Characterization of DrrAB Complex from Streptomyces Peucetius as A Multidrug Transporter

摘要: The soil bacterium Streptomyces peucetius produces two widely used anticancer antibiotics doxorubicin and daunorubicin. Present within the biosynthesis gene cluster in S. is drrAB operon which codes for a dedicated ATP-binding cassette type transporter export of these closely related antibiotics. DrrAB system was believed to be single-drug due its nature; however, our study demonstrated under both vivo vitro conditions that can transport not only but also Hoechst 33342 ethidium bromide. Moreover, many other well-studied multi-drug resistance proteins substrates (including verapamil, vinblastine rifampicin) inhibit DrrAB-mediated transport, indicating they are pump. Kinetic studies show competitive inhibition by rifampicin noncompetitive suggesting possibility more than one drug binding site system. This first in-depth from producer organism, it shows efflux like contains specificity multiple drugs. Our provides direct evidence dual role metalloprotease FtsH biogenesis membrane proteins. We found responsible proteolysis unassembled DrrB protein plays much broader complex. DrrA expressed together temperature sensitive ftsH mutant strain were non-functional their incorrect assembly. Simultaneous expression wild-type trans resulted normal efflux. Strikingly, could restored cells irrespective whether simultaneously with or after had already accumulated an inactive conformation, thus providing crucial ability refold misassembled Complementation experiments showed catalytic ATP domain chaperone-like activity, however proteolytic domains required present work coordinately participate complex membrane. INDEX WORDS: Multi-drug Resistance, ABC transporter, DrrAB, FtsH, Drug CHARACTERIZATION OF DRRAB COMPLEX FROM STREPTOMYCES PEUCETIUS AS A MULTIDRUG TRANSPORTER