Oiwa Kazuhiro, Kamimura Shinji, Iwamoto Hiroyuki
Kobe Advanced ICT Research Center, National Institute of Information and Communications Technology, 588-2 Iwaoka, Nishi-ku, Kobe 651-2492, Japan.
Methods Cell Biol. 2009;91:89-109. doi: 10.1016/S0091-679X(08)91005-0. Epub 2009 Dec 1.
Eukaryotic cilia and flagella are highly ordered and precisely assembled cellular organelles. Here, to understand the mechanism of the orderly undulations of cilia and flagella, we shall draw a blueprint of their core structures and supporting scaffolds, that is, axonemes, and we shall describe the dynamic structural changes of components of the organelles. Small-angle X-ray scattering and diffraction are among the principal tools used to study protein polymers. These methods are now well established as indispensable tools that complement electron microscopy, providing information on the structure and dynamics of biological materials at atomic resolution in near-physiological environments. For instance, X-ray diffraction studies of skeletal muscles have contributed greatly to our understanding of the structure and molecular mechanisms of muscles. However, owing to the minute size and low diffracting power of axonemes, few attempts at X-ray diffraction of axonemes have been reported. The advent of third-generation synchrotron radiation facilities now makes these attempts feasible, because we now have stable and intense X-rays that enable us to obtain diffractions from the axonemes. In this chapter, we provide a concise practical guide to this new avenue for structural analysis of axonemes.
真核生物的纤毛和鞭毛是高度有序且精确组装的细胞器。在此，为了解纤毛和鞭毛有序波动的机制，我们将绘制其核心结构和支撑支架（即轴丝）的蓝图，并描述细胞器各组成部分的动态结构变化。小角X射线散射和衍射是研究蛋白质聚合物的主要工具。这些方法现已成为不可或缺的工具，可补充电子显微镜的不足，在近生理环境中以原子分辨率提供有关生物材料结构和动力学的信息。例如，骨骼肌的X射线衍射研究对我们理解肌肉的结构和分子机制有很大贡献。然而，由于轴丝尺寸微小且衍射能力低，很少有关于轴丝X射线衍射的尝试报道。第三代同步辐射设施的出现使这些尝试变得可行，因为我们现在有稳定且强烈的X射线，能够使我们从轴丝获得衍射。在本章中，我们为轴丝结构分析的这一新途径提供简要实用指南。
