Srigiriraju Srikanth V, Powers Thomas R
Division of Engineering, Box D, Brown University, Providence, Rhode Island 02912, USA.
Phys Rev Lett. 2005 Jun 24;94(24):248101. doi: 10.1103/PhysRevLett.94.248101. Epub 2005 Jun 21.
Bacterial flagellar filaments can abruptly change shape in response to mechanical load or changes in solution pH or ionic strength. These polymorphic transformations are an instance of a ubiquitous phenomenon, the spread of conformational change in large macromolecular assemblies. We propose a new theory for polymorphism, whose essential elements are two molecular switches and an elastic mismatch strain between the inner and outer cores of the filament. We calculate the phase diagram for helical and straight states, and the response of a helical filament to an external moment.
细菌鞭毛丝可根据机械负荷、溶液pH值或离子强度的变化而突然改变形状。这些多态转变是一种普遍现象的实例，即构象变化在大型大分子组装体中的传播。我们提出了一种关于多态性的新理论，其基本要素是两个分子开关以及鞭毛丝内外核之间的弹性失配应变。我们计算了螺旋态和直态的相图，以及螺旋鞭毛丝对外力矩的响应。
