SAXS STUDY OF NUCLEOTIDE-DEPENDENT CONFORMATIONAL CHANGE IN AB-TUBULIN AND HSP90

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。抗体微管蛋白和分子伴侣HSP90在真核细胞的生命中具有重要的非重叠作用。这两种蛋白结合并水解核苷酸三磷酸（GTP用于微管蛋白，ATP用于HSP90），并且已知采用多种构象，作为其功能循环的一部分。然而，尚不清楚这些构象变化是直接作为核苷酸状态的功能引起的，还是作为蛋白质：蛋白质相互作用的结果（在HSP90的情况下，抗体微管蛋白自组装成微管，底物/共伴侣结合）。研究两种不同蛋白质的构象如何对核苷酸状态作出反应将是对其功能形成有意义的机制理解的重要的第一步。我们建议使用小角度x射线散射（SAXS）来测量作为核苷酸状态函数的散射曲线，从而获得这些蛋白质构象偏好的任何潜在变化的重要结构见解。

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. Ab-tubulin and the molecular chaperone HSP90 have essential non-overlapping roles in the life of eukaryotic cells. Both proteins bind and hydrolyze nucleotide triphosphates (GTP for tubulin, ATP for HSP90), and are known to adopt multiple conformations, as part of their functional cycle. It is not known, however, whether these conformational changes arise directly as a function of nucleotide state, or instead as a result of protein:protein interactions (self-assembly into microtubules for Ab-tubulin, substrate/co-chaperone binding in the case of HSP90). Studying how the conformations these of two different proteins respond to nucleotide state will be an essential first step in formulating a meaningful mechanistic understanding of their function. We propose to use small-angle X-ray scattering (SAXS) to measure scattering profiles as a function of nucleotide state, and thereby obtain vital structural insight into any potential changes in the conformational preferences of these proteins.