scholarly journals Proton-motive-force-dependent step in the pathway to lysis of Escherichia coli induced by bacteriophage phi X174 gene E product.

1987 ◽  
Vol 169 (4) ◽  
pp. 1750-1752 ◽  
Author(s):  
A Witte ◽  
W Lubitz ◽  
E P Bakker
Keyword(s):  
Escherichia Coli ◽  
Proton Motive Force ◽  
Motive Force

scholarly journals Changes in the proton-motive force in Escherichia coli in response to external oxidoreduction potential

1999 ◽  
Vol 262 (2) ◽  
pp. 595-599 ◽  
Author(s):  
Christophe Riondet ◽  
Remy Cachon ◽  
Yves Wache ◽  
, Gerard Alcaraz ◽  
Charles Divies
Keyword(s):  
Escherichia Coli ◽  
Proton Motive Force ◽  
Motive Force ◽  
Oxidoreduction Potential

scholarly journals In Vivo Synthesis of the Periplasmic Domain of TonB Inhibits Transport through the FecA and FhuA Iron Siderophore Transporters of Escherichia coli

2001 ◽  
Vol 183 (20) ◽  
pp. 5885-5895 ◽  
Author(s):  
S. Peter Howard ◽  
Christina Herrmann ◽  
Chad W. Stratilo ◽  
V. Braun
Keyword(s):  
Escherichia Coli ◽  
Cytoplasmic Membrane ◽  
Signal Sequence ◽  
Outer Membrane Proteins ◽  
Proton Motive Force ◽  
Motive Force ◽  
In Vivo Studies ◽  
Siderophore Transport

ABSTRACT The siderophore transport activities of the two outer membrane proteins FhuA and FecA of Escherichia coli require the proton motive force of the cytoplasmic membrane. The energy of the proton motive force is postulated to be transduced to the transport proteins by a protein complex that consists of the TonB, ExbB, and ExbD proteins. In the present study, TonB fragments lacking the cytoplasmic membrane anchor were exported to the periplasm by fusing them to the cleavable signal sequence of FecA. Overexpressed TonB(33-239), TonB(103-239), and TonB(122-239) fragments inhibited transport of ferrichrome by FhuA and of ferric citrate by FecA, transcriptional induction of the fecABCDE transport genes by FecA, infection by phage φ80, and killing of cells by colicin M via FhuA. Transport of ferrichrome by FhuAΔ5-160 was also inhibited by TonB(33-239), although FhuAΔ5-160 lacks the TonB box which is involved in TonB binding. The results show that TonB fragments as small as the last 118 amino acids of the protein interfere with the function of wild-type TonB, presumably by competing for binding sites at the transporters or by forming mixed dimers with TonB that are nonfunctional. In addition, the interactions that are inhibited by the TonB fragments must include more than the TonB box, since transport through corkless FhuA was also inhibited. Since the periplasmic TonB fragments cannot assume an energized conformation, these in vivo studies also agree with previous cross-linking and in vitro results, suggesting that neither recognition nor binding to loaded siderophore receptors is the energy-requiring step in the TonB-receptor interactions.

scholarly journals The role of the proton motive force and electron flow in solute transport in Escherichia coli

1985 ◽  
Vol 153 (1) ◽  
pp. 161-165 ◽  
Author(s):  
Marieke G. L. ELFERINK ◽  
Klaas J. HELLINGWERF ◽  
Wil N. KONINGS
Keyword(s):  
Escherichia Coli ◽  
Solute Transport ◽  
Electron Flow ◽  
Proton Motive Force ◽  
Motive Force

scholarly journals Dissipation of Proton Motive Force is not Sufficient to Induce the Phage Shock Protein Response in Escherichia coli

2011 ◽  
Vol 62 (5) ◽  
pp. 1374-1385 ◽  
Author(s):  
Christoph Engl ◽  
Alex Ter Beek ◽  
Martijn Bekker ◽  
Joost Teixeira de Mattos ◽  
Goran Jovanovic ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Proton Motive Force ◽  
Motive Force ◽  
Protein Response

scholarly journals The effects of partial and selective reduction in the components of the proton-motive force on lactose uptake in Escherichia coli

1981 ◽  
Vol 200 (3) ◽  
pp. 583-589 ◽  
Author(s):  
S Ahmed ◽  
I R Booth
Keyword(s):  
Escherichia Coli ◽  
Steady State ◽  
Membrane Potential ◽  
Selective Reduction ◽  
Proton Motive Force ◽  
Motive Force ◽  
Ph Gradient ◽  
A Value ◽  
The Relationship ◽  
Lactose Transport

The relationship between the steady state lactose accumulation (delta plac) and the magnitude of the membrane potential (delta psi) and pH gradient (delta pH) has been studied at pHo5.5 and pHo7.5. An attempt has been made to differentiate between two possible means by which lactose accumulation may be reduced below the proton-motive force (delta p). Firstly, that delta psi and delta pH are not equivalent in driving lactose transport and secondly, that ‘slip’ reactions (beta-galactoside exit via the carrier without a proton) may reduce accumulation. The data support the latter; however, our conclusions are tempered by the observation that the apparent stoichiometry (delta plac/delta p) increases to a value of at least 2 at values of delta p below 130 mV.

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