte T antigen, in addition to its affinity to Ii system antigens. These antigens were reported to be overexpressed and to contribute to tumor progression and invasion. In healthy human sera, there are antibodies against them, stimulated by the normal intestinal microflora, which bear similar glycoforms. Since the levels of these antibodies were reported to be lower in most cancer patients' sera, we have examined the applicability of AGL to isolation of enteric commensal Escherichia coli strains which bear glycoforms cross-reacting with the cancer-associated antigens. Among 30 E. coli isolates examined, two were agglutinated by AGL. One of them was also agglutinated by certain related galactophilic lectins, which bind to the T and Tn antigens. The agglutination of the two bacteria by healthy human sera, as a group, was stronger than that displayed by the cancer patients' sera. These results indicate that AGL might be useful for identification of the desired bacteria, which could potentially serve for cancer diagnosis and therapy. [source] Prepolymerization and postpolymerization functionalization approaches to fluorescent conjugated carbazole-based glycopolymers via "click chemistry"JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 11 2009Qi Chen Abstract Facile prepolymerization and postpolymerization functionalization approaches to prepare well-defined fluorescent conjugated glycopolymers through Cu(I)-catalyzed azide/alkyne "Click" ligation were explored. Two well-defined carbazole-based fluorescent conjugated glycopolymers were readily synthesized based on these strategies and characterized by 1H NMR, 13C NMR, IR spectra, and UV-vis spectra. The "Click" ligation offers a very effective conjugation method to covalently attach carbohydrate residues to fluorescent conjugated polymers. In addition, the studies of carbohydrate,lectin interactions were performed by titration of concanavalin A (Con A) to D -glucose-bearing poly(anthracene- alt -carbazole) copolymer P-2 resulting in significant fluorescence quenching of the polymer due to carbohydrate,lectin interactions. When peanut agglutinin (PNA) was added, no distinct change in the fluorescent properties of P-2 was observed. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2948,2957, 2009 [source] Single-molecule pair studies of the interactions of the ,-GalNAc (Tn-antigen) form of porcine submaxillary mucin with soybean agglutininBIOPOLYMERS, Issue 9 2009Marit Sletmoen Abstract Mucins form a group of heavily O -glycosylated biologically important glycoproteins that are involved in a variety of biological functions, including modulating immune response, inflammation, and adhesion. Mucins are also involved in cancer and metastasis and often express diagnostic cancer antigens. Recently, a modified porcine submaxillary mucin (Tn-PSM) containing GalNAc,1- O -Ser/Thr residues was shown to bind to soybean agglutinin (SBA) with ,106 -fold enhanced affinity relative to GalNAc,1- O -Ser, the pancarcinoma carbohydrate antigen. In this study, dynamic force spectroscopy is used to investigate molecular pairs of SBA and Tn-PSM. A number of force jumps that demonstrate unbinding or rebinding events were observed up to a distance equal to 2.0 ,m, consistent with the length of the mucin chain. The unbinding force increased from 103 to 402 pN with increasing force loading rate. The position of the activation barrier in the energy landscape of the interaction was 0.1 nm. The lifetime of the SBA,TnPSM complex in the absence of applied force was determined to be in the range 1.3,1.9 s. Kinetic parameters describing the rate of dissociation of other sugar lectin interactions are in the range 3.3 × 10,3,2.5 × 10,3 s. The long lifetime of the SBA-TnPSM complex is compatible with a binding model in which lectin molecules "bind and jump" from ,-GalNAc residue to ,-GalNAc residue along the polypeptide chain of Tn-PSM before dissociating. These findings have important implications for the molecular recognition properties of mucins. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 719,728, 2009. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] Dynamic Combinatorial Carbohydrate Libraries: Probing the Binding Site of the Concanavalin A LectinCHEMISTRY - A EUROPEAN JOURNAL, Issue 7 2004Olof Ramström Dr. Abstract Dynamic combinatorial chemistry (DCC) has emerged as an efficient approach to receptor/ligand identification based on the generation of combinatorial libraries by reversible interconversion of the library constituents. In this study, the implementation of such libraries on carbohydrate,lectin interactions was examined with the plant lectin Concanavalin A as a target species. Dynamic carbohydrate libraries were generated from a pool of carbohydrate aldehydes and hydrazide linker/scaffold components through reversible acylhydrazone exchange, resulting in libraries containing up to 474 constituents. Dynamic deconvolution allowed the efficient identification of the structural features required for binding to Concanavalin A and the selection of a strong binder, a tritopic mannoside, showing an IC50 -value of 22,,M. [source] Modulation of O-GlcNAc glycosylation during Xenopus oocyte maturation,JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 5 2004Tony Lefebvre Abstract O-linked N -acetylglucosamine (O-GlcNAc) glycosylation is a post-translational modification, which is believed antagonises phosphorylation. We have studied the O-GlcNAc level during Xenopus oocyte meiotic resumption, taking advantage of the high synchrony of this model which is dependent upon a burst of phosphorylation. Stimulation of immature stage VI oocytes using progesterone was followed by a 4.51,±,0.32 fold increase in the GlcNAc content, concomitantly to an increase in phosphorylation, notably on two cytoplasmic proteins of 66 and 97 kDa. The increase of O-GlcNAc for the 97 kDa protein, which we identified as ,-catenin was partly related to its accumulation during maturation, as was demonstrated by the use of the protein synthesis inhibitor,cycloheximide. Microinjection of free GlcNAc, which inhibits O-glycosylated proteins,lectins interactions, delayed the progesterone-induced maturation without affecting the O-GlcNAc content. Our results suggest that O-GlcNAc glycosylation could regulate protein,protein interactions required for the cell cycle kinetic. © 2004 Wiley-Liss, Inc. [source] | ||||||||||