APC/Asef多肽抑制剂的设计、合成及构效关系研究

Design, synthesis and structure-activity relationship study of APC/Asef inhibitors

目的·设计并合成结肠腺瘤息肉易感基因/鸟苷酸交换因子(APC/Asef)多肽抑制剂,探讨构效关系,为后续的抑制剂改造提供基础。方法·基于已有的多肽抑制剂MAI-400,在此基础上重新设计合成11条多肽,包括对N端封端、第1位丙氨酸、第5位亮氨酸以及第7位谷氨酸的改造。通过荧光偏振活性检测体系测定新合成多肽的活性,联合该结果与分子对接结果对其进行构效关系研究。结果·新设计的11条多肽中,MPI-11亲和力最高,其半数抑制浓度(IC50)为0.9731mmol/L。多肽N端封端维持苄氧羰基最为合适;丙氨酸替换为色氨酸、组氨酸以及苏氨酸都会显著降低活性,替换为酪氨酸或者苯丙氨酸对活性的影响较小,5位氨基酸引入苯环也对活性的影响不大,C端的谷氨酸将侧链羧基替换成酰胺对活性影响不大。结论·N端封端不宜改为小基团,1位丙氨酸不能轻易改变。

Objective · To design and synthesize APC/Asef peptide inhibitors and investigate the structure-activity relationship between peptides inhibitors and APC protein for exploring better inhibitors. Methods·Based on the best-class inhibitor we had found before-MAI-400, eleven peptide inhibitors were designed, which included the changes of N-terminal capping group, the first amino acid Ala, the fifth amino acid Leu and the last amino acid Glu. According to the results of fluorescence polarization activity detection system and molecular docking, the structure-activity relationship of peptide inhibitors was investigated. Results · Among the eleven peptides, MPI-11 had the highest affinity, whose half maximal inhibitory concentration (IC50) was 0.973 1 mmol/L. The capping group of peptide N-terminal with tert-butoxycarbonyl group reduced the activity slightly. The substitution of the Ala caused different results, changing into Trp, His and Thr definitely reduced the activity but the substitution by Tyr or Phe did not influence the activity too much. And introducing benzene ring into the side chain of Leu had few effects on activity improving. The substitution of side chain carboxyl for amide at the C-terminal glutamate had little effect on the activity. Conclusion· Among the eleven peptides, the capping group of peptide N-terminal cannot be substituted into small groups and Ala cannot be substituted into other amino acids.