NADH-ubiquinone oxidoreductases of the Escherichia coli aerobic respiratory chain

Biochemistry ◽  
1987 ◽  
Vol 26 (24) ◽  
pp. 7732-7737 ◽  
Author(s):  
Kazunobu Matsushita ◽  
Tomoko Ohnishi ◽  
H. Ronald Kaback
Keyword(s):  
Escherichia Coli ◽  
Respiratory Chain ◽  
Ubiquinone Oxidoreductases

scholarly journals The oxygen reaction of the cytochrome d -terminated respiratory chain of Escherichia coli at sub-zero temperatures

FEBS Letters ◽  
1985 ◽  
Vol 190 (2) ◽  
pp. 227-231 ◽  
Author(s):  
C. Kumar ◽  
R.K. Pooler ◽  
I. Salmon ◽  
B. Chance
Keyword(s):  
Escherichia Coli ◽  
Respiratory Chain ◽  
Cytochrome D ◽  
Oxygen Reaction

scholarly journals Cultivation at high osmotic pressure confers ubiquinone 8–independent protection of respiration on Escherichia coli

2019 ◽  
Vol 295 (4) ◽  
pp. 981-993 ◽  
Author(s):  
Laura Tempelhagen ◽  
Anita Ayer ◽  
Doreen E. Culham ◽  
Roland Stocker ◽  
Janet M. Wood
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Escherichia Coli ◽  
Electron Transfer ◽  
Oxygen Uptake ◽  
Osmotic Pressure ◽  
Respiratory Chain ◽  
Membrane Lipid ◽  
E Coli ◽  
Uptake Rates

Ubiquinone 8 (coenzyme Q8 or Q8) mediates electron transfer within the aerobic respiratory chain, mitigates oxidative stress, and contributes to gene expression in Escherichia coli. In addition, Q8 was proposed to confer bacterial osmotolerance by accumulating during growth at high osmotic pressure and altering membrane stability. The osmolyte trehalose and membrane lipid cardiolipin accumulate in E. coli cells cultivated at high osmotic pressure. Here, Q8 deficiency impaired E. coli growth at low osmotic pressure and rendered growth osmotically sensitive. The Q8 deficiency impeded cellular O2 uptake and also inhibited the activities of two proton symporters, the osmosensing transporter ProP and the lactose transporter LacY. Q8 supplementation decreased membrane fluidity in liposomes, but did not affect ProP activity in proteoliposomes, which is respiration-independent. Liposomes and proteoliposomes prepared with E. coli lipids were used for these experiments. Similar oxygen uptake rates were observed for bacteria cultivated at low and high osmotic pressures. In contrast, respiration was dramatically inhibited when bacteria grown at the same low osmotic pressure were shifted to high osmotic pressure. Thus, respiration was restored during prolonged growth of E. coli at high osmotic pressure. Of note, bacteria cultivated at low and high osmotic pressures had similar Q8 concentrations. The protection of respiration was neither diminished by cardiolipin deficiency nor conferred by trehalose overproduction during growth at low osmotic pressure, but rather might be achieved by Q8-independent respiratory chain remodeling. We conclude that osmotolerance is conferred through Q8-independent protection of respiration, not by altering physical properties of the membrane.

Sign in / Sign up

Export Citation Format

Share Document