CryoEM structure of Hsp104 and its mechanistic implication for protein disaggregation
CryoEM structure of Hsp104 and its mechanistic implication for protein disaggregation
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DOI：
10.1073/pnas.1003572107
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发表时间：
2010-05-04
影响因子：
11.1
通讯作者：
Tsai, Francis T. F.
中科院分区：
文献类型：
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作者：
Lee, Sukyeong;Sielaff, Bernhard;Tsai, Francis T. F.
热休克蛋白104是一个成环的AAA+机器，它识别聚集的蛋白质和朊病毒原纤维作为底物，并与热休克蛋白70系统一起，以ATP依赖的方式重塑底物。而解聚蛋白质的能力是依赖于热休克蛋白104的M-结构域，M-结构域的位置是有争议的，其确切的功能仍然未知。在这里，我们目前的cryoEM结构的两个热休克蛋白104变体的交联和非交联的形式，除了一个功能性的热休克蛋白104嵌合体窝藏T4溶菌酶内的M-结构域螺旋L2的结构。出乎意料的是，我们发现我们的Hsp 104嵌合体已经获得了功能，并且可以在不存在Hsp 70系统的情况下溶解热聚集的β-半乳糖苷酶（β-gal）。我们的拟合结构证实了Hsp 104的亚基排列与其他AAA+机器相似，并将M结构域置于Hsp 104外部，在那里它们可能与大的聚集蛋白相互作用。
Hsp104 is a ring-forming AAA+ machine that recognizes both aggregated proteins and prion-fibrils as substrates and, together with the Hsp70 system, remodels substrates in an ATP-dependent manner. Whereas the ability to disaggregate proteins is dependent on the Hsp104 M-domain, the location of the M-domain is controversial and its exact function remains unknown. Here we present cryoEM structures of two Hsp104 variants in both crosslinked and noncrosslinked form, in addition to the structure of a functional Hsp104 chimera harboring T4 lysozyme within the M-domain helix L2. Unexpectedly, we found that our Hsp104 chimera has gained function and can solubilize heat-aggregated beta-galactosidase (beta-gal) in the absence of the Hsp70 system. Our fitted structures confirm that the subunit arrangement of Hsp104 is similar to other AAA+ machines, and place the M-domains on the Hsp104 exterior, where they can potentially interact with large, aggregated proteins.