Cites the study 'Structure-based design of a potent purine-based cyclin-dependent kinase inhibitor,' conducted by T.G. Davies and colleagues, published in the October 2002 issue of 'Nature Structural Biology.' Description of hydrophobic slot; Inhibition of purine-based inhibitor O6-cyclohexylmethyl guanine in CDK1 and CDK2; Role of the sulphonamide group in increasing the potency.