(515ag) Using Ruthenium Organometallic Compounds For Kinome Atp Binding Site Profiling

A focused-library of 58 compounds for kinase inhibition was synthesized utilizing ruthenium organometallic chemistry based on the indolocarbazole moiety of staurosporine, a natural compound which displays strong affinity for many kinases. These ruthenium compounds have demonstrated the ability to inhibit specific kinases with Kd values in the sub-nanomolar range. The rigidity of the Ru coordinate bonds allow these compounds to take a very specific shape, and the relative ease of adding side-chains allows for the rapid synthesis of many different molecular motifs. This small library of 58 ruthenium compounds was tested against 50 different human kinases in a quantitative high throughput screening (qHTS) campaign at 1 uM ATP to generate 2900 IC50 values. This kinome-compound IC50 "heatmap" allowed for the identification of multiple hits with low nanomolar IC50 values against several kinases, including CDK2, HIPK2, MELK, SGK, DAPK1, FLT4, and especially PIM1 and GSK3. This data was then clustered to provide a map which illustrated how similar the different kinases were to each other with respect to the library inhibitory activity. Next, a second, more specific library of 438 compounds was synthesized to further probe 10 different kinases with the purpose of finding compounds which inhibit only one kinase preferentially. Several low nM inhibitors were identified for future optimization. Given the unique spatial and charge properties of each compound, important and characteristic chemical features of a kinase's binding site can be elucidated if there is an interaction with the probe. A computational analysis of the molecular structure of each hit against the kinase can pinpoint the interactions that make a compound successful against that particular kinase.