ARCHAEAL 20S MUTANTS COMPLEXED TO PA26

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。 蛋白酶体是一种大的多亚单位的蛋白水解酶，负责真核生物中大多数胞浆和核蛋白的调节降解。它由28个亚基组成，它们组装成一个圆柱形的紧密复合体 四个堆叠的环，每个环有七个亚基。活性部位被隔离在蛋白酶体内部的一个空穴中，无法从外部接触到。底物被结合到圆柱体末端的激活剂识别并呈现给蛋白酶体。 最近，我们的实验室表明，活化剂PA26通过诱导蛋白酶体α亚基N端的对称开放构象，打开酵母蛋白酶体中的一个孔。我们无法证明蛋白酶体和激活剂之间的结合特异性实际上是由蛋白酶体和激活剂之间的结合特异性决定的，因为该区域的数据很差，而且缺乏对称性。我现在已经创造了古生菌蛋白酶体突变体，它与我们在之前的论文中使用的激活剂结合在一起。突变体分别模仿酵母蛋白酶体的任何结合口袋。 目前的工作是扩大蛋白酶体激活剂复合体的分辨率，并清楚地了解PA26中与结合有关的两个特征，即激活环和C端尾，以及它们与蛋白酶体中残基的相互作用。我将极大地受益于完美的七重对称络合物的非晶体对称性平均。

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. The proteasome is a large multi-subunit protease that is responsible for the regulated degradation of most cytosolic and nuclear proteins in eukaryotes. It consists of 28 subunits that assemble into a tight complex with the general shape of a cylinder of four stacked rings of seven subunits each. The active sites are sequestered in a cavitity in the interior of the proteasome, inaccessible from the outside. Substrates are recognized and presented to the proteasome by activators that bind to the ends of the cylinder. Recently, our lab showed that the activator PA26 opens>a pore into the yeast proteasome by inducing a symmetric open conformation in the N termini of the proteasomal alpha-subunits. We could not show was actually determines binding specificity between proteasome and activator because of poor data and the lack of symmetry in that region. I have now created archaeal proteasome mutants that bind to the same activator that we used in our previous paper. The mutants individually mimick any of the binding pockets of the yeast proteasome. Current work is to extend the resolution of the proteasome activator complex and obtain a clear view of the two features in PA26 implicated in binding, the activation loop and the C-terminal tails, and their interaction with residues in the proteasome. I will greatly benefit from non-crystallographic symmetry averaging of the perfectly sevenfold symmetric complex.