Wemmer D, Ribeiro A A, Bray R P, Wade-Jardetzky N G, Jardetzky O
Biochemistry. 1981 Feb 17;20(4):829-33. doi: 10.1021/bi00507a027.
At temperatures below 20 degrees C, the lac repressor headpiece (N-terminal amino acids 1--51) has a well-defined structure which is independent of ionic strength. Its unfolding with increasing temperature proceeds gradually with a characteristic transition temperature which depends on ionic strength. Unfolding has been studied by using NMR and CD. Shifts of several methyl and all of the tyrosyl resonances can be followed, allowing a detailed analysis of the temperature denaturation. At high ionic strength (1 M), the unfolding is complete at 85 degrees C, while at low ionic strength (0.01 M), it is complete by 65 degrees C. Native and partially unfolded structures are in rapid exchange during the unfolding, and the process appears completely reversible at all ionic strengths.
在20摄氏度以下的温度时，乳糖阻遏蛋白的头部结构域（N端氨基酸1 - 51）具有明确的结构，且该结构与离子强度无关。随着温度升高，其展开过程逐渐进行，具有一个取决于离子强度的特征转变温度。通过核磁共振（NMR）和圆二色性（CD）对展开过程进行了研究。可以追踪几个甲基和所有酪氨酸残基共振峰的位移，从而对温度变性进行详细分析。在高离子强度（1 M）下，85摄氏度时展开完成，而在低离子强度（0.01 M）下，65摄氏度时展开完成。在展开过程中，天然结构和部分展开的结构处于快速交换状态，并且在所有离子强度下该过程似乎都是完全可逆的。
