小鼠重组PeriostinC端肽在大肠杆菌中的表达及其产的的活性检测

目的：利用大肠杆菌系统表达小鼠重组PeriostinC端肽。方法：将编码小鼠PeriostinC的基因自然克隆到大肠杆菌表达载体pRSET-B上，使其受控于T7启动子，构建成表达质粒pRS－B－Peri，以大肠杆菌E．coli BL219(DE3)为宿主菌。对工程菌用异丙基硫代－β－D－半乳糖苷（sopropylthio－β－D－galacto-side，IPTG)诱导表达，表达产物纯化后进行复性处理，再通过观察成骨细胞的伸展性检测其生物活性。结果：经IPTG诱导5h，工程菌在SDS－PAGE上出现一条新蛋白带，相对分子质量（Mr）与预期的一致，约为36000，主要以包涵体形式存在。所得包涵体经纯化和复性处理，得到纯度高于95％的有良好活性的小鼠重组PeriosinC端肽。结论：小鼠重组PeriostinC端肽在大肠杆菌中得到表达并具有良好的生物学活性。

Expression of recombinant terminal C peptide of mouse Periostin in E.coli and identification of the biological activity of the expressed product

AIM: To express the recombinant mouse periostin in Escherichia coli and identify the biological activity of the expressed product. METHODS: The DNA fragment encoding the terminal C of periostin was inserted into expression vector pRSET-B, in which the foreign gene is controlled by T7 promoters. The recombinant plasmid pRS-B-Periostin was transformed into E.coli BL21(DE3) and induced at IPTG to express the encoded protein The expressed product was purified and refolded. Its adhesion and spreading activity were assayed in vitro . RESULTS: After induction with IPTG for 5h, a new anticipated 36000 M r protein band appeared on SDS-PAGE gel. The expressed product existed in a form of inclusion body. After being purified and refolded, recombinant periostin with purity more than 95% was obtained, which could promote the adhesion and spreading of osteoblast. CONCLUSION: The recombinant mouse periostin has been successfully expressed in engineered E. coli BL21(DE3) with good biological activity. [