Palmer K A, Scheraga H A, Riordan J F, Vallee B L
Proc Natl Acad Sci U S A. 1986 Apr;83(7):1965-9. doi: 10.1073/pnas.83.7.1965.
A preliminary three-dimensional structure of angiogenin has been computed, based on its homology to bovine pancreatic ribonuclease A. A standard-geometry structure of ribonuclease was first obtained from its x-ray coordinates. The fit of the backbone of angiogenin to that of ribonuclease was then optimized by taking account of amino acid deletions and by minimizing its conformational energy-plus-a-penalty distance function constraining its backbone to that of ribonuclease. Side-chain and backbone dihedral angles were allowed to vary throughout the cycles of energy minimization. In the last stages of minimization, the penalty distance function was removed. A low-energy structure resembling ribonuclease was obtained.
基于血管生成素与牛胰核糖核酸酶A的同源性，已计算出其初步的三维结构。首先从核糖核酸酶的X射线坐标中获得其标准几何结构。然后通过考虑氨基酸缺失并最小化其构象能量加惩罚距离函数（该函数将其主链限制为核糖核酸酶的主链），优化血管生成素主链与核糖核酸酶主链的匹配。在能量最小化的整个循环过程中，侧链和主链二面角可以变化。在最小化的最后阶段，去除惩罚距离函数。获得了一种类似于核糖核酸酶的低能量结构。
