scholarly journals NorM of Vibrio parahaemolyticus Is an Na+-Driven Multidrug Efflux Pump

2000 ◽  
Vol 182 (23) ◽  
pp. 6694-6697 ◽  
Author(s):  
Yuji Morita ◽  
Atsuko Kataoka ◽  
Sumiko Shiota ◽  
Tohru Mizushima ◽  
Tomofusa Tsuchiya
Keyword(s):  
Vibrio Parahaemolyticus ◽  
Efflux Pump ◽  
Sequence Similarity ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Significant Sequence Similarity ◽  
Wide Range ◽  
New Type ◽  
Biological World ◽  
Energy Dependent

ABSTRACT NorM of Vibrio parahaemolyticusapparently is a new type of multidrug efflux protein, with no significant sequence similarity to any known transport proteins. Based on the following experimental results, we conclude that NorM is an Na+-driven Na+/drug antiporter. (i) Energy-dependent ethidium efflux from cells possessing NorM was observed in the presence of Na+ but not of K+. (ii) An artificially imposed, inwardly directed Na+gradient elicited ethidium efflux from cells. (iii) The addition of ethidium to cells loaded with Na+ elicited Na+efflux. Thus, NorM is an Na+/drug antiporting multidrug efflux pump, the first to be found in the biological world. Judging from the similarity of the NorM sequence to those of putative proteins in sequence databases, it seems that Na+/drug antiporters are present not only in V. parahaemolyticus but also in a wide range of other organisms.

NorM, a Putative Multidrug Efflux Protein, of Vibrio parahaemolyticus and Its Homolog in Escherichia coli

1998 ◽  
Vol 42 (7) ◽  
pp. 1778-1782 ◽  
Author(s):  
Yuji Morita ◽  
Kazuyo Kodama ◽  
Sumiko Shiota ◽  
Tomoyuki Mine ◽  
Atsuko Kataoka ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Vibrio Parahaemolyticus ◽  
Sequence Similarity ◽  
Multidrug Efflux ◽  
Chromosomal Dna ◽  
Efflux System ◽  
Significant Sequence Similarity ◽  
E Coli ◽  
Energy Dependent ◽  
Multidrug Efflux System

ABSTRACT We found that cells of Vibrio parahaemolyticus possess an energy-dependent efflux system for norfloxacin. We cloned a gene for a putative norfloxacin efflux protein from the chromosomal DNA ofV. parahaemolyticus by using an Escherichia coli mutant lacking the major multidrug efflux system AcrAB as the host and sequenced the gene (norM). Cells of E. coli transformed with a plasmid carrying the norMgene showed elevated energy-dependent efflux of norfloxacin. The transformants showed elevated resistance not only to norfloxacin and ciprofloxacin but also to the structurally unrelated compounds ethidium, kanamycin, and streptomycin. These results suggest that this is a multidrug efflux system. The hydropathy pattern of the deduced amino acid sequence of NorM suggested the presence of 12 transmembrane domains. The deduced primary structure of NorM showed 57% identity and 88% similarity with that of a hypothetical E. coli membrane protein, YdhE. No reported drug efflux protein in the sequence databases showed significant sequence similarity with NorM. Thus, NorM seems to be a novel type of multidrug efflux protein. We cloned the ydhE gene from E. coli. Cells ofE. coli transformed with the cloned ydhE gene showed elevated resistance to norfloxacin, ciprofloxacin, acriflavine, and tetraphenylphosphonium ion, but not to ethidium, when MICs were measured. Thus, it seems that NorM and YdhE differ somehow in substrate specificity.

scholarly journals Role of VltAB, an ABC Transporter Complex, in Viologen Tolerance inStreptococcus mutans

2011 ◽  
Vol 55 (4) ◽  
pp. 1460-1469 ◽  
Author(s):  
Saswati Biswas ◽  
Indranil Biswas
Keyword(s):  
Abc Transporter ◽  
Efflux Pump ◽  
Ammonium Compound ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Antibiotic Resistance Marker ◽  
Gram Positive ◽  
Wide Range ◽  
Insertion Mutants

ABSTRACTStreptococcus mutans, a Gram-positive organism, is the primary causative agent in the formation of dental caries in humans. To persist in the oral cavity,S. mutansmust be able to tolerate rapid environmental fluctuations and exposure to various toxic chemicals. However, the mechanisms underlying the ability of this cariogenic pathogen to survive and proliferate under harsh environmental conditions remain largely unknown. Here, we wanted to understand the mechanisms by whichS. mutanswithstands exposure to methyl viologen (MV), a quaternary ammonium compound (QAC) that generates superoxide radicals in the cell. To elucidate the essential genes for MV tolerance, screening of ∼3,500 mutants generated by ISS1mutagenesis, revealed 15 MV-sensitive mutants. Among them, five and four independent insertions had occurred in SMU.905 and SMU.906 genes, respectively. These two genes are appeared to be organized in an operon and encode a putative ABC transporter complex; we designated the genes asvltAandvltB, forviologentransporter. To verify our results,vltAwas deleted by using an antibiotic resistance marker; the mutant was just as sensitive to MV as the ISS1insertion mutants. Furthermore,vltAandvltBmutants were also sensitive to other viologen compounds such as benzyl and ethyl viologens. Complementation assays were also carried out to confirm the role of VltA and VltB in viologen tolerance. Sensitivity to various drugs, including a wide range of QACs, was evaluated. It appears that a functional VltA is also required for full resistance toward acriflavin, ethidium bromide, and safranin; all are well-known QACs. These results indicate that VltA/B constitute a heterodimeric multidrug efflux pump of the ABC family. BLAST-P analysis suggests that homologs of VltA/B are widely present in streptococci, enterococci, and other important Gram-positive pathogens.

scholarly journals An H+-Coupled Multidrug Efflux Pump, PmpM, a Member of the MATE Family of Transporters, from Pseudomonas aeruginosa

2004 ◽  
Vol 186 (1) ◽  
pp. 262-265 ◽  
Author(s):  
Gui-Xin He ◽  
Teruo Kuroda ◽  
Takehiko Mima ◽  
Yuji Morita ◽  
Tohru Mizushima ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Host Cells ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
E Coli ◽  
Tetraphenylphosphonium Chloride ◽  
Pcr Method ◽  
Energy Dependent

ABSTRACT We cloned the gene PA1361 (we designated the gene pmpM), which seemed to encode a multidrug efflux pump belonging to the MATE family, of Pseudomonas aeruginosa by the PCR method using the drug-hypersensitive Escherichia coli KAM32 strain as a host. Cells of E. coli possessing the pmpM gene showed elevated resistance to several antimicrobial agents. We observed energy-dependent efflux of ethidium from cells possessing the pmpM gene. We found that PmpM is an H+-drug antiporter, and this finding is the first reported case of an H+-coupled efflux pump in the MATE family. Disruption and reintroduction of the pmpM gene in P. aeruginosa revealed that PmpM is functional and that benzalkonium chloride, fluoroquinolones, ethidium bromide, acriflavine, and tetraphenylphosphonium chloride are substrates for PmpM in this microorganism.

scholarly journals Phylogenetic and functional characterisation of the Haemophilus influenzae multidrug efflux pump AcrB

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Martijn Zwama ◽  
Akihito Yamaguchi ◽  
Kunihiko Nishino
Keyword(s):  
Haemophilus Influenzae ◽  
Efflux Pump ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Efflux Pump Inhibitor ◽  
Over Expression ◽  
Multidrug Efflux Pumps ◽  
Functional Characterisation ◽  
Outer Membrane Porin ◽  
Wide Range

Abstract Multidrug resistance in Gram-negative bacteria can arise by the over-expression of multidrug efflux pumps, which can extrude a wide range of antibiotics. Here we describe the ancestral Haemophilus influenzae efflux pump AcrB (AcrB-Hi). We performed a phylogenetic analysis of hundreds of RND-type transporters. We found that AcrB-Hi is a relatively ancient efflux pump, which nonetheless can export the same range of antibiotics as its evolved colleague from Escherichia coli. AcrB-Hi was not inhibited by the efflux pump inhibitor ABI-PP, and could export bile salts weakly. This points to an environmental adaptation of RND transporters. We also explain the sensitivity of H. influenzae cells to β-lactams and novobiocin by the outer membrane porin OmpP2. This porin counterbalances the AcrB-Hi efflux by leaking the drugs back into the cells. We hypothesise that multidrug recognition by RND-type pumps is not an evolutionarily acquired ability, and has been present since ancient promiscuous transporters.

scholarly journals Functional Characterization of Brucella melitensis NorMI, an Efflux Pump Belonging to the Multidrug and Toxic Compound Extrusion Family

2002 ◽  
Vol 46 (9) ◽  
pp. 3050-3053 ◽  
Author(s):  
Martine Braibant ◽  
Laurence Guilloteau ◽  
Michel S. Zygmunt
Keyword(s):  
Vibrio Parahaemolyticus ◽  
Efflux Pump ◽  
Brucella Melitensis ◽  
Functional Characterization ◽  
Multidrug Efflux ◽  
Toxic Compound ◽  
Efflux Mechanism ◽  
M Genome ◽  
Energy Dependent

ABSTRACT Two putative proteins (NorMI and NorMII) similar to the multidrug efflux protein NorM of Vibrio parahaemolyticus are encoded by the Brucella melitensis 16 M genome. We show that a drug-hypersusceptible Escherichia coli strain overexpressing NorMI displays increased resistance to norfloxacin, ciprofloxacin, gentamicin, tetraphenylphosphonium ion, acriflavine, and berberine. This elevated resistance was proven to be mediated by an energy-dependent efflux mechanism. NorMI belongs to the multidrug and toxic compound extrusion family and is the first multidrug efflux protein identified in Brucella spp.

scholarly journals Multidrug Efflux Pump MdtBC of Escherichia coli Is Active Only as a B2C Heterotrimer

2009 ◽  
Vol 192 (5) ◽  
pp. 1377-1386 ◽  
Author(s):  
Hong-Suk Kim ◽  
Daniel Nagore ◽  
Hiroshi Nikaido
Keyword(s):  
Escherichia Coli ◽  
Efflux Pump ◽  
Proton Translocation ◽  
Drug Binding ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Wide Range ◽  
Resistance Nodulation Division ◽  
Covalently Linked ◽  
Made In

ABSTRACT RND (resistance-nodulation-division) family transporters in Gram-negative bacteria frequently pump out a wide range of inhibitors and often contribute to multidrug resistance to antibiotics and biocides. An archetypal RND pump of Escherichia coli, AcrB, is known to exist as a homotrimer, and this construction is essential for drug pumping through the functionally rotating mechanism. MdtBC, however, appears different because two pump genes coexist within a single operon, and genetic deletion data suggest that both pumps must be expressed in order for the drug efflux to occur. We have expressed the corresponding genes, with one of them in a His-tagged form. Copurification of MdtB and MdtC under these conditions showed that they form a complex, with an average stoichiometry of 2:1. Unequivocal evidence that only the trimer containing two B protomers and one C protomer is active was obtained by expressing all possible combinations of B and C in covalently linked forms. Finally, conversion into alanine of the residues, known to form a proton translocation pathway in AcrB, inactivated transport only when made in MdtB, not when made in MdtC, a result suggesting that MdtC plays a different role not directly involved in drug binding and extrusion.

scholarly journals The eefABC Multidrug Efflux Pump Operon Is Repressed by H-NS in Enterobacter aerogenes

2005 ◽  
Vol 187 (11) ◽  
pp. 3894-3897 ◽  
Author(s):  
Muriel Masi ◽  
Jean-Marie Pagès ◽  
Claude Villard ◽  
Elizabeth Pradel
Keyword(s):  
Escherichia Coli ◽  
Efflux Pump ◽  
Enterobacter Aerogenes ◽  
Dominant Negative ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
E Coli ◽  
Laboratory Conditions ◽  
Wide Range

ABSTRACT The Enterobacter aerogenes eefABC locus, which encodes a tripartite efflux pump, was cloned by complementation of an Escherichia coli tolC mutant. E. aerogenes ΔacrA expressing EefABC became less susceptible to a wide range of antibiotics. Data from eef::lacZ fusions showed that eefABC was not transcribed in the various laboratory conditions tested. However, increased transcription from Peef was observed in an E. coli hns mutant. In addition, EefA was detected in E. aerogenes expressing a dominant negative E. coli hns allele.

The pseudo-atomic structure of an RND-type tripartite multidrug efflux pump

2015 ◽  
Vol 396 (9-10) ◽  
pp. 1073-1082 ◽  
Author(s):  
Dijun Du ◽  
Jarrod Voss ◽  
Zhao Wang ◽  
Wah Chiu ◽  
Ben F. Luisi
Keyword(s):  
Antimicrobial Agents ◽  
Transmembrane Domain ◽  
Efflux Pump ◽  
Cell Envelope ◽  
Toxic Substances ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Transporter Family ◽  
Wide Range ◽  
Rnd Transporter

Abstract Microorganisms encode several classes of transmembrane molecular pumps that can expel a wide range of chemically distinct toxic substances. These machines contribute to the capacity of the organisms to withstand harsh environments, and they help to confer resistance against clinical antimicrobial agents. In Gram-negative bacteria, some of the pumps comprise tripartite assemblies that actively transport drugs and other harmful compounds across the cell envelope. We describe recent structural and functional data that have provided insights into the architecture and transport mechanism of the AcrA-AcrB-TolC pump of Escherichia coli. This multidrug efflux pump is powered by proton electrochemical gradients through the activity of AcrB, a member of the resistance/nodulation/cell division (RND) transporter family. Crystallographic data reveal how the small protein AcrZ binds to AcrB in a concave surface of the transmembrane domain, and we discuss how this interaction may affect the efflux activities of the transporter.

scholarly journals BpeAB-OprB, a Multidrug Efflux Pump in Burkholderia pseudomallei

2004 ◽  
Vol 48 (4) ◽  
pp. 1128-1135 ◽  
Author(s):  
Y. Y. Chan ◽  
T. M. C. Tan ◽  
Y. M. Ong ◽  
K. L. Chua
Keyword(s):  
Membrane Protein ◽  
Burkholderia Pseudomallei ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Efflux Pump Inhibitor ◽  
Membrane Fusion Protein ◽  
Wide Range ◽  
Inner Membrane Protein

ABSTRACT Burkholderia pseudomallei, the causative agent of melioidosis, is intrinsically resistant to a wide range of antimicrobial agents, including β-lactams, aminoglycosides, macrolides, and polymyxins. An operon, bpeR-bpeA-bpeB-oprB, which encodes a putative repressor, a membrane fusion protein, an inner membrane protein, and an outer membrane protein, respectively, of a multidrug efflux pump of the resistance-nodulation-division family was identified in B. pseudomallei. The divergently transcribed bpeR gene encodes a putative repressor protein of the TetR family which probably regulates the expression of the bpeAB-oprB gene cluster. Comparison of the MICs and minimal bactericidal concentrations of antimicrobials for bpeAB deletion mutant KHWΔbpeAB and its isogenic wild-type parent, KHW, showed that the B. pseudomallei BpeAB-OprB pump is responsible for the efflux of the aminoglycosides gentamicin and streptomycin, the macrolide erythromycin, and the dye acriflavine. Antibiotic efflux by the BpeAB-OprB pump was dependent on a proton gradient and differs from that by the AmrAB-OprA pump in that it did not efflux the aminoglycoside spectinomycin or the macrolide clarithromycin. The broad-spectrum efflux pump inhibitor MC-207,110 did not potentiate the effectiveness of the antimicrobials erythromycin and streptomycin in B. pseudomallei.

scholarly journals A Two-Component Multidrug Efflux Pump, EbrAB, in Bacillus subtilis

2000 ◽  
Vol 182 (8) ◽  
pp. 2307-2310 ◽  
Author(s):  
Yoko Masaoka ◽  
Yasuhiro Ueno ◽  
Yuji Morita ◽  
Teruo Kuroda ◽  
Tohru Mizushima ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Efflux Pump ◽  
Sequence Similarity ◽  
Multidrug Efflux ◽  
Chromosomal Dna ◽  
Multidrug Efflux Pump ◽  
High Sequence Similarity ◽  
Small Multidrug Resistance ◽  
Multidrug Efflux Pumps ◽  
Safranin O

ABSTRACT Genes (ebrAB) responsible for ethidium resistance were cloned from chromosomal DNA of Bacillus subtilis ATCC 9372. The recombinant plasmid produced elevated resistance against ethidium bromide, acriflavine, pyronine Y, and safranin O not only inEscherichia coli but also in B. subtilis. It also caused an elevated energy-dependent efflux of ethidium in E. coli. EbrA and EbrB showed high sequence similarity with members of the small multidrug resistance (SMR) family of multidrug efflux pumps. Neither ebrA nor ebrB was sufficient for resistance, but introduction of the two genes carried on different plasmids conferred drug resistance. Thus, both EbrA and EbrB appear to be necessary for activity of the multidrug efflux pump. In known members of the SMR family, only one gene produces drug efflux. Thus, EbrAB is a novel SMR family multidrug efflux pump with two components.

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