Wan Z L, Liang D C
Institute of Biophysics, Academia Sinica, Beijing.
Sci Sin B. 1988 Dec;31(12):1426-38.
In order to study the biological effect of alterations to the N-terminus of the insulin A-chain, we have determined the crystal structure of A1-(L-Trp) insulin and discovered that it belongs to the trigonal system with space group R3. The parameters of the unit cell are a = b = 80.3A, c = 37.5A. The model was adjusted and refined by using a stereochemically-restrained least squares program, assisted by manual revision of the model based on the difference Fourier map, to a final R-factor of 0.195. The main and side chains of both A1-(L-Trp) residues in the asymmetric unit are well ordered. It was found that the A1-Trp residue of molecule I occupied two distinct positions. We have proposed from the results of the three-dimensional structure that the 4-zinc insulin hexameric form is a stored state of insulin molecules in a conformation of low activity. The structural details of the insulin molecule and its structure and function relationship have also been discussed.
为了研究胰岛素A链N端改变的生物学效应，我们测定了A1-(L-色氨酸)胰岛素的晶体结构，发现它属于三方晶系，空间群为R3。晶胞参数为a = b = 80.3埃，c = 37.5埃。使用立体化学约束最小二乘法程序对模型进行调整和精修，并基于差值傅里叶图对模型进行人工修正，最终R因子为0.195。不对称单元中两个A1-(L-色氨酸)残基的主链和侧链排列良好。发现分子I的A1-色氨酸残基占据两个不同的位置。我们从三维结构的结果中提出，4-锌胰岛素六聚体形式是胰岛素分子处于低活性构象的储存状态。还讨论了胰岛素分子的结构细节及其结构与功能的关系。
