Na+-coupled versus H+-coupled energy transduction in bacteria

Lolkema, Juke S.; Speelmans, Gea; Konings, Wil N.

doi:10.1016/0005-2728(94)90113-9

Cited by 49 publications

(29 citation statements)

References 17 publications

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“…The protein also folds in 12 TMSs, but in contrast to what is observed for many other secondary carriers, the C-terminal half is characterized by large periplasmic and short cytoplasmic loops. Also, in this part of the molecule, von Heynes "positive inside rule" is not very apparent (19). The hydropathy profile of the primary sequences is highly conserved in the 2-hydroxycarboxylate transporter family, and similar models are predicted for CitP and MleP (13).…”

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confidence: 74%

Membrane Topology of the Sodium Ion-dependent Citrate Carrier of Klebsiella pneumoniae

Geest

Lolkema

1996

Journal of Biological Chemistry

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The predicted secondary structure model of the sodium ion-dependent citrate carrier of Klebsiella pneumoniae (CitS) presents the 12-transmembrane helix motif observed for many secondary transporters. Biochemical evidence presented in this paper is not consistent with this model. N-terminal and C-terminal fusions of CitS with the biotin acceptor domain of the oxaloacetate decarboxylase of K. pneumoniae catalyze citrate transport, showing the correct folding of the CitS part of the fusion proteins in the membrane. Proteolysis experiments with these fusion proteins revealed that the N terminus of CitS is located in the cytoplasm, while the C terminus faces the periplasm. The membrane topology was studied further by constructing a set of 20 different fusions of N-terminal fragments of the citrate transporter with the reporter enzyme alkaline phosphatase (CitS-PhoA fusions). Most fusion points were selected in hydrophilic areas flanking the putative transmembrane-spanning domains in CitS that are predicted from the hydropathy profile of the primary sequence. The alkaline phosphatase activities of cells expressing the CitS-PhoA fusions suggest that the polypeptide traverses the membrane nine times and that the C-terminal half of the protein is characterized by two large hydrophobic periplasmic loops and two large hydrophilic cytoplasmic loops.CitS belongs to the family of the 2-hydroxycarboxylate transporters in which also the citrate carriers, CitPs, of lactic acid bacteria and the malate transporter, MleP, of Lactococcus lactis are found. Since the hydrophobicity profile of CitS is very similar to the hydrophobicity profiles of CitP and MleP, it is most likely that the new structural motif of nine transmembrane segments is shared within this new transporter family.Bacterial secondary solute transporters use the free energy stored in electrochemical gradients of H ϩ and/or Na ϩ to drive the uptake of solutes by coupling the translocation of solute and cation(s) across the membrane. In Klebsiella pneumoniae a unique Na ϩ -dependent citrate carrier (CitS) is induced upon anaerobic growth on citrate (1). The gene coding for the transporter has been cloned and sequenced (2, 3), and the enzyme has been characterized and purified to homogeneity after expression in Escherichia coli. Studies with whole cells of E. coli expressing CitS and with membrane vesicles prepared from these cells have demonstrated that CitS obligatorily couples the translocation of the divalent citrate anion (Hcit 2Ϫ ) to the translocation of two sodium ions and one proton (4, 5). More recent studies with purified CitS (6) reconstituted in proteoliposomes have raised some doubt about the electrogenic nature of the translocation catalyzed by the transporter, and it was concluded that one of the two Na ϩ ions recycle during the translocation of citrate (7).The citS gene encodes a highly hydrophobic protein with a predicted molecular mass of 47,531 Da. The gene is homologous to the genes coding for the citrate carriers of lactic acid bacteria, CitPs (8, ...

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confidence: 74%

Membrane Topology of the Sodium Ion-dependent Citrate Carrier of Klebsiella pneumoniae

Geest

Lolkema

1996

Journal of Biological Chemistry

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“…Most of the environments of alkaliphilic micro-organisms have high Na + concentrations. The function of this ion in neutrophiles (Lolkema et al, 1994), as well as alkaliphiles (Krulwich & Guffanti, 1989 ;Krulwich et al, 1990) and some extremophiles (Speelmans et al, 1995), is either as a coupling ion for energy transduction or in pH homeostasis. We have demonstrated previously that Na + ions play a crucial role in the energy transduction of strain LBS3 T (Prowe et al, 1996).…”

Section: Salt Tolerancementioning

confidence: 99%

Anaerobranca gottschalkii sp. nov., a novel thermoalkaliphilic bacterium that grows anaerobically at high pH and temperature.

Prowe¹,

Antranikian²

2001

International Journal of Systematic and Evolutionary Microbiology

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A novel thermoalkaliphilic, obligately anaerobic bacterium was isolated from a humid soil sample of a hot inlet of Lake Bogoria, Kenya. The newly isolated strain grows optimally at pH 9 5 and 50-55 SC and its growth range is pH 6 0-10 5 and 30-65 SC. Unlike the already known thermoalkaliphiles, the strain grows heterotrophically on a variety of mono-and polysaccharides (glucose, ribose, mannose, fructose, sucrose, maltose, starch, pullulan, xylan and cellulose) and on proteinaceous substrates such as yeast extract, peptone and tryptone. No dissimilatory sulfate reduction was observed, whereas thiosulfate was found to enhance growth when glucose or starch were used as substrates. Under optimal conditions, the doubling time is 48 min. Sodium ions are necessary for growth, with an optimal concentration of 230 mM (1 % NaCl, w/v) at pH 9 5. The rod-shaped cells are motile in the exponential growth phase under optimal growth conditions. Despite the Gram-negative staining and negative KOH assay, the strain is a Gram-positive organism, having an atypically thin cell wall. A sheath-like structure occurs at the cell separation area and parts of a surface layer-like structure were also observed. Based on physiological properties and molecular biological analysis, the strain falls within the radiation of the clostridia and represents a new species of Anaerobranca within the Clostridium/Bacillus subphylum of the Gram-positive bacteria. Strain LBS3 T (l DSM 13577 T ) is named Anaerobranca gottschalkii sp. nov. and is designated as the type strain.

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“…A large number of diverse bacterial species, including pathogens, use sodium as a chemiosmotic coupling ion in addition to, or even instead of, protons (2)(3)(4)(5). The sodium motive force (SMF) may be generated either by primary sodium pumps, such as Na ϩ -translocating NADH:ubiquinone oxidoreductases (NQR), or by secondary sodium pumps, such as Na ϩ /H ϩ antiporters, that are energized by the proton motive force (PMF).…”

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confidence: 99%

Na ⁺ /H ⁺ Antiport Is Essential for Yersinia pestis Virulence

et al. 2013

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e Na؉ /H ؉ antiporters are ubiquitous membrane proteins that play a central role in the ion homeostasis of cells. In this study, we examined the possible role of Na ؉ /H ؉ antiport in Yersinia pestis virulence and found that Y. pestis strains lacking the major Na ؉ /H ؉ antiporters, NhaA and NhaB, are completely attenuated in an in vivo model of plague. The Y. pestis derivative strain lacking the nhaA and nhaB genes showed markedly decreased survival in blood and blood serum ex vivo. Complementation of either nhaA or nhaB in trans restored the survival of the Y. pestis nhaA nhaB double deletion mutant in blood. The nhaA nhaB double deletion mutant also showed inhibited growth in an artificial serum medium, Opti-MEM, and a rich LB-based medium with Na ؉ levels and pH values similar to those for blood. Taken together, these data strongly suggest that intact Na ؉ /H ؉ antiport is indispensable for the survival of Y. pestis in the bloodstreams of infected animals and thus might be regarded as a promising noncanonical drug target for infections caused by Y. pestis and possibly for those caused by other blood-borne bacterial pathogens.

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Na+-coupled versus H+-coupled energy transduction in bacteria

Cited by 49 publications

References 17 publications

Membrane Topology of the Sodium Ion-dependent Citrate Carrier of Klebsiella pneumoniae

Membrane Topology of the Sodium Ion-dependent Citrate Carrier of Klebsiella pneumoniae

Anaerobranca gottschalkii sp. nov., a novel thermoalkaliphilic bacterium that grows anaerobically at high pH and temperature.

Na ⁺ /H ⁺ Antiport Is Essential for Yersinia pestis Virulence

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Na+-coupled versus H+-coupled energy transduction in bacteria

Cited by 49 publications

References 17 publications

Membrane Topology of the Sodium Ion-dependent Citrate Carrier of Klebsiella pneumoniae

Membrane Topology of the Sodium Ion-dependent Citrate Carrier of Klebsiella pneumoniae

Anaerobranca gottschalkii sp. nov., a novel thermoalkaliphilic bacterium that grows anaerobically at high pH and temperature.

Na + /H + Antiport Is Essential for Yersinia pestis Virulence

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Na ⁺ /H ⁺ Antiport Is Essential for Yersinia pestis Virulence