HSP90 CONFORMATIONAL REQUIREMENTS FOR KINASE MATURATION

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。 HSP90是真核生物中一种重要的伴侣蛋白，参与了多种蛋白激酶的成熟过程。由于许多致癌蛋白依赖于Hsp90的功能，Hsp90已成为抗癌治疗的一个有前途的靶点。有效的Hsp90抑制剂的设计将得益于对Hsp90机制的分子理解。最近，已经确定了Hsp90的两种结构，都是C-末端结构域形成了稳定的二聚体。在一种结构中，N-末端结构域也被二聚化形成闭合状态，而在另一种结构中，N-末端结构域以很大的距离(60埃)分开。小角X射线散射(SAXS)实验符合ATP结合使Hsp90从开放构象转变为闭合构象的模型。为了确定开放构象是否参与了激酶的成熟，我们设计了一个带有螺旋线圈的HSP90，在没有ATP结合的情况下将N-结构域保持在闭合构象中。APS的SAXS实验将提供关键数据，以确定我们设计的Hsp90分子在存在和不存在ATP的情况下的构象状态。结合目前正在进行的分析激酶成熟的体内研究，SAXS的数据将为生物学和医学中的一个基本过程提供重要的见解。

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. Hsp90 is an essential chaperone in eukaryotes that is involved in the maturation of numerous kinases. Because numerous oncogenic kinases rely on Hsp90 for their function, Hsp90 has emerged as a promising target for anti-cancer therapeutics. The design of effective Hsp90 inhibitors would benefit from a molecular understanding of Hsp90 mechanism. Recently, two structures of Hsp90 have been determined both with the C-terminal domain forming a stable dimer. In one structure the N-terminal domain is also dimerized forming a closed state, and in the other structure the N-terminal domain is separated by a large distance (>60 Angstroms). Small-angle X-ray scattering (SAXS) experiments are consistent with a model where ATP-binding shifts Hsp90 from the open to the closed conformation. To determine if the open conformation is involved in kinase maturation, we have engineered Hsp90 with a coiled-coil to hold the N-domain in the closed conformation in the absence of ATP binding. SAXS experiments at APS would provide critical data to determine the conformational states of our engineered Hsp90 molecules both in the presence and absence of ATP. Combined with in vivo studies currently underway to analyze kinase maturation, the SAXS data will provide important insights into a fundamental process in biology and medicine.