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Holyoake LV, Poole RK, Shepherd M. The CydDC Family of Transporters and Their Roles in Oxidase Assembly and Homeostasis. Adv Microb Physiol 2015. [PMID: 26210105 DOI: 10.1016/bs.ampbs.2015.04.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The CydDC complex of Escherichia coli is a heterodimeric ATP-binding cassette type transporter (ABC transporter) that exports the thiol-containing redox-active molecules cysteine and glutathione. These reductants are thought to aid redox homeostasis of the periplasm, permitting correct disulphide folding of periplasmic and secreted proteins. Loss of CydDC results in the periplasm becoming more oxidising and abolishes the assembly of functional bd-type respiratory oxidases that couple the oxidation of ubiquinol to the reduction of oxygen to water. In addition, CydDC-mediated redox control is important for haem ligation during cytochrome c assembly. Given the diverse roles for CydDC in redox homeostasis, respiratory metabolism and the maturation of virulence factors, this ABC transporter is an intriguing system for researchers interested in both the physiology of redox perturbations and the role of low-molecular-weight thiols during infection.
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2
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Yoshimune K, Morimoto H, Hirano Y, Sakamoto J, Matsuyama H, Yumoto I. The obligate alkaliphile Bacillus clarkii K24-1U retains extruded protons at the beginning of respiration. J Bioenerg Biomembr 2010; 42:111-6. [PMID: 20306123 DOI: 10.1007/s10863-010-9278-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2009] [Accepted: 02/24/2010] [Indexed: 10/19/2022]
Abstract
Alkaliphiles grow under alkaline conditions that might be disadvantageous for the transmembrane pH gradient (Delta pH, outside acidic). In this study, the behaviors of extruded protons by the respiration of obligate alkaliphilic Bacillus clarkii K24-1U were investigated by comparison with those of neutralophilic Bacillus subtilis IAM 1026. Although whole-cell suspensions of both Bacillus species consumed oxygen immediately after the addition of air, there were lag times before the suspensions were acidified. Under alkaline conditions, the lag time for B. clarkii significantly increased, whereas that for B. subtilis decreased. In the presence of valinomycin or ETH-157, which disrupts the membrane electrical potential (Delta psi), the cell suspensions of both Bacillus species acidified immediately after the addition of air. Artificial electroneutral antiporters (nigericin and monensin) that eliminate the Delta pH exhibited no significant effect on the lag times of the two Bacillus species except that monensin increased the lag times of B. clarkii. The inhibition of ATPase and the Na(+) channel also exhibited little effects on the lag times. The increased lag time for B. clarkii may represent the Delta psi-dependent proton retention on the outer surface of the cytoplasmic membrane to generate a sufficient Delta pH under alkaline conditions.
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Affiliation(s)
- Kazuaki Yoshimune
- Research Institute of Genome-based Biofactory, Tsukisamu-Higashi, Toyohira-ku, Sapporo, Hokkaido, 062-8517, Japan.
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Tsueng G, Lam KS. A preliminary investigation on the growth requirement for monovalent cations, divalent cations and medium ionic strength of marine actinomycete Salinispora. Appl Microbiol Biotechnol 2010; 86:1525-34. [PMID: 20084507 DOI: 10.1007/s00253-009-2424-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Revised: 12/13/2009] [Accepted: 12/24/2009] [Indexed: 11/28/2022]
Abstract
In this paper, we report that three species of Salinispora, S. arenicola, S. tropica, and S. pacifica, require magnesium and calcium, for growth, with S. pacifica having the most stringent growth requirement for these ions. Interaction between these ions in supporting the growth of Salinispora was observed. We also demonstrated that the absolute requirement of sodium to support the growth of Salinispora has not been established as all three species of Salinispora can use either potassium or lithium to replace sodium to support maximum growth. While lithium can replace sodium to support maximum growth of Salinispora, it is more toxic to S. arenicola than S. tropica and S. pacifica, inhibiting the growth of S. arenicola at 189 mM but without effect on the growth of S. tropica and S. pacifica. Using both sodium chloride-based and lithium chloride-based media, we showed that Salinispora has a growth requirement for divalent ions, magnesium and calcium as well as growth requirement for ionic strength (8.29 to 15.2 mS/cm). S. arenicola has a lower growth requirement for ionic strength than S. tropica and S. pacifica.
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Affiliation(s)
- Ginger Tsueng
- Nereus Pharmaceuticals, Inc, 10480 Wateridge Circle, San Diego, CA, 92121, USA
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4
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Mulkidjanian AY, Dibrov P, Galperin MY. The past and present of sodium energetics: may the sodium-motive force be with you. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1777:985-92. [PMID: 18485887 DOI: 10.1016/j.bbabio.2008.04.028] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 04/18/2008] [Accepted: 04/18/2008] [Indexed: 10/22/2022]
Abstract
All living cells routinely expel Na(+) ions, maintaining lower concentration of Na(+) in the cytoplasm than in the surrounding milieu. In the vast majority of bacteria, as well as in mitochondria and chloroplasts, export of Na(+) occurs at the expense of the proton-motive force. Some bacteria, however, possess primary generators of the transmembrane electrochemical gradient of Na(+) (sodium-motive force). These primary Na(+) pumps have been traditionally seen as adaptations to high external pH or to high temperature. Subsequent studies revealed, however, the mechanisms for primary sodium pumping in a variety of non-extremophiles, such as marine bacteria and certain bacterial pathogens. Further, many alkaliphiles and hyperthermophiles were shown to rely on H(+), not Na(+), as the coupling ion. We review here the recent progress in understanding the role of sodium-motive force, including (i) the conclusion on evolutionary primacy of the sodium-motive force as energy intermediate, (ii) the mechanisms, evolutionary advantages and limitations of switching from Na(+) to H(+) as the coupling ion, and (iii) the possible reasons why certain pathogenic bacteria still rely on the sodium-motive force.
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Ascón-Cabrera M, Ascón-Reyes D, Lebeault J. Degradation activity of adhered and suspendedPseudomonascells cultured on 2,4,6-trichlorophenol, measured by indirect conductimetry. ACTA ACUST UNITED AC 2008. [DOI: 10.1111/j.1365-2672.1995.tb00945.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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6
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Yumoto I. Bioenergetics of alkaliphilic Bacillus spp. J Biosci Bioeng 2005; 93:342-53. [PMID: 16233213 DOI: 10.1016/s1389-1723(02)80066-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2002] [Accepted: 02/28/2002] [Indexed: 10/27/2022]
Abstract
Alkaliphilic microorganisms are widely distributed in nature. Among them, several aerobic alkaliphilic Bacillus spp. have been studied in terms of their mechanisms of physiological adaptation under an extremely alkaline condition. On the basis of chemiosmotic theories, neutrophiles produce H+ electrochemical potential (deltap), which is the sum of transmembrane pH gradient (deltapH) (alkaline, inside) and membrane potential (deltapsi) (negative, inside), for active transport of solutes, motility, and ATP synthesis. In the case of alkaliphiles, it seems that Mitchell's chemiosmotic theories alone cannot explain clearly their positive H+ electrochemical potential (deltap) across the membrane because these bacteria exhibit deltaph in a direction opposite to that in neutrophiles, which seems to be causing extensively negative to produce energy, theoretically. Nevertheless, it is reported that ATP synthesis is more rapid at high alkaline pH than at near neutral pH in the facultative alkaliphile Bacillus pseudofirmus OF4. The respiratory system of alkaliphilic microorganisms might have an important role in compensating the reversed transmembrane pH gradient by means of ATP synthesis. To understand the function of the respiratory system in alkaliphiles, several respiratory components in alkaliphilic Bacillus spp. were isolated and characterized. In these studies, respiratory components of alkaliphiles exhibiting several unique characteristics are identified. These characteristics may have an important role in obtaining energy in alkaline environments. Information obtained from bioenergetics studies of alkaliphiles will reveal new important findings on general energy coupling phenomena.
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Affiliation(s)
- Isao Yumoto
- Research Institute of Biological Resources, National Institute of Advanced Industrial Science and Technology, Tsukisamu-Higashi, Toyohira-ku, Sapporo 062-8517, Japan.
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7
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Häse CC, Fedorova ND, Galperin MY, Dibrov PA. Sodium ion cycle in bacterial pathogens: evidence from cross-genome comparisons. Microbiol Mol Biol Rev 2001; 65:353-70, table of contents. [PMID: 11528000 PMCID: PMC99031 DOI: 10.1128/mmbr.65.3.353-370.2001] [Citation(s) in RCA: 189] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Analysis of the bacterial genome sequences shows that many human and animal pathogens encode primary membrane Na+ pumps, Na+-transporting dicarboxylate decarboxylases or Na+ translocating NADH:ubiquinone oxidoreductase, and a number of Na+ -dependent permeases. This indicates that these bacteria can utilize Na+ as a coupling ion instead of or in addition to the H+ cycle. This capability to use a Na+ cycle might be an important virulence factor for such pathogens as Vibrio cholerae, Neisseria meningitidis, Salmonella enterica serovar Typhi, and Yersinia pestis. In Treponema pallidum, Chlamydia trachomatis, and Chlamydia pneumoniae, the Na+ gradient may well be the only energy source for secondary transport. A survey of preliminary genome sequences of Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, and Treponema denticola indicates that these oral pathogens also rely on the Na+ cycle for at least part of their energy metabolism. The possible roles of the Na+ cycling in the energy metabolism and pathogenicity of these organisms are reviewed. The recent discovery of an effective natural antibiotic, korormicin, targeted against the Na+ -translocating NADH:ubiquinone oxidoreductase, suggests a potential use of Na+ pumps as drug targets and/or vaccine candidates. The antimicrobial potential of other inhibitors of the Na+ cycle, such as monensin, Li+ and Ag+ ions, and amiloride derivatives, is discussed.
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Affiliation(s)
- C C Häse
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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Katz A, Pick U. Plasma membrane electron transport coupled to Na(+) extrusion in the halotolerant alga Dunaliella. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1504:423-31. [PMID: 11245805 DOI: 10.1016/s0005-2728(01)00157-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The halotolerant alga Dunaliella adapts to exceptionally high salinity and maintains low [Na(+)](in) at hypersaline solutions, suggesting that it possesses efficient mechanisms for regulating intracellular Na(+). In this work we examined the possibility that Na(+) export in Dunaliella is linked to a plasma membrane electron transport (redox) system. Na(+) extrusion was induced in Dunaliella cells by elevation of intracellular Na(+) with Na(+)-specific ionophores. Elevation of intracellular Na(+) was found to enhance the reduction of an extracellular electron acceptor ferricyanide (FeCN). The quinone analogs NQNO and dicumarol inhibited FeCN reduction and led to accumulation of Na(+) by inhibition of Na(+) extrusion. These inhibitors also diminished the plasma membrane potential in Dunaliella. Anaerobic conditions elevated, whereas FeCN partially decreased intracellular Na(+) content. Cellular NAD(P)H level decreased upon enhancement of plasma membrane electron transport. These results are consistent with the operation of an electrogenic NAD(P)H-driven redox system coupled to Na(+) extrusion in Dunaliella plasma membrane. We propose that redox-driven Na(+) extrusion and recycling in Dunaliella evolved as means of adaptation to hypersaline environments.
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Affiliation(s)
- A Katz
- Department of Biological Chemistry, The Weizmann Institute of Science, 76100, Rehovot, Israel.
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9
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Poole RK, Cook GM. Redundancy of aerobic respiratory chains in bacteria? Routes, reasons and regulation. Adv Microb Physiol 2001; 43:165-224. [PMID: 10907557 DOI: 10.1016/s0065-2911(00)43005-5] [Citation(s) in RCA: 185] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Bacteria are the most remarkable organisms in the biosphere, surviving and growing in environments that support no other life forms. Underlying this ability is a flexible metabolism controlled by a multitude of environmental sensors and regulators of gene expression. It is not surprising, therefore, that bacterial respiration is complex and highly adaptable: virtually all bacteria have multiple, branched pathways for electron transfer from numerous low-potential reductants to several terminal electron acceptors. Such pathways, particularly those involved in anaerobic respiration, may involve periplasmic components, but the respiratory apparatus is largely membrane-bound and organized such that electron flow is coupled to proton (or sodium ion) transport, generating a protonmotive force. It has long been supposed that the multiplicity of pathways serves to provide flexibility in the face of environmental stresses, but the existence of apparently redundant pathways for electrons to a single acceptor, say dioxygen, is harder to explain. Clues have come from studying the expression of oxidases in response to growth conditions, the phenotypes of mutants lacking one or more oxidases, and biochemical characterization of individual oxidases. Terminal oxidases that share the essential properties of substrate (cytochrome c or quinol) oxidation, dioxygen reduction and, in some cases, proton translocation, differ in subunit architecture and complement of redox centres. Perhaps more significantly, they differ in their affinities for oxidant and reductant, mode of regulation, and inhibitor sensitivity; these differences to some extent rationalize the presence of multiple oxidases. However, intriguing requirements for particular functions in certain physiological functions remain unexplained. For example, a large body of evidence demonstrates that cytochrome bd is essential for growth and survival under certain conditions. In this review, the physiological basis of the many phenotypes of Cyd-mutants is explored, particularly the requirement for this oxidase in diazotrophy, growth at low protonmotive force, survival in the stationary phase, and resistance to oxidative stress and Fe(III) chelators.
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Affiliation(s)
- R K Poole
- Krebs Institute for Biomolecular Research, University of Sheffield, UK
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Krebs W, Steuber J, Gemperli AC, Dimroth P. Na+ translocation by the NADH:ubiquinone oxidoreductase (complex I) from Klebsiella pneumoniae. Mol Microbiol 1999; 33:590-8. [PMID: 10417649 DOI: 10.1046/j.1365-2958.1999.01506.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Complex I is the site for electrons entering the respiratory chain and therefore of prime importance for the conservation of cell energy. It is generally accepted that the complex I-catalysed oxidation of NADH by ubiquinone is coupled specifically to proton translocation across the membrane. In variance to this view, we show here that complex I of Klebsiella pneumoniae operates as a primary Na+ pump. Membranes from Klebsiella pneumoniae catalysed Na+-stimulated electron transfer from NADH or deaminoNADH to ubiquinone-1 (0.1-0.2 micromol min-1 mg-1). Upon NADH or deaminoNADH oxidation, Na+ ions were transported into the lumen of inverted membrane vesicles. Rate and extent of Na+ transport were significantly enhanced by the uncoupler carbonylcyanide-m-chlorophenylhydrazone (CCCP) to values of approximately 0.2 micromol min-1 mg-1 protein. This characterizes the responsible enzyme as a primary Na+ pump. The uptake of sodium ions was severely inhibited by the complex I-specific inhibitor rotenone with deaminoNADH or NADH as substrate. N-terminal amino acid sequence analyses of the partially purified Na+-stimulated NADH:ubiquinone oxidoreductase from K. pneumoniae revealed that two polypeptides were highly similar to the NuoF and NuoG subunits from the H+-translocating NADH:ubiquinone oxidoreductases from enterobacteria.
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Affiliation(s)
- W Krebs
- Mikrobiologisches Institut der Eidgenössischen Technischen Hochschule, ETH-Zentrum, Schmelzbergstr. 7, CH-8092 Zürich, Switzerland
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11
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Skulachev VP. Bacterial energetics at high pH: what happens to the H+ cycle when the extracellular H+ concentration decreases? NOVARTIS FOUNDATION SYMPOSIUM 1999; 221:200-13; discussion 213-7. [PMID: 10207921 DOI: 10.1002/9780470515631.ch13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
A decrease in the extracellular H+ concentration creates difficulties for membrane-linked energetics in bacteria employing H+ as the coupling ion. At high extracellular pH (pHo), H+ ions pumped from the cell by, say, the respiratory chain, are immediately neutralized by the alkaline extracellular medium. Under such conditions, the only driving force that might compel outer H+ ions to return to cytosol and perform their function is the electric potential difference across the cytoplasmic membrane (delta psi). However, when delta pH in the opposite direction is equal to, e.g., 2 pH units (intracellular pH = 7.5 at pHo = 9.5), delta psi would be so high that the risk of membrane electric breakdown would increase. This is why some bacteria deal with high pH by, for example, replacing H+ by Na+ as the coupling ion rather than by increasing delta psi. It has been shown in several species of bacteria that the alkalinization of the growth medium induces primary Na+ pumps (e.g. Na(+)-motive respiratory chain enzymes and Na+ ATPase). Electrogenic Na+ efflux via these pumps produces an electrochemical Na+ potential difference (delta mu Na+) composed of delta psi and delta pNa+. delta mu Na+ can be used to perform various types of membrane-linked work. The delta psi constituent of delta mu Na+ may maintain electrophoretic influx of H+ such that the alkalinization of cytoplasm is prevented. The latter function may be supported by a mechanism based on the uphill influx of Cl- instead of Na+. This seems to be the case for alkaliphilic and halophilic Natronobacter pharaonis. There is an indication that not only Na+ but also Ca2+ may substitute for H+ in Gleobacter violaceus growing at high pH.
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Affiliation(s)
- V P Skulachev
- Department of Bioenergetics, A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia
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12
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Cook GM, Loder C, Søballe B, Stafford GP, Membrillo-Hernández J, Poole RK. A factor produced by Escherichia coli K-12 inhibits the growth of E. coli mutants defective in the cytochrome bd quinol oxidase complex: enterochelin rediscovered. MICROBIOLOGY (READING, ENGLAND) 1998; 144 ( Pt 12):3297-3308. [PMID: 9884221 DOI: 10.1099/00221287-144-12-3297] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Escherichia coli produces an extracellular factor that inhibits the aerobic growth of Cyd- mutants, defective in the synthesis or assembly of the cytochrome bd-type quinol oxidase. This paper shows that such a factor is the iron-chelating siderophore enterochelin. Mutants in entA or aroB, defective in the production of enterochelin, did not produce the factor that inhibits the growth of cydAB and cydDC mutants; purified enterochelin inhibited the growth of Cyd- mutants, but not that of wild-type cells. Other iron-chelating agents, particularly ethylenediamine-di(o-hydroxyphenylacetic acid) (EDDHA), whose complex with Fe(III) has a large stability constant (log K = 33.9), also inhibited the growth of Cyd- mutants at micromolar concentrations, but not that of wild-type cells. Supplementation of agar plates with Fe(III) or boiled catalase prevented the inhibition of Cyd- mutants by the extracellular factor. Spontaneous mutants isolated by being able to grow in the presence of the extracellular factor on plates also showed increased resistance to iron chelators. The reducing agent ascorbate, ascorbate plus In(III), ascorbate plus Ga(III), or Ga(III) alone, also alleviated inhibition by the extracellular factor, presumably by reducing iron to Fe(II) and complexing of the siderophore with alternative trivalent metal cations. The preferential inhibition of Cyd- mutants by the extracellular factor and other iron chelators is not due to decrease in expression, activity or assembly of cytochrome bo', the major alternative oxidase mediating quinol oxidation. Cyd- mutants overproduce siderophores, presumably reflecting intracellular iron deprivation.
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13
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Verkhovskaya ML, Barquera B, Verkhovsky MI, Wikström M. The Na+ and K+ transport deficiency of an E. coli mutant lacking the NhaA and NhaB proteins is apparent and caused by impaired osmoregulation. FEBS Lett 1998; 439:271-4. [PMID: 9845336 DOI: 10.1016/s0014-5793(98)01380-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Cells of the E. coli mutant EP432, which lacks the two Na+/H+ antiporters, NhaA and NhaB, have been reported to have an impaired sodium transport activity (Harel-Bronstein et al. (1995) J. Biol. Chem. 270, 3816-3822). Here we report that active transport of Na+ in EP432 cells can be restored to wild-type levels, either by a high K+ concentration or by an increase in the medium osmolarity. We suggest that this mutant is primarily deficient in osmoregulation rather than in cation transport per se.
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Affiliation(s)
- M L Verkhovskaya
- Department of Medical Chemistry, Institute of Biomedical Sciences, University of Helsinki, Finland.
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14
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Abstract
Some marine bacteria have a special energy-transducing mechanism that is different from those found in Escherichia coli or most of the freshwater and terrestrial bacteria. These marine bacteria specifically require Na+ for their growth and utilize a Na+ circuit for various cellular functions. So far, three types of primary Na+ pump have been identified (i.e. respiration-dependent, decarboxylase-driven and Na+ ATP synthase). Among them, the first type of Na+ pump plays the major role in the marine environment. Recently, the gene sequence and distribution of this Na+ pump have been clarified. In addition, information on genetics and the ecological significance of Na+ driven flagellar motors has also been accumulating. This recent progress in the research of the 'Na+ world' is revealing an interesting way of life that is unique to marine microorganisms.
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Affiliation(s)
- K Kogure
- Ocean Research Institute, University of Tokyo 1-15-1, Japan.
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15
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Kirichenko A, Vygodina T, Mkrtchyan HM, Konstantinov A. Specific cation binding site in mammalian cytochrome oxidase. FEBS Lett 1998; 423:329-33. [PMID: 9515733 DOI: 10.1016/s0014-5793(98)00117-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Calcium ion binds reversibly with cytochrome c oxidase from beef heart mitochondria (Kd approximately 2 microM) shifting alpha- and gamma-absorption bands of heme a to the red. Two sodium ions compete with one Ca2+ for the binding site with an average dissociation constant square root[K1(Na) x K2(Na)] approximately 3.6 mM. The Ca2+-induced spectral shift of heme a is specific for mammalian cytochrome c oxidase and is not observed in bacterial or yeast aa3 oxidases although the Ca2+-binding site has been revealed in the bacterial enzyme [Ostermeier, C., Harrenga, A., Ermler, U. and Michel, H. (1997) Proc. Natl. Acad. Sci. USA 94, 10547-10553]. As His-59 and Gln-63 involved in Ca2+ binding with Subunit I of P. denitrificans oxidase are not conserved in bovine oxidase, these residues have to be substituted by alternative ligands in mammalian enzyme, which is indeed the case as shown by refined structure of bovine heart cytochrome oxidase (S. Yoshikawa, personal communication). We propose that it is interaction of Ca2+ with the species-specific ligand(s) in bovine oxidase that accounts for perturbation of heme a. The Ca2+/Na2+-binding site may be functionally associated with the exit part of 'pore B' proton channel in subunit I of mammalian cytochrome c oxidase.
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Affiliation(s)
- A Kirichenko
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia
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16
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Cook GM, Membrillo-Hernández J, Poole RK. Transcriptional regulation of the cydDC operon, encoding a heterodimeric ABC transporter required for assembly of cytochromes c and bd in Escherichia coli K-12: regulation by oxygen and alternative electron acceptors. J Bacteriol 1997; 179:6525-30. [PMID: 9335308 PMCID: PMC179575 DOI: 10.1128/jb.179.20.6525-6530.1997] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The expression of the cydDC operon was investigated by using a chromosomal phi(cydD-lacZ) transcriptional fusion and primer extension analysis. A single transcriptional start site was found for cydD located 68 bp upstream of the translational start site, and Northern blot analysis confirmed that cydDC is transcribed as a polycistronic message independently of the upstream gene trxB. cydDC was highly expressed under aerobic growth conditions and during anaerobic growth with alternative electron acceptors. Aerobic expression was independent of ArcA and Fnr, but induction of cydDC by nitrate and nitrite was dependent on NarL and Fnr.
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Affiliation(s)
- G M Cook
- Department of Molecular Biology and Biotechnology, The Krebs Institute for Biomolecular Research, The University of Sheffield, United Kingdom
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17
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Affiliation(s)
- S Jünemann
- Glynn Laboratory of Bioenergetics, Department of Biology, University College London, UK.
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18
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Verkhovskaya ML, Verkhovsky MI, Wikström M. K+-dependent Na+ transport driven by respiration in Escherichia coli cells and membrane vesicles. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1273:207-16. [PMID: 8616158 DOI: 10.1016/0005-2728(95)00142-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Respiration-driven Na+ transport from Escherichia coli cells and right-side-out membrane vesicles is strictly dependent on K+. Cells from an E. colic mutant deficient in three major K+ transport systems were incapable of accumulating K+ or expelling Na+ unless valinomycin was added. Membrane vesicles from an E. coli mutant from which the genes encoding the two known electrogenic Na+/nH+ antiporters nhaA and nhaB were deleted transported Na+ as well as did vesicles from wild-type cells. Quantitative analysis of Delta psi and Delta pH showed a high driving force for electrogenic Na+/nH+ antiport whether K+ was present or not, although Na+ transport occurred only in its presence. These results suggest that an Na+/nH+ antiporter is not responsible for the Na+ transport. Respiration-driven efflux of Na+ from vesicles was found to be accompanied by primary uphill efflux of K+. Also, no respiration-dependent efflux of K+ was observed in the absence of Na+. Such coupling between Na+ and K+ fluxes may be explained by the operation of an Na+, K+/H+ antiporter previously described in E. coli membrane vesicles (Verkhovskay, M.L., Verkhovsky, M.I. and Wikström, M. (1995) FEBS Lett. 363, 46-48). Active Na+ transport is abolished when delta mu H+ is eliminated by a protonophore, but at low concentrations the protonophore actually accelerated Na+ transport. Such an effect may be expected if the Na+, K+/H+ antiporter normally operates in tight conjunction with respiratory chain complexes, thus exhibiting some phenomenological properties of a primary redox-linked sodium pump.
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Affiliation(s)
- M L Verkhovskaya
- Helsinki Bioenergetics Group, Institute of Biomedical Sciences, Department of Medical Chemistry, University of Helsinki, Finland
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19
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Bogachev AV, Murtazine RA, Shestopalov AI, Skulachev VP. Induction of the Escherichia coli cytochrome d by low delta mu H+ and by sodium ions. EUROPEAN JOURNAL OF BIOCHEMISTRY 1995; 232:304-8. [PMID: 7556165 DOI: 10.1111/j.1432-1033.1995.tb20812.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Regulation of synthesis of cytochrome d in Escherichia coli has been studied using mutants with cytochrome-d--beta-galactosidase gene fusions. It was shown that various protonophorous uncouplers, when added to the growth medium, cause induction of the cytochrome d synthesis. The cytochrome-d-inducing activity of uncouplers correlates with their ability to inhibit such a delta mu (H+)-driven function as motility of the E. coli cells. An increase in the Na+ concentration in the growth medium from 1.5 mM to 25 mM results in induction of the cytochrome d synthesis. The cytochrome-d-inducing effect of uncouplers is much more pronounced when the Na+ concentration is high than when it is low. These data are in agreement with the assumption that cytochrome d is involved in the Na+ energetics substituting for the H+ energetics when the latter appears to be inefficient. Mutations in arcA or arcB genes (but not in fnr gene) completely prevent the increase in the cytochrome d level induced by uncouplers but are without effect on that induced by Na+. It is assumed that in the control of the cytochrome d synthesis, the Arc system is involved in the delta mu H+ sensing whereas sensing of delta mu Na+ (or of the Na+ concentration) is mediated by some other receptor system.
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Affiliation(s)
- A V Bogachev
- Department of Bioenergetics, A. N. Belozersky Institute of Phisico-Chemical Biology, Moscow State University, Russia
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Na+ as coupling ion in energy transduction in extremophilic Bacteria and Archaea. World J Microbiol Biotechnol 1995; 11:58-70. [DOI: 10.1007/bf00339136] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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21
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Skulachev VP. Chemiosmotic concept of the membrane bioenergetics: what is already clear and what is still waiting for elucidation? J Bioenerg Biomembr 1994; 26:589-98. [PMID: 7721720 DOI: 10.1007/bf00831533] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The present state of the chemiosmotic concept is reviewed. Special attention is paid to (i) further progress in studies on the Na(+)-coupled energetics and (ii) paradoxical bioenergetic effects when protonic or sodium potentials are utilized outside the coupling membrane (TonB-mediated uphill transports across the outer bacterial membrane). A hypothesis is put forward assuming that the same principle is employed in the bacterial flagellar motor.
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Affiliation(s)
- V P Skulachev
- Department of Bioenergetics, A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia
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22
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Smigán P, Majerník A, Greksák M. Na(+)-driven ATP synthesis in Methanobacterium thermoautotrophicum and its differentiation from H(+)-driven ATP synthesis by rhodamine 6G. FEBS Lett 1994; 349:424-8. [PMID: 8050608 DOI: 10.1016/0014-5793(94)00716-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Rhodamine 6G (3 microM) effectively inhibited delta pH-driven ATP synthesis in Methanobacterium thermoautotrophicum while delta pNA-driven ATP synthesis was not affected by it. Rhodamine 6G inhibited Mg(2+)-stimulated ATPase activity of membrane vesicles prepared from these cells but the ATPase catalytic sector detached from the membrane was insensitive to this inhibitor. Methanogenesis-driven ATP synthesis at pH 6.8 of the cells grown in the presence of 50 mM NaCl was inhibited by rhodamine 6G both in the presence of 5 mM and 50 mM NaCl. On the other hand, the methanogenesis-driven ATP synthesis at pH 8.0 of cells grown in the presence of 50 mM NaCl was slightly inhibited by rhodamine 6G in the presence of 5 mM NaCl and was not inhibited at all in the presence of 50 mM NaCl. The growth experiments have shown that cells of Methanobacterium thermoautotrophicum can grow under alkaline conditions even in the presence of rhodamine 6G and of high NaCl concentration when the growth media were inoculated with the cells which had been grown in the presence of 50 mM NaCl. These results indicate that sodium-motive force-driven ATP synthase in Methanobacterium thermoautotrophicum operates effectively at alkaline conditions and it might be the sole ATP synthesizing system when the proton motive force-supported ATP synthesis is inhibited by rhodamine 6G.
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Affiliation(s)
- P Smigán
- Institute of Animal Biochemistry and Genetics, Slovak Academy of Sciences, Ivanka pri Dunaji
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Smigán P, Majerník A, Greksák M. Na(+)-driven ATP synthesis in Methanobacterium thermoautotrophicum and its differentiation from H(+)-driven ATP synthesis by rhodamine 6G. FEBS Lett 1994; 347:190-4. [PMID: 8034000 DOI: 10.1016/0014-5793(94)00535-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Rhodamine 6G (3 microM) effectively inhibited delta pH-driven ATP synthesis in Methanobacterium thermoautotrophicum while delta pNa-driven ATP synthesis was not affected by it. Rhodamine 6G inhibited Mg(2+)-stimulated ATPase activity of membrane vesicles prepared from these cells but the ATPase catalytic sector detached from the membrane was insensitive to this inhibitor. Methanogenesis-driven ATP synthesis at pH 6.8 of cells grown in the presence of 50 mM NaCl was inhibited by rhodamine 6G both in the presence of 5 mM and 50 mM NaCl. On the other hand, the methanogenesis-driven ATP synthesis at pH 8.0 of cells grown in the presence of 50 mM NaCl was slightly inhibited by rhodamine 6G in the presence of 5 mM NaCl and was not inhibited at all in the presence of 50 mM NaCl. The growth experiments have shown that cells of Methanobacterium thermoautotrophicum can grow under alkaline conditions even in the presence of rhodamine 6G and of high NaCl concentration when the growth media were inoculated with the cells which had been grown in the presence of 50 mM NaCl. These results indicate that sodium-motive force-driven ATP synthase in Methanobacterium thermoautotrophicum operates effectively in alkaline conditions and it might be the sole ATP synthesizing system when the proton-motive force-supported ATP synthesis is inhibited by rhodamine 6G.
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Affiliation(s)
- P Smigán
- Institute of Animal Biochemistry and Genetics, Slovak Academy of Sciences, Ivanka pri Dunaji
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Balnokin YV, Popova LG. The ATP-driven Na(+)-pump in the plasma membrane of the marine unicellular alga, Platymonas viridis. FEBS Lett 1994; 343:61-4. [PMID: 8163019 DOI: 10.1016/0014-5793(94)80607-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The ATP-supported 22NA+ uptake by plasma membrane vesicles from the marine microalga, Platymonas viridis, was studied. At pH 7 in the medium, Na+ uptake did not occur in the presence of ATP although delta pH across the plasma membrane was generated. The ATP-dependent Na+ uptake was induced by adding the protonophore, ClCCP. At pH 8, Na+ uptake took place when ATP was added even without ClCCP. The delta pH generated across the plasma membrane was negligible under these conditions. The Na+ uptake at pH 8 was not affected by ClCCP and amiloride, an inhibitor of the Na+/H+ antiporter. It is concluded that the ATP-supported Na+ uptake by Pl. viridis vesicles is catalyzed by Na(+)-ATPase.
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Affiliation(s)
- Y V Balnokin
- Laboratory of Salt Exchange and Salt Tolerance, Russian Academy of Science, Moscow
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Skulachev VP. Bioenergetics: the evolution of molecular mechanisms and the development of bioenergetic concepts. Antonie Van Leeuwenhoek 1994; 65:271-84. [PMID: 7832586 DOI: 10.1007/bf00872213] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Possible routes for the evolution of cell energetics are considered. It is assumed that u.v. light was the primary energy source for the precursors of the primordial living cell and that primitive energetics might have been based on the use of the adenine moiety of ADP as the u.v. chromophore. It is proposed that the excitation of the adenine residue facilitated phosphorylation of its amino group with subsequent transfer of a phosphoryl group to the terminal phosphate of ADP to form ATP. ATP-driven carbohydrate synthesis is considered as a mechanism for storing u.v.-derived energy, which was then used in the dark. Glycolysis presumably produced compounds like ethanol and CO2, which easily penetrate the membrane and therefore were lost by the cell. Later lactate-producing glycolysis appeared, the end product being non-penetrant and, hence, retained inside the cell to be utilized to regenerate carbohydrates when light energy became available. Production of lactate was accompanied by accumulation of equimolar H+. To avoid acidification of the cell interior, an F0-type H+ channel was employed. Later it was supplemented with F1. This allowed the ATP energy to be used for 'uphill' H+ pumping to the medium, which was acidified due to glycolytic activity of the cells. In the subsequent course of evolution, u.v. light was replaced by visible light, which has lower energy but is less dangerous for the cell. It is assumed that bacteriorhodopsin, a simple and very stable light-driven H+ pump which still exists in halophilic and thermophilic Archaea, was the primary system utilizing visible light. The delta mu-H+ formed was used to reverse the H(+)-ATPase, which began to function as H(+)-ATP-synthase. Later, bacteriorhodopsin photosynthesis was substituted by a more efficient chlorophyll photosynthesis, producing not only ATP, but also carbohydrates. O2, a side product of this process, was consumed by the H(+)-motive respiratory chain to form delta mu-H+ in the dark. At the next stage of evolution, a parallel energy-transducing mechanism appeared which employed Na+ instead of H+ as the coupling ion (the Na+ cycle).(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- V P Skulachev
- Department of Bioenergetics, A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia
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Muntyan MS, Bloch DA, Ustiyan VS, Drachev LA. Kinetics of CO binding to H(+)-motive oxidases of the caa3-type from Bacillus FTU and of the o-type from Escherichia coli. FEBS Lett 1993; 327:351-4. [PMID: 8348963 DOI: 10.1016/0014-5793(93)81019-v] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The kinetics of CO rebinding with isolated Bacillus FTU caa3-type oxidase and with solubilized Escherichia coli membranes (GO103 strain) containing the o-type oxidase as the main O2-reducing enzyme were studied under reducing conditions by laser flash photolysis of the CO-oxidase complexes. The spectra of the optical absorbance changes upon photolysis were characteristic of CO-caa3- and CO-o-oxidase complexes in Bac. FTU and E. coli, respectively. Small quantities of d-type oxidase in E. coli GO103 membranes were detected. The kinetics of CO reassociation with reduced caa3- and o-type oxidases were monophasic with tau 25-30 ms in both cases.
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Affiliation(s)
- M S Muntyan
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russian Federation
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Bogachev AV, Murtasina RA, Shestopalov AI, Skulachev VP. The role of protonic and sodium potentials in the motility of E. coli and Bacillus FTU. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1142:321-6. [PMID: 8386939 DOI: 10.1016/0005-2728(93)90160-h] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The motility of Escherichia coli and of alkalo- and halotolerant Bacillus FTU has been studied. It is found that Bac. FTU motility (i) requires Na+, (ii) is resistant to the protonophorous uncoupler pentachlorophenol (PCP) if cells grow at high pH, and is sensitive to the uncouplers at neutral pH, (iii) is sensitized to the uncouplers with the addition of monensin, (iv) sensitive to amiloride and (v) can be supported by an artificially imposed Na+ gradient in the presence of uncoupler, cyanide and arsenate. On the other hand, E. coli motility (a) does not require Na+, (b) is always uncoupler-sensitive, (c) is amiloride-resistant, and (d) can be supported by an artificially-imposed gradient of H+, not Na+. It is concluded that the motilities of Bac. FTU and E. coli are due to the operation of the Na+ and the H+ motors, respectively. In Bac. FTU growing at alkaline pH, the Na+ motors are assumed to be energized by delta mu Na+ produced by the Na(+)-motive respiratory chain, and therefore delta mu H+ is not involved in the motility process. As to Bac. FTU growing in a neutral medium, delta mu Na+ is produced secondarily, via the Na+/H(+)-antiporter, i.e., at the expense of delta mu H+ formed by the H(+)-motive respiratory chain.
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Affiliation(s)
- A V Bogachev
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia
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Avetisyan AV, Bogachev AV, Murtasina RA, Skulachev VP. ATP-driven Na+ transport and Na(+)-dependent ATP synthesis in Escherichia coli grown at low delta mu H+. FEBS Lett 1993; 317:267-70. [PMID: 8425616 DOI: 10.1016/0014-5793(93)81290-g] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In inverted subcellular vesicles of Escherichia coli grown at high delta mu H+ (neutral pH, no protonophorous uncoupler), ATP-driven Na+ transport and oxidative phosphorylation are completely inhibited by the protonophore CCCP. If E. coli was grown at low delta mu H+, i.e. at high pH or in the presence of uncoupler, some oxidative phosphorylation was observed in the vesicles even in CCCP-containing medium, and Na+ transport was actually stimulated by CCCP. The CCCP-resistant transport and phosphorylation were absent from the unc mutant lacking F0F1 ATPase. Both processes proved to be sensitive to (i) the Na+/H+ antiporter monensin, (ii) the Na+ uniporter ETH 157, (iii) the F0 inhibitors DCCD and venturicidin, and (iv) the F1 inhibitor aurovertin. The CCCP-resistant oxidative phosphorylation was stimulated by Na+ and arrested by oppositely directed delta pNa. These data are consistent with the assumption that, under appropriate growth conditions, the F0F1-type ATPase of E. coli becomes competent in transporting Na+ ions.
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Affiliation(s)
- A V Avetisyan
- Department of Bioenergetics, A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia
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Krulwich TA, Guffanti AA. Proton-coupled bioenergetic processes in extremely alkaliphilic bacteria. J Bioenerg Biomembr 1992; 24:587-99. [PMID: 1334072 DOI: 10.1007/bf00762351] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Oxidative phosphorylation, which involves an exclusively proton-coupled ATP synthase, and pH homeostasis, which depends upon electrogenic antiport of cytoplasmic Na+ in exchange for H+, are the two known bioenergetic processes that require inward proton translocation in extremely alkaliphilic bacteria. Energy coupling to oxidative phosphorylation is particularly difficult to fit to a strictly chemiosmotic model because of the low bulk electrochemical proton gradient that follows from the maintenance of a cytoplasmic pH just above 8 during growth at pH 10.5 and higher. A large quantitative and variable discrepancy between the putative chemiosmotic driving force and the phosphorylation potential results. This is compounded by a nonequivalence between respiration-dependent bulk gradients and artificially imposed ones in energizing ATP synthesis, and by an apparent requirement for specific respiratory chain complexes that do not relate solely to their role in generation of bulk gradients. Special features of the synthase may contribute to the mode of energization, just as novel features of the Na+ cycle may relate to the extraordinary capacity of the extreme alkaliphiles to achieve pH homeostasis during growth at, or sudden shifts to, an external pH of 10.5 and above.
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Affiliation(s)
- T A Krulwich
- Department of Biochemistry, Mount Sinai School of Medicine, City University of New York, New York 10029
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Dybas M, Konisky J. Energy transduction in the methanogen Methanococcus voltae is based on a sodium current. J Bacteriol 1992; 174:5575-83. [PMID: 1324904 PMCID: PMC206501 DOI: 10.1128/jb.174.17.5575-5583.1992] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
We provide experimental support for the proposal that ATP production in Methanococcus voltae, a methanogenic member of the archaea, is based on an energetic system in which sodium ions, not protons, are the coupling ions. We show that when grown at a pH of 6.0, 7.1, or 8.2, M. voltae cells maintain a membrane potential of approximately -150 mV. The cells maintain a transmembrane pH gradient (pH(in) - pH(out)) of -0.1, -0.2, and -0.2, respectively, values not favorable to the inward movement of protons. The cells maintain a transmembrane sodium concentration gradient (sodium(out)/sodium(in)) of 1.2, 3.4, and 11.6, respectively. While the protonophore 3,3',4',5-tetrachlorosalicylanilide inhibits ATP formation in cells grown at pH 6.5, neither ATP formation nor growth is inhibited in cells grown in medium at pH 8.2. We show that when grown at pH 8.2, cells synthesize ATP in the absence of a favorably oriented proton motive force. Whether grown at pH 6.5 or pH 8.2, M. voltae extrudes Na+ via a primary pump whose activity does not depend on a proton motive force. The addition of protons to the cells leads to a harmaline-sensitive efflux of Na+ and vice versa, indicating the presence of Na+/H+ antiporter activity and, thus, a second mechanism for the translocation of Na+ across the cell membrane. M. voltae contains a membrane component that is immunologically related to the H(+)-translocating ATP synthase of the archaeabacterium Sulfolobus acidocaldarius. Since we demonstrated that ATP production can be driven by an artificially imposed membrane potential only in the presence of sodium ions, we propose that ATP production in M. voltae is mediated by an Na+-translocating ATP synthase whose function is coupled to a sodium motive force that is generated through a primary Na+ pump.
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Affiliation(s)
- M Dybas
- Department of Microbiology, University of Illinois, Urbana 61801
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Abstract
Recent progress in membrane bioenergetics studies has resulted in the important discovery that Na+ can effectively substitute for H+ as the energy coupling ion. This means that living cells can possess three convertible energy currencies, i.e. ATP, protonic and sodium potentials. Analysis of interrelations of these components in various types of living cells allows bioenergetic laws of universal applicability to be inferred.
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Affiliation(s)
- V P Skulachev
- Department of Bioenergetics, A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia
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Khan S, Ivey DM, Krulwich TA. Membrane ultrastructure of alkaliphilic Bacillus species studied by rapid-freeze electron microscopy. J Bacteriol 1992; 174:5123-6. [PMID: 1629169 PMCID: PMC206330 DOI: 10.1128/jb.174.15.5123-5126.1992] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Cells of Bacillus firmus OF4 and Bacillus alcalophilus were examined by rapid-freeze freeze-fracture and freeze-substitution electron microscopy. No special vesicular structures linked to growth at alkaline pH were found, either within or associated with the cytoplasmic membrane. The cytoplasmic membranes of the alkaliphilic bacilli and the neutrophilic Bacillus subtilis BD99 were indistinguishable. Distinctive intramembrane particle rings, presumed to be flagellar structures on the basis of distribution and morphological characteristics, were found in all of these species. These observations indicate that the adaptations required to effect oxidative phosphorylation and flagellar rotation at extreme alkaline pH occur without gross morphological rearrangement.
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Affiliation(s)
- S Khan
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, New York, New York 10461
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Avetisyan AV, Bogachev AV, Murtasina RA, Skulachev VP. Involvement of a d-type oxidase in the Na(+)-motive respiratory chain of Escherichia coli growing under low delta mu H+ conditions. FEBS Lett 1992; 306:199-202. [PMID: 1321735 DOI: 10.1016/0014-5793(92)80999-w] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
An attempt has been made to find out which of the two terminal oxidases, the d-type or the o-type, operates as a Na+ pump in Escherichia coli grown at low delta mu H+ conditions. For this purpose, mutants lacking either d or o oxidase have been studied. It is shown that a d-,o+ mutant grows slowly or does not grow at all under low delta mu H+ conditions (alkaline or protonophore-containing growth media were used). Inside-out subcellular vesicles from the d-,o+ mutant cannot oxidize ascorbate and TMPD, and cannot transport Na+ when succinate is oxidized in the presence of a protonophore. The same vesicles are found to transport Na+ when NADH is oxidized as if the Na(+)-motive NADH-quinone oxidase were operative. On the other hand, a mutant lacking o oxidase (d+,o-) grows at low delta mu H+ conditions as fast as the maternal E. coli strain containing both d and o oxidases. Corresponding vesicles oxidize ascorbate and TMPD as well as succinate, the oxidations being coupled to the protonophore-stimulated Na+ transport. Growth in the presence of a protonophore is found to induce a strong increase in the d oxidase level in the maternal d+,o+ E.coli strain. It is concluded that oxidase of the d-type, rather than of the o-type, operates as a Na+ pump in E. coli grown under conditions unfavorable for the H+ cycle.
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Affiliation(s)
- A V Avetisyan
- Department of Bioenergetics, A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia
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35
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Verkhovskaya M, Verkhovsky M, Wikström M. pH dependence of proton translocation by Escherichia coli. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)42076-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Chapter 2 Chemiosmotic systems and the basic principles of cell energetics. MOLECULAR MECHANISMS IN BIOENERGETICS 1992. [DOI: 10.1016/s0167-7306(08)60170-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Skulachev VP. Chemiosmotic systems in bioenergetics: H(+)-cycles and Na(+)-cycles. Biosci Rep 1991; 11:387-441; discussion 441-4. [PMID: 1668527 DOI: 10.1007/bf01130214] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The development of membrane bioenergetic studies during the last 25 years has clearly demonstrated the validity of the Mitchellian chemiosmotic H+ cycle concept. The circulation of H+ ions was shown to couple respiration-dependent or light-dependent energy-releasing reactions to ATP formation and performance of other types of membrane-linked work in mitochondria, chloroplasts, some bacteria, tonoplasts, secretory granules and plant and fungal outer cell membranes. A concrete version of the direct chemiosmotic mechanism, in which H+ potential formation is a simple consequence of the chemistry of the energy-releasing reaction, is already proved for the photosynthetic reaction centre complexes. Recent progress in the studies on chemiosmotic systems has made it possible to extend the coupling-ion principle to an ion other than H+. It was found that, in certain bacteria, as well as in the outer membrane of the animal cell, Na+ effectively substitutes for H+ as the coupling ion (the chemiosmotic Na+ cycle). A precedent is set when the Na+ cycle appears to be the only mechanism of energy production in the bacterial cell. In the more typical case, however, the H+ and Na+ cycles coexist in one and the same membrane (bacteria) or in two different membranes of one and the same cell (animals). The sets of delta mu H+ and delta mu Na+ generators as well as delta mu H+ and delta mu Na+ consumers found in different types of biomembranes, are listed and discussed.
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Affiliation(s)
- V P Skulachev
- Department of Bioenergetics, A. N. Belozersky Laboratory of Molecular Biology and Bioorganic Chemistry, Moscow State University, USSR
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