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通过V-life计算机模拟软件建立cRGD(cyclic Arg-Gly-Asp,cRGD)多肽类分子库,利用V-life软件中的DOCK功能对分子库内cRGD肽结构进行筛选评分,挑选出能与整合素αν3β受体高特异性结合的cRGD结构。将该结构进行改造后制备成二聚体,用99Tcm对该结构进行标记,制备成肿瘤分子探针。并对其标记条件、稳定性、水溶性和亲和力进行评价。结果表明,DOCK功能计算出评分最佳的cRGD分子结构为Cys-Arg-Gly-Asp-(D)Ser-Cys。将该结构进行改造制备成二聚体后,室温下、ρ(SnCl2.2H2O)=1 g/L、反应时间为30 min时,标记率可达(87.42±3.21)%,经Sephadex G10层析柱纯化后,其放化纯大于95%;在室温和37℃条件下,99Tcm-cRGD于生理盐水和正常人新鲜血清中均保持良好的标记稳定性;其脂水分配系数对数值lgP(正辛醇/生理盐水)为-1.96±0.01;与U87人神经胶质瘤细胞进行受体的放射性配基结合分析(radioligand binding assay of receptors,RBA)实验,其平衡解离常数(equilibrium dissociation constant,Kd)为(0.089±0.052)×10-9L/mol。这表明,通过计算机模拟系统筛选出的cRGD肽可与整合素ανβ3特异性结合,是一种有前景的整合素ανβ3受体阳性肿瘤显像剂。
The cRGD (cRGD) polypeptide library was established by V-life computer simulation software. The DOCK function in V-life software was used to screened the cRGD peptide structure in the library. cRGD structure with high specific binding of [alpha] v3 [beta] receptors. The structure was modified to prepare a dimer, and the structure was labeled with 99Tcm to prepare a tumor molecular probe. The labeling conditions, stability, water solubility and affinity were evaluated. The results showed that DOCK function calculated the best scoring molecular structure of CRGD Cys-Arg-Gly-Asp- (D) Ser-Cys. After the structure was modified to prepare a dimer, the labeling efficiency reached 87.42 ± 3.21% at ρ (SnCl2.2H2O) = 1 g / L and the reaction time was 30 min at room temperature. Sephadex G10 chromatography 99Tcm-cRGD maintained good labeling stability in both normal saline and normal fresh serum at room temperature and 37 ℃. The lipid-water partition coefficient was proportional to the value of lgP (positive Octanol / normal saline) was -1.96 ± 0.01. The U87 human glioma cells were exposed to radioligand binding assay of receptors (RBA). The equilibrium dissociation constant Kd) was (0.089 ± 0.052) × 10 -9 L / mol. This indicates that the cRGD peptide screened by the computer simulation system can specifically bind to integrin ανβ3 and is a promising integrin ανβ3 receptor positive tumor imaging agent.