A BIVALENT METHODOLOGY FOR TARGETING PROTEIN KINASES: CONJUGATING PHAGE DISPLAY SELECTED CYCLIC PEPTIDES TO STAUROSPORINE

Abstract

Protein kinases constitute essential biological and target class owing to the vital function of reversible phosphorylation catalyzed by these enzymes. With more than 500 kinases in the human genome, containing conserved structure and overlapping function, pose challenging targets for inhibition. Alternative methods for targeting protein kinases remain warranted as the traditional methods are biased toward ATP-competitive compounds. These methods have yielded successful therapeutics, however toxicity due to nonselectivity and limited development potential due to intense drug discovery efforts renders alternative modes of action attractive as new goals for protein kinase inhibition.Herein is presented a bivalent methodology for targeting protein kinases comprising staurosporine tethered a phage display cyclic peptide library such that the cyclic peptide is directed to areas on the kinase surface distinct from the ATP-site where staurosporine is bound. Presented in detail is this strategy as it was successfully applied to Protein Kinase A and the subsequent analysis of bivalent ligands. Since this initial study several kinases have been targeted with this methodology and Application to Aurora Kinase A will be explored in detail. An essential analysis of results to date is included as it applies to the redesign, construction, and application of new cyclic phage libraries. Finally, to complete the first successful application against Protein Kinase A, we explore kinase expression for structural studies.