荧光标识的环糊精二聚体与小肽衍生物之间的包合行为研究

报道了利用荧光偏振方法研究导硫氰酸盐荧光素（FITC）标识，并由天冬氨酸 、谷氨酸、(1R, 3R)-1-氨基-1，3-二羟基环丁烷和（1R， 3R）-1-氨基-1，3-二 羟基环戊烷衍生物桥联的环糊精二聚体（1～4，作为主体），在pH = 7.4的水溶液 中与几个低分子量的多肽衍生物:Adm-Lys(Adm)-Arg-Arg 5; Adm-Lys(Adm)-D-Arg- D-Arg 6; Adm-Cha-Arg-Arg 7; Adm-Cha-D-Arg-D-Arg 8（作为客体，其中Arg, Lys, Cha和Adm分别为精氨酸，赖氨酸，β-环已烷丙氨酸和1-羟基金刚烷）之间 的键合常数（K_b)和包合反应的热力学参数（△G°，△H°，△S°）。从主-客体 键合常数的比较、客体嵌入基团的结构与周边环境的考察发现，主、客体之间的键 合能力因客体非进入基团（Arg)空间构型上的变化而有所不同。通过比较主体包结 一对手性异构体的自由能变化增量（-△△G_(DL)°）以及一对手性异构体（L-与 D-）与同一主体的键合常数之比（K_L/K_D)，讨论了环糊精二聚体对D-型或L-型多 肽衍生物的手性识别能力。根据各体系T△S°与△H°之间较好的线性关系，探讨 了环糊精二聚体与多肽衍生物之间相互作用的焓-熵补偿行为。

Study on Inclusion Behavior of Labeling CD Dimers with a Fluorescence Tracer to Small Peptide Derivatives

The interaction between small peptide derivatives and cyclodextrin dimers was studied by fluorescence polarization method. Four small peptide derivatives, Adm-Lys (Adm)-Arg-Arg 5; Adm-Lys (Adm)-D-Arg-D- Arg 6; Adm-Cha-Arg-Arg 7; Adm-Cha-D-Arg 8 (where Arg, Lys, Cha and Adm are the abbreviation of arginine, lysine, β-cyclohexylalanine and 1- carboxyl-adamantane, respectively) were used as guest molecules, and four cyclodextrin dimers 1 ～ 4, bridged with derivatives of aspartic acid; glutamic acid; (1R, 3R)-1-aminocyclobutane-cis-1, 3-dicarboxylic acid, (1R, 3R)-1-aminocyclopentane-cis-1, 3-dicarboxylic acid respectively, were used as host molecules. The binding constants (K_b) and thermodynamic parameters (△G°，△H°，△S°) of these host-guest systems were reported. The data showed that the complexation was accompanied by large negative changes in enthalpy and the bonding affinity of host to guest varied with the spatial arrangement of non- penetrating groups, the structure and properties of penetrating group in guest molecules. The molecular recognition ability of cyclodextrin dimer to the peptide derivatives was discussed based on the values of - △△G_(DL)°and K_L/K_D. According to the good linear relationship of △ H° versus T△S°, enthalpy-entropy compensation of the complexation of labeled cyclodextrin dimers with several small peptide derivatives was investigated.