STRUCTURAL STUDIES ON PROTEINS THAT CONTROL APOPTOSIS, SULFUR ASSIMILATION & NEU

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。 SSRL需要时间对来自三个不同生物系统的蛋白质进行高分辨率结构测定。其中一个系统涉及抑制细胞凋亡的病毒蛋白。在这项提议的更新中，我的实验室正在积极地研究病毒蛋白和细胞半胱氨酸天冬氨酸酶之间的复合体的结构，它们抑制了这种复合体的结构。我们最近生长了解理前和解理后复合体的晶体，它们在光束线9-1上分别衍射到5？和4.6？分辨率。我们目前正在进行实验，以提高晶体中的有序度，以改善衍射。第二个系统涉及将环境中的无机硫吸收到生物体内的蛋白质。我们最近从两个不同的物种中确定了催化硫同化的第一步的酶--三磷酸腺苷硫酰基酶的结构。我们现在将使用定点突变来创建突变体来研究结构-功能关系，以了解变构调节以及研究人类的这些酶。最后一个需要时间的系统是PLP依赖的酶--γ-氨基丁酸氨基转移酶。这种酶是用于治疗癫痫、亨廷顿病、精神分裂症和阿尔茨海默病的神经活性药物的重要靶点。我们已经解决了大肠杆菌的酶结构，并将研究药物和抑制剂复合抑制的结构方面。来自SSRL的高通量将以更高的分辨率产生更高质量的数据，并使人们能够更好地、更详细地了解这三个系统中的所有蛋白质结构。

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. Time is requested at SSRL for high-resolution structure determination of proteins from three different biological systems. One system involves viral proteins that inhibit apoptosis. In this proposal renewal, my laboratory is actively pursuing structure determination of complexes between the viral protein and the cellular caspases, which they inhibit. We recently have grown crystals both of the pre- and post-cleavage complex that diffract to 5 ¿ and 4.6 ¿ resolution respectively on beam line 9-1. We are currently pursuing experiments to increase the order in the crystals to improve diffraction. The second system involves proteins that assimilate inorganic sulfur from the environment into living organisms. We have recently determined the structure of the enzyme ATP sulfurylase, which catalyzes the first committed step in sulfur assimilation, from two different species. We will now be employing site-directed mutagenesis to create mutants to study structure-function relationships to understand the allosteric regulation as well as study these enzymes from human. The last system for which time is requested is on a PLP dependent enzyme gamma-aminobutyrate aminotransferase. This enzyme is an important target for neuroactive drugs used in treatment of epilepsy, Huntington's disease, schizophrenia and Alzheimer's disease. We have solved the E. coli enzyme structure and will study structural aspects of inhibition complexed with drugs and inhibitors. The high flux from SSRL will result in higher quality data at much higher resolution and enable better more detailed understanding for all the protein structures in these three systems.