水在稳定肌红蛋白天然结构中的作用

在０－１００％相对湿度（ＲＨ）范围内用付里叶变换红外光谱和曲线拟合法研究了水合对肌红蛋白二级结构的影响。干燥蛋白的α－螺旋、伸展和无序结构含量分别为６１％、２２％和１７％。随水合度增加，无序结构含量减少，有序二级结构含量增加，在４４％ＲＨ以下这种变化最显著，在８６－１００％ＲＨ范围，结构有较复杂的调整，三种亚结构含量分别约为７５％、２１％和４％，与晶态或溶液态下的结构相同。这一结果进一步证实了我们

THE ROLE OF WATER IN STABILIZING THE NATURAL STRUCTURE OF MYOGLOBIN-A FOURIER TRANSFORM INFRARED SPECTROSCOPIC STUDY

The effects of water on the secondary structure of myoglobin was investigated in the relative huminity (RH) range of 0 to 100% by means of Fourier transform infrared spectroscopy and curve-fitting. At dryness, the relative contents of a-helix, extended and disordered structures are about 61%, 22% and 17%, respectively. As the degree of hydration increases, the content of disordered structure decreases and those of ordered secondary sturcture increase. Such a structure transition is most significant at the RH lower than 44% and a complicated interchange of disordered to ordered structure takes place at 86 to 100%RH, Where the relative contents of the three substructures are 75%, 21% and 4%, respectively, the same as those in crystal and solution. The results confirm our previous conclusion that water acts as a plasticizer for the flexibility and a catalyst for mobility and conformation of peptide chains.