Department of Physics, North Carolina State University, Raleigh, NC 27695, USA.
Structure. 2011 Apr 13;19(4):566-76. doi: 10.1016/j.str.2011.01.011.
Intrinsically disordered proteins (IDPs) participate in critical cellular functions that exploit the flexibility and rapid conformational fluctuations of their native state. Limited information about the native state of IDPs can be gained by the averaging over many heterogeneous molecules that is unavoidable in ensemble approaches. We used single molecule fluorescence to characterize native state conformational dynamics in five synaptic proteins confirmed to be disordered by other techniques. For three of the proteins, SNAP-25, synaptobrevin and complexin, their conformational dynamics could be described with a simple semiflexible polymer model. Surprisingly, two proteins, neuroligin and the NMDAR-2B glutamate receptor, were observed to stochastically switch among distinct conformational states despite the fact that they appeared intrinsically disordered by other measures. The hop-like intramolecular diffusion found in these proteins is suggested to define a class of functionality previously unrecognized for IDPs.
无规卷曲蛋白质（IDPs）参与关键的细胞功能，利用其天然状态的灵活性和快速构象波动。在集合方法中，不可避免地需要对许多异构分子进行平均化，从而限制了对 IDPs 天然状态的了解。我们使用单分子荧光技术来描述通过其他技术证实为无序的五种突触蛋白的天然状态构象动力学。对于三种蛋白质，SNAP-25、突触融合蛋白和复合蛋白，可以用简单的半柔性聚合物模型来描述它们的构象动力学。令人惊讶的是，尽管通过其他方法发现两种蛋白质，神经连接蛋白和 NMDAR-2B 谷氨酸受体，表现出随机地在不同构象状态之间切换，但它们似乎是无规卷曲的。在这些蛋白质中发现的类 hopping 分子内扩散被认为定义了一类以前未被 IDPs 识别的功能。
