title: Fragment-based screening maps inhibitor interactions in the ATP-binding site of checkpoint kinase 2.
abstract: Checkpoint kinase 2 (CHK2) is an important serine/threonine kinase in the cellular response to DNA damage. A fragment-based screening campaign using a combination of a high-concentration AlphaScreen™ kinase assay and a biophysical thermal shift assay, followed by X-ray crystallography, identified a number of chemically different ligand-efficient CHK2 hinge-binding scaffolds that have not been exploited in known CHK2 inhibitors. In addition, it showed that the use of these orthogonal techniques allowed efficient discrimination between genuine hit matter and false positives from each individual assay technology. Furthermore, the CHK2 crystal structures with a quinoxaline-based fragment and its follow-up compound highlight a hydrophobic area above the hinge region not previously explored in rational CHK2 inhibitor design, but which might be exploited to enhance both potency and selectivity of CHK2 inhibitors.
authors.affiliation: Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom.
authors.forename: M Cris
authors.initials: MC
authors.lastname: Silva-Santisteban
authors.forename: Isaac M
authors.initials: IM
authors.lastname: Westwood
authors.forename: Kathy
authors.initials: K
authors.lastname: Boxall
authors.forename: Nathan
authors.initials: N
authors.lastname: Brown
authors.forename: Sam
authors.initials: S
authors.lastname: Peacock
authors.forename: Craig
authors.initials: C
authors.lastname: McAndrew
authors.forename: Elaine
authors.initials: E
authors.lastname: Barrie
authors.forename: Meirion
authors.initials: M
authors.lastname: Richards
authors.forename: Amin
authors.initials: A
authors.lastname: Mirza
authors.forename: Antony W
authors.initials: AW
authors.lastname: Oliver
authors.forename: Rosemary
authors.initials: R
authors.lastname: Burke
authors.forename: Swen
authors.initials: S
authors.lastname: Hoelder
authors.forename: Keith
authors.initials: K
authors.lastname: Jones
authors.forename: G Wynne
authors.initials: GW
authors.lastname: Aherne
authors.forename: Julian
authors.initials: J
authors.lastname: Blagg
authors.forename: Ian
authors.initials: I
authors.lastname: Collins
authors.forename: Michelle D
authors.initials: MD
authors.lastname: Garrett
authors.forename: Rob L M
authors.initials: RL
authors.lastname: van Montfort
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D001665:Binding Sites / Q000235:genetics; D064447:Checkpoint Kinase 2 / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism*; D003461:Crystallography; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D015394:Molecular Structure; D011487:Protein Conformation; D047428:Protein Kinase Inhibitors / Q000737:chemistry
chemical_list: D047428:Protein Kinase Inhibitors; D000255:Adenosine Triphosphate; D064447:Checkpoint Kinase 2