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针对目标分子柔性大的特点,在比较分子场分析(CoMFA)方法中采用交叉验证相关系数平方R~2引导的构象选择法.对12个皂甙分子的生物活性进行了三维定量构效关系研究.探讨了几种探针对构效关系结果的影响,并选择了一种较合理的“复合”探针方案.应用该复合探针构建CoMFA模型,发现影响药效的立体场与静电场的贡献分别为40％和4O％,其它能量项的贡献为20％.该模型交叉验证的相关系数平方R~2为0.653,非交叉验证的R~2为0.991,方差比F(4,7)值130.195(即置信度99％以上),活性预计的标准偏差与极差比(s/Δγ)为4.2％,表明模型具有较好的预测能力.根据该模型,预计在指定位置添加位阻较大的基团活性值提高将会比较明显.
Aiming at the large flexibility of the target molecule, the conformational selection method of cross-validation correlation coefficient squared R 2 was used in the comparative molecular field analysis (CoMFA) method, and the three-dimensional quantitative structure-activity relationship of 12 saponins was studied. The effects of several probes on the structure-activity relationship were discussed, and a more reasonable “compound” probe scheme was chosen.Using the probe to construct the CoMFA model, we found the contribution of the three-dimensional field and electrostatic field 40% and 40% respectively, and the contribution of other energy items is 20% .The correlation coefficient of cross-validation for this model is R65 = 0.653, non-cross-validation R ~ 2 is 0.991, and variance ratio F (4,7) 130.195 (ie, the confidence level is above 99%), and the standard deviation of expected activity is 4.2% (s / Δγ), indicating that the model has a good prediction ability. According to this model, The group activity value will be more obvious.