重组葡萄球菌肠毒素SEQ的生物活性及其结构关系分析

Bioactivity of the Recombinant Staphylococcal Enterotoxin Q and Its Structure Relationship Analysis

采用原核表达系统表达、亲和纯化重组蛋白、Western-blot、MTT比色法及同源模建的方法,分析了新型葡萄球菌肠毒素SEQ的生物学活性及其与结构的关系,预测了发挥超抗原活性的功能位点。结果表明,表达纯化的可溶性重组GST-SEQ、His-SEQ蛋白表达量分别占菌体蛋白的20%和25%,且均具有良好的免疫原性以及诱导小鼠脾淋巴细胞分化增殖的能力,SEQ成熟肽中α-螺旋、β-折叠、无规则蜷曲分别约32,68,116aa;SEQ毒素潜在的与MHCⅡVβ链结合的关键位点为H169、H207、D209,而与TCR的结合域位于α3-β8环区域。2种重组SEQ肠毒素均具有超抗原活性,这与其存在于细胞MHCⅡVβ链及TCR作用的结合域有关。

The bioactivity and the structure relationship of the new kind Staphylococcal Enterotoxin Q were analyzed,and the function sits related to the superantigen activity were predicated in this study,by the methods of prokaryotic expression,affinity purification,western-blot,MTT colorimetry and homology modeling. The results showed that the rate of the expression of the purified recombinant protein GST-SEQ and His-SEQ was at 20% and 25% level of the whole protein in host cells,respectively,and the two recombined fusion protein both had good immunogenicity and the ability to induced proliferation of mouse spleen cells. The α-helices,β-strands and random coils of the SEQ mature peptide were about 32,68,116 amino acid resides,respectively,and the potential binding sits in SEQ with MHCⅡ Vβ chain were H169,H207,D209,while the binding domain with TCR was α3-β8 loop. The recombine Staphylococcus enterotoxin Q present a superantigen activity which was relate with its structure domain binding with MHCⅡVβ chain and TCR of mouse spleen cells.