title: Gene cloning and characterization of MdeA, a novel multidrug efflux pump in Streptococcus mutans.
abstract: Multidrug resistance, especially multidrug efflux mechanisms that extrude structurally unrelated cytotoxic compounds from the cell by multidrug transporters, is a serious problem and one of the main reasons for the failure of therapeutic treatment of infections by pathogenic microorganisms as well as of cancer cells. Streptococcus mutans is considered one of the primary causative agents of dental caries and periodontal disease, which comprise the most common oral diseases. A fragment of chromosomal DNA from S. mutans KCTC3065 was cloned using Escherichia coli KAM32 as host cells lacking major multidrug efflux pumps. Although E. coli KAM32 cells were very sensitive to many antimicrobial agents, the transformed cells harboring a recombinant plasmid became resistant to several structurally unrelated antimicrobial agents such as tetracycline, kanamycin, rhodamin 6G, ampicillin, acriflavine, ethidium bromide, and tetraphenylphosphonium chloride. This suggested that the cloned DNA fragment carries a gene encoding a multidrug efflux pump. Among 49 of the multidrug-resistant transformants, we report the functional gene cloning and characterization of the function of one multidrug efflux pump, namely MdeA from S. mutans, which was expressed in E. coli KAM32. Judging from the structural and biochemical properties, we concluded that MdeA is the first cloned and characterized multidrug efflux pump using the proton motive force as the energy for efflux drugs.
authors: Department of Life Science and Biotechnology, Dongeui University, Busan 614-714, Korea.
authors: Do Kyun
authors: DK
authors: Kim
authors: Kyoung Hoon
authors: KH
authors: Kim
authors: Eun Ji
authors: EJ
authors: Cho
authors: Seoung-Je
authors: SJ
authors: Joo
authors: Jung-Min
authors: JM
authors: Chung
authors: Byoung Yil
authors: BY
authors: Son
authors: Jong Hwa
authors: JH
authors: Yum
authors: Young-Man
authors: YM
authors: Kim
authors: Hyun-Ju
authors: HJ
authors: Kwon
authors: Byung-Woo
authors: BW
authors: Kim
authors: Tae Hoon
authors: TH
authors: Kim
authors: Eun-Woo
authors: EW
authors: Lee
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D001693:Biological Transport, Active; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D007364:Intercalating Agents / Q000378:metabolism / Q000494:pharmacology; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D009861:Onium Compounds / Q000378:metabolism / Q000494:pharmacology; D009943:Organophosphorus Compounds / Q000378:metabolism / Q000494:pharmacology; D018892:Proton-Motive Force; D013295:Streptococcus mutans / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D007364:Intercalating Agents; D026901:Membrane Transport Proteins; D009861:Onium Compounds; D009943:Organophosphorus Compounds; C013289:tetraphenylphosphonium