title: Molecular cloning and characterization of the HmrM multidrug efflux pump from Haemophilus influenzae Rd.
abstract: We cloned a gene responsible for norfloxacin resistance from the chromosomal DNA of Haemophilus influenzae Rd, and designated the gene as hmrM. HmrM showed sequence similarity with NorM of Vibrio parahaemolyticus and YdhE of Escherichia coli and others that belong to the MATE family multidrug efflux pumps. The recombinant plasmid carrying the hmrM gene conferred elevated resistance not only to norfloxacin but also to acriflavine, 4 ', 6-diamidino-2-phenylindole, doxorubicin, ethidium bromide, tetraphenylphosphonium chloride, Hoechst 33342, daunomycin, berberine, and sodium deoxycholate in Escherichia coli KAM32, a drug-hypersensitive strain. We observed an Na+-dependent efflux of ethidium and an ethidium-induced efflux of Na+ in E. coli KAM32 cells harboring the plasmid carrying the hmrM gene. These results indicate that HmrM is an Na+/drug antiporter-type multidrug efflux pump. A difference in substrate preference was observed between HmrM, NorM, and YdhE.
authors.affiliation: Department of Microbiology, Faculty of Pharmaceutical Sciences, Okayama University Tsushima, Okayama, Japan.
authors.forename: Xing-Jue
authors.initials: XJ
authors.lastname: Xu
authors.forename: Xian-Zhong
authors.initials: XZ
authors.lastname: Su
authors.forename: Yuji
authors.initials: Y
authors.lastname: Morita
authors.forename: Teruo
authors.initials: T
authors.lastname: Kuroda
authors.forename: Tohru
authors.initials: T
authors.lastname: Mizushima
authors.forename: Tomofusa
authors.initials: T
authors.lastname: Tsuchiya
mesh_terms: D000890:Anti-Infective Agents / Q000378:metabolism / Q000494:pharmacology*; D017920:Antiporters / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001693:Biological Transport, Active; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins; D004996:Ethidium / Q000378:metabolism; D005798:Genes, Bacterial; D006193:Haemophilus influenzae / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D009643:Norfloxacin / Q000378:metabolism / Q000494:pharmacology*; D010957:Plasmids; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D012965:Sodium Chloride / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D000890:Anti-Infective Agents; D017920:Antiporters; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C114619:NorM protein, bacteria; D011994:Recombinant Proteins; C491958:mdtK protein, E coli; D012965:Sodium Chloride; D004996:Ethidium; D009643:Norfloxacin