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基于[L-Met]_(BO)牛胰岛素(LMBBI)晶体的对称性和分子密堆积法的基本原理,确定了只使用一维的旋转和一维的平移即可确定分子在晶胞中的位置和取向的结构测定方案,依据此方案,使分子置换法的旋转函数的计算和用R因子搜索法精化旋转平移位置的计算大大简化。运用生物大分子刚体修正技术对模型进行了初步精化,用能量极小化的立体化学制约的最小二乘修正技术并辅以差值Fourier图人工分析对模型进行了调整和精化。在最终的电子密度图上,B链N端加长的L-Met在独立区两个分子中的表现比较清晰,相对于三方二锌猪胰岛素分子,B链N端的构象发生了较大的变化。
Based on the symmetry of the [L-Met] _ (BO) bovine insulin (LMBBI) crystals and the principle of close-packed molecular packing, it was determined that only one-dimensional rotation and one- According to this scheme, the calculation of the rotation function of the molecular displacement method and the calculation of the rotational translation position refined by the R factor search method are greatly simplified. The biomacromolecule rigid body modification technique was used to preliminarily refine the model, and the model was adjusted and refined with least-squares modified least-squares technique and energy difference Fourier diagram. In the final electron density map, the L-Met elongated at the N-terminal of the B chain is more clearly expressed in two molecules in the independent region, and the conformation of the N-terminal of the B chain is greatly changed relative to the tripartite Zinc porcine insulin molecule.