氨基酸置换增强肿瘤坏死因子受体封闭肽的生物学效应

Increasing the Biological Effects of TNFR Blocking Peptide by Replacing Amino Acids

目的增强肿瘤坏死因子受体(TNFR)封闭肽的生物学效应。方法通过计算机模建,模拟并推测提高TNFR封闭肽生物学效应需置换的位点和氨基酸;合成原封闭肽和突变肽;受体竞争抑制结合实验比较原肽与突变肽对绿色荧光蛋白-肿瘤坏死因子融合蛋白(GFP-TNF)结合TNFR的竞争抑制效应;细胞毒作用抑制实验比较原肽与突变肽对TNFR的封闭效应。结果受体竞争抑制结合实验结果显示:两种肽均可与GFP-TNF竞争结合U937细胞表面的TNFR。原肽的半数抑制浓度(IC50)为140μg/ml,而突变肽为100μg/ml,提示突变肽的竞争抑制效应高于原肽;细胞毒抑制实验显示:突变肽对于TNF-α杀伤U937细胞的细胞毒作用的抑制率为57%,高于原肽的40%(P<0.01)。结论突变肽的生物学效应强于原肽。

Objective Increasing the biological effects of tumor necrosis factor receptor （TNFR） blocking peptide. Methods Mimicry and spcculation on possible displaced amino acids in proper positions of peptide increased the biological effects of TNFR blocking peptide by compute modeling. The original peptide and its mutant were synthesized. The competitively inhibitory effects on green fluorescence protein-tumor necrosis factor fusion protein （GFP TNF） with TNFR were compared between original peptide and its mutant （receptor competitively inhibitory binding assays）. The inhibitory effects on cytotoxicity were compared between original pcptide and its mutant. Results The results of receptor competitively inhibitory binding assays revealed that 2 synthesized peptides both could compete with GFP TNF for binding TNFR on U937 cell surface. IC50 （the dose needed for 50%inhibition） of original peptidc was 140 μg/ml and IC50 of its mutant was 100 μg/ml, suggesting that the competitively inhibitory effect of mutant was highcr than that of original peptide. The inhibitory effects on cytotoxicity of TNF-α on U937 cells showcd that the 57% inhibition by mutant was higher than 40% by original peptide （P〈0.01）. Conclusion The biological effects of mutant is higher than that of original TNFR blocking peptide.