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

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

报道了利用荧光偏振方法研究异硫氰酸盐荧光素 (FITC)标识 ,并由天冬氨酸、谷氨酸、(1R ,3R) 1 氨基 1,3 二羧基环丁烷和 (1R ,3R) 1 氨基 1,3 二羧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 环己烷丙氨酸和 1 羧基金刚烷 )之间的键合常数 (Kb)和包合反应的热力学参数 (ΔG° ,ΔH° ,ΔS°) .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 (-ΔΔGDL°)以及一对手性异构体 (L 与D )与同一主体的键合常数之比 (KL KD) ,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TΔS°与ΔH°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 .

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 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; (1 R ,3 R ) 1 aminocyclobutane cis 1,3 dicarboxylic acid, (1 R ,3 R ) 1 aminocyclopentane cis 1,3 dicarboxylic acid respectively, were used as host molecules. The binding constants ( K b) and thermodynamic parameters (Δ G °, Δ H °, Δ 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 -ΔΔ G DL ° and K L/ K D. According to the good linear relationship of Δ H ° versus T Δ S °, enthalpy entropy compensation of the complexation of labeled cyclodextrin dimers with several small peptide derivatives was investigated.