SAT-712 Computational Study of the Effect of Androgen Receptor BF 3 Site Mutations on DDE Binding

Exposure to endocrine disrupting chemicals (EDCs) affects the function of the androgen receptor (AR) causing reproductive system problems such as reduced sperm counts, increased infertility, testicular dysgenesis syndrome, and testicular and prostate cancers, as well as reduced bone mass and diabetes mellitus in males. Experimental results have shown that the presence of EDCs such as the diphenyl compound DDT and its analogue DDE, allosterically cause the release of the stably bound dihydrotestosterone (DHT) from the steroid binding site of the AR ligand binding domain. It was hypothesized that EDCs mediate this effect via binding to the Binding Function 3 (BF 3) surface binding site. Five mutations of three BF 3 amino acids (F673K, F673W, G724R, G724M, and L830D) showed that the ability of DDE to inhibit AR activity was reduced, suggesting that DDE binds to the BF 3 site and allosterically regulates AR activity. In this study, the Induced Fit Docking protocol of the Schrodinger software was used to dock DDE into the BF 3 site of the wild type AR ligand binding domain as well as the five mutant BF 3 sites. The docking poses generated for each receptor were clustered and representative structures were selected. The receptor-ligand complexes were energy minimized using the Schrodinger module Macromodel. Finally, the energy of interaction between DDE and the BF 3 site amino acids was evaluated for each of the selected docks of the wild type and mutant receptors. The relationship between the energies of interaction and the experimental results for DDE inhibition of the mutant AR activities will be discussed.