摘要/Abstract

摘要： 目的 ·设计并合成结肠腺瘤息肉易感基因（ adenomatous polyposis coli，APC）/鸟苷酸交换因子（ APC-stimulated guanine nucleotide exchange factor，Asef）多肽抑制剂，探讨该抑制剂不同构效之间的关系。方法 ·基于 APC-MAI-150复合物结构，一方面在 MAI-150多肽 N端用 3-苯基丙酰（3-phenylpropane）、Glu-Glu（GG）和 β-Ala-Ala（β-AA）取代连氨基基团苄氧羰基（carbobenzoxy， CBZ），另一方面尝试将 MAI-150中 N端第 6位 Tyr侧链苯环上的对位羟基替换为 -CN、-NO2、-NH2和 -F，设计合成新的 7条多肽。荧光偏振活性检测多肽亲和力，并根据活性结果将多肽 MDL-3、MDL-4和 MDL-5对接到 APC蛋白中，联合计算机对接的多肽和 APC蛋白的结合模式，探讨该 3条多肽的构效关系。结果 ·新合成的 7条多肽中，多肽 MDL-5的 N端 3-phenylpropane连氨基亲和力最高，其半数有效抑制浓度（ half maximal inhibitory concentration，IC50）为 2.35 μmol/L；与 MDL-5相比，多肽 N端用 GG（MDL-6）和 β-AA（MDL-7）连接氨基亲和力明显降低；MDL-3和 MDL-4的 N端第 6位 Tyr侧链苯环上的对位羟基替换为 -NH2和 -F亲和力相比较于替换为 -CN（MDL-1）和 -NO2（MDL-2）要明显提高；但新合成的多肽亲和力均低于 MAI-150。结论 ·改造多肽 N端连氨基基团和第 6位 Tyr侧链苯环上的对位羟基无助于提高多肽的亲和力。
关键词: 结肠腺瘤息肉易感基因 /鸟苷酸交换因子, 多肽抑制剂, 构效关系
Abstract:
Objective · To design and synthesize APC/Asef peptide inhibitors, and investigate the relationship between the structures and affinity of peptides. Methods · Based on crystal structure of the APC-MAI-150 complex, on the one hand, 3-phenylpropane, Glu-Glu (GG) and β-Ala-Ala (β-AA) were used to replace carbobenzoxy (CBZ) at the N terminal of MAI-150 to bind -NH2; on the other hand, -CN, -NO2, -NH2, and -F were replaced the parahydroxyl on the sixth tyrosine (Tyr) side chain benzene at the N terminal of MAI-150. And seven peptides were synthesized. Fluorescence polarization was applied to test peptide affinity, and molecular design laboratory-3 (MDL-3), MDL-4 and MDL-5 were docked into APC protein based on the results of activity. The structure-activity relationship of the three peptides was studiedcombining the binding patterns of computer docked peptide and APC protein. Results · Among the seven peptides, the N terminal 3-phenylpropane linked -NH2 of peptide MDL-5 had the highest affinity, which IC50 was 2.35 μmol/L. Compared with MDL-5, the affinity of MDL-6 and MDL-7 were significantly reduced. The para-hydroxyl on the sixth Tyr side chain benzene at the N terminal replaced with -NH2 (MDL-3) and -F (MDL-4), which the affinity were higher than -CN (MDL-1) and -NO2 (MDL-2). However, the affinity of newly synthesized peptides was lower than MAI-150. Conclusion · Transforming peptide N terminal linked -NH2 and the para-hydroxyl group on the sixth Tyr side chain benzene doesnt help to improve the affinity of peptides.
Key words: APC/Asef, peptide inhibitor, structure-activity relationship


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