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目的 构建和筛选既能稳定、高效表达SS融合蛋白，又能使这种融合蛋白保持良好的SS抗原性和高水溶性等特点的重组质粒。方法 用 BamH I/Xho I (B/X）和 BamH I/EcoR I（B/E）双酶切，将含有SS基因的片段由pThioHis A中切出，然后分别克隆到 pT7ZZa中的相应酶切位点，得到pSSB/X（短尾）和pSS-B/E(长尾)两个重组质粒，用常规表达技术在大肠杆菌中对其进行表达。结果 pSS-B/X和pSS-B/E两个重组质粒在宿主菌BL21（DE3）中均获得表达，pSS-B/X获得高效表达后融合蛋白占菌体总蛋白的30．6％。两个表达菌经超声裂解后电泳发现，SS－B/X－ZZ和SS－B/E－ZZ这两种融合蛋白基本为可溶性蛋白，沉淀中含量极低。二者均具有良好的抗原性，结论pSS-B/X重组质粒很有希望成为SS基因疫苗的候选质粒。
Objective To construct and screen recombinant plasmids which can express SS fusion protein stably and efficiently and maintain good SS antigenicity and high water solubility of the fusion protein. Methods The fragment containing the SS gene was digested with BamH I / Xho I (B / X) and BamH I / EcoR I (B / E). The fragment was digested with pThioHis A and then cloned into pT7ZZa Site, two recombinant plasmids, pSSB / X (short tail) and pSS-B / E (long tail), were obtained and expressed in E. coli using conventional expression techniques. Results The two recombinant plasmids pSS-B / X and pSS-B / E were expressed in the host strain BL21 (DE3). After high expression of pSS-B / X, the fusion protein accounted for 30.6% of the total bacterial proteins. The results of electrophoresis showed that the two fusion proteins of SS-B / X-ZZ and SS-B / E-ZZ were soluble protein and the content of precipitate was extremely low. Both of them have good antigenicity. Conclusion The pSS-B / X recombinant plasmid is promising candidate for SS gene vaccine.