Structural basis for accommodation of nonsteroidal ligands in the androgen receptor
Structural basis for accommodation of nonsteroidal ligands in the androgen receptor
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DOI：
10.1074/jbc.m507464200
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发表时间：
2005-11-11
影响因子：
4.8
通讯作者：
Dalton, JT
中科院分区：
文献类型：
--
作者：
Bohl, CE;Miller, DD;Dalton, JT
雄激素受体（AR）区分激动剂和拮抗剂配体的机制知之甚少。AR拮抗剂目前用于治疗前列腺癌。然而，突变通常在患者中发生，将这些化合物转化为激动剂。最近，我们的实验室发现了选择性雄激素受体调节剂，其结构类似于非甾体AR拮抗剂比卡鲁胺和羟基芴醇，但作为雄激素受体的激动剂，在组织选择性的方式。为了研究为什么配体和受体的细微结构变化（即突变）会导致活性的急剧变化，我们通过晶体学和定点诱变研究了非甾体AR配体的结构-活性关系，比较了R-比卡鲁胺、羟基氟替卡松和两种先前报道的非甾体雄激素S-1和R-3的结合构象。这些研究为非甾体配体与野生型AR相互作用的机制提供了第一个晶体学证据。我们已经表明，诱导的Trp-741，Thr-877和Met-895的位置的变化允许AR结合口袋内的配体调节，并且当与T877 A AR变体结合时，存在与Leu-873的骨架氧和羟基芴酮的水介导的氢键。此外，我们证明了R-比卡鲁胺刺激携带M895 T点突变的AR的转录激活。总体而言，这些研究为基于受体的非甾体AR激动剂和拮抗剂药物设计提供了重要的新见解。
The mechanism by which the androgen receptor (AR) distinguishes between agonist and antagonist ligands is poorly understood. AR antagonists are currently used to treat prostate cancer. However, mutations commonly develop in patients that convert these compounds to agonists. Recently, our laboratory discovered selective androgen receptor modulators, which structurally resemble the nonsteroidal AR antagonists bicalutamide and hydroxyflutamide but act as agonists for the androgen receptor in a tissue-selective manner. To investigate why subtle structural changes to both the ligand and the receptor (i.e. mutations) result in drastic changes in activity, we studied structure-activity relationships for nonsteroidal AR ligands through crystallography and site-directed mutagenesis, comparing bound conformations of R-bicalutamide, hydroxyflutamide, and two previously reported nonsteroidal androgens, S-1 and R-3. These studies provide the first crystallographic evidence of the mechanism by which nonsteroidal ligands interact with the wild type AR. We have shown that changes induced to the positions of Trp-741, Thr-877, and Met-895 allow for ligand accommodation within the AR binding pocket and that a water-mediated hydrogen bond to the backbone oxygen of Leu-873 and the ketone of hydroxyflutamide is present when bound to the T877A AR variant. Additionally, we demonstrated that R-bicalutamide stimulates transcriptional activation in AR harboring the M895T point mutation. As a whole, these studies provide critical new insight for receptor-based drug design of nonsteroidal AR agonists and antagonists.