血管紧张素Ⅰ和Ⅱ的N端三肽分子印迹预作用的理论研究

Theoretical Research on Molecular Imprinted Polymer Pre-Action with the N-Terminal Tripeptide of Ang Ⅰ and Ang Ⅱ

以血管紧张素I和II共同的N端三肽分子(AT)为模板分子,丙烯酸(AAc)为功能单体,采用DFT/B3LYP方法和6-31G(d,p)基组,模拟模板分子与功能单体分子印迹预作用体系的构型.通过研究AT与AAc在印迹比例不同时形成复合物的几何构型、电荷转移及结合能,对AT与AAc预作用的模式进行探讨.另外,进一步比较AT、BT和CT(BT是血管紧张素I结构中C端的三肽分子,CT是血管紧张素II结构中C端的三肽分子)分别与AAc形成最大印迹比例复合物的作用模式及结合能.计算结果表明:AT与AAc通过氢键作用形成分子结构互补的复合物,当AT与AAc印迹比例为1∶6时,电荷转移最大,氢键数目最多,复合物的结合能最低(-361.78 k J/mol),氢键作用的位置显示精氨酸(Arginine,Arg)在印迹复合物中起重要作用;而BT和CT分别与AAc形成的复合物,最大印迹比例都为1∶5,结合能分别为-324.68、-284.66 k J/mol.与BT和CT相比,AT更适合作分子印迹聚合物的模板分子.

Molecular imprinted interaction model was constructed with the common N-terminal tripeptide of Ang I and Ang II（ AT）,as template molecule,and acrylic acid（ AAc） as functional monomer. Density functional theory（ DFT） method at the B3LYP/6- 31G（ d,p） level was used to investigate the geometry optimization,the charge transfer and the binding energy of the complexes in various imprinted ratio with ATand AAc in order to discuss the acting models between ATand AAc. Furthermore,complexes in the maximum imprinted ratio with AT,BT,CT（ BT is the C-terminal tripeptide of Ang I and CTis the C-terminal tripeptide of Ang II） and AAc compared the binding energy and the acting models for evaluation of molecular imprinted effect. Calculational results indicated that,AT and AAc formed complex via the hydrogen bonding interaction. The complex with a ratio of AT-AAc（ 1∶6） has the maximum charge transfer,hydrogen bonds number and binding energy（- 361. 78 k J / mol）. The position of hydrogen bonds from AT-AAc（ 1∶6） indicated the arginine（ Arg） was the important section in the molecular imprinted interaction. The complexes with a ratio of BT-AAc（ 1∶5） and CT-AAc（ 1∶5） had the binding energy of- 324. 68 and- 284. 66 k J / mol,respectively. This means among above three angiotensin bioactive peptide ATis the most suitable template molecule to the molecular imprinted polymers with AAc,theoretically.