Deletion of a Ure2 C-terminal prion-inhibiting region promotes the rate of fibril seed formation and alters interaction with Hsp40
Deletion of a Ure2 C-terminal prion-inhibiting region promotes the rate of fibril seed formation and alters interaction with Hsp40
复制标题
Ure2 C 端朊病毒抑制区的缺失可促进原纤维种子形成的速率并改变与 Hsp40 的相互作用
DOI：
10.1093/protein/gzq100
复制
发表时间：
2011-01-01
影响因子：
2.4
通讯作者：
Perrett, Sarah
中科院分区：
文献类型：
--
作者：
Chen, Li;Chen, Li-Jun;Perrett, Sarah
朊病毒是一种蛋白质，它可以经历一个可遗传的构象变化，成为一种聚集的淀粉样状态，然后传递给其他类似的分子。Ure 2是酿酒酵母的氮代谢调节因子，在体内表现出朊病毒特性，在体外形成淀粉样纤维。Ure 2由N端朊病毒诱导结构域和C端功能结构域组成。先前的研究表明，影响Ure 2朊病毒特性的突变并不限于N-末端朊病毒结构域：C-结构域中残基151-158的缺失增加了Ure 2体内朊病毒诱导倾向。在这里，我们在体外表征了该突变体，并发现151-158缺失对蛋白质的热力学稳定性或折叠性质具有最小的影响。然而，残基151-158的缺失在体外加速淀粉样蛋白样聚集体的成核、生长和片段化，并且形成的聚集体能够播种野生型蛋白原纤维的形成。此外，发现151-158的不存在破坏了Hsp 40伴侣Ydj 1对Ure 2原纤维形成的抑制作用。这些结果表明，151-158缺失突变体体内朊病毒诱导能力的增强是由于其产生朊病毒种子的能力增强。
Prions are proteins that can undergo a heritable conformational change to an aggregated amyloid-like state, which is then transmitted to other similar molecules. Ure2, the nitrogen metabolism regulation factor of Saccharomyces cerevisiae, shows prion properties in vivo and forms amyloid fibrils in vitro. Ure2 consists of an N-terminal prion-inducing domain and a C-terminal functional domain. Previous studies have shown that mutations affecting the prion properties of Ure2 are not restricted to the N-terminal prion domain: the deletion of residues 151-158 in the C-domain increases the in vivo prion-inducing propensity of Ure2. Here, we characterized this mutant in vitro and found that the 151-158 deletion has minimal effect on the thermodynamic stability or folding properties of the protein. However, deletion of residues 151-158 accelerates the nucleation, growth and fragmentation of amyloid-like aggregates in vitro, and the aggregates formed are able to seed formation of fibrils of the wild-type protein. In addition, the absence of 151-158 was found to disrupt the inhibitory effect of the Hsp40 chaperone Ydj1 on Ure2 fibril formation. These results suggest that the enhanced in vivo prion-inducing ability of the 151-158 deletion mutant is due to its enhanced ability to generate prion seeds.