氯霉素驱动的β-半乳糖苷酶互补体系的构建

Construction of Chloramphenicol-driven β-galactosidase Complementation

目的构建氯霉素驱动的β-半乳糖苷酶(β-gal)互补体系,以期建立氯霉素残留检测用非竞争性均相酶互补免疫分析系统(OS-ECIA)。方法从大肠杆菌DH5α和BL21株分别克隆β-galΔα和Δω基因,采用重叠延伸PCR组装含抗氯霉素抗体可变区的互补肽融合蛋白,在T7启动子驱动下于大肠杆菌宿主株中表达,表达产物纯化与复性后进行酶互补活性分析。结果成功克隆和高效表达融合肽基因VH-CAP-Δα和VL-CAP-Δω,表达产物为包涵体蛋白,经纯化和复性后呈现特征性酶学互补活性,且酶活性呈现氯霉素依赖性增加。结论成功构建氯霉素驱动的β-gal互补体系。

Objective To establish a noncompetitive and homogeneous immunoassay for chloramphenicol based on the antigen-dependent reassociation of antibody variable fragment and β-galactosidase （ β-gal ） complementation （ open sandwich enzymatic complementation immunoassay,OS-ECIA）,chloramphenicol-driven complementation fragment of β-gal were constructed. Method Coding sequences of Δα and Δω of β-gal were amplified from genomic DNA of Escherichia coli cell lines DH5α and BL21, respectively, then fused to antibody variable region gene （ VH-CAP or VL-CAP ） against chloramphenicol by a linker according to OS-ECIA model,and expressed under the control of promoter T7 in E. coli. Inclusion proteins were renatured after purification and analyzed for β-gal complementation activity. Results VH-CAP-Δα and VL-CAP-Δω genes were cloned as designed. Both fusion peptides gene were over-expressed as inclusion proteins. Inclusion proteins were purified to a purity over 80% ,then refolded by dilution method,and both refolded fusion proteins showed typical chloramphenicol-dependent complementation activity. Coclusion chloramphenicol-driven complmentary system of β-gal were successfully constructed.