Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 50 for “"proton motive force"”.
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The Mechanism of Aerotaxis in SALMONELLA TYPHIMURIUM
… mutant displayed normal aerotaxis. The proton motive force fulfilled the requirements for the signal carrier. A temporal correlation between the response to an oxygen stimulus and changes in membrane potential was measured with the fluorescent cyanine dye diS-C<sub>3</sub>-(5) in a …
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Aerotaxis in HALOBACTERIUM HALOBIUM
… In a spatial assay a mutant strain lacking the proton motive force (pmf)-generating pigments, bacteriorhodopsin (bR) and halorhodopsin (hR), exhibited enhanced aerotaxis bands relative to the bR<sup>+</sup>hR<sup>+</sup> parent. The enhanced aerotaxis in the mutant cells was not due solely to an …
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Characterization of alternative enzymes in bacterial respiration
… coupling its reaction to the generation of a proton motive force. To qualitatively test for the generation of a proton motive force by the ACIII, lipophilic fluorescent dyes that respond to changes in either the pH gradient or the potential gradient across the membranes were used with …
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Studies on the cytochrome bd-type oxygen reductase superfamily and the discovery of a novel nitric oxide reductase
… during redox reactions to the creation of proton motive force. Combined with biochemical studies, the evolution of these superfamilies deduced from bioinformatics is very informative about the structural and functional features that are most useful to conserve energy by the creation of …
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Structural and biochemical studies of the regulation and catalytic mechanism of ATP synthase
… of ATP from ADP and orthophosphate by using the proton motive force established across a membrane by photosynthesis or oxidative phosphorylation. The ATP synthase of eukaryotic mitochondria is located in the inner membrane and is comprised of two domains. The globular F1 domain protrudes into the …
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Geochemistry and Microbiology of Extremely Alkaline (Ph > 12) Ground Water in the Calumet Slag -Fill Aquifer
… ions (H+) is likely to interfere with the proton motive force, and with the need to maintain a circum-neutral intracellular pH (Horikoshi and Akiba, 1982). Here I describe a diverse microbial community that inhabits extremely alkaline (pH ≈ 12--13) groundwater from the Lake Calumet …
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Investigations of the mechanism of mitochondrial complex I by electron cryomicroscopy
… the energy released to the translocation of four protons across the inner membrane, generating the proton motive force that powers vital cellular processes. The major question of how the energy liberated by NADH:ubiquinone oxidoreduction is captured and efficiently exploited to drive proton …
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Mechanistic insights into the secondary-active multidrug transporter LmrP
… is driven by the membrane potential and chemical proton gradient that exist across the plasma membrane as the two components of the proton motive force. We have previously demonstrated the role of catalytic carboxylates in LmrP in proton coupling. In this PhD project, the role of these …
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Elucidating mechanisms of toxicity and engineering Escherichia coli for tolerance of short chain fatty acids
… pH, γ-amino butyric acid determination, proton motive force simulation, genome reverse engineering, and biocatalyst zeta potential. These methods allow greater insight into the mechanisms of toxicity of carboxylic acids and how bacteria cells improve tolerance.</p> <p>Hexanoic, octanoic …
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Identifying the mechanism of second proton release from the bc1 complex Qo-site
… QH2 in a bifurcated reaction which generates a proton-motive force used for ATP synthesis. It is widely accepted to operate according to a modified Q-cycle, but there is still debate over some aspects of the mechanism. We used the pH-sensitive dye neutral red to study the release of protons from …
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Substrate targeting and recognition in the flagellar type III secretion pathway
… in the centre of each flagellum energised by the proton motive force (PMF) and facilitated by a cytoplasmic ATPase complex comprising FliH, FliI and FliJ, which are evolutionarily related to components of the F1 ATPase. Unfolded subunits transit the length of the channel to the flagellum tip where …
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Studies of the assembly pathway of human ATP synthase
… genome. The respiratory complexes generate the proton motive force (PMF), which ATP synthase uses to generate ATP from ADP and Pi. Rotation of the α- and β-subunits with the central stalk γ-, δ- and ε-subunits is prevented by coupling the F1 domain to the FO domain via the peripheral stalk (the …
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The AA3 Type Cytochrome C Oxidase From Rhodobacter Sphaeroides: Insights Into the Proton Pumping Mechanism From the N139D Mutation in the D-Channel
… and generates a transmembrane electrochemical proton gradient. This transmembrane gradient provides the proton-motive force that is used by ATP synthase to generate ATP from ADP and inorganic phosphate. The chemistry of the oxygen reduction reaction involves the uptake of electrons from the N …
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Structure and Dynamics of AcrA, a Periplasmic Component of a Multidrug Efflux Pump
… is the inner membrane (IM) pump that utilizes proton-motive force for the active transport, TolC is the outer membrane (OM) channel, and AcrA coordinates the actions of AcrB and TolC, so that substrates are expelled across the two membranes, bypassing the periplasm. It has been proposed that …
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Oxygen Sensing by the Aer and Tsr Receptors of Escherichia Coli
… (ETS) in a previously unidentified mechanism. Proton motive force (PMF) and electron flow were proposed as possible sensory signals but, distinguishing between the two was not possible, previously, in live, motile cells. I differentiated PMF from electron flow by creating a series of ETS mutant …
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Biohydrogen production in Escherichia coli – a synthetic biology approach
… could be improved by increasing/maintaining the proton motive force across the cytoplasmic membrane, through the heterologous expression of a proton-pumping proteorhodopsin. Finally the bidirectionality of E. coli Hyd-2, i.e. H2 oxidation and H2 production, was demonstrated, suggesting that it …
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Structural and functional studies of mitochondrial NADH:ubiquinone oxidoreductase (complex I)
… of ubiquinone, coupled to the translocation of protons across the mitochondrial inner membrane, maintaining the proton motive force used for ATP synthesis. Complex I is the least understood of the respiratory enzymes; although the mechanisms of NADH oxidation and intramolecular electron transfer …
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Transient intra- and extra-cellular thermometry as probes of thermogenesis
… changes during stimulated mitochondrial proton uncoupling in neurons of Aplysia californica. We find that a transient proton motive force dissipation is more dominant than steady-state substrate oxidation in stimulated thermogenesis. Our measurements demonstrate the utility of transient …
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Using molecular approaches to understand Complex I deficiency in mouse models
… electron transfer from NADH to ubiquinone to proton pumping across the mitochondrial inner membrane, and generates the proton motive force that drives ATP synthesis and transport processes. The ~1 MDa mammalian complex contains 45 subunits, and pathological mutations in both its mitochondrial …
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Structure and regulatory mechanism of human uncoupling protein 1
… is activated by free fatty acids and catalyses proton leak, dissipating the proton motive force, which mitochondria use to drive ATP synthesis. Therefore, UCP1 uncouples the oxidation of nutrients from the phosphorylation of ADP, releasing heat instead of generating ATP. The thermogenic …
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