Department of Chemistry, University of Illinois, Urbana, Illinois, USA.
Biophys J. 2010 Nov 3;99(9):L69-71. doi: 10.1016/j.bpj.2010.08.066.
We compare the folding kinetics of a fluorescent phosphoglycerate kinase construct in 30 mammalian cells with that in aqueous buffer. In both environments, the kinetics can be fitted to the functional form exp[-(t/τ)(β)]. A histogram of τ shows that the average folding relaxation time in cells is only twice as long as in aqueous buffer. Consideration of the folding free energy and of β reveals that only some of the variation in τ arises from perturbation of the protein's energy landscape. Thus, the diffusion that controls barrier crossing during protein folding is nearly as fast in cells as in vitro, even though translational diffusion of phosphoglycerate kinase in the cell is slow compared to in vitro.
我们比较了在 30 种哺乳动物细胞中和在水溶液缓冲液中荧光磷酸甘油酸激酶结构域的折叠动力学。在这两种环境中，动力学都可以拟合为 exp[-(t/τ)(β)]的函数形式。τ的直方图表明，细胞中折叠松弛时间的平均值仅为水溶液缓冲液中的两倍。考虑到折叠自由能和β，发现τ的变化仅部分源于蛋白质能量景观的扰动。因此，在细胞中控制蛋白质折叠过程中势垒穿越的扩散速度与体外几乎一样快，尽管与体外相比，磷酸甘油酸激酶在细胞中的平动扩散速度较慢。
