Interaction between Cytochrome caa3 and F1F0-ATP Synthase of Alkaliphilic Bacillus pseudofirmus OF4 Is Demonstrated by Saturation Transfer Electron Paramagnetic Resonance and Differential Scanning Calorimetry Assays

Li, Xiaoying; Gong, Xing; Hicks, David; Krulwich, Terry A.; Yu, Linda

doi:10.1021/bi0619167

Cited by 33 publications

(21 citation statements)

References 52 publications

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“…Sequestration could be mediated by fast movement of protons along the membrane surface as has been demonstrated in other systems (45,46) and by a "surface proton-motive" force of greater magnitude than the bulk proton-motive force (22,47). It is further possible that OXPHOS in some settings involves direct dynamic interactions between respiratory chain complexes and the ATP synthase, as was recently shown for alkaliphile cytochrome oxidase and ATP synthase in a reconstituted system (48). This study extends initial evidence that alkaliphilespecific motifs that are predicted to be just outside the membrane surface (26) or within the membrane are adaptations of the ATP synthase machinery itself that are required for OXPHOS in the alkaliphile context.…”

Section: Discussionmentioning

confidence: 77%

Characterization of the Functionally Critical AXAXAXA and PXXEXXP Motifs of the ATP Synthase c-Subunit from an Alkaliphilic Bacillus

Fujisawa²,

Hicks

et al. 2009

Journal of Biological Chemistry

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The membrane-embedded rotor in the F 0 sector of protontranslocating ATP synthases is formed from hairpin-like c-subunits that are protonated and deprotonated during energization of ATP synthesis. This study focuses on two c-subunit motifs that are unique to synthases of extremely alkaliphilic Bacillus species. One motif is the AXAXAXA sequence found in the N-terminal helix-1 instead of the GXGXGXG of non-alkaliphiles. Quadruple A3 G chromosomal mutants of alkaliphilic Bacillus pseudofirmus OF4 retain 50% of the wild-type hydrolytic activity (ATPase) but <18% of the ATP synthase capacity at high pH. Consistent with a structural impact of the four alanine replacements, the mutant ATPase activity showed enhanced inhibition by dicyclohexylcarbodiimide, which blocks the helix-2 carboxylate. Single, double, or triple A3 G mutants exhibited more modest defects, as monitored by malate growth. The key carboxylate is in the second motif, which is P 51 XXE 54 XXP in extreme alkaliphiles instead of the (A/G)XX(E/ D)XXP found elsewhere. Mutation of Pro 51 to alanine had been shown to severely reduce malate growth and ATP synthesis at high pH. Here, two Pro 51 to glycine mutants of different severities retained ATP synthase capacity but exhibited growth deficits and proton leakiness. A Glu 54 to Asp 54 change increased proton leakiness and reduced malate growth 79 -90%. The Pro 51 and the Glu 54 mutants were both more dicyclohexylcarbodiimide-sensitive than wild type. The results highlight the requirement for c-subunit adaptations to achieve alkaliphile ATP synthesis with minimal cytoplasmic proton loss and suggest partial suppression of some mutations by changes outside the atp operon.

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Section: Discussionmentioning

confidence: 77%

Characterization of the Functionally Critical AXAXAXA and PXXEXXP Motifs of the ATP Synthase c-Subunit from an Alkaliphilic Bacillus

Fujisawa²,

Hicks

et al. 2009

Journal of Biological Chemistry

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“…Enlarged c rings are also found in alkaliphilic cyanobacteria (21,22). The observation in B. pseudofirmus OF4 that the caa 3 terminal oxidase interacts with the F 1 F o -ATP synthase in a 1:1 stoichiometry suggests that these two complexes may be coordinately regulated to achieve optimal ATP synthesis coupled to proton pumping of the respiratory chain to generate the membrane potential (12). Current studies are aimed at determining the transcriptional response of C. thermarum strain TA2.A1 to external pH to identify the gene complement required for thermoalkaliphilic growth.…”

Section: Resultsmentioning

confidence: 97%

Nonfermentative Thermoalkaliphilic Growth Is Restricted to Alkaline Environments

McMillan

Keis

Berney

et al. 2009

Appl Environ Microbiol

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Caldalkalibacillus thermarum strain TA2.A1 grew in pH-controlled batch culture containing a fermentable growth substrate (i.e., sucrose) from pH 7.5 to 10.0 with no significant change in the specific growth rate, suggesting that this bacterium was a facultative alkaliphile. However, when strain TA2.A1 was grown on a nonfermentable carbon source, such as succinate or malate, no growth was observed until the external pH was >9.0, suggesting that this bacterium was an obligate alkaliphile. Succinate transport and sucrose transport by strain TA2.A1 showed pH profiles similar to that of growth on these carbon sources, and the molar growth yield on sucrose was higher at pH 9.5 than at pH 7.5, despite the increased energy demands on the cell for intracellular pH regulation. Succinate transport, succinate-dependent oxygen consumption, and succinate dehydrogenase and F 1 F o -ATPase specific activities were all significantly lower in cultures of strain TA2.A1 grown at pH 7.5 than in those cultured at pH 9.5. No significant ATP synthesis via the F 1 F o -ATP synthase was detected until the external pH was >8.5. On the basis of these results, we propose that nonfermentative thermoalkaliphilic growth is specialized to function at high pH values, but not at pH values near neutral pH.Alkaliphilic microorganisms have been isolated from a diverse range of environments and have traditionally been classified into two distinct groups based on their pH profile for growth (8). Bacteria that grow across a broad pH range from 7.0 to 11.0 have been classified as facultative alkaliphiles (e.g., Bacillus pseudofirmus OF4) (28), and those that are able to grow only above pH 9.0 have been classified as obligate alkaliphiles (e.g., Bacillus alcalophilus) (4). The reasons why obligate alkaliphiles fail to grow below pH 9.0 remain speculative.While the classification of alkaliphilic bacteria based on pH profiles for growth has gained universal acceptance, it does not consider the nature of the carbon source that is used to grow the cells, and for aerobic alkaliphiles, this may have important consequences. For example, growth on succinate in aerobic bacteria is strictly coupled to oxidative phosphorylation and ATP is produced in the cell via the membrane-bound F 1 F o -ATP synthase. Growth on fermentable carbon sources, such as glucose, allows the cells to bypass this machinery, as ATP can be produced via substrate-level phosphorylation and incomplete oxidation of glucose to acetate can occur.A thermoalkaliphilic bacterium, Bacillus sp. strain TA2.A1, capable of optimal aerobic growth at a temperature of 65°C at pH 9.5 was isolated from an alkaline thermal bore at Mt. Te Aroha, New Zealand (19). The 16S rRNA gene sequence of strain TA2.A1, compared with those available in the EMBL database, shows 99.5% similarity to Caldalkalibacillus thermarum strain HA6T , an aerobic, heterotrophic, thermophilic bacterium isolated from an alkaline hot spring in China (30). On the basis of the similarity of its phenotypic and genotypic characteristics to thos...

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“…Although little is known regarding a possible interaction between ATP synthase and respiratory proton translocating complexes, the interaction between the caa 3 oxygen reductase and the ATP synthase of Bacillus pseudofirmus has been suggested [24]. Furthermore, oligomers of ATP synthase have been reported in bovine heart mitochondria and seem to shape the inner membrane cristae [25].…”

Section: Introductionmentioning

confidence: 99%

Supramolecular organizations in the aerobic respiratory chain of Escherichia coli

et al. 2011

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a b s t r a c tThe organization of respiratory chain complexes in supercomplexes has been shown in the mitochondria of several eukaryotes and in the cell membranes of some bacteria. These supercomplexes are suggested to be important for oxidative phosphorylation efficiency and to prevent the formation of reactive oxygen species.Here we describe, for the first time, the identification of supramolecular organizations in the aerobic respiratory chain of Escherichia coli, including a trimer of succinate dehydrogenase. Furthermore, two heterooligomerizations have been shown: one resulting from the association of the NADH:quinone oxidoreductases NDH-1 and NDH-2, and another composed by the cytochrome bo 3 quinol:oxygen reductase, cytochrome bd quinol:oxygen reductase and formate dehydrogenase (fdo). These results are supported by blue native-electrophoresis, mass spectrometry and kinetic data of wild type and mutant E . coli strains.

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Interaction between Cytochrome caa₃ and F₁F₀-ATP Synthase of Alkaliphilic Bacillus pseudofirmus OF4 Is Demonstrated by Saturation Transfer Electron Paramagnetic Resonance and Differential Scanning Calorimetry Assays

Cited by 33 publications

References 52 publications

Characterization of the Functionally Critical AXAXAXA and PXXEXXP Motifs of the ATP Synthase c-Subunit from an Alkaliphilic Bacillus

Characterization of the Functionally Critical AXAXAXA and PXXEXXP Motifs of the ATP Synthase c-Subunit from an Alkaliphilic Bacillus

Nonfermentative Thermoalkaliphilic Growth Is Restricted to Alkaline Environments

Supramolecular organizations in the aerobic respiratory chain of Escherichia coli

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