Butyl pocket formation in the vitamin d receptor strongly affects the agonistic or antagonistic behavior of ligands
Yoshimoto, N., Sakamaki, Y., Haeta, M., Kato, A., Inaba, Y., Itoh, T., Nakabayashi, M., Ito, N., Yamamoto, K.(2012) J Med Chem 55: 4373-4381
- PubMed: 22512505 
- DOI: https://doi.org/10.1021/jm300230a
- Primary Citation of Related Structures:  
3VRT, 3VRU, 3VRV, 3VRW - PubMed Abstract: 
Previously, we reported that 22S-butyl-25,26,27-trinor-1α,24-dihydroxyvitamin D(3)2 represents a new class of antagonist for the vitamin D receptor (VDR). The crystal structure of the ligand-binding domain (LBD) of VDR complexed with 2 showed the formation of a butyl pocket to accommodate the 22-butyl group and insufficient interactions between ligand 2 and the C-terminus of VDR. Here, we designed and synthesized new analogues 5a-c and evaluated their biological activities to probe whether agonistic activity is recovered when the analogue restores interactions with the C-terminus of VDR. Analogues 5a-c exhibited full agonistic activity in transactivation. Interestingly, 5c, which bears a 24-diethyl group, completely recovered agonistic activity, although 3c and 4c act as an antagonist and a weak agonist, respectively. The crystal structures of VDR-LBD complexed with 3a, 4a, 5a, and 5c were solved, and the results confirmed that butyl pocket formation in VDR strongly affects the agonistic or antagonistic behaviors of ligands.
Organizational Affiliation: 
Laboratory of Drug Design and Medicinal Chemistry, Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan.