title: Exploring weak ligand-protein interactions by long-lived NMR states: improved contrast in fragment-based drug screening.
abstract: Ligands that have an affinity for protein targets can be screened very effectively by exploiting favorable properties of long-lived states (LLS) in NMR spectroscopy. In this work, we describe the use of LLS for competitive binding experiments to measure accurate dissociation constants of fragments that bind weakly to the ATP binding site of the N-terminal ATPase domain of heat shock protein 90 (Hsp90), a therapeutic target for cancer treatment. The LLS approach allows one to characterize ligands with an exceptionally wide range of affinities, since it can be used for ligand concentrations [L] that are several orders of magnitude smaller than the dissociation constants K(D). This property makes the LLS method particularly attractive for the initial steps of fragment-based drug screening, where small molecular fragments that bind weakly to a target protein must be identified, which is a difficult task for many other biophysical methods.
authors.affiliation: Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, Batochime (BCH), 1015 Lausanne (Switzerland). roberto.buratto@epfl.ch.
authors.forename: Roberto
authors.initials: R
authors.lastname: Buratto
authors.forename: Daniele
authors.initials: D
authors.lastname: Mammoli
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Chiarparin
authors.forename: Glyn
authors.initials: G
authors.lastname: Williams
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Bodenhausen
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001665:Binding Sites; D004353:Drug Evaluation, Preclinical / Q000379:methods; D018841:HSP90 Heat-Shock Proteins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008024:Ligands; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011485:Protein Binding; D054852:Small Molecule Libraries / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D018841:HSP90 Heat-Shock Proteins; D008024:Ligands; D054852:Small Molecule Libraries; D000255:Adenosine Triphosphate
keywords: NMR spectroscopy; dissociation constants; drug discovery; fragment screening; ligand binding