Schlichter J, Friedrich J, Herenyi L, Fidy J
Lehrstuhl für Physik Weihenstephan, Technische Universität München, D-85350 Freising, Germany.
Biophys J. 2001 Apr;80(4):2011-7. doi: 10.1016/S0006-3495(01)76171-1.
We performed spectral diffusion experiments in trehalose-enriched glycerol/buffer-glass on horseradish peroxidase where the heme was replaced by metal-free mesoporphyrin IX, and compared them with the respective behavior in a pure glycerol/buffer-glass (Schlichter et al., J. Chem. Phys. 2000, 112:3045-3050). Trehalose has a significant influence: spectral diffusion broadening speeds up compared to the trehalose-free glass. This speeding up is attributed to a shortening of the correlation time of the frequency fluctuations most probably by preventing water molecules from leaving the protein interior. Superimposed to the frequency fluctuation dynamics is a relaxation dynamics that manifests itself as an aging process in the spectral diffusion broadening. Although the trehalose environment speeds up the fluctuations, it does not have any influence on the relaxation. Both relaxation and fluctuations are governed by power laws in time. The respective exponents do not seem to change with the protein environment. From the spectral dynamics, the mean square displacement in conformation space can be determined. It is governed by anomalous diffusion. The associated frequency correlation time is incredibly long, demonstrating that proteins at low temperatures are truly nonergodic systems.
我们在富含海藻糖的甘油/缓冲液-玻璃体系中对辣根过氧化物酶进行了光谱扩散实验，其中血红素被无金属的中卟啉IX取代，并将其与纯甘油/缓冲液-玻璃体系中的相应行为进行了比较（施利希特等人，《化学物理杂志》，2000年，112:3045 - 3050）。海藻糖有显著影响：与不含海藻糖的玻璃相比，光谱扩散展宽速度加快。这种加快归因于频率涨落相关时间的缩短，很可能是通过阻止水分子离开蛋白质内部实现的。叠加在频率涨落动力学之上的是一种弛豫动力学，它在光谱扩散展宽中表现为老化过程。尽管海藻糖环境加快了涨落，但对弛豫没有任何影响。弛豫和涨落都由时间幂律支配。各自的指数似乎不会随蛋白质环境而改变。从光谱动力学中，可以确定构象空间中的均方位移。它由反常扩散支配。相关的频率关联时间长得惊人，表明低温下的蛋白质是真正的非遍历系统。
