Vacuuming the Periplasm

Lomovskaya, Olga; Totrov, Maxim

doi:10.1128/jb.187.6.1879-1883.2005

Cited by 37 publications

(21 citation statements)

References 41 publications

(37 reference statements)

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“…They form protein complexes with a trimeric outer membrane factor OMF (Koronakis et al 2000;) and a bridging periplasmic adapter protein (Akama et al 2004;Andersen et al 2001;Higgins et al 2004) of the MFP family. This protein complex is supposed to ''vacuum-clean'' the periplasma and interior of the cytoplasmic membrane by export of toxic substances to the outside (Lomovskaya and Totrov 2005). The RND proteins drives this process as a kind of peristaltic pump (Dastidar et al 2007;Murakami et al 2006), which is driven by the proton-motive force (Goldberg et al 1999).…”

Section: Overviewmentioning

confidence: 99%

Cupriavidus metallidurans: evolution of a metal-resistant bacterium

Rozycki

Nies

2008

Antonie van Leeuwenhoek

155

115

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Cupriavidus metallidurans CH34 has gained increasing interest as a model organism for heavy metal detoxification and for biotechnological purposes. Resistance of this bacterium to transition metal cations is predominantly based on metal resistance determinants that contain genes for RND (resistance, nodulation, and cell division protein family) proteins. These are part of transenvelope protein complexes, which seem to detoxify the periplasm by export of toxic metal cations from the periplasm to the outside. Strain CH34 contains 12 predicted RND proteins belonging to a protein family of heavy metal exporters. Together with many efflux systems that detoxify the cytoplasm, regulators and possible metal-binding proteins, RND proteins mediate an efficient defense against transition metal cations. To shed some light into the origin of genes encoding these proteins, the genomes of C. metallidurans CH34 and six related proteobacteria were investigated for occurrence of orthologous and paralogous proteins involved in metal resistance. Strain CH34 was not much different from the other six bacteria when the total content of transport proteins was compared but CH34 had significantly more putative transition metal transport systems than the other bacteria. The genes for these systems are located on its chromosome 2 but especially on plasmids pMOL28 and pMOL30. Cobalt-nickel and chromate resistance determinants located on plasmid pMOL28 evolved by gene duplication and horizontal gene transfer events, leading to a better adaptation of strain CH34 to serpentine-like soils. The czc cobalt-zinc-cadmium resistance determinant, located on plasmid pMOL30 in addition copper, lead and mercury resistance determinants, arose by duplication of a czcICAB core determinant on chromosome 2, plus addition of the czcN gene upstream and the genes czcD, czcRS, czcE downstream of czcICBA. C. metallidurans apparently evolved metal resistance by horizontal acquisition and by duplication of genes for transition metal efflux, mostly on the two plasmids, and decreased the number of uptake systems for those metals.

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Section: Overviewmentioning

confidence: 99%

Cupriavidus metallidurans: evolution of a metal-resistant bacterium

Rozycki

Nies

2008

Antonie van Leeuwenhoek

155

115

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“…Although at the time of this writing no agents are available for inhibition of type C ␤-lactamases, a variety of agents have been identified as having the potential to inhibit overexpressed efflux pumps of Gram-negative bacteria [10]. However, although some of these inhibitors of efflux pumps affect the function of the pump itself [efflux pump inhibitors (EPIs)] [11,12], there is now evidence that some EPIs may have an effect on regulatory genes involved in the control of efflux expression and genes that code for transporters [13,14]. Because of this, assessment of EPIs must also include their potential genetic actions.…”

Section: Introductionmentioning

confidence: 99%

Physiological characterisation of the efflux pump system of antibiotic-susceptible and multidrug-resistant Enterobacter aerogenes

Martins

Spengler

Martins

et al. 2010

International Journal of Antimicrobial Agents

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Enterobacter aerogenes predominates amongst Enterobacteriaceae species that are increasingly reported as producers of extended-spectrum beta-lactamases. Although this mechanism of resistance to beta-lactams is important, other mechanisms bestowing a multidrug-resistant (MDR) phenotype in this species are now well documented. Amongst these mechanisms is the overexpression of efflux pumps that extrude structurally unrelated antibiotics prior to their reaching their targets. Interestingly, although knowledge of the genetic background behind efflux pumps is rapidly advancing, few studies assess the physiological nature of the overall efflux pump system of this, or for that matter any other, bacterium. The study reported here evaluates physiologically the efflux pump system of an E. aerogenes ATCC reference as well as two strains whose MDR phenotypes are mediated by overexpressed efflux pumps. The activities of the efflux pumps in these strains are modulated by pH and glucose, although the effects of the latter are essentially restricted to pH 8, suggesting the presence of two general efflux pump systems, i.e. proton-motive force-dependent and ABC transporter types, respectively.

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“…Because P-glycoprotein is perhaps the best-studied efflux pump and has offered important insights into the mechanism of bacterial pumps (see references 8, 290, 419, 448, and 539 for a review), we will periodically refer briefly to work on this eukaryotic system. Efflux systems are now thought to play an important role in bacterial drug resistance (278,288,372). Whereas some efflux pumps are selective for a given substrate, many transporters are able to extrude a plethora of structurally unrelated drugs, conferring a multidrug resistance (MDR) phenotype (263,278).…”

Section: Drug Efflux Pumps In Bacteriamentioning

confidence: 99%

Structure, Function, and Evolution of Bacterial ATP-Binding Cassette Systems

Davidson

Dassa

Orelle

et al. 2008

Microbiol Mol Biol Rev

1,185

1,137

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SUMMARY ATP-binding cassette (ABC) systems are universally distributed among living organisms and function in many different aspects of bacterial physiology. ABC transporters are best known for their role in the import of essential nutrients and the export of toxic molecules, but they can also mediate the transport of many other physiological substrates. In a classical transport reaction, two highly conserved ATP-binding domains or subunits couple the binding/hydrolysis of ATP to the translocation of particular substrates across the membrane, through interactions with membrane-spanning domains of the transporter. Variations on this basic theme involve soluble ABC ATP-binding proteins that couple ATP hydrolysis to nontransport processes, such as DNA repair and gene expression regulation. Insights into the structure, function, and mechanism of action of bacterial ABC proteins are reported, based on phylogenetic comparisons as well as classic biochemical and genetic approaches. The availability of an increasing number of high-resolution structures has provided a valuable framework for interpretation of recent studies, and realistic models have been proposed to explain how these fascinating molecular machines use complex dynamic processes to fulfill their numerous biological functions. These advances are also important for elucidating the mechanism of action of eukaryotic ABC proteins, because functional defects in many of them are responsible for severe human inherited diseases.

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Vacuuming the Periplasm

Cited by 37 publications

References 41 publications

Cupriavidus metallidurans: evolution of a metal-resistant bacterium

Cupriavidus metallidurans: evolution of a metal-resistant bacterium

Physiological characterisation of the efflux pump system of antibiotic-susceptible and multidrug-resistant Enterobacter aerogenes

Structure, Function, and Evolution of Bacterial ATP-Binding Cassette Systems

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