Are Escherichia coli OXPHOS complexes concentrated in specialized zones within the plasma membrane?

2008 ◽  
Vol 36 (5) ◽  
pp. 1032-1036 ◽  
Author(s):  
Tchern Lenn ◽  
Mark C. Leake ◽  
Conrad W. Mullineaux
Keyword(s):  
Escherichia Coli ◽  
Plasma Membrane ◽  
Respiratory Function ◽  
Mitochondrial Membrane ◽  
Terminal Oxidase ◽  
Inner Mitochondrial Membrane ◽  
High Concentration ◽  
E Coli ◽  
Cytochrome Bd ◽  
Biochemical Level

Most organisms are able to synthesize ATP by OXPHOS (oxidative phosphorylation). Mitochondria in eukaryotes perform OXPHOS in the inner mitochondrial membrane, whereas the plasma membrane is used by prokaryotes. However, whereas OXPHOS is a well-understood process at the biochemical level, relatively little is known about its operation at the level of the whole-organelle/cell. We observed that a fluorescently labelled terminal oxidase, the cytochrome bd complex, is heterogeneously distributed in the Escherichia coli plasma membrane. This observation forms the basis of a working hypothesis that patches of the E. coli plasma membrane (‘respirazones’) are dedicated to respiratory function by the high concentration of OXPHOS components in these zones relative to the adjacent membrane. The formulation and physiological significance of this hypothesis are discussed in this paper.

scholarly journals Cardiolipin enhances the enzymatic activity of cytochrome bd and cytochrome bo3 solubilized in dodecyl-maltoside

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amer H. Asseri ◽  
Albert Godoy-Hernandez ◽  
Hojjat Ghasemi Goojani ◽  
Holger Lill ◽  
Junshi Sakamoto ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Oxygen Consumption ◽  
Integral Membrane Proteins ◽  
Terminal Oxidase ◽  
Geobacillus Thermodenitrificans ◽  
E Coli ◽  
Cytochrome Bd ◽  
Cytochrome Bo3 ◽  
Dodecyl Maltoside ◽  
Consumption Activity

AbstractCardiolipin (CL) is a lipid that is found in the membranes of bacteria and the inner membranes of mitochondria. CL can increase the activity of integral membrane proteins, in particular components of respiratory pathways. We here report that CL activated detergent-solubilized cytochrome bd, a terminal oxidase from Escherichia coli. CL enhanced the oxygen consumption activity ~ twofold and decreased the apparent KM value for ubiquinol-1 as substrate from 95 µM to 35 µM. Activation by CL was also observed for cytochrome bd from two Gram-positive species, Geobacillus thermodenitrificans and Corynebacterium glutamicum, and for cytochrome bo3 from E. coli. Taken together, CL can enhance the activity of detergent-solubilized cytochrome bd and cytochrome bo3.

scholarly journals In Escherichia coli Ammonia Inhibits Cytochrome bo3 But Activates Cytochrome bd-I

Antioxidants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 13
Author(s):  
Elena Forte ◽  
Sergey A. Siletsky ◽  
Vitaliy B. Borisov
Keyword(s):  
Escherichia Coli ◽  
Molecular Mechanisms ◽  
Dissociation Constants ◽  
Reductase Activity ◽  
Ammonia Concentration ◽  
High Concentration ◽  
E Coli ◽  
Cytochrome Bd ◽  
Cytochrome Bo3 ◽  
Oxygen Reductase

Interaction of two redox enzymes of Escherichia coli, cytochrome bo3 and cytochrome bd-I, with ammonium sulfate/ammonia at pH 7.0 and 8.3 was studied using high-resolution respirometry and absorption spectroscopy. At pH 7.0, the oxygen reductase activity of none of the enzymes is affected by the ligand. At pH 8.3, cytochrome bo3 is inhibited by the ligand, with 40% maximum inhibition at 100 mM (NH4)2SO4. In contrast, the activity of cytochrome bd-I at pH 8.3 increases with increasing the ligand concentration, the largest increase (140%) is observed at 100 mM (NH4)2SO4. In both cases, the effector molecule is apparently not NH4+ but NH3. The ligand induces changes in absorption spectra of both oxidized cytochromes at pH 8.3. The magnitude of these changes increases as ammonia concentration is increased, yielding apparent dissociation constants Kdapp of 24.3 ± 2.7 mM (NH4)2SO4 (4.9 ± 0.5 mM NH3) for the Soret region in cytochrome bo3, and 35.9 ± 7.1 and 24.6 ± 12.4 mM (NH4)2SO4 (7.2 ± 1.4 and 4.9 ± 2.5 mM NH3) for the Soret and visible regions, respectively, in cytochrome bd-I. Consistently, addition of (NH4)2SO4 to cells of the E. coli mutant containing cytochrome bd-I as the only terminal oxidase at pH 8.3 accelerates the O2 consumption rate, the highest one (140%) being at 27 mM (NH4)2SO4. We discuss possible molecular mechanisms and physiological significance of modulation of the enzymatic activities by ammonia present at high concentration in the intestines, a niche occupied by E. coli.

scholarly journals A factor produced by Escherichia coli K-12 inhibits the growth of E. coli mutants defective in the cytochrome bd quinol oxidase complex: enterochelin rediscovered

Microbiology ◽  
1998 ◽  
Vol 144 (12) ◽  
pp. 3297-3308 ◽  
Author(s):  
G. M. Cook ◽  
C. Loder ◽  
B. Soballe ◽  
G. P. Stafford ◽  
J. Membrillo-Hernandez ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Quinol Oxidase ◽  
E Coli ◽  
Cytochrome Bd ◽  
K 12

scholarly journals The Impact of Plasma Membrane Lipid Composition on Flagellum-Mediated Adhesion of Enterohemorrhagic Escherichia coli

mSphere ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Hélène Cazzola ◽  
Laurine Lemaire ◽  
Sébastien Acket ◽  
Elise Prost ◽  
Luminita Duma ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Plasma Membrane ◽  
Fatty Acid ◽  
Linolenic Acid ◽  
Lipid Rafts ◽  
Bacterial Adhesion ◽  
Human Pathogen ◽  
Content Type ◽  
E Coli ◽  
The Impact

ABSTRACT Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a major cause of foodborne gastrointestinal illness. The adhesion of EHEC to host tissues is the first step enabling bacterial colonization. Adhesins such as fimbriae and flagella mediate this process. Here, we studied the interaction of the bacterial flagellum with the host cell’s plasma membrane using giant unilamellar vesicles (GUVs) as a biologically relevant model. Cultured cell lines contain many different molecular components, including proteins and glycoproteins. In contrast, with GUVs, we can characterize the bacterial mode of interaction solely with a defined lipid part of the cell membrane. Bacterial adhesion on GUVs was dependent on the presence of the flagellar filament and its motility. By testing different phospholipid head groups, the nature of the fatty acid chains, or the liposome curvature, we found that lipid packing is a key parameter to enable bacterial adhesion. Using HT-29 cells grown in the presence of polyunsaturated fatty acid (α-linolenic acid) or saturated fatty acid (palmitic acid), we found that α-linolenic acid reduced adhesion of wild-type EHEC but not of a nonflagellated mutant. Finally, our results reveal that the presence of flagella is advantageous for the bacteria to bind to lipid rafts. We speculate that polyunsaturated fatty acids prevent flagellar adhesion on membrane bilayers and play a clear role for optimal host colonization. Flagellum-mediated adhesion to plasma membranes has broad implications for host-pathogen interactions. IMPORTANCE Bacterial adhesion is a crucial step to allow bacteria to colonize their hosts, invade tissues, and form biofilm. Enterohemorrhagic Escherichia coli O157:H7 is a human pathogen and the causative agent of diarrhea and hemorrhagic colitis. Here, we use biomimetic membrane models and cell lines to decipher the impact of lipid content of the plasma membrane on enterohemorrhagic E. coli flagellum-mediated adhesion. Our findings provide evidence that polyunsaturated fatty acid (α-linolenic acid) inhibits E. coli flagellar adhesion to the plasma membrane in a mechanism separate from its antimicrobial and anti-inflammatory functions. In addition, we confirm that cholesterol-enriched lipid microdomains, often called lipid rafts, are important in bacterial adhesion. These findings demonstrate that plasma membrane adhesion via bacterial flagella play a significant role for an important human pathogen. This mechanism represents a promising target for the development of novel antiadhesion therapies.

scholarly journals Bacterial plasma membrane is the main cellular target of silver nanoparticles in Escherichia coli and Pseudomonas aeruginosa

2018 ◽  
Author(s):  
Olesja M Bondarenko ◽  
Mariliis Sihtmäe ◽  
Julia Kuzmičiova ◽  
Lina Ragelienė ◽  
Anne Kahru ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Silver Nanoparticles ◽  
Plasma Membrane ◽  
Antimicrobial Properties ◽  
Consumer Products ◽  
Minimal Bactericidal Concentration ◽  
Flow Cytometry Analysis ◽  
E Coli ◽  
Cellular Target

ABSTRACTSilver nanoparticles (AgNP) are widely used in consumer products, mostly due to their excellent antimicrobial properties. One of the well-established antibacterial mechanisms of AgNP is their efficient contact with bacteria and dissolution on cell membranes. To our knowledge, the primary mechanism of cell wall damage and the event(s) initiating bactericidal action of AgNP are not yet elucidated.In this study we used a combination of different assays to reveal the effect of AgNP on i) bacterial envelope in general, ii) outer membrane (OM) and iii) on plasma membrane (PM). We showed that bacterial PM was the main target of AgNP in Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. AgNP depolarized bacterial PM, induced the leakage of the intracellular K+, inhibited respiration and caused the depletion of the intracellular ATP. In contrast, AgNP had no significant effect on the bacterial OM. Most of the adverse effects on bacterial envelope and PM occurred within the seconds and in the concentration range of 7-160 μM AgNP, depending on the bacteria and assay used, while irreversible inhibition of bacterial growth (minimal bactericidal concentration after 1-h exposure of bacteria to AgNP) occurred at 40 μM AgNP for P. aeruginosa and at 320 μM AgNP for E. coli.Flow cytometry analysis showed that AgNP were binding to P. aeruginosa but not to E. coli cells and were found inside the P. aeruginosa cells. Taking into account that AgNP did not damage OM, we speculate that AgNP entered P. aeruginosa via specific mechanism, e.g., transport through porins.

scholarly journals Ethanol production by Escherichia coli from detoxified lignocellulosic teak wood hydrolysates with high concentration of phenolic compounds

2021 ◽  
Author(s):  
Estefanía Sierra-Ibarra ◽  
Jorge Alcaraz-Cienfuegos ◽  
Alejandra Vargas-Tah ◽  
Alberto Rosas-Aburto ◽  
Ángeles Valdivia-López ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Phenolic Compounds ◽  
Ethanol Production ◽  
Enzymatic Saccharification ◽  
Coli Strain ◽  
High Concentration ◽  
E Coli ◽  
Thermochemical Pretreatment ◽  
Teak Wood ◽  
Ethanologenic Escherichia Coli

Abstract Teak wood residues were subjected to thermochemical pretreatment, enzymatic saccharification, and detoxification to obtain syrups with a high concentration of fermentable sugars for ethanol production with the ethanologenic Escherichia coli strain MS04. Teak is a hardwood, and thus a robust deconstructive pretreatment was applied followed by enzymatic saccharification. The resulting syrup contained 60 g L−1 glucose, 18 g L−1 xylose, 6 g L−1 acetate, less than 0.1 g L−1 of total furans, and 12 g L−1 of soluble phenolic compounds (SPC). This concentration of SPC is toxic to E. coli, and thus two detoxification strategies were assayed: 1) treatment with Coriolopsis gallica laccase followed by addition of activated carbon and 2) overliming with Ca(OH)2. These reduced the phenolic compounds by 40 and 76%, respectively. The detoxified syrups were centrifuged and fermented with E. coli MS04. Cultivation with the over-limed hydrolysate showed a 60% higher volumetric productivity (0.45 gETOH L−1 h−1). The bioethanol/sugars yield was over 90% in both strategies.

scholarly journals In Vitro Studies with Purified Components Reveal Signal Recognition Particle (SRP) and SecA/SecB as Constituents of Two Independent Protein-targeting Pathways of Escherichia coli

1999 ◽  
Vol 10 (7) ◽  
pp. 2163-2173 ◽  
Author(s):  
Hans-Georg Koch ◽  
Thomas Hengelage ◽  
Christoph Neumann-Haefelin ◽  
Juan MacFarlane ◽  
Hedda K. Hoffschulte ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Plasma Membrane ◽  
Membrane Proteins ◽  
Signal Recognition Particle ◽  
Membrane Vesicles ◽  
Secretory Proteins ◽  
Signal Recognition ◽  
Free System ◽  
E Coli

The molecular requirements for the translocation of secretory proteins across, and the integration of membrane proteins into, the plasma membrane of Escherichia coli were compared. This was achieved in a novel cell-free system from E. coliwhich, by extensive subfractionation, was simultaneously rendered deficient in SecA/SecB and the signal recognition particle (SRP) components, Ffh (P48), 4.5S RNA, and FtsY. The integration of two membrane proteins into inside-out plasma membrane vesicles of E. coli required all three SRP components and could not be driven by SecA, SecB, and ΔμH+. In contrast, these were the only components required for the translocation of secretory proteins into membrane vesicles, a process in which the SRP components were completely inactive. Our results, while confirming previous in vivo studies, provide the first in vitro evidence for the dependence of the integration of polytopic inner membrane proteins on SRP in E. coli. Furthermore, they suggest that SRP and SecA/SecB have different substrate specificities resulting in two separate targeting mechanisms for membrane and secretory proteins in E. coli. Both targeting pathways intersect at the translocation pore because they are equally affected by a blocked translocation channel.

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