A Transmembrane location for the proton‐translocating reduced ubiquinone→ nitrate reductase segment of the respiratory chain of <i>Escherichia coli</i>

Boxer, David H.; Clegg, Roger A.

doi:10.1016/0014-5793(75)80417-0

Cited by 35 publications

(34 citation statements)

References 17 publications

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“…Recently it was demonstrated that quinones participate also in the nitrate respiration system [8,9,33,34]. The effect of irradiation with near ultraviolet light on formate-nitrate driven glutamate transport are in agreement with these results (Fig.…”

Section: Involvement Of Quinones In Formate-dependent Ferricyanide Resupporting

confidence: 82%

“…The effect of near ultraviolet irradiation on transport energized by formate-nitrate and formate-ferricyanide suggests that quinones are involved in the electron transfer from formate to nitrate and to ferricyanide and ubiquinone itself appears to be an attractive candidate for the site of electron transfer. Such an indication has also been obtained by studies of the effects of nitrate respiration on proton translocation [9,34]. On the basis of these results Garland et al [9] presented a model of the nitrate respiration system in E. coli.…”

Section: Discussionmentioning

confidence: 77%

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Active Transport by Membrane Vesicles from Anaerobically Grown Escherichia coli Energized by Electron Transfer to Ferricyanide and Chlorate

Boonstra

Sips

Konings

1976

European Journal of Biochemistry

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Active transport of amino acids by membrane vesicles from Eschrricizicr cnli, grown anaerobically on glucose in the presence of nitrate, can be energized under anaerobic conditions by electron transfer in the nitrate respiration system with formate as electron donor and nitrate as acceptor. A high rate of amino acid transport is also obtained under anaerobic conditions by electron transfer from formate to the nitrate analogue chlorate or to the membrane-impermeable electron acceptor ferricyanide. Electron transfer from formate to nitrate results in the generation of an electrical potential as is indicated by the uptake of the lipophilic cation triphenylmethylphosphonium.Ferricyanide accepts electrons from at least two sites of the nitrate respiration system. One of these sites appears to be nitrate reductase, because cytochrome 6, reduced by formate, is completely reoxidized by ferricyanide and glutamate transport energized by formate plus ferricyanide and formate plus nitrate are affected by the same electron transfer inhibitors. A second site of electron transfer to ferricyanide appears to be located prior to nitrate reductase in the nitrate respiration system, since formate is oxidized at a higher rate in the presence of ferricyanide than with nitrate while formate/ferricyanide energizes transport of amino acids at a lower rate than formate/nitrate. Moreover, electron transfer inhibitors block electron transfer from formate to nitrate to a significantly higher extent than from formate to ferricyanide. The effects of irradiation of the membrane vesicles with near ultra-violet light suggest that quinones play an essential role in the electron transfer from formate to nitrate or ferricyanide. Irradiation blocks completely formate-dependent nitrate and ferricyanide reduction and active transport driven by formate/nitrate and formate/ferricyanide, but has hardly any effect on the activity of formate dehydrogenase and on ascorbate/phenazine methosulphatejoxygen-driven transport. Similar effects of ferricyanide have been observed in membrane vesicles from E. coli, grown anaerobically in the presence of fumarate. In these membrane vesicles a high rate of lactose and triphenylmethylphosphonium uptake under anaerobic conditions is obtained by electron transfer from glycerol 1 -phosphate to fumarate and also to ferricyanide and evidence has been presented for the involvement of cytochromes in these electron transfers.Active transport of many solutes by cytoplasmic membrane vesicles from a variety of bacteria can be energized by electron transfer in the absence of ATP or other nucleoside triphosphates [l -61. In membrane vesicles from Escherichia coli three distinct electron transfer systems can supply the energy for active transport of solutes. Active transport is coupled to the oxidation of D-lactate or phenazine methosulphate via the respiratory chain to oxygen as terminal electron acceptor in membrane vesicles from aerobically grown cells [l-41. Growth of E. coli under anaerobic conditions in the presence of nitrate ...

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Section: Involvement Of Quinones In Formate-dependent Ferricyanide Resupporting

confidence: 82%

Section: Discussionmentioning

confidence: 77%

Active Transport by Membrane Vesicles from Anaerobically Grown Escherichia coli Energized by Electron Transfer to Ferricyanide and Chlorate

Boonstra

Sips

Konings

1976

European Journal of Biochemistry

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“…Earlier studies on the arrangement of the subunits of nitrate reductase with the cytoplasmic membrane of .Y, coZi have failed to locate the /3-subunit [3,4] Nitrate reductase was purified as in [IO]. Contrary to the findings in [lo] but in accordance with those in [ 181, the isolated enzyme was free of spectroscopically detectable cytochrome.…”

Section: Labelling Of Isolated Nitrate Reductasementioning

confidence: 87%

“…Chemical modification of E. coli spheroplasts by lactoperoxidase-catalysed radio-iodination [3], transglutaminase-catalysed incorporation of dansyl cadaverine [4], ['*'I]DDISA, [35S]DABS and exposure to antibodies specific for the a-subunit of the enzyme [5], all fail to locate the a-subunit at the periplasmic surface of the membrane. All of these agents interact with the a-subunit in the isolated enzyme.…”

Section: Discussionmentioning

confidence: 99%

“…The use of artificial permeant and non-permeant reductants [2] has established that the cytochrome b-556No; can accept electrons at the periplasmic surface and that at least part of nitrate reductase is able to donate electrons to oxidised dyes at the internal surface of the cytoplasmic membrane. Lactoperoxidase-catalysed radio-iodination [3] has located the cytochrome b-556No; at the periplasmic face and the a-subunit ofnitrate reductase (M, 150 000) at the cytoplasmic face of the membrane. Thislocation of the a-subunit has been confirmed by transglutaminase-catalysed covalent labelling [4] and by immunofluorescence studies using antibodies specific for the a-subunit [ 51.…”

Section: Introductionmentioning

confidence: 99%

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