超抗原SED空间结构的同源建模及其免疫识别位点的预测

Homologous modeling of three-dimensional structure and prediction of active sites of immune recognition of superantigen SED

目的 对金黄色葡萄球菌肠毒素口 (SED)的空间结构和免疫识别位点进行预测。方法 运用同源建模的方法构建了SED的三维空间结构模型 ,比较SED与其它金黄色葡萄球菌肠毒素超抗原的氨基酸序列、二级结构和空间结构的差异 ,对可能的活性位点进行预测。结果 SED的空间结构与其它肠毒素超抗原相似 ,具有两个结构域 :氨基末端结构域和羧基末端结构域。α 螺旋和 β 折叠可能与维持SED超抗原的空间结构以及与MHC的结合有关 ,而环状区域更多的参与SED与TCR的相互作用。结论 结合已有的研究结果 ,最终确定SED的N2 3、F45、L5 9、N61、I92和F2 0

Objective To predict the three dimensional structure and active sites of immune recognition of SED. Methods The three dimensional structure of SED was constructed by homology modeling method. The amino acid sequences, secondary structure and three dimensional structure of SED were compared with those of other enterotoxin superantigens. On the basis of the results of the comparison, the active sites were predicted. Results The three dimensional structure of SED, similar to that of other enterotoxin superantigens, was composed of two domains: amino terminal domain and carboxyl terminal domain. α helix and β sheet might probably be involved in the maintenance of the structure of SED and binding of SED to MHC. The loop domain of SED probably interacted with TCR. Conclusion According to our analysis and the previous studies, we predict that N23, F45, L59, N61, I92 and F203 on SED may be the active sites of immune recognition.