Walther Kirstin A, Gräter Frauke, Dougan Lorna, Badilla Carmen L, Berne Bruce J, Fernandez Julio M
Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
Proc Natl Acad Sci U S A. 2007 May 8;104(19):7916-21. doi: 10.1073/pnas.0702179104. Epub 2007 Apr 30.
We unfold and extend single proteins at a high force and then linearly relax the force to probe their collapse mechanisms. We observe a large variability in the extent of their recoil. Although chain entropy makes a small contribution, we show that the observed variability results from hydrophobic interactions with randomly varying magnitude from protein to protein. This collapse mechanism is common to highly extended proteins, including nonfolding elastomeric proteins like PEVK from titin. Our observations explain the puzzling differences between the folding behavior of highly extended proteins, from those folding after chemical or thermal denaturation. Probing the collapse of highly extended proteins with force spectroscopy allows separation of the different driving forces in protein folding.
我们在高力作用下展开并拉伸单个蛋白质，然后线性松弛力以探究其折叠机制。我们观察到它们回缩程度存在很大差异。尽管链熵贡献较小，但我们表明观察到的差异源于蛋白质之间疏水相互作用的大小随机变化。这种折叠机制对于高度伸展的蛋白质是常见的，包括像肌联蛋白中的PEVK这样的非折叠弹性蛋白。我们的观察结果解释了高度伸展蛋白质的折叠行为与化学或热变性后折叠的蛋白质之间令人困惑的差异。用力谱法探测高度伸展蛋白质的折叠可以分离蛋白质折叠中不同的驱动力。
