STRUCTURAL STUDIES OF SACSIN AND EDD UBIQUITIN LIGASE

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。 常染色体隐性遗传性痉挛共济失调(SACS)是一种早发性神经退行性疾病，在加拿大魁北克省Charlevoix-Saint-Jean地区有较高的发病率。负责Sacs的基因编码Sacsin，这是一种含有4000多个残基的蛋白质。为了更好地了解该蛋白的功能及其与疾病的关系，我们启动了对Sacsin的各个结构域的结构研究。我们最近获得了Sacsin的HEPN和UBL域的晶体。这两种晶体在原产地的衍射率都在2.8-2.9A之间，但没有通过使用远距离相关结构的分子置换找到解决方案(同源性低于30%)。我们计划提高衍射数据的分辨率，并利用MAD实验寻找实验相。 肿瘤抑制因子增生盘蛋白(Hyd)，也被称为EDD(差异显示分离的E3)或UBR5，是Hect(与E6-AP羧基末端同源)E3泛素连接酶家族的成员，其靶向是泛素介导的蛋白水解酶。EDD的突变不能正确地终止增殖，导致肿瘤，还会导致发育异常，如由于生殖细胞缺陷而导致的成人不育。我们结晶了EDD的Hect结构域。晶体的本源衍射率为3.0A。未发现分子置换溶液。我们将使用MAD实验进行实验性的定相，以提高晶体的分辨率。该结构对研究EDD的底物特异性具有重要意义。

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. Autosomal recessive spastic ataxia of Charlevoix¿¿"Saguenay (SACS) is an early-onset neurodegenerative disease with high prevalence in the Charlevoix¿¿"Saguenay¿¿"Lac-Saint-Jean region of Quebec (Canada). The gene responsible for SACS codes for sacsin, a protein containing more than 4000 residues. In order to better understand the function of this protein and its relation to the disease, we initiated structural studies of individual domains of sacsin. We recently obtained crystals of HEPN and UBL domains of sacsin. Both crystals diffract to 2.8-2.9A at the home source, but no solution was found by molecular replacement using distantly related structures (below 30% identity). We plan to improve resolution of the diffraction data and find experimental phases using MAD experiments. The tumor suppressor hyperplastic discs protein (HYD), also known as EDD (E3 isolated by differential display) or UBR5, is a member of the family of HECT (homologous to E6-AP carboxyl terminus) E3 ubiquitin ligases, which target specific proteins for ubiquitin-mediated proteolysis. Mutations in EDD fail to properly terminate proliferation leading to tumors and also result in developmental abnormalities such as adult sterility due to germ cells defects. We crystallized HECT domain of EDD. The crystals diffract to 3.0A at the home source. No molecular replacement solution was found. We are going to use MAD experiment for experimental phasing and to improve resolution of the crystals. The structure will be important to study a substrate specificity of EDD.