Sasahara K, Nitta K
Division of Biological Sciences, Graduate School of Science, Hokkaido University, Japan.
Protein Sci. 1999 Jul;8(7):1469-74. doi: 10.1110/ps.8.7.1469.
The pressure-induced unfolding of lysozyme was investigated in an aqueous guanidinium chloride solution by means of ultraviolet spectroscopy. Assuming a two-state transition model, volume changes were calculated from the slope of free energy vs. pressure plots over a temperature range of 10 to 60 degrees C. Between 25 and 60 degrees C, almost constant volume changes were observed in the transition region, which was reflected in almost identical slopes of the free energy change vs. pressure plots. On the other hand, the different slopes were observed in the pressure dependence of free energy change at temperatures lower than 25 degrees C. These data were interpreted as suggesting that a two-state model is not appropriate at low temperature, but instead one or more intermediates are present under these conditions. The volume changes for unfolding became less negative at temperatures higher than 25 degrees C.
通过紫外光谱法，在氯化胍水溶液中研究了压力诱导的溶菌酶去折叠。假设为两态转变模型，在10至60摄氏度的温度范围内，根据自由能对压力的曲线斜率计算体积变化。在25至60摄氏度之间，在转变区域观察到几乎恒定的体积变化，这反映在自由能变化对压力的曲线几乎相同的斜率上。另一方面，在低于25摄氏度的温度下，自由能变化的压力依赖性中观察到不同的斜率。这些数据被解释为表明两态模型在低温下不合适，而是在这些条件下存在一个或多个中间体。在高于25摄氏度的温度下，去折叠的体积变化变得不那么负。
