Table of contents entryWe have solved crystal structures of CDK7--selective inhibitors bound to CDK2.We have used a combination of structural, biophysical and modelling approaches to model the binding of these inhibitors to CDK7, and have used this information to explain their selectivity. We identify specific CDK7 residues that contribute to these inhibitors' specificity.
AbstractDeregulation of the cell cycle by mechanisms that lead to elevated activities of cyclin--dependent kinases (CDK) is a feature of many human diseases, in particular cancer. We have identified small molecule inhibitors that selectively inhibit CDK7, the kinase that phosphorylates cell cycle CDKs to promote their activities. To investigate the selectivity of these inhibitors we have used a combination of structural, biophysical and modelling approaches. We have determined crystal structures of the CDK7 selective compounds ICEC0942 and ICEC0943 bound to CDK2, and used these to build models of inhibitor binding to CDK7. Molecular dynamics simulations of inhibitors bound to CDK2 and CDK7 have generated possible models of inhibitor binding. In order to experimentally 3 validate these models, we measured isothermal titration calorimetry (ITC) binding data for recombinant wild type and binding site mutants of CDK7 and CDK2. We have identified specific residues of CDK7, notably Asp155, that are involved in determining inhibitor selectivity. Our molecular dynamics simulations also show that the flexibility of the G--rich and activation loops of CDK7 is likely an important determinant of inhibitor specificity similar to CDK2.4