Quantitative chirality in the binding of androgens to their receptor

Chirality is a binary yes/no molecular property that nevertheless can be described by a continuous chirality measure function. Chirality measure values can be understood as sensitive descriptors of molecular shape. In this study, we evaluated the role of quantitative chirality (measures) in binding of androgens to their receptor. We demonstrate that a simple Quantitative Structure-Activity Relationship equation correlating the binding affinity with the partial charges of pharmacophoric oxygen atoms is significantly improved upon introducing quantitative chirality descriptors as additional variables. In such models, the charge descriptors account for the strength of the formed hydrogen bonds. However, the picture is completed by the chirality measures that indirectly contain information on the geometries of the hydrogen bond networks and subtle differences in the van der Waals contacts connected with different local or global shapes of the molecules. The model case studied here (11 simple and very similar steroids) proves that both global and local chirality is important in the androgen binding to their receptors.