Nisin-rbLF-N融合基因的构建及其在大肠杆菌中的表达

针对乳链菌肽(nisin)抑菌谱窄的缺点，选择对抗菌谱较广且具有较强抗性的牛乳铁蛋白氨基末端多肽(rbLF-N)为材料，构建融合基因Nisin-rbLF-N。将融合基因克隆到原核表达载体pGEX-4T1 中，转化E. coli BL21(DE3)进行诱导表达，将诱导表达的产物进行Tricine-SDS-PAGE 蛋白电泳及抑菌活性检测。结果表明，克隆菌经诱导后可表达出可观的融合蛋白，融合蛋白以包涵体形式存在，包涵体经洗涤、尿素溶解、复性后具有抗菌生物活性。

Construction of Nisin-rbLF-N Fusion Gene and Its Expression in Escherichia coli

Considering that Nisin has a narrow antibacterial spectrum, rbLF-N with strong inhibitory activity against a wide range of bacteria was used to construct fusion gene Nisin-rbLF-N. The fusion gene was cloned into the expression vector pGEX- 4T1, followed by transformation into the E. coli BL21 prokaryotic expression system for protein expression under IPTG induction. The expressed protein encoded by Nisin- rbLF-N gene was detected by Tricine-SDS-PAGE protein electrophoresis and it inhibitory activities against Gram positive and negative bacteria were also assayed. A considerable amount of fusion protein was expressed in E. coli BL21 cells and the protein was mainly found in inclusion bodies. The product obtained from the inclusion bodies subjected to washing, dissolution in 8 mol/L urea and protein refolding had good inhibitory activity against Gram positive bacteria rather than their negative counterparts.