title: A structural comparison of inhibitor binding to PKB, PKA and PKA-PKB chimera.
abstract: Although the crystal structure of the anti-cancer target protein kinase B (PKBbeta/Akt-2) has been useful in guiding inhibitor design, the closely related kinase PKA has generally been used as a structural mimic due to its facile crystallization with a range of ligands. The use of PKB-inhibitor crystallography would bring important benefits, including a more rigorous understanding of factors dictating PKA/PKB selectivity, and the opportunity to validate the utility of PKA-based surrogates. We present a "back-soaking" method for obtaining PKBbeta-ligand crystal structures, and provide a structural comparison of inhibitor binding to PKB, PKA, and PKA-PKB chimera. One inhibitor presented here exhibits no PKB/PKA selectivity, and the compound adopts a similar binding mode in all three systems. By contrast, the PKB-selective inhibitor A-443654 adopts a conformation in PKB and PKA-PKB that differs from that with PKA. We provide a structural explanation for this difference, and highlight the ability of PKA-PKB to mimic the true PKB binding mode in this case.
authors.affiliation: Astex Therapeutics Ltd, 436 Cambridge Science Park, Milton Road, Cambridge, CB4 0QA, UK. t.davies@astex-therapeutics.com
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Davies
authors.forename: Marcel L
authors.initials: ML
authors.lastname: Verdonk
authors.forename: Brent
authors.initials: B
authors.lastname: Graham
authors.forename: Susanne
authors.initials: S
authors.lastname: Saalau-Bethell
authors.forename: Christopher C F
authors.initials: CC
authors.lastname: Hamlett
authors.forename: Tatiana
authors.initials: T
authors.lastname: McHardy
authors.forename: Ian
authors.initials: I
authors.lastname: Collins
authors.forename: Michelle D
authors.initials: MD
authors.lastname: Garrett
authors.forename: Paul
authors.initials: P
authors.lastname: Workman
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Woodhead
authors.forename: Harren
authors.initials: H
authors.lastname: Jhoti
authors.forename: David
authors.initials: D
authors.lastname: Barford
mesh_terms: D000818:Animals; D001665:Binding Sites; D002417:Cattle; D018360:Crystallography, X-Ray; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008958:Models, Molecular; D011487:Protein Conformation; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055672:Static Electricity
chemical_list: D011993:Recombinant Fusion Proteins; D051057:Proto-Oncogene Proteins c-akt; D017868:Cyclic AMP-Dependent Protein Kinases