Kishimoto Aiko, Hasegawa Kazuya, Suzuki Hirofumi, Taguchi Hideki, Namba Keiichi, Yoshida Masasuke
Chemical Resources Laboratory, Tokyo Institute of Technology, Yokohama, Japan.
Biochem Biophys Res Commun. 2004 Mar 12;315(3):739-45. doi: 10.1016/j.bbrc.2004.01.117.
We have studied the core structure of amyloid fibers of yeast prion protein Sup35. We developed procedures to prepare straight fibers of relatively uniform diameters from three kinds of fragments; N (1-123), NMp (1-189), and NM (1-253). X-ray fiber diffraction patterns from dried oriented fibers gave common reflections in all three cases; a sharp meridional reflection at 4.7A, and a diffuse equatorial peak at around 9A, apparently supporting the typical "cross-beta" structure with stacked beta-sheets proposed for many different amyloid fibers. However, X-ray fiber diffraction from hydrated fibers showed the meridional reflection at 4.7A but no equatorial reflections at 9A in all three cases, indicating that the stack of beta-sheets in dried fibers is an artifact produced by drying process. Thus, the core structure of these amyloid fibers made of the N domain is likely to be beta-helix nanotube as proposed by Perutz et al.
我们研究了酵母朊病毒蛋白Sup35淀粉样纤维的核心结构。我们开发了从三种片段（N（1-123）、NMp（1-189）和NM（1-253））制备直径相对均匀的直纤维的方法。干燥取向纤维的X射线纤维衍射图谱在所有三种情况下都给出了共同的反射；在4.7埃处有一个尖锐的子午线反射，在9埃左右有一个漫射赤道峰，这显然支持了为许多不同淀粉样纤维提出的具有堆叠β-折叠的典型“交叉β”结构。然而，水合纤维的X射线纤维衍射在所有三种情况下都显示出4.7埃处的子午线反射，但没有9埃处的赤道反射，这表明干燥纤维中的β-折叠堆叠是干燥过程产生的假象。因此，由N结构域构成的这些淀粉样纤维的核心结构可能如佩鲁茨等人所提出的是β-螺旋纳米管。
