Reduction of nonheme iron in the respiratory chain of Escherichia coli

1970 ◽  
Vol 48 (7) ◽  
pp. 777-783 ◽  
Author(s):  
P. D. Bragg
Keyword(s):  
Escherichia Coli ◽  
Cytochrome B ◽  
Respiratory Chain ◽  
Nonheme Iron ◽  
Particulate Fraction ◽  
Phenazine Methosulfate ◽  
Iron Species ◽  
E Coli

A particulate fraction of E. coli contained flavoprotein, nonheme iron, ubiquinone, and cytochromes b1 and o. About 20% of the nonheme iron was reducible by NADH, ascorbate – phenazine methosulfate, and dithionite to a form which reacted rapidly with o-phenanthroline. Reduction of this o-phenanthroline-reacting nonheme iron species by NADH was inhibited by 2-heptyl-4-hydroxyquinoline N-oxide which inhibited the respiratory chain between ubiquinone and cytochrome b1. Reduction of cytochrome b1 could occur without reduction of this nonheme iron species. These results are discussed relative to the position of nonheme iron in the respiratory chain of E. coli.

scholarly journals Cultivation at high osmotic pressure confers ubiquinone 8–independent protection of respiration on Escherichia coli

2019 ◽  
Vol 295 (4) ◽  
pp. 981-993 ◽  
Author(s):  
Laura Tempelhagen ◽  
Anita Ayer ◽  
Doreen E. Culham ◽  
Roland Stocker ◽  
Janet M. Wood
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Escherichia Coli ◽  
Electron Transfer ◽  
Oxygen Uptake ◽  
Osmotic Pressure ◽  
Respiratory Chain ◽  
Membrane Lipid ◽  
E Coli ◽  
Uptake Rates

Ubiquinone 8 (coenzyme Q8 or Q8) mediates electron transfer within the aerobic respiratory chain, mitigates oxidative stress, and contributes to gene expression in Escherichia coli. In addition, Q8 was proposed to confer bacterial osmotolerance by accumulating during growth at high osmotic pressure and altering membrane stability. The osmolyte trehalose and membrane lipid cardiolipin accumulate in E. coli cells cultivated at high osmotic pressure. Here, Q8 deficiency impaired E. coli growth at low osmotic pressure and rendered growth osmotically sensitive. The Q8 deficiency impeded cellular O2 uptake and also inhibited the activities of two proton symporters, the osmosensing transporter ProP and the lactose transporter LacY. Q8 supplementation decreased membrane fluidity in liposomes, but did not affect ProP activity in proteoliposomes, which is respiration-independent. Liposomes and proteoliposomes prepared with E. coli lipids were used for these experiments. Similar oxygen uptake rates were observed for bacteria cultivated at low and high osmotic pressures. In contrast, respiration was dramatically inhibited when bacteria grown at the same low osmotic pressure were shifted to high osmotic pressure. Thus, respiration was restored during prolonged growth of E. coli at high osmotic pressure. Of note, bacteria cultivated at low and high osmotic pressures had similar Q8 concentrations. The protection of respiration was neither diminished by cardiolipin deficiency nor conferred by trehalose overproduction during growth at low osmotic pressure, but rather might be achieved by Q8-independent respiratory chain remodeling. We conclude that osmotolerance is conferred through Q8-independent protection of respiration, not by altering physical properties of the membrane.

The formation of phosphatidylethanolamine from diglyceride by extracts of Escherichia coli

1980 ◽  
Vol 58 (8) ◽  
pp. 655-659 ◽  
Author(s):  
P. Proulx ◽  
C. Tomalty ◽  
F. Landry ◽  
J. J. Milczarek
Keyword(s):  
Escherichia Coli ◽  
Phosphatidic Acid ◽  
Particulate Fraction ◽  
E Coli

Extensively dialyzed cell-free homogenates or washed particulate fractions, of Escherichia coli in the presence of added CTP, Mg2+, serine, and rac-glycerol 3-phosphate, incorporated [32P]phosphatidic acid into phosphatidylglycerol and cardiolipin but not into phosphatidylethanolamine. [14C]Phosphatidic acid could be incorporated by these preparations into phosphatidylethanolamine in the absence of added CTP and Mg2+. CDP-diglyceride did not significantly affect the formation of [14C]phosphatidylethanolamine from [14C]phosphatidic acid. 14C-labeled diglyceride was also readily incorporated into phosphatidylethanolamine in the absence of added cofactors by both homogenate and particulate fraction. Serine stimulated the incorporation somewhat whereas CTP + Mg2+ diminished this conversion slightly because of concurrent [14C]phosphatidic acid and [14C]phosphatidylglycerol formation. CDP-diglyceride did not significantly affect the conversion of 14C-labeled diglyceride to phosphatidylethanolamine. Dialyzed 14C-labeled cytosol fractions of E. coli, obtained from cells grown in medium containing [14C]serine, transferred some of their label to phosphatidylethanolamine in the presence of fresh particulate fraction. This transfer was stimulated by added diglyceride. The results indicate that phosphatidylethanolamine can be synthesized from exogenous diglyceride by a pathway which does not require CDP-diglyceride as an intermediate but which likely makes use of an endogenous cofactor supplying phosphorylethanolamine and (or) phosphorylserine.

scholarly journals The reconstitution of oxidase activity in membranes derived from a 5-aminolaevulinic acid-requiring mutant of Escherichia coli

1973 ◽  
Vol 136 (4) ◽  
pp. 877-884 ◽  
Author(s):  
Bruce A. Haddock
Keyword(s):  
Escherichia Coli ◽  
Electron Transport ◽  
Cytochrome B ◽  
Oxidase Activity ◽  
Nadh Dehydrogenase ◽  
Carbon Sources ◽  
Protoporphyrin Ix ◽  
Side Chain ◽  
E Coli ◽  
Aminolaevulinic Acid

1. The reconstitution of oxidase activity in cell-free extracts of a mutant of Escherichia coli K12Ymel, that require 5-aminolaevulinic acid for growth on non-fermentable carbon sources, is described. 2. The reconstitution is dependent on haematin or a haem extract from a prototrophic strain of E. coli, and the product of the reaction has been identified as NADH-reducible cytochrome b. 3. The requirement for haematin cannot be replaced by four other porphyrins. Coproporphyrin III does not inhibit the haematin-dependent reconstitution, mesoporphyrin IX and protoporphyrin IX apparently compete with haematin for a binding site on the cytochrome apoprotein(s) and deuteroporphyrin IX binds to cytochrome apoprotein(s) and cannot be subsequently replaced by haematin. 4. The properties of electron-transport particles from cell-free extracts of the mutant strain, grown aerobically in the presence or absence of 5-aminolaevulinic acid, are described. In the absence of 5-aminolaevulinic acid no detectable cytochromes are produced, and oxidase activities are lowered but there is no apparent effect on the activities of the NADH dehydrogenase and d-lactate dehydrogenase. 5. The reconstitution of oxidase activity by electron-transport particles from cells grown in the absence of 5-aminolaevulinic acid requires ATP and haematin, and the product of the reaction was identified as NADH-reducible cytochrome b. 6. It is concluded that the cytochrome apoproteins are synthesized and incorporated into the cytoplasmic membrane of E. coli in the absence of haem synthesis. The subsequent reconstitution of functional cytochrome(s) requires protohaem, but the nature of the side chain on the 2 and 4 positions of the porphyrin appears to be important.

scholarly journals The ms2io6A37 Modification of tRNA inSalmonella typhimurium Regulates Growth on Citric Acid Cycle Intermediates

1998 ◽  
Vol 180 (12) ◽  
pp. 3144-3151 ◽  
Author(s):  
Britt C. Persson ◽  
Ólafur Ólafsson ◽  
Hans K. Lundgren ◽  
Lars Hederstedt ◽  
Glenn R. Björk
Keyword(s):  
Escherichia Coli ◽  
Citric Acid ◽  
Salmonella Typhimurium ◽  
Gene Product ◽  
Respiratory Chain ◽  
Citric Acid Cycle ◽  
Dicarboxylic Acids ◽  
Acid Cycle ◽  
E Coli ◽  
Isopentenyl Adenosine

ABSTRACT The modified nucleoside 2-methylthio-N-6-isopentenyl adenosine (ms2i6A) is present in position 37 (adjacent to and 3′ of the anticodon) of tRNAs that read codons beginning with U except tRNA I,V Ser inEscherichia coli. In Salmonella typhimurium, 2-methylthio-N-6-(cis-hydroxy)isopentenyl adenosine (ms2io6A; also referred to as 2-methylthio cis-ribozeatin) is found in tRNA, most likely in the species that have ms2i6A in E. coli. Mutants (miaE) of S. typhimurium in which ms2i6A hydroxylation is blocked are unable to grow aerobically on the dicarboxylic acids of the citric acid cycle. Such mutants have normal uptake of dicarboxylic acids and functional enzymes of the citric acid cycle and the aerobic respiratory chain. The ability of S. typhimurium to grow on succinate, fumarate, and malate is dependent on the state of modification in position 37 of those tRNAs normally having ms2io6A37 and is not due to a second cellular function of tRNA (ms2io6A37)hydroxylase, themiaE gene product. We suggest that S. typhimurium senses the hydroxylation status of the isopentenyl group of the tRNA and will grow on succinate, fumarate, or malate only if the isopentenyl group is hydroxylated.

scholarly journals Characterization and phenotypic control of the cytochrome content of Escherichia coli

1979 ◽  
Vol 182 (2) ◽  
pp. 465-472 ◽  
Author(s):  
Graeme A. Reid ◽  
W. John Ingledew
Keyword(s):  
Escherichia Coli ◽  
Electron Transport ◽  
Cytochrome B ◽  
Terminal Electron Acceptor ◽  
E Coli ◽  
Reduction Potentials ◽  
Electrode Potentials ◽  
Point Potential ◽  
Oxidation Reduction ◽  
Cytochrome D

1. Electron-transport particles derived from Escherichia coli grown aerobically contain three b-type cytochromes with mid-point oxidation–reduction potentials at pH7 of +260mV, +80mV and −50mV, with n=1 for each. The variation of these values with pH was determined. 2. E. coli develops a different set of b-type cytochromes when grown anaerobically on glycerol with fumarate or nitrate as terminal electron acceptor. Electron-transport particles of fumarate-grown cells contain b-type cytochromes with mid-point potentials at pH7 of +140mV and +250mV (n=1). These two cytochromes are also present in cells grown with nitrate as terminal acceptor, where an additional cytochrome b with a mid-point potential of +10mV (n=1) is developed. 3. The wavelengths of the α-absorption-band maxima of the b-type cytochromes at 77K were: (a) for aerobically grown cells, cytochrome b (Em7 +260mV), 556nm and 563nm, cytochrome b (Em7 +80mV), 556nm and cytochrome b (Em7−50mV), 558nm; (b) for anaerobically grown cells, cytochrome b (Em7 +250mV), 558nm, cytochrome b (Em7 +40mV), 555nm and cytochrome b (Em7 +10mV), 556nm. 4. Cytochrome d was found to have a mid-point potential at pH7 of +280mV (n=1). 5. Cytochrome a1 was resolved as two components of equal magnitude with mid-point potentials of +260mV and +160mV (n=1). 6. Redox titrations performed in the presence of CO showed that one of the b-type cytochromes in the aerobically grown cultures was reduced, even at the upper limits of our range of electrode potentials (above +400mV). Cytochrome d was also not oxidizable in the presence of CO. Neither of the cytochromes a1 was affected by the presence of CO.

Effect of Near-Ultraviolet Light on the Respiratory Chain of Escherichia coli

1971 ◽  
Vol 49 (5) ◽  
pp. 492-495 ◽  
Author(s):  
P. D. Bragg
Keyword(s):  
Ultraviolet Light ◽  
Cytochrome B ◽  
Respiratory Chain ◽  
Nadh Oxidase ◽  
Reductase Activity ◽  
State Level ◽  
Progressive Increase ◽  
E Coli ◽  
Near Ultraviolet ◽  
Nadh Oxidase Activity

Irradiation of a particulate fraction from E. coli with near-ultraviolet light destroyed NADH oxidase activity. This treatment did not affect markedly the levels of cytochromes b1 and o, and ubiquinone in this preparation. Cytochrome a2 was destroyed by irradiation. A progressive increase in the aerobic steady state level of cytochrome b1 reduction during irradiation confirmed that irradiation affected the cytochrome oxidase region of the respiratory chain. There was a second site of inactivation between substrate and cytochrome b1. This was indicated by lowered NADH:cytochrome b1 reductase activity. Partial reactivation of this activity was obtained by addition of ubiqumone-2 but not ubiquinone-8.

scholarly journals Respiration-driven proton translocation in Escherichia coli (Short Communication)

1973 ◽  
Vol 136 (1) ◽  
pp. 217-220 ◽  
Author(s):  
Hugh G. Lawford ◽  
Bruce A. Haddock
Keyword(s):  
Escherichia Coli ◽  
Energy Conservation ◽  
Respiratory Chain ◽  
Short Communication ◽  
Proton Translocation ◽  
Exponential Phase ◽  
Glycerol Oxidation ◽  
Intact Cells ◽  
E Coli

Measurements were made of the stoicheiometry of respiration-driven proton translocation coupled to the oxidation of NAD(P)-linked or flavin-linked substrates in intact cells of Escherichia coli. Observed stoicheiometries (→H+/O quotient; Mitchell, 1966) were approx. 4 with l-malate as substrate and approx. 2 for succinate, d-lactate and glycerol oxidation. It is concluded that the potential number of equivalent energy-conservation sites associated with the respiratory chain is 2 in aerobically grown cells of E. coli harvested during the exponential phase of growth.

scholarly journals Microcin J25 Has Dual and Independent Mechanisms of Action in Escherichia coli: RNA Polymerase Inhibition and Increased Superoxide Production

2007 ◽  
Vol 189 (11) ◽  
pp. 4180-4186 ◽  
Author(s):  
Augusto Bellomio ◽  
Paula A. Vincent ◽  
Beatriz F. de Arcuri ◽  
Ricardo N. Farías ◽  
Roberto D. Morero
Keyword(s):  
Escherichia Coli ◽  
Oxygen Consumption ◽  
Rna Polymerase ◽  
Respiratory Chain ◽  
Bacterial Cells ◽  
Outer Membrane Receptor ◽  
E Coli ◽  
First Time ◽  
Intracellular Targets ◽  
Microcin J25

ABSTRACT Microcin J25 (MccJ25) uptake by Escherichia coli requires the outer membrane receptor FhuA and the inner membrane proteins TonB, ExbD, ExbB, and SbmA. MccJ25 appears to have two intracellular targets: (i) RNA polymerase (RNAP), which has been described in E. coli and Salmonella enterica serovars, and (ii) the respiratory chain, reported only in S. enterica serovars. In the current study, it is shown that the observed difference between the actions of microcin on the respiratory chain in E. coli and S. enterica is due to the relatively low microcin uptake via the chromosomally encoded FhuA. Higher expression by a plasmid-encoded FhuA allowed greater uptake of MccJ25 by E. coli strains and the consequent inhibition of oxygen consumption. The two mechanisms, inhibition of RNAP and oxygen consumption, are independent of each other. Further analysis revealed for the first time that MccJ25 stimulates the production of reactive oxygen species (O2·−) in bacterial cells, which could be the main reason for the damage produced on the membrane respiratory chain.

scholarly journals Identification of membrane anchor polypeptides of Escherichia coli fumarate reductase

1982 ◽  
Vol 152 (3) ◽  
pp. 1126-1131
Author(s):  
B D Lemire ◽  
J J Robinson ◽  
J H Weiner
Keyword(s):  
Escherichia Coli ◽  
Gene Cloning ◽  
Nonheme Iron ◽  
Fumarate Reductase ◽  
Alkaline Ph ◽  
Membrane Anchor ◽  
E Coli ◽  
Molecular Weights ◽  
Membrane Bound ◽  
Triton X

Fumarate reductase of Escherichia coli has been shown to be a membrane-bound enzyme composed of a 69,000-dalton catalytic-flavin-containing subunit and a 27,000-dalton nonheme-iron-containing subunit. Using gene cloning and amplification techniques, we have observed two additional polypeptides encoded by the frd operon, with apparent molecular weights of 15,000 and 14,000, which are expressed when E. coli is grown anaerobically on glycerol plus fumarate. Expression of these two small polypeptides is necessary for the two large subunits to associate with the membrane. The four subunits remain associated in Triton X-100 extracts of the membrane, and a holoenzyme form of fumarate reductase containing one copy of each of the four polypeptides has been isolated. Unlike the well-characterized two-subunit form, the holoenzyme is not dependent on anions for activity and is not labile at alkaline pH. In these respects, it more closely resembles the membrane-bound activity.

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