scholarly journals Energy coupling to active transport in anaerobically grown mutants of Escherichia Coli K12

1976 ◽  
Vol 154 (3) ◽  
pp. 731-734 ◽  
Author(s):  
S J. Gutowski ◽  
H Rosenberg
Keyword(s):  
Escherichia Coli ◽  
Electron Transport ◽  
Active Transport ◽  
Adenosine Triphosphatase ◽  
Energy Coupling ◽  
High Energy ◽  
Escherichia Coli K12 ◽  
Anaerobic Electron Transport ◽  
Glutamine Uptake

1. Anaerobic uptake of proline requires either the presence of a coupled Mg2+-stimulated adenosine triphosphatase or anaerobic electron transport. 2. Anaerobic uptake of glutamine does not require anaerobic electron transport even in the absence of a coupled Mg+2-stimulated adenosine triphosphatase. 3. These results support previous suggestions [Berger (1973) Proc. Natl. Acad. Sci. U.S.A. 70, 1514––1518; Berger & Heppel (1974) J. Biol. Chem. 249, 7747-7755; Kobayashi, Kin & Anraku (1974) J. Biochem. (Tokyo) 76, 251-261] that two distinct mechanisms of energy coupling to active transport exist in Escherichia coli in that energization of anaerobic proline uptake requires the ‘high-energy membrane state’, whereas the energization of anaerobic glutamine uptake does not.

scholarly journals Metabolite transport in mutants of Escherichia coli K12 defective in electron transport and coupled phosphorylation

1975 ◽  
Vol 146 (2) ◽  
pp. 417-423 ◽  
Author(s):  
H Rosenberg ◽  
G B Cox ◽  
J D Butlin ◽  
S J Gutowski
Keyword(s):  
Escherichia Coli ◽  
Electron Transport ◽  
Active Transport ◽  
Adenosine Triphosphatase ◽  
Minimal Medium ◽  
Sole Source ◽  
Whole Cells ◽  
Escherichia Coli K12 ◽  
Mutant Strains ◽  
Uptake Medium

1. The uptakes of Pi and serine by whole cells of mutant strains of Escherichia coli K12, grown under both aerobic and anaerobic conditions, were studied. 2. Uptake by aerobic cells was low in a ubiquinone-less mutant but normal in two mutant strains unable to couple phosphorylation to electron transport. 3. One of these uncoupled strains, carrying the unc-405 allele, does not form a membrane-bound Mg2+-stimulated adenosine triphosphatase aggregate, and it is concluded that the Mg2+-stimulated adenosine triphosphatase does not serve a structural role in the aerobic active transport of Pi or serine. 4. The other uncoupled strain, in which aerobic uptake is unaffected, carries a mutation in the uncB gene, thus distinguishing this gene from the etc gene, previously shown to be concerned with the coupling of electron transport to active transport. 5. The uptakes of Pi and serine by anaerobic cells were normal in the ubiquinone-less mutant, but defective in both the uncoupled strains. 6. The uptake of Pi and serine by anaerobic cells of the uncB mutant could be increased by the addition of fumarate to the uptake medium. The unc-405 mutant, however, required the addition of fumarate for growth and for uptake. 7. The uncB mutant, unlike the unc-405 mutant, is able to grow anaerobically in a minimal medium with glucose as sole source of carbon. Similarly a strain carrying a mutation in the frd gene, which is the structural gene for the enzyme fumarate reductase, is able to grow anaerobically in a glucose-minimal medium. However, a mutant strain carrying mutations in both the uncB and frd genes resembles the unc-405 mutant in not being able to grow under these conditions.

scholarly journals Oxidative phosphorylation in Escherichia coli K12. An uncoupled mutant with altered membrane structure

1974 ◽  
Vol 138 (2) ◽  
pp. 211-215 ◽  
Author(s):  
G. B. Cox ◽  
F. Gibson ◽  
L. McCann
Keyword(s):  
Escherichia Coli ◽  
Electron Transport ◽  
Membrane Structure ◽  
Mutant Allele ◽  
Adenosine Triphosphatase ◽  
Mineral Salts ◽  
Normal Cells ◽  
E Coli ◽  
Escherichia Coli K12 ◽  
Membrane Bound

1. A new mutant strain (AN228) of Escherichia coli K12, unable to couple phosphorylation to electron transport, has been isolated. The mutant allele (unc-405), in strain AN228, was found to map near the uncA and uncB genes at about minute 74 on the E. coli genome. 2. A transductant strain (AN285) carrying the unc-405 allele is similar to the uncA and uncB mutants described previously in that it is unable to grow on succinate, gives a low aerobic yield on limiting concentrations of glucose, has a normal rate of electron transport, is unable to couple phosphorylation to electron transport, and lacks ATP-dependent transhydrogenase activity. 3. Strain AN285 (unc-405) is similar to an uncA mutant, but different from an uncB mutant, in that it is unable to grow anaerobically in a glucose–mineral-salts medium, and membrane preparations do not have Mg2+-stimulated adenosine triphosphatase activity. 4. Strain AN285 (unc-405) does not form an aggregate analogous to the membrane-bound Mg2+-stimulated adenosine triphosphatase aggregate found in normal cells. In this respect it differs from strain AN249 (uncA−), which forms an inactive membrane-bound Mg2+-stimulated adenosine triphosphatase aggregate.

scholarly journals A mutation affecting a second component of the F0 portion of the magnesium ion-stimulated adenosine triphosphatase of Escherichia coli K12. The uncC424 allele

1977 ◽  
Vol 164 (1) ◽  
pp. 193-198 ◽  
Author(s):  
F Gibson ◽  
G B Cox ◽  
J A Downie ◽  
J Radik
Keyword(s):  
Escherichia Coli ◽  
Electron Transport ◽  
Fluorescence Quenching ◽  
Mutant Strain ◽  
Mutant Allele ◽  
Adenosine Triphosphatase ◽  
Magnesium Ion ◽  
New Mutation ◽  
Similar Phenotype

A new mutant strain of Escherichia coli in which phosphorylation is uncoupled from electron transport was isolated. The new mutant strain has a similar phenotype to the uncB mutant described previously; results from reconstitution experiments in vitro indicate that the new mutation also affects a component of the F0 portion of the Mg2+-stimulated adenosine triphosphatase. A method was developed to incorporate mutant unc alleles into plasmids. Partial diploid strains were prepared in which the uncB402 allele was incorporated into the plasmid and the new unc mutation into the chromosome, or vice versa. Complementation between the mutant unc alleles was indicated by growth on succinate, growth yields on glucose, ATP-dependent transhydrogenase activities, ATP-induced atebrin-fluorescence quenching and oxidative-phosphorylation measurements. The gene in which the new mutation occurs is therefore distinct from the uncB gene, and the mutant allele was designated uncC424.

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.

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