Trachtenberg S, Hammel I
Department of Membrane and Ultrastructure Research, Hebrew University, Hadassah Medical School, Jerusalem, Israel.
J Struct Biol. 1992 Jul-Aug;109(1):18-27. doi: 10.1016/1047-8477(92)90063-g.
We determined and correlated the rigidity of Salmonella typhimurium, Escherichia coli, and Rhizobium lupini flagellar filaments representing various structural and polymorphic states (plain, complex, straight, superhelical, and right- and left-handed). Persistence length, from which the filament's rigidity and other parameters (Young's modulus, bending force constant, buckling persistence length, flexural deformation, and flexural time) were derived, was determined from electron micrographs of isolated, negatively stained filaments. Outer diameters and radii of strong intersubunit connectivity were determined from three-dimensional image reconstructions and radial mass density profiles from scanning transmission electron microscopy. All filaments appear to be highly rigid with no evident correlation with their helical sense or superhelicity. The complex filament of R. lupini is rigid to the extent that it becomes brittle. The overall flexibility of the flagellum seems to stem mainly from the hook and not from the filament. Polymorphism is probably related to the propelling properties and hydrodynamic shape of the filament rather than to its rigidity.
我们测定并关联了鼠伤寒沙门氏菌、大肠杆菌和羽扇豆根瘤菌鞭毛丝的刚性，这些鞭毛丝呈现出各种结构和多态状态（普通型、复合型、直型、超螺旋型以及右手和左手螺旋型）。持久长度是从分离的、经负染色的鞭毛丝的电子显微照片中确定的，由此可推导出鞭毛丝的刚性及其他参数（杨氏模量、弯曲力常数、屈曲持久长度、弯曲变形和弯曲时间）。通过三维图像重建以及扫描透射电子显微镜的径向质量密度剖面图确定了亚基间强连接性的外径和半径。所有鞭毛丝似乎都具有很高的刚性，与其螺旋方向或超螺旋性没有明显关联。羽扇豆根瘤菌的复合鞭毛丝非常刚性，以至于变得易碎。鞭毛的整体柔韧性似乎主要源于钩部而非鞭毛丝。多态性可能与鞭毛丝的推进特性和流体动力学形状有关，而非与其刚性有关。
