Murata Takeshi, Kuwagaki Misato, Shin Tomoko, Gotoh Naomasa, Nishino Takeshi
Department of Microbiology, Kyoto Pharmaceutical University, Yamashina, 607-8414, Kyoto, Japan.
Biochem Biophys Res Commun. 2002 Nov 29;299(2):247-51. doi: 10.1016/s0006-291x(02)02626-8.
The tripartite efflux systems MexAB-OprM and MexCD-OprJ of Pseudomonas aeruginosa each display characteristic substrate specificity against a variety of antimicrobial agents. The chimeric efflux system MexC-MexB-OprJ/DeltaMexD constructed by exchange of MexD with MexB endowed the recombinant host the same resistance profile as MexAB-OprM rather than MexCD-OprJ. The change of substrate specificity was shown to be due to extrusion from the chimeric efflux system by cellular accumulation experiments using tetracycline, erythromycin, and ethidium bromide. Thus, we conclude that MexB and MexD are primary components of the efflux system responsible for sorting extrusion substrates.
铜绿假单胞菌的三联外排系统MexAB - OprM和MexCD - OprJ对多种抗菌剂各自表现出特征性的底物特异性。通过将MexD与MexB交换构建的嵌合外排系统MexC - MexB - OprJ/ΔMexD赋予重组宿主与MexAB - OprM相同而非MexCD - OprJ的耐药谱。通过使用四环素、红霉素和溴化乙锭的细胞积累实验表明，底物特异性的改变是由于从嵌合外排系统中排出所致。因此，我们得出结论，MexB和MexD是负责分选排出底物的外排系统的主要成分。
