title: SmdAB, a heterodimeric ABC-Type multidrug efflux pump, in Serratia marcescens.
abstract: We cloned genes, designated smdAB, that encode a multidrug efflux pump from the chromosomal DNA of clinically isolated Serratia marcescens NUSM8906. For cells of the drug-hypersensitive strain Escherichia coli KAM32 harboring a recombinant plasmid carrying smdAB, structurally unrelated antimicrobial agents such as norfloxacin, tetracycline, 4',6-diamidino-2-phenylindole (DAPI), and Hoechst 33342 showed elevated MICs. The deduced amino acid sequences of both SmdA and SmdB exhibited similarities to the sequences of ATP-binding cassette (ABC)-type multidrug efflux pumps. The efflux of DAPI and Hoechst 33342 from E. coli cells expressing SmdAB was observed, and the efflux activities were inhibited by sodium o-vanadate, which is a well-known ATPase inhibitor. The introduction of smdA or smdB alone into E. coli KAM32 did not elevate the MIC of DAPI; thus, both SmdA and SmdB were required for function. These results indicate that SmdAB is probably a heterodimeric multidrug efflux pump of the ABC family in S. marcescens.
authors.affiliation: Department of Genome Applied Microbiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima, Okayama, 700-8530, Japan.
authors.forename: Taira
authors.initials: T
authors.lastname: Matsuo
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Minato
authors.forename: Wakano
authors.initials: W
authors.lastname: Ogawa
authors.forename: Tohru
authors.initials: T
authors.lastname: Mizushima
authors.forename: Teruo
authors.initials: T
authors.lastname: Kuroda
authors.forename: Tomofusa
authors.initials: T
authors.lastname: Tsuchiya
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics* / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001562:Benzimidazoles / Q000494:pharmacology; D001693:Biological Transport, Active / Q000235:genetics; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics; D007211:Indoles / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009643:Norfloxacin / Q000494:pharmacology; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012706:Serratia marcescens / Q000235:genetics* / Q000378:metabolism; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D018528:ATP-Binding Cassette Transporters; D000900:Anti-Bacterial Agents; D001562:Benzimidazoles; D004269:DNA, Bacterial; D007211:Indoles; C007293:DAPI; D013752:Tetracycline; D009643:Norfloxacin; C017807:bisbenzimide ethoxide trihydrochloride