MOLECULAR RECOGNITION IN STEROID SIGNALING

本研究旨在利用X射线晶体学来了解丰富的界面化学参与类固醇结合和核类固醇受体的歧视。 类固醇结合诱导受体构象变化，最终调节类固醇应答基因的转录。 为了了解这个家族中类固醇识别的立体化学机制，必须可视化位于受体配体结合域（LBD）内的结合决定簇。 几个甾醇结合相互作用的交叉检查将揭示保守的识别机制和独特的指定功能，介导配体歧视。 由于许多LBD中的点突变与类固醇不敏感性、严重的发育功能障碍和癌症有关，因此我们所寻找的结构可用于精确定位缺陷。雄激素受体，过度生产和绑定到合成睾酮类似物提出了我们的结构研究的第一个候选人。 该受体特异性结合用于治疗前列腺癌的类固醇和非类固醇雄激素拮抗剂。 许多与雄激素不敏感综合征相关的点突变已被定位到其LBD。 此外，越来越多的内分泌干扰物似乎以这种受体为目标。 我们建议扩大我们的初步衍射研究，以：1）了解激动剂与拮抗剂识别的机制和相应的构象变化诱导在一个单一的受体，和2）了解类固醇歧视的机制，通过分析多种不同的LBD-配体相互作用。

This study seeks to use X-ray crystallography to understand the rich interfacial chemistry involved in steroid binding and discrimination by the nuclear steroid receptors. The steroid binding induces receptor conformational changes that ultimately modulate transcription from steroid responsive genes. To understand the stereochemical mechanisms of steroid recognition in this family, it is essential to visualize the binding determinants located within the receptors' ligand binding domains (LBD). A cross examination of several sterol binding interactions will reveal both the conserved mechanisms of recognition and the unique specifying features that mediate ligand discrimination. Because point mutations in a number of LBDs have been associated with steroid insensitivity, profound developmental dysfunction and cancer, the structures we seek may be used to pinpoint the precise defects. The androgen receptor, overproduced and bound to a synthetic testosterone analog presents the fist candidate for our structural studies. This receptor specifically binds both steroid and non-steroid androgen antagonists used for the treatment of prostate cancer. Numerous point mutations associated with androgen insensitivity syndrome and have been mapped to its LBD. In addition, there are an increasing number of endocrine disrupters which appear to target this receptor. We propose to expand our preliminary diffraction studies in order to: 1) learn the mechanisms of agonist versus antagonist recognition and the corresponding conformational changes induced in a single receptor, and 2) understand the mechanisms of steroid discrimination through analysis of multiple different LBD-ligand interactions.