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Carbohydrate Ligands (carbohydrate + ligand)
Selected AbstractsA Polycation Scaffold Presenting Tunable "Click" Sites: Conjugation to Carbohydrate Ligands and Examination of Hepatocyte-Targeted pDNA DeliveryMACROMOLECULAR BIOSCIENCE, Issue 6 2010Chen-Chang Lee Abstract A versatile polycation scaffold that can easily be modified with targeting ligands has been designed, synthesized, and characterized. A series of galactose-containing polymers has been produced to demonstrate the ease of modification of this polynucleotide delivery vehicle motif via the click reaction and to study how various structural modifications affect recognition by ASGPr on hepatocytes. A small library of structures was created where DCS and alkyl spacer length between the targeting group and the polymer backbone was varied. The novel polymer scaffold described proves to be a valuable tool for understanding structure/activity relationships of complexes made with receptor-targeted polymers. [source] A Facile Method for the Preparation of Gold Glyconanoparticles from Free Oligosaccharides and Their Applicability in Carbohydrate-Protein Interaction Studies,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 17 2005Koen M. Halkes Abstract The weak binding affinity of monomeric oligosaccharides with carbohydrate-binding proteins are hampering their use in in-vivo and in-vitro bio-assays. Gold glyconanoparticles (GNPs), prepared from synthetic oligosaccharides, have been used to overcome this weak binding affinity. In this paper, a convenient method for the preparation of GNPs from free oligosaccharides is presented. The reductive amination of saccharides with trityl-protected cysteamine, followed by de-tritylation, afforded cysteamine-extended saccharides that could be used for the preparation of GNPs under reducing conditions in water. The robust chemistry and facile purification of intermediate and final compounds ensure high yields and reproducible results and the, subsequent, preparation of GNPs proceeded smoothly, even with minute quantities (nanomolar scale) of the cysteamine-extended saccharide. The described method was used to synthesize a series of gluco - and manno -oligosaccharide-containing GNPs. The prepared GNPs were validated in interaction studies with Con A, using either surface plasmon resonance (SPR), UV/Vis spectroscopy, or transmission electron microscopy (TEM). The described method for the preparation of water-soluble gold glyconanoparticles can be used for the identification of carbohydrate ligands for novel carbohydrate-binding proteins, and can find application as inhibitors of pathological interactions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Glyconanomaterials: Synthesis, Characterization, and Ligand PresentationADVANCED MATERIALS, Issue 17 2010Xin Wang Abstract Glyconanomaterials, nanomaterials carrying surface-tethered carbohydrate ligands, have emerged and demonstrated increasing potential in biomedical imaging, therapeutics, and diagnostics. These materials combine the unique properties of nanometer-scale objects with the ability to present multiple copies of carbohydrate ligands, greatly enhancing the weak affinity of individual ligands to their binding partners. Critical to the performance of glyconanomaterials is the proper display of carbohydrate ligands, taking into consideration of the coupling chemistry, the type and length of the spacer linkage, and the ligand density. This article provides an overview of the coupling chemistry for attaching carbohydrate ligands to nanomaterials, and discusses the need for thorough characterization of glyconanomaterials, especially quantitative analyses of the ligand density and binding affinities. Using glyconanoparticles synthesized by a versatile photocoupling chemistry, methods for determining the ligand density by colorimetry and the binding affinity with lectins by a fluorescence competition assay are determined. The results show that the multivalent presentation of carbohydrate ligands significantly enhances the binding affinity by several orders of magnitude in comparison to the free ligands in solution. The effect is sizeable even at low surface ligand density. The type and length of the spacer linkage also affect the binding affinity, with the longer linkage promoting the association of bound ligands with the corresponding lectins. [source] Study of peptide,sugar non-covalent complexes by infrared atmospheric pressure matrix-assisted laser desorption/ionizationJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 7 2004Christopher E. Von Seggern Abstract Infrared atmospheric pressure matrix-assisted laser desorption/ionization quadrupole ion trap mass spectrometry was applied to the study of siglec binding to oligosaccharide ligands. Peptides were designed to mimic the binding sites of three members of the siglec family: sialoadhesin, MAG and CD22. These peptides were tested for their ability to complex with their carbohydrate ligands 3, -sialyllactose (3,SL) and 6, -sialyllactose (6,SL). All peptides demonstrated the ability to bind to the carbohydrates, with the peptide representing sialoadhesin maintaining its binding specificity for 3,SL in preference to 6,SL. This technique can be used to study other protein,sugar interactions and can be expanded to create high-throughput screening techniques. Copyright © 2004 John Wiley & Sons, Ltd. [source] Specific Interaction of the Legume Lectins, Concanavalin A and Peanut Agglutinin, with PhycocyaninPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2009Gunjan Pandey In a recent study, we found that jacalin, a T-antigen specific lectin could interact with phycocyanin (PC) in a carbohydrate-independent manner. We show here that concanavalin A and peanut agglutinin too can interact with PC, although the nature of the interaction is distinctly different from that for jacalin. The legume lectins bind PC weaker in the presence of their specific carbohydrate ligands. Like jacalin, the legume lectins too interact with PC via two distinct sites. Higher ionic strengths resulted in a weakening of the interaction at site 1 and did not affect the interaction at site 2, clearly indicating that the interactions involve charged residues at the former and hydrophobic interactions at the latter site. The implications for the use of these lectin,PC complexes in photodynamic therapy and other clinical applications are discussed. [source] Crystallization and preliminary X-ray diffraction analysis of mouse galectin-4 N-terminal carbohydrate recognition domain in complex with lactoseACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2008Veronika Krej, íková Galectin-4 is thought to play a role in the process of tumour conversion of cells of the alimentary tract and the breast tissue; however, its exact function remains unknown. With the aim of elucidating the structural basis of mouse galectin-4 (mGal-4) binding specificity, we have undertaken X-ray analysis of the N-terminal domain, CRD1, of mGal-4 in complex with lactose (the basic building block of known galectin-4 carbohydrate ligands). Crystals of CRD1 in complex with lactose were obtained using vapour-diffusion techniques. The crystals belong to tetragonal space group P4212 with unit-cell parameters a = 91.1, b = 91.16, c = 57.10,Ĺ and preliminary X-ray diffraction data were collected to 3.2,Ĺ resolution. An optimized crystallization procedure and cryocooling protocol allowed us to extend resolution to 2.1,Ĺ. Structure refinement is currently under way; the initial electron-density maps clearly show non-protein electron density in the vicinity of the carbohydrate binding site, indicating the presence of one lactose molecule. The structure will help to improve understanding of the binding specificity and function of the potential colon cancer marker galectin-4. [source] | |||||||||||||