Carbohydrates on the surface of both normal and transformed cells function as receptor determinants in various biological recognition processes. Three classes of these covalently bound molecules are called high mannose, complex, and hybrid type oligosaccharides, which each form a variety of structures. Although they function as cell surface receptors, little is known of the molecular binding properties of these oligosaccharides, other than they are substrates for glycosylases, and that they bind to lectins. Lectins are plant and animal proteins which bind to specific carbohydrate determinants without modifying them. Plant lectins have a wide number of biological applications, including their use in exploring the structure and dynamic properties of the membranes of normal and transformed cells. Among the more widely employed plant metallolectins are Concanavalin A (Con A), and the lentil (LcH), pea (PSA), soybean (SBA) and lima-bean (LBL) lectins, all of which possess different binding specificities, and a range of different biological activities. Our objectives are to determine the molecular binding mechanisms of high mannose complex, and hybrid type glycopeptides and related synthetic oligosaccharides with lectins in order to investigate the molecular recognition determinants of these cell surface receptors. The spectroscopic properties of the lectins including their bound metal ions will be investigated, since the metal ions can serve as intrinsic reporter groups for monitoring the interactions of the carbohydrates with the proteins. Our discovery of a method of preparing metal ion derivatives of LcH and PSA now makes in possible to study the interactions of these two lectins, in addition to the other lectins, with the carbohydrates by a variety of spectroscopic techniques, including nuclear magnetic resonance (NMR), electron spin resonance (EPR) and spin-echo, and circular dichroism (CD) measurements. NMR techniques will include solvent proton NMR dispersion measurements, and high resolution 1H, 19F, 13C, and 113Cd NMR experiments. These studies will provide direct data on the molecular binding properties of these important classes of cell surface carbohydrates, as well as the binding specificities of the lectins.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA016054-13
Application #
3164343
Study Section
Pathobiochemistry Study Section (PBC)
Project Start
1977-07-01
Project End
1991-11-30
Budget Start
1988-12-01
Budget End
1989-11-30
Support Year
13
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Albert Einstein College of Medicine
Department
Type
Schools of Medicine
DUNS #
009095365
City
Bronx
State
NY
Country
United States
Zip Code
10461
Dam, Tarun K; Talaga, Melanie L; Fan, Ni et al. (2016) Measuring Multivalent Binding Interactions by Isothermal Titration Calorimetry. Methods Enzymol 567:71-95
Sletmoen, Marit; Dam, Tarun K; Gerken, Thomas A et al. (2009) Single-molecule pair studies of the interactions of the alpha-GalNAc (Tn-antigen) form of porcine submaxillary mucin with soybean agglutinin. Biopolymers 91:719-28
Dam, Tarun K; Gerken, Thomas A; Brewer, C Fred (2009) Thermodynamics of multivalent carbohydrate-lectin cross-linking interactions: importance of entropy in the bind and jump mechanism. Biochemistry 48:3822-7
Dam, Tarun K; Brewer, C Fred (2008) Effects of clustered epitopes in multivalent ligand-receptor interactions. Biochemistry 47:8470-6
Dam, Tarun K; Gerken, Thomas A; Cavada, Benildo S et al. (2007) Binding studies of alpha-GalNAc-specific lectins to the alpha-GalNAc (Tn-antigen) form of porcine submaxillary mucin and its smaller fragments. J Biol Chem 282:28256-63
Dolnick, Ree; Wu, Qi; Angelino, Norman J et al. (2005) Enhancement of 5-fluorouracil sensitivity by an rTS signaling mimic in H630 colon cancer cells. Cancer Res 65:5917-24
Dam, Tarun K; Oscarson, Stefan; Roy, Rene et al. (2005) Thermodynamic, kinetic, and electron microscopy studies of concanavalin A and Dioclea grandiflora lectin cross-linked with synthetic divalent carbohydrates. J Biol Chem 280:8640-6
Dam, Tarun K; Gabius, Hans-J; Andre, Sabine et al. (2005) Galectins bind to the multivalent glycoprotein asialofetuin with enhanced affinities and a gradient of decreasing binding constants. Biochemistry 44:12564-71
Ahmad, Nisar; Gabius, Hans-J; Andre, Sabine et al. (2004) Galectin-3 precipitates as a pentamer with synthetic multivalent carbohydrates and forms heterogeneous cross-linked complexes. J Biol Chem 279:10841-7
Dam, Tarun K; Brewer, C Fred (2004) Multivalent protein-carbohydrate interactions: isothermal titration microcalorimetry studies. Methods Enzymol 379:107-28

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