title: A comparative study of fragment screening methods on the p38α kinase: new methods, new insights.
abstract: The stress-activated kinase p38α was used to evaluate a fragment-based drug discovery approach using the BioFocus fragment library. Compounds were screened by surface plasmon resonance (SPR) on a Biacore(™) T100 against p38α and two selectivity targets. A sub-set of our library was the focus of detailed follow-up analyses that included hit confirmation, affinity determination on 24 confirmed, selective hits and competition assays of these hits with respect to a known ATP binding site inhibitor. In addition, functional activity against p38α was assessed in a biochemical assay using a mobility shift platform (LC3000, Caliper LifeSciences). A selection of fragments was also evaluated using fluorescence lifetime (FLEXYTE(™)) and microscale thermophoresis (Nanotemper) technologies. A good correlation between the data for the different assays was found. Crystal structures were solved for four of the small molecules complexed to p38α. Interestingly, as determined both by X-ray analysis and SPR competition experiments, three of the complexes involved the fragment at the ATP binding site, while the fourth compound bound in a distal site that may offer potential as a novel drug target site. A first round of optimization around the remotely bound fragment has led to the identification of a series of triazole-containing compounds. This approach could form the basis for developing novel and active p38α inhibitors. More broadly, it illustrates the power of combining a range of biophysical and biochemical techniques to the discovery of fragments that facilitate the development of novel modulators of kinase and other drug targets.
authors: BioFocus, Chesterford Research Park, Saffron Walden, Essex, CB10 1XL, United Kingdom.
authors: Scott J
authors: SJ
authors: Pollack
authors: Kim S
authors: KS
authors: Beyer
authors: Christopher
authors: C
authors: Lock
authors: Ilka
authors: I
authors: Müller
authors: David
authors: D
authors: Sheppard
authors: Mike
authors: M
authors: Lipkin
authors: David
authors: D
authors: Hardick
authors: Peter
authors: P
authors: Blurton
authors: Philip M
authors: PM
authors: Leonard
authors: Paul A
authors: PA
authors: Hubbard
authors: Daniel
authors: D
authors: Todd
authors: Christine M
authors: CM
authors: Richardson
authors: Thomas
authors: T
authors: Ahrens
authors: Manuel
authors: M
authors: Baader
authors: Doris O
authors: DO
authors: Hafenbradl
authors: Kate
authors: K
authors: Hilyard
authors: Roland W
authors: RW
authors: Bürli
mesh_terms: D001665:Binding Sites; D001643:Bridged Bicyclo Compounds / Q000737:chemistry; D055808:Drug Discovery / Q000379:methods*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D006801:Humans; D008024:Ligands; D048308:Mitogen-Activated Protein Kinase 14 / Q000737:chemistry*; D008968:Molecular Conformation; D010446:Peptide Fragments / Q000737:chemistry; D011485:Protein Binding; D054852:Small Molecule Libraries / Q000737:chemistry*; D020349:Surface Plasmon Resonance / Q000379:methods; D014230:Triazoles / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D001643:Bridged Bicyclo Compounds; D008024:Ligands; D010446:Peptide Fragments; D054852:Small Molecule Libraries; D014230:Triazoles; D048308:Mitogen-Activated Protein Kinase 14