INTEGRAL MEMBRANE ENZYMES IN ESTROGEN BIOSYNTHESIS

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 人甾体（雌酮/脱氢表雄酮）硫酸酯酶（STS）和细胞色素P450芳香化酶（P450 arom）是内质网中两种重要的膜蛋白，催化活性雌激素的生物合成。 通过高亲和力、高特异性的小分子抑制剂选择性抑制这些酶中的一种或多种，可以提供预防和治疗乳腺癌依赖性乳腺癌的有效手段。 我们已经确定了从人胎盘中纯化的全长STS的晶体结构，分辨率为2.1埃。 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复合物的结构。 计划是收集新生长的STS抑制复合物晶体的X射线衍射数据。 最近，我们首次生长了全长P450 arom的雄烯二酮复合物的大单晶，也是从人胎盘中纯化的。 利用CHESS光束时间，我们计划进行低温保护优化实验，并收集衍射数据以解决晶体结构。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. 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.