Escherichia coli K-12 tolZ mutants tolerant to colicins E2, E3, D, Ia, and Ib: defect in generation of the electrochemical proton gradient.

1984 ◽  
Vol 160 (2) ◽  
pp. 733-739 ◽  
Author(s):  
H Matsuzawa ◽  
S Ushiyama ◽  
Y Koyama ◽  
T Ohta
Keyword(s):  
Escherichia Coli ◽  
Proton Gradient ◽  
Electrochemical Proton Gradient ◽  
K 12

The electrochemical proton gradient and phenylalanine transport in Escherichia coli irradiated with near-ultraviolet light

1977 ◽  
Vol 23 (12) ◽  
pp. 1683-1688 ◽  
Author(s):  
G. D. Sprott ◽  
J. R. Usher
Keyword(s):  
Escherichia Coli ◽  
Uv Light ◽  
Electrical Potential ◽  
Proton Gradient ◽  
Close Coupling ◽  
Near Ultraviolet ◽  
Chemical Potentials ◽  
Electrochemical Proton Gradient ◽  
Sufficient Energy ◽  
Phenylalanine Transport

Irradiation of Escherichia coli with near-ultraviolet (near-UV) light diminished the electrochemical proton gradient and the accumulation of L-phenylalanine. Inhibitors known to collapse the proton gradient and the comparison of two techniques measuring the electrical potential substantiated the estimates made. At several fluences (doses), a linear relationship was observed between the phenylalanine gradient and the combined electrical and chemical potentials (the electrochemical proton gradient), suggesting a close coupling between them. However, additional effects of near-UV light on the phenylalanine permease were not discounted. The combined potentials provided sufficient energy for the observed accumulation of phenylalanine, assuming a proton to amino acid cotransport ratio of 1. An increase in membrane permeability did not contribute to the loss of phenylalanine transport, as shown by an increase in the rate and extent of α-methylglucoside uptake.

Electrochemical proton gradient in inverted membrane vesicles from Escherichia coli

Biochemistry ◽  
1980 ◽  
Vol 19 (1) ◽  
pp. 1-9 ◽  
Author(s):  
William W. Reenstra ◽  
Lekha Patel ◽  
Hagai Rottenberg ◽  
H. Ronald Kaback
Keyword(s):  
Escherichia Coli ◽  
Membrane Vesicles ◽  
Proton Gradient ◽  
Electrochemical Proton Gradient ◽  
Inverted Membrane Vesicles
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