The iron-sulphur centres of the Escherichia coli electron transport chain: changes in response to aerobic growth on different carbon sources

1984 ◽  
Vol 12 (3) ◽  
pp. 501-502 ◽  
Author(s):  
MICHELLE C. KIRBY ◽  
W. JOHN INGLEDEW
Keyword(s):  
Escherichia Coli ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Carbon Sources ◽  
Aerobic Growth ◽  
Transport Chain

scholarly journals Physiological Evidence for Isopotential Tunneling in the Electron Transport Chain of Methane-Producing Archaea

2017 ◽  
Vol 83 (18) ◽  
Author(s):  
Nikolas Duszenko ◽  
Nicole R. Buan
Keyword(s):  
Escherichia Coli ◽  
Electron Transport ◽  
Stationary Phase ◽  
Exponential Growth ◽  
Electron Transport Chain ◽  
Methanosarcina Barkeri ◽  
Metabolic Efficiency ◽  
Methanosarcina Acetivorans ◽  
Content Type ◽  
Transport Chain

ABSTRACT Many, but not all, organisms use quinones to conserve energy in their electron transport chains. Fermentative bacteria and methane-producing archaea (methanogens) do not produce quinones but have devised other ways to generate ATP. Methanophenazine (MPh) is a unique membrane electron carrier found in Methanosarcina species that plays the same role as quinones in the electron transport chain. To extend the analogy between quinones and MPh, we compared the MPh pool sizes between two well-studied Methanosarcina species, Methanosarcina acetivorans C2A and Methanosarcina barkeri Fusaro, to the quinone pool size in the bacterium Escherichia coli. We found the quantity of MPh per cell increases as cultures transition from exponential growth to stationary phase, and absolute quantities of MPh were 3-fold higher in M. acetivorans than in M. barkeri. The concentration of MPh suggests the cell membrane of M. acetivorans, but not of M. barkeri, is electrically quantized as if it were a single conductive metal sheet and near optimal for rate of electron transport. Similarly, stationary (but not exponentially growing) E. coli cells also have electrically quantized membranes on the basis of quinone content. Consistent with our hypothesis, we demonstrated that the exogenous addition of phenazine increases the growth rate of M. barkeri three times that of M. acetivorans. Our work suggests electron flux through MPh is naturally higher in M. acetivorans than in M. barkeri and that hydrogen cycling is less efficient at conserving energy than scalar proton translocation using MPh. IMPORTANCE Can we grow more from less? The ability to optimize and manipulate metabolic efficiency in cells is the difference between commercially viable and nonviable renewable technologies. Much can be learned from methane-producing archaea (methanogens) which evolved a successful metabolic lifestyle under extreme thermodynamic constraints. Methanogens use highly efficient electron transport systems and supramolecular complexes to optimize electron and carbon flow to control biomass synthesis and the production of methane. Worldwide, methanogens are used to generate renewable methane for heat, electricity, and transportation. Our observations suggest Methanosarcina acetivorans, but not Methanosarcina barkeri, has electrically quantized membranes. Escherichia coli, a model facultative anaerobe, has optimal electron transport at the stationary phase but not during exponential growth. This study also suggests the metabolic efficiency of bacteria and archaea can be improved using exogenously supplied lipophilic electron carriers. The enhancement of methanogen electron transport through methanophenazine has the potential to increase renewable methane production at an industrial scale.

scholarly journals Exploration of Nitrate Reductase Metabolic Pathway inCorynebacterium pseudotuberculosis

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Sintia Almeida ◽  
Cassiana Sousa ◽  
Vinícius Abreu ◽  
Carlos Diniz ◽  
Elaine M. S. Dorneles ◽  
...  
Keyword(s):  
Electron Transport ◽  
Nitrate Reductase ◽  
Virulence Factors ◽  
Electron Transport Chain ◽  
Drug Targets ◽  
Carbon Sources ◽  
The Other ◽  
Ecological Niches ◽  
Transport Chain ◽  
In Silico Methods

Based on the ability of nitrate reductase synthesis,Corynebacterium pseudotuberculosisis classified into two biovars: Ovis and Equi. Due to the presence of nitrate reductase, the Equi biovar can survive in absence of oxygen. On the other hand, Ovis biovar that does not have nitrate reductase is able to adapt to various ecological niches and can grow on certain carbon sources. Apart from these two biovars, some other strains are also able to carry out the reduction of nitrate. The enzymes that are involved in electron transport chain are also identified by in silico methods. Findings about pathogen metabolism can contribute to the identification of relationship between nitrate reductase and theC. pseudotuberculosispathogenicity, virulence factors, and discovery of drug targets.

scholarly journals Effects of sulphate-limited growth in continuous culture on the electron-transport chain and energy conservation in Escherichia coli K12

1975 ◽  
Vol 152 (3) ◽  
pp. 537-546 ◽  
Author(s):  
R K Poole ◽  
B A Haddock
Keyword(s):  
Escherichia Coli ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Functional Organization ◽  
Extracellular Polysaccharide ◽  
Limited Growth ◽  
Escherichia Coli K12 ◽  
Transport Chain ◽  
Respiratory Chains ◽  
Energy Dependent

Growth of Escherichia coli K12 in a chemostat was limited by sulphate concentrations lower than 300 muM. The synthesis of extracellular polysaccharide and a change in morphology accompanied sulphate-limited growth. Growth yields with respect to the amount of glycerol or oxygen consumed were sixfold and twofold lower respectively under these conditions than when growth was limited by glycerol. Sulphate-limited cells lacked the proton-translocating oxidoreduction segment of the electron-transport chain between NADH and the cytochromes, and particles prepared from these cells lacked the energy-dependent reduction of NAD+ by succinate, DL-α-glycerophosphate or D-lactate, suggesting the loss of site-I phosphorylation. Glycerol-limited cells contained cytochrome b556, b562 and o, ubiquinone and low concentrations of menaquinone. Sulphate limitation resulted in the additional synthesis of cytochromes d, a1, b558 and c550; the amount of ubiquinone was decreased and menaquinone was barely detectable. Non-haem iron and acid-labile sulphide concentrations were twofold lower in electron-transport particles prepared from sulphate-limited cells. Recovery of site-I phosphorylation could not be demonstrated after incubating sulphate-limited cells with or without glycerol, in either the absence or presence of added sulphate. The loss of site-I phosphorylation in sulphate-limited cells is discussed with reference to the accompanying alterations in cytochrome composition of such cells. Schemes are proposed for the functional organization of the respiratory chains of E. coli grown under conditions of glycerol or sulphate limitation.

Growth-inhibitory activities of some 1,4-naphthoquinones and related compounds on Staphylococcus aureus and Escherichia coli

1968 ◽  
Vol 14 (6) ◽  
pp. 661-666 ◽  
Author(s):  
G. J. Leahy ◽  
D. J Currie ◽  
H. L. Holmes ◽  
J. R. Maltman
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Growth Inhibitory ◽  
Transport Chain ◽  
Half Wave ◽  
Inhibitory Activities ◽  
Related Compounds

Growth-inhibitory activities of some or all of 98 1,4-naphthoquinones and 16 related compounds on Escherichia coli and two strains of Staphylococcus aureus were determined alone or in combination. These values, when plotted against their polarographic half-wave potentials and those of their C2-n-butylthio analogs support the hypothesis that these compounds, or the products resulting from their reaction with a protein nucleophile, function by short-circuiting one or other of the quinones present in the electron-transport chain.

scholarly journals CtaM Is Required for Menaquinol Oxidaseaa3Function inStaphylococcus aureus

mBio ◽  
2016 ◽  
Vol 7 (4) ◽  
Author(s):  
Neal D. Hammer ◽  
Lici A. Schurig-Briccio ◽  
Svetlana Y. Gerdes ◽  
Robert B. Gennis ◽  
Eric P. Skaar
Keyword(s):  
Staphylococcus Aureus ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Molecular Mechanisms ◽  
Carbon Sources ◽  
Spectroscopic Studies ◽  
Uncharacterized Protein ◽  
Terminal Oxidases ◽  
Transport Chain ◽  
Genes Encoding

ABSTRACTStaphylococcus aureusis the leading cause of skin and soft tissue infections, bacteremia, osteomyelitis, and endocarditis in the developed world. The ability ofS. aureusto cause substantial disease in distinct host environments is supported by a flexible metabolism that allows this pathogen to overcome challenges unique to each host organ. One feature of staphylococcal metabolic flexibility is a branched aerobic respiratory chain composed of multiple terminal oxidases. Whereas previous biochemical and spectroscopic studies reported the presence of three different respiratory oxygen reductases (otype,bdtype, andaa3type), the genome contains genes encoding only two respiratory oxygen reductases,cydABandqoxABCD. Previous investigation showed thatcydABandqoxABCDare required to colonize specific host organs, the murine heart and liver, respectively. This work seeks to clarify the relationship between the genetic studies showing the unique roles of thecydABandqoxABCDin virulence and the respiratory reductases reported in the literature. We establish that QoxABCD is anaa3-type menaquinol oxidase but that this enzyme is promiscuous in that it can assemble as abo3-type menaquinol oxidase. However, thebo3form of QoxABCD restricts the carbon sources that can support the growth ofS. aureus. In addition, QoxABCD function is supported by a previously uncharacterized protein, which we have named CtaM, that is conserved in aerobically respiringFirmicutes. In total, these studies establish the heme A biosynthesis pathway inS. aureus, determine that QoxABCD is a typeaa3menaquinol oxidase, and reveal CtaM as a new protein required for typeaa3menaquinol oxidase function in multiple bacterial genera.IMPORTANCEStaphylococcus aureusrelies upon the function of two terminal oxidases, CydAB and QoxABCD, to aerobically respire and colonize distinct host tissues. Previous biochemical studies support the conclusion that a third terminal oxidase is also present. We establish the components of theS. aureuselectron transport chain by determining the heme cofactors that interact with QoxABCD. This insight explains previous observations by revealing that QoxABCD can utilize different heme cofactors and confirms that the electron transport chain ofS. aureusis comprised of two terminal menaquinol oxidases. In addition, a newly identified protein, CtaM, is found to be required for the function of QoxABCD. These results provide a more complete assessment of the molecular mechanisms that support staphylococcal respiration.

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