PMID: 17275837 , Related PDB ids: 2JDO, 2JDR, 2JDS, 2JDT, 2JDV

Authors:

Davies TG, Verdonk ML, Graham B, Saalau-Bethell S, Hamlett CC, McHardy T, Collins I, Garrett MD, Workman P, Woodhead SJ, Jhoti H, Barford D

Title:

A structural comparison of inhibitor binding to PKB, PKA and PKA-PKB chimera.

Journal:

J Mol Biol. 2007 Mar 30;367(3):882-94. Epub 2007 Jan 9.

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.