Department of Physics, University of California at San Diego, La Jolla, 92093, USA.
Phys Rev Lett. 2011 Nov 11;107(20):208301. doi: 10.1103/PhysRevLett.107.208301. Epub 2011 Nov 7.
Single-molecule pulling experiments on the folding of biomolecules are usually interpreted with one-dimensional models in which the dynamics occurs on the "pulling coordinate." Paradoxically, the free-energy profile along this coordinate may lack a refolding barrier, yet a barrier is known to exist for folding; thus, it has been argued that pulling experiments do not probe folding. Here, we show that transitions monitored in pulling experiments probe the true folding barrier but that the barrier may be hidden in the projection onto the pulling coordinate. However, one-dimensional theory using the pulling coordinate still yields physically meaningful energy landscape parameters.
单分子生物分子折叠的拉伸实验通常用一维模型进行解释，其中动力学发生在“拉伸坐标”上。矛盾的是，沿这个坐标的自由能分布可能缺乏重折叠势垒，但众所周知折叠存在势垒；因此，有人认为拉伸实验不能探测折叠。在这里，我们表明，在拉伸实验中监测到的转变确实探测到了真实的折叠势垒，但这个势垒可能隐藏在对拉伸坐标的投影中。然而，使用拉伸坐标的一维理论仍然可以得到具有物理意义的能量景观参数。
