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深入理解药物分子和核酸碱基间的相互作用机制对合理设计研发新型高效药物有重要意义.本文运用密度泛函理论B3LYP方法对核酸碱基尿嘧啶和胸腺嘧啶与药物分子槲皮素间的氢键相互作用位点进行了研究.使用B3LYP/6-31G(d)方法优化得到了30个稳定的氢键复合物结构,使用B3LYP/6-311++G(3df,2p)方法计算了这些复合物的结合能.研究结果表明,槲皮素可以使用5个不同的结合位点与尿嘧啶或胸腺嘧啶形成氢键复合物,尿嘧啶或胸腺嘧啶可以使用3个不同的结合位点与槲皮素形成氢键复合物.当槲皮素的结合位点固定时,槲皮素与尿嘧啶的位点u1或胸腺嘧啶的位点t1形成的氢键作用最强,与位点u2或位点t2形成的氢键强度最弱;当尿嘧啶或胸腺嘧啶的作用位点固定时,二者与槲皮素的位点qu1形成的氢键作用最强,与位点qu5作用强度次之,与位点qu3的作用强度最弱.分子中原子(AIM)和自然键轨道(NBO)分析计算结果表明,轨道作用在氢键中起重要作用.
It is of great significance to understand the mechanism of interaction between drug molecules and nucleic acid bases in order to rationally design and develop novel and effective drugs.In this paper, the density functional theory (B3LYP) method was used to study the interaction between nucleic acid bases uracil, thymine and quercetin Bond interaction sites were studied.At the same time, 30 stable hydrogen-bonding complexes were obtained by B3LYP / 6-31G (d) method and B3LYP / 6-311 ++ G (3df, 2p) Complex binding energy.The results show that quercetin can use five different binding sites and uracil or thymine hydrogen bond complexes, uracil or thymine can use three different binding sites and the mistletoe When the binding site of quercetin is fixed, the hydrogen bond formed between quercetin and uracil locus u1 or thymine locus t1 is the strongest, and the site of u2 or The hydrogen bond strength formed by the point t2 is the weakest; when the site of uracil or thymine is fixed, the hydrogen bond formed by the quercetin locus qu1 and hydrogen quercetin is the strongest, followed by the locus qu5, The weakest interaction with site qu3 is atomicity (AIM) in the molecule Calculation bond orbital (NBO) results showed that the orbital interaction plays an important role in hydrogen bonds.