Mass analysis by scanning transmission electron microscopy and electron diffraction validate predictions of stacked beta-solenoid model of HET-s prion fibrils.
Mass analysis by scanning transmission electron microscopy and electron diffraction validate predictions of stacked beta-solenoid model of HET-s prion fibrils.
复制标题
通过扫描透射电子显微镜和电子衍射进行的质量分析验证了 HET-s 朊病毒原纤维的堆叠 β-螺线管模型的预测。
DOI：
10.1074/jbc.m611464200
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Steven,AlasdairC
中科院分区：
文献类型：
--
作者：
Sen,Anindito;Baxa,Ulrich;Simon,MarthaN;Wall,JosephS;Sabate,Raimon;Saupe,SvenJ;Steven,AlasdairC
Fungal prions are infectious filamentous polymers of proteins that are soluble in uninfected cells. In its prion form, the HET-s protein ofPodospora anserinaparticipates in a fungal self/non-self recognition phenomenon called heterokaryon incompatibility. Like other prion proteins, HET-s has a so-called “prion domain” (its C-terminal region, HET-s-(218–289)) that is responsible for induction and propagation of the prionin vivoand for fibril formationin vitro. Prion fibrils are thought to have amyloid backbones of polymerized prion domains. A relatively detailed model has been proposed for prion domain fibrils of HET-s based on a variety of experimental constraints (Ritter, C., Maddelein, M. L., Siemer, A. B., Luhrs, T., Ernst, M., Meier, B. H., Saupe, S. J., and Riek, R. (2005)Nature435, 844–848). To test specific predictions of this model, which envisages axial stacking of β-solenoids with two coils per subunit, we examined fibrils by electron microscopy. Electron diffraction gave a prominent meridional reflection at (0.47 nm)-1, indicative of cross-β structure, as predicted. STEM (scanning transmission electron microscopy) mass-per-unit-length measurements yielded 1.02 ± 0.16 subunits per 0.94 nm, in agreement with the model prediction (1 subunit per 0.94 nm). This is half the packing density of ∼1 subunit per 0.47 nm previously obtained for fibrils of the yeast prion proteins, Ure2p and Sup35p, whence it follows that the respective amyloid architectures are basically different.
