【摘要】 指出了大肠杆菌的毒素-抗毒素系统(TAs)能介导解离后致死机制维持细菌质粒的稳定性和参与环境胁迫诱导细菌生长抑制或死亡,在鱼腥藻PCC7120质粒上的基因对alr9029/asr9028具有与TA系统较高的同源性.为了证实该基因对属于TA系统,通过生物信息学分析了alr9029/asr9028的遗传结构,设计特异性引物,扩增得到大小为198 bp的asr9028和387 bp的alr9029.PCR产物经Bam H I和HindШ双酶切后被插入p MD18-T和p ET-30a中,依次构建克隆载体和表达载体.经SDS-PAGE电泳检测,含有His6标签的表达蛋白相对分子量分别为12.4k Da和19.2 k Da,且为可溶性蛋白.故初步认定asr9028为抗毒素基因,alr9029为毒素基因,二者共同构成一个TA系统.更多还原

【Abstract】 Toxin-Antitoxin systems( TAs) in E. coli can mediate post-segregational killing to maintain the stability of plasmids and induce bacterial growth inhibition or death responding to environmental stresses. Gene pair alr9029 / asr9028 in plasmid of Anabaena sp. PCC7120 is homologous with TAs. To verify that the genes belong to TAs,bioinformatic techniques were used to analyze the genetic structure of alr9029 / asr9028. The specific primers were designed to amplify target genes asr9028 with 198 bp and alr9029 with 387 bp by PCR. The products were inserted into p MD18-T and p ET-30 a by double digestion of Bam H I and Hind Ш to construct clone and expression vectors successively. SDS-PAGE showed that the molecular weights of the expressed proteins with His6 tag were 12. 4 k Da and 19. 2 k Da respectively,and both were soluble. It was preliminarily determined that the gene pair alr9029-asr9028 constructed a toxin-antitoxin system,with asr9028 as antitoxin and alr9029 as toxin.更多还原