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冠肽是环肽的特殊构型,其结构中的酰胺键主链呈规则排列,形成类似于冠醚的冠型构象,具有高度的对称性,易于形成实现与离子/分子结合的孔径或通道,达到预期的识别作用以及作为超分子离子载体的运输能力。用密度泛函理论的B3LYP方法,以环丙四肽的冠状构象(冠丙四肽)为模型基础,在真空体系中,对其与卤族氧族阴离子结合体系进行了几何构型优化、能量、Mulliken布局数、前沿轨道等方面的理论研究。结果表明:冠丙四肽的构型在与离子结合前后几乎没有改变,结合过程中电子由非金属阴离子移向冠肽主体,价键作用表现为阴离子与氨基氢之间的氢键作用,其中氟与冠型环丙四肽的结合作用并不特别明显优于氯和溴,而氧与冠型环丙四肽的结合作用则明显优于硫和硒;同等情况下,与二价离子的结合作用更显为显著。
Crown peptides are a special configuration of cyclic peptides whose amide backbone backbones are regularly arranged to form a crown-like conformation resembling crown ether with a high degree of symmetry that makes it easy to form pores or channels that allow ionic / molecular conjugation , To achieve the desired recognition and transport ability as a supramolecular ionophore. Based on the B3LYP method of density functional theory (DFT) and the coronary conformation (crown-tetrapeptide) of the cyclopropane tetrapeptide, the geometrical configuration of the conjugated system with halogen anions was optimized in a vacuum system. The energy , Mulliken layout number, frontier orbit theory research. The results showed that the configuration of the captopril tetrapeptide had almost no change before and after binding with the ions. During the binding process, the electrons migrated from the non-metal anions to the corona peptide and the valence bond functioned as the hydrogen bonding between the anion and the amino hydrogen. Among them, The binding of fluorine to crown cyclopropane is not particularly superior to that of chlorine and bromine, and the binding of oxygen to crown cyclopropane is significantly better than that of sulfur and selenium. In the same case, The combination is even more pronounced.