INTEGRAL MEMBRANE ENZYMES IN ESTROGEN BIOSYNTHESIS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 人类类固醇(雌酮/脱氢表雄酮)硫酸酯酶(STS)和细胞色素P450芳香酶(P450arom)是内质网的两种完整的膜蛋白，催化活性雌激素的生物合成。用高亲和力、高特异性的小分子抑制剂选择性地抑制这些酶中的一个或多个，可以为激素依赖性乳腺癌的预防和治疗提供一种有效的手段。 我们以2.1埃分辨率测定了从人胎盘中纯化的全长STS的晶体结构。为了研究酶的激活和抑制的分子机制，我们继续分析其与配体和抑制剂的络合物的结构。该计划是收集新生长的STS受抑制络合物晶体的X射线衍射数据。最近，我们首次生长出雄烯二酮的大单晶--全长P450arom的复合体，也是从人胎盘中提纯的。利用国际象棋光束时间，我们计划进行低温保护优化实验，并收集衍射数据，以求解出晶体结构。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Human steroid (Estrone/DHEA) sulfatase (STS) and cytochrome P450 aromatase (P450arom), two integral membrane proteins of the endoplasmic reticulum, catalyze biosynthesis of the active estrogens. Selective inhibition of one or more of these enzymes by high affinity, highly specific small molecule inhibitors could provide an effective means of prevention and treatment of hormone-dependent breast carcinoma. We have determined the crystal structure of full-length STS purified from human placenta at 2.1 angstrom resolution. In order to investigate molecular mechanisms of activation and inhibition of the enzyme, we continue to analyze the structures of its complexes with ligands and inhibitors. The plan is to gather X-ray diffraction data on newly grown crystals of inhibited complexes of STS. Recently, we have for the first time grown large single crystals of androstenedione-complex of the full-length P450arom, also purified from human placenta. With CHESS beam time, we plan to conduct cryo-protection optimization experiments and collect diffraction data for solving the crystal structure.