title: (15)N and (13)C group-selective techniques extend the scope of STD NMR detection of weak host-guest interactions and ligand screening.
abstract: Saturation transfer difference (STD) is a valuable tool for studying the binding of small molecules to large biomolecules and for obtaining detailed information on the binding epitopes. Here, we demonstrate that the proposed (15)N/(13)C variants of group-selective, "GS-STD" experiments provide a powerful approach to mapping the binding epitope of a ligand even in the absence of efficient spin diffusion within the target protein. Therefore, these experimental variants broaden the scope of STD studies to smaller and/or more-dynamic targets. The STD spectra obtained in four different experimental setups (selective (1)H STD, (15)N GS-STD, (13)C(Ar) and (13)C(aliphatic) GS-STD approaches) revealed that the signal-intensity pattern of the difference spectra is affected by both the type and the spatial distribution of the excited "transmitter" atoms, as well as by the efficiency of the spin-diffusion-mediated magnetization transfer. The performance of the experiments is demonstrated on a system by using the lectin, galectin-1 and its carbohydrate ligand, lactose.
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Debrecen, 4032 Debrecen, Hungary. kover@tigris.unideb.hu
authors.forename: Katalin E
authors.initials: KE
authors.lastname: Kövér
authors.forename: Edit
authors.initials: E
authors.lastname: Wéber
authors.forename: Tamás A
authors.initials: TA
authors.lastname: Martinek
authors.forename: Eva
authors.initials: E
authors.lastname: Monostori
authors.forename: Gyula
authors.initials: G
authors.lastname: Batta
mesh_terms: D002247:Carbon Isotopes / Q000737:chemistry; D019281:Dimerization; D037483:Galectin 1 / Q000737:chemistry; D007785:Lactose / Q000737:chemistry; D008024:Ligands; D009587:Nitrogen Isotopes / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D017434:Protein Structure, Tertiary
chemical_list: D002247:Carbon Isotopes; D037483:Galectin 1; D008024:Ligands; D009587:Nitrogen Isotopes; D007785:Lactose