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  • Articles  (17)
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  • Blackwell Publishing Ltd
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  • 2000-2004
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  • Springer  (17)
  • American Geophysical Union
  • American Institute of Physics (AIP)
  • American Physical Society
  • Blackwell Publishing Ltd
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  • 2000-2004
  • 1995-1999  (17)
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  • 1
    Electronic Resource
    Electronic Resource
    Reconstitution of the Mitochondrial ATP-Dependent Potassium Channel into Bilayer Lipid Membrane1 (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 159-163 
    Details
    ISSN: 1573-6881
    Keywords: KATP-channel ; solubilization ; mitochondria ; bilayer lipid membrane ; reconstruction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Electrical properties and regulation of the mitochondrialATP-dependent potassium channel were studied. The channel protein wassolubilized from the mitochondrial membrane using an ethanol/water mixture.Reconstituted into a bilayer lipid membrane BLM), the protein formed aslightly voltage-dependent channel with a conductance of 10 pS in 100 mM KCl.Often, several channels worked simultaneously (clusters) when many channelswere incorporated into the BLM. The elementary channel and the clusters wereboth highly potassium selective. At concentrations of 1 to 10 μM, ATPfavors channel opening, while channels become closed at 1–3 mM ATP. GDP(0.5 mM) reactivated the ATP-closed channels without affecting the untreatedchannels. The sulfhydryl-reducing agent ditiothreitol increased the openprobability at concentrations of 1 to 3 mM, but damaged the selectivity ofthe channel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005408029549
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  • 2
    Electronic Resource
    Electronic Resource
    A History of the First Uncoupling Protein, UCP1 (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 399-406 
    Details
    ISSN: 1573-6881
    Keywords: Brown adipose tissue ; mitochondria ; uncoupling protein ; UCP1 ; transport ; nucleotide ; fatty acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The lack of energy conservation in brown adipose tissue mitochondria when prepared byconventional methods was established in the 1960s and was correlated with the thermogenicfunction of the tissue. In order to observe energy conservation, two requirements had to bemet: the removal of the endogenous fatty acids and the addition of a purine nucleotide. Thesetwo factors have been the essential tools that led to the discovery of the energy dissipationpathway, the uncoupling protein UCP1. The activity is regulated by these two ligands. Purinenucleotides bind from the cytosolic side of the protein and inhibit transport. Fatty acids actas seconds messengers of noradrenaline and increase the proton conductance. This reviewpresents a historical perspective of the steps that led to the discovery of UCP1, its regulation,and our current view on its mechanism of transport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005436121005
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  • 3
    Electronic Resource
    Electronic Resource
    The Mechanisms of Fatty Acid-Induced Proton Permeability of the Inner Mitochondrial Membrane (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 447-455 
    Details
    ISSN: 1573-6881
    Keywords: Fatty acid ; uncoupling ; proton permeability ; adenine nucleotide translocase ; dicarboxylate carrier, glutamate/aspartate carrier ; permeability transition pore ; mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Nonesterified long-chain fatty acids have long been known as uncouplers of oxidativephosphorylation. They are efficient protonophores in the inner mitochondrial membrane but not so inartificial phospholipid membranes. In the un-ionized form, they undergo a rapid spontaneoustransbilayer movement (flip-flop). However, the transbilayer passage of the dissociated(anionic) form is hindered by the negatively charged hydrophilic carboxylic group. In theinner mitochondrial membrane, the transfer of fatty acid anions is mediated by the adeninenucleotide translocase, the dicarboxylate carrier, and the glutamate/aspartate carrier. As a result,the passage of protons and electric charges is a concerted effect of the spontaneous flip-flopof the undissociated (protonated) form in one direction and carrier-facilitated transfer of theionized (deprotonated) form in the other direction. In addition, fatty acids also promote openingof the mitochondrial permeability transition pore, presumably due to their interaction with oneof its constituents, the adenine nucleotide translocase, thus forming an additional route fordissipation of the proton gradient. Structural prerequisites for these proton-conductingmechanisms are (1) a weakly ionized carboxylic group and (2) a hydrocarbon chain of appropriatelength without substituents limiting its mobility and hydrophobicity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005444322823
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  • 4
    Electronic Resource
    Electronic Resource
    Mitochondrial Redox Signaling during Apoptosis (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 327-334 
    Details
    ISSN: 1573-6881
    Keywords: Apoptosis ; redox ; mitochondria ; E h ; ROS ; ASK-1 ; thioredoxin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The regulatory role of cellular redox state during apoptosis is still controversial. Early redoxsignaling can transduce divergent upstream signals to mitochondria and initiate apoptosis. Onthe other hand, release of mitochondrial cytochrome c triggers generation of reactive oxygenspecies (ROS) and renders apoptotic cells much more oxidized. Although the sequential caspaseactivation does not have apparent redox-sensitive components, redox signaling provides aseparate pathway that is parallel with the caspase cascade. The function of theapoptosis-associated redox change is uncertain. It could provide positive feedback mechanisms, such asactivating mitochondrial permeability transition and apoptosis signaling kinase (ASK-1). Sinceapoptotic cells are designated to be quickly eliminated, the dramatic cellular oxidation couldbe involved in the final degradation of apoptotic bodies and even the termination of theproteolytic activity after phagocytosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005423818280
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  • 5
    Electronic Resource
    Electronic Resource
    Mitochondrial Oxygen Radical Generation and Leak: Sites of Production in States 4 and 3, Organ Specificity, and Relation to Aging and Longevity (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 347-366 
    Details
    ISSN: 1573-6881
    Keywords: Free radicals ; H2O2 ; complex I ; heart ; brain ; free-radical leak ; complex III ; mitochondria ; aging ; longevity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Studies in heart and nonsynaptic brain mitochondria from two mammals and three birds showthat complex I generates oxygen radicals in heart and nonsynaptic brain mitochondria in States4 and 3, whereas complex III does it only in heart mitochondria and only in State 4. Theincrease in oxygen consumption during the State 4 to 3 transition is not accompanied by aproportional increase in oxygen radical generation. This will protect mitochondria and tissuesduring bursts of activity. Comparisons between young and old rodents do not show a consistentpattern of variation in mitochondrial oxygen radical production during aging. However, allthe interspecies comparisons performed to date between different mammals, and betweenmammals and birds, agree that animals with high maximum longevities have low rates ofmitochondrial oxygen radical production, irrespective of the value of their basal specificmetabolic rate. The sites and mechanisms allowing this, the recently described low degree ofmembrane fatty acid unsaturation of longevous animals, and their relation to longevity andaging are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005427919188
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  • 6
    Electronic Resource
    Electronic Resource
    Anion Carriers in Fatty Acid-Mediated Physiological Uncoupling (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 431-445 
    Details
    ISSN: 1573-6881
    Keywords: Uncoupling ; thermoregulation ; mitochondria ; ATP/ADP antiporter ; aspartate/glutamate antiporter ; uncoupling proteins 1, 2, 3 ; plant uncoupling protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Physiological aspects of uncoupling of oxidation and phosphorylation are reviewed in thecontext of involvement of mitochondrial anion carriers. It is assumed that the carriers facilitateelectrophoretic translation of fatty acid anion, RCOO-, from the inner to the outer leaflet ofthe mitochondrial membrane, whereas back movement of the protonated fatty acid, RCOOH,from the outer to the inner leaflet represents flip-flop of RCOOH via the phospholipid bilayerof the membrane. The RCOO- transport seems to be catalyzed by the ATP/ADP and aspartate/glutamate antiporters, dicarboxylate carrier, and uncoupling proteins (UCP1, UCP2, UCP3L,UCP3s, and plant UCP). The fatty acid uncoupling is shown to be involved in thethermoregulatory heat production in animals and plants exposed to cold, as well as in performance ofrespiratory functions other than ATP synthesis, i.e., formation of useful substances,decomposition of unwanted substances, and antioxidant defense. Moreover, partial uncoupling might takepart in optimization of the rate of ATP synthesis in aerobic cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005492205984
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  • 7
    Electronic Resource
    Electronic Resource
    Mitochondrial Proton Leak and the Uncoupling Proteins (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 517-524 
    Details
    ISSN: 1573-6881
    Keywords: Proton leak ; uncoupling proteins ; UCP1 ; UCP2 ; UCP3 ; BMCP1 ; thermogenesis ; sequence homology ; mitochondria ; respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract An energetically significant leak of protons occurs across the mitochondrial inner membranesof eukaryotic cells. This seemingly wasteful proton leak accounts for at least 20% of thestandard metabolic rate of a rat. There is evidence that it makes a similar contribution tostandard metabolic rate in a lizard. Proton conductance of the mitochondrial inner membranecan be considered as having two components: a basal component present in all mitochondria,and an augmentative component, which may occur in tissues of mammals and perhaps ofsome other animals. The uncoupling protein of brown adipose tissue, UCP1, is a clear exampleof such an augmentative component. The newly discovered UCP1 homologs, UCP2, UCP3,and brain mitochondrial carrier protein 1 (BMCP1) may participate in the augmentativecomponent of proton leak. However, they do not appear to catalyze the basal leak, as this isobserved in mitochondria from cells which apparently lack these proteins. Whereas UCP1plays an important role in thermogenesis, the evidence that UCP2 and UCP3 do likewiseremains equivocal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005456725549
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  • 8
    Electronic Resource
    Electronic Resource
    Inactivation of the Reconstituted Oxoglutarate Carrier from Bovine Heart Mitochondria by Pyridoxal 5′-Phosphate (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 535-541 
    Details
    ISSN: 1573-6881
    Keywords: Oxoglutarate carrier ; pyridoxal 5′-phosphate ; transport ; proteoliposomes ; mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The effect of pyridoxal 5′-phosphate and some other lysine reagents on the purified,reconstituted mitochondrial oxoglutarate transport protein has been investigated. The inhibition ofoxoglutarate/oxoglutarate exchange by pyridoxal 5′-phosphate can be reversed by passing theproteoliposomes through a Sephadex column but the reduction of the Schiff's base by sodiumborohydride yielded an irreversible inactivation of the oxoglutarate carrier protein. Pyridoxal5′-phosphate, which caused a time- and concentration-dependent inactivation of oxoglutaratetransport with an IC50 of 0.5 mM, competed with the substrate for binding to the oxoglutaratecarrier (K i = 0.4 mM). Kinetic analysis of oxoglutarate transport inhibition by pyridoxal5′-phosphate indicated that modification of a single amino acid residue/carrier molecule wassufficient for complete inhibition of oxoglutarate transport. After reduction with sodiumborohydride [3H]pyridoxal 5′-phosphate bound covalently to the oxoglutarate carrier. Incubation ofthe proteoliposomes with oxoglutarate or L-malate protected the carrier against inactivationand no radioactivity was found associated with the carrier protein. In contrast, glutarate andsubstrates of other mitochondrial carrier proteins were unable to protect the carrier. Mersalyl,which is a known sulfhydryl reagent, also failed to protect the oxoglutarate carrier againstinhibition by pyridoxal 5′-phosphate. These results indicate that pyridoxal 5′-phosphateinteracts with the oxoglutarate carrier at a site(s) (i.e., a lysine residue(s) and/or the amino-terminalglycine residue) which is essential for substrate translocation and may be localized at or nearthe substrate-binding site.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026414826457
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  • 9
    Electronic Resource
    Electronic Resource
    Subunit f of the Yeast Mitochondrial ATP Synthase: Topological and Functional Studies (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 85-94 
    Details
    ISSN: 1573-6881
    Keywords: yeast ; mitochondria ; ATP synthase ; ATP17 gene ; subunit f ; orientation ; cross-linking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Modified versions of subunit f were produced by mutagenesis of theATP17 gene of Saccharomyces cerevisiae. A version of subunit f devoid of thelast 28 amino acid residues including the unique transmembranous domaincomplemented the oxidative phosphorylation of the null mutant. However, atwo-fold decrease in the specific ATP synthase activity was measured andattributed to a decrease in the stability of the mutant ATP synthase complexas shown by the low oligomycin-sensitive ATPase activity at alkaline pH. Themodification or not by non-permeant maleimide reagents of cysteine residuesintroduced at the N and C termini of subunit f indicated aNin-Cout orientation. From the C terminus of subunit fit was possible to cross-link subunit 4 (also called subunit b), which isanother component of the F0 sector and which also displays a shorthydrophilic segment exposed to the intermembrane space.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005407525915
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  • 10
    Electronic Resource
    Electronic Resource
    The Role of the Amino-Terminal β-Barrel Domain of the α and β Subunits in the Yeast F1-ATPase (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 95-104 
    Details
    ISSN: 1573-6881
    Keywords: F1-ATPase ; β-barrel domain ; mitochondria ; assembly ; yeast ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The crystal structure of mitochondrial F1-ATPase indicatesthat the α and β subunits fold into a structure defined by threedomains: the top β-barrel domain, the middle nucleotide-binding domain,and the C-terminal α-helix bundle domain (Abraham et al.1994); Bianchet et al., 1998). The β-barrel domains of theα and β subunits form a crown structure at the top ofF1, which was suggested to stabilize it (Abraham et al.1994). In this study. the role of the β-barrel domain in the α andβ subunits of the yeast Saccharomyces cerevisiae F1,with regard to its folding and assembly, was investigated. The β-barreldomains of yeast F1 α and β subunits were expressedindividually and together in Escherichia coli. When expressedseperately, the β-barrel domain of the β subunit formed a largeaggregate structure, while the domain of the α subunit waspredominately a monomer or dimer. However, coexpression of the β-barreldomain of α subunit domain. Furthermore, the two domains copurified incomplexes with the major portion of the complex found in a small molecularweight form. These results indicate that the β-barrel domain of theα and β subunits interact specifically with each other and thatthese interactions prevent the aggregation of the β-barrel domain of theβ subunit. These results mimic in vivo results and suggest thatthe interactions of the β-barrel domains may be critical during thefolding and assembly of F1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005443609985
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  • 11
    Electronic Resource
    Electronic Resource
    On the Role of the General Transcription Factor Sp1 in the Activation and Repression of Diverse Mammalian Oxidative Phosphorylation Genes* (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 129-135 
    Details
    ISSN: 1573-6881
    Keywords: mitochondria ; promoter ; transcription regulation ; Sp1 ; repressor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract To gain insight into the role of the general transcription factor,Sp1, in the expression of nuclear genes involved in mitochondrial biogenesis,we investigated Sp1 activation of the adenine nucleotide translocator 2,cytochrome c1, F1-ATPase β subunit, and themitochondria transcription factor (mtTFA) promoters transfected intoDrosophila cell lines. The numbers and organization of GC elementsvary in the four promoters, but the magnitude of activation by coexpressedhuman Sp1 was similar. A feature common to the four promoters is the presenceof multiple, proximal Sp1-activating elements that account for 50% ormore of the transcription activation by Sp1. The distribution and function ofindividual distal Sp1 elements is less defined and appear to be morepromoter-specific. Finally, data from transfected Drosophila cellsprovide the first direct proof for the involvement of Sp1 in the negativeregulation of the ANT2 promoter and as a possible participant in repressionof the β-subunit promoter. The role of Sp1 in both the positive andnegative regulation of OXPHOS promoters is unique.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005499727732
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  • 12
    Electronic Resource
    Electronic Resource
    Activation and Deactivation of F0F1-ATPase in Yeast Mitochrondia (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 105-117 
    Details
    ISSN: 1573-6881
    Keywords: mitochondria ; F0F1 ATPase ; ATP synthase ; ATP hydrolysis ; IF1 ; yeast ; regulation ; inactivation ; proton gradient ; detergent
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The regulation of membrane-bound proton F0F1ATPase by the protonmotive force and nucleotides was studied in yeastmitochondria. Activation occurred in whole mitochondria and the ATPaseactivity was measured just after disrupting the membranes with Triton X-100.Deactivation occurred either in whole mitochondria uncoupled with FCCP, or indisrupted membranes. No effect of Triton X-100 on the ATPase was observed,except a slow reactivation observed only in the absence of MgADP. BothAMPPNP and ATP increased the ATPase deactivation rate, thus indicating thatoccupancy of nucleotidic sites by ATP is more decisive than catalyticturnover for this process. ADP was found to stimulate the energy-dependentATPase activation. ATPase deactivated at the same rate in uncoupled anddisrupted mitochondria. This suggests that deactivation is not controlled byrebinding of some soluble factor, like IF1, but rather by the conversion ofthe F1.IF1 complex into an inactive form.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005495626823
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  • 13
    Electronic Resource
    Electronic Resource
    Mutation of K234 and K236 in the Voltage-Dependent Anion Channel 1 Impairs Its Insertion into the Mitochondrial Outer Membrane (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 137-142 
    Details
    ISSN: 1573-6881
    Keywords: VDAC1 ; mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Previous in vitro studies indicated that mutation of bothK234 and K236 to arginine, glutamine, or glutamic acid impaired the abilityof the voltage-dependent anion channel (VDAC1) to insert into the outermembrane of the mitochondria (Smith et al. 1995). These same mutantswere expressed in a strain of Saccharomyces cerevisiae with adisruption in the VDAC1 gene. The mutant VDAC1 forms were found in themitochondria suggesting that they were correctly sorted to the outermembrane. However, only very small amounts of the mutants were inserted intothe mitochondrial membranes. Mitochondria isolated from the strains expressingthe mutants were capable of catalyzing the translocation of both wild-typeVDAC1 and pre-alcohol dehydrogenase III indicating that the translocationapparatus was functional. These results confirm the previously drawnconclusion that K234 and K236 are part of a membrane insertion motif. Thefailure of the mutant VDAC1 forms to insert did not cause VDAC1 precursors toaccumulate in the soluble cell cytoplasm or in the microsomal fraction. Theapparent lack of a “precursor pool” suggested that apost-transcriptional control mechanism might limit the amounts of VDAC1precursors in the cell. Such a control mechanism is consistent with theobservation that the amount of VDAC1 was very similar after epichromosomal(gene in a 2u plasmid controlled by a Gal1 promoter) and chromosomalexpression (endogenous gene controlled by the endogenous promoter).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005451811802
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  • 14
    Electronic Resource
    Electronic Resource
    Mutations in the Voltage-Dependent Anion Channel of the Mitochondrial Outer Membrane Cause a Dominant Nonlethal Growth Impairment (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 143-151 
    Details
    ISSN: 1573-6881
    Keywords: VDAC1 ; mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Point mutations at K234 and K236 in the yeast voltage-dependent anionchannel 1 (VDAC1) of the mitochondrial outer membrane have been shown tomarkedly impair the membrane insertion of this protein (Smith etal., 1995; Angeles et al., 1998). Mutants of this type wereexpressed in vivo in a strain of yeast with a disruption in theVDAC1 gene. Expression of the various VDAC1 forms was under the control of aGal1 promoter. Wild-type VDAC1 expression fully complemented the slow growthphenotype caused by the disruption. VDAC1 mutants in which K234 and K236 werereplaced by arginine, glutamate, or glutamine caused a more severe negativeeffect on growth. This effect appeared to be dominant since the mutant VDAC1forms suppressed growth in a yeast strain that retained its VDAC1 gene. Thisapparent dominant negative effect on growth did not seem to be specific forany stage of the cell cycle. However, the growth defect was not lethal as theaffected cells still could accumulate the vital stain, FUN1. Expression of amutant in which K234 had been replaced by glutamate had more serious negativegrowth effects than did a similar mutation at K236. Expression ofΔ71-116 VDAC1 complemented the VDAC1 disruption; however, expression ofthe same deletion mutant in which the lysines corresponding to K234 and K236were mutated to glutamate severely impaired growth. These results have shownthat a deficiency of lysine at positions 234 and 236 in VDAC1 causes anonlethal growth defect that is more severe than deletion of 45 amino acidsfrom VDAC1 or disruption of the VDAC1 gene. They also indicate that there is ahierarchy in the importance of these lysines with mutations at K234 being themore serious.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005403928641
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  • 15
    Electronic Resource
    Electronic Resource
    Mitochondrial Events in the Life and Death of Animal Cells: A Brief Overview (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 291-304 
    Details
    ISSN: 1573-6881
    Keywords: Cell death ; aging ; necrosis ; apoptosis ; mitochondria ; oxidative phosphorylation ; electron transport chain ; ATP synthase ; cytochrome c ; mitochondrial DNA ; reactive oxygen species (ROS)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Traditionally, mitochondria have been viewed as the “powerhouse” of the cell, i.e., the site of theoxidative phosphorylation machinery involved in ATP production. Consequently, much of theresearch conducted on mitochondria over the past 4 decades has focused on elucidating both thosemolecular events involved in ATP synthesis by oxidative phosphorylation and those involved inthe biogenesis of the oxidative phosphorylation machinery. While monumental achievements havebeen made, and continue to be made, in the study of these remarkable but extremely complexprocesses essential for the life of most animal cells, it has been only in recent years that a largebody of biological and biomedical scientists have come to recognize that mitochondria participatein other important processes. Two of these are cell death and aging which, not surprisingly, are relatedprocesses both involving, in part, the oxidative phosphorylation machinery. This new awareness hassparked a new and growing area of mitochondrial research, that has become of great interest to awide variety of scientists ranging from those involved in elucidating the role of mitochondria incell death and aging to those interested in either suppressing or facilitating these processes as itrelates to identifying new therapies or drugs for human disease. It is the purpose of this briefintroductory review to provide an overview of those mitochondrial events involved in the life anddeath of animal cells and to indicate how these events might relate to the human aging process.Much more is known, much remains controversial, and even more remains to be learned as indicatedin the excellent set of minireviews that follow.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005453700533
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  • 16
    Electronic Resource
    Electronic Resource
    Inhibitory Properties of Ruthenium Amine Complexes on Mitochondrial Calcium Uptake (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 551-557 
    Details
    ISSN: 1573-6881
    Keywords: Calcium uniporter inhibitors ; mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The recent finding that the inhibition of Ca2+-stimulated respiration by ruthenium red is mainlydue to a binuclear ruthenium complex (Ru360) present in the commercial samples of the classicalinhibitor ruthenium red (Ying et. al., 1991), showed that this complex is the more potent andspecific inhibitor of the mitochondrial calcium uniporter. This work was aimed to provideinsights into the mechanism by which Ru360 and other ruthenium-related compounds inhibitscalcium uptake. Ruthenium red and a synthesized analog (Rrphen) were compared with Ru360.The inhibition by this binuclear complex was noncompetitive, with a K i of 9.89 nM. Thenumber of specific binding sites for Ru360 was 6.2 pmol/mg protein. Ruthenium red and Ru360were mutually exclusive inhibitors. Bound La3+ was not displaced by Ru360. Rrphen was theleast effective for inhibiting calcium uptake. The results support the notion of a specific bindingsite in the uniporter for the polycationic complexes and a negative charged region from thephospholipids in the membrane, closely associated with the uniporter inhibitor-binding site.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005464927366
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  • 17
    Electronic Resource
    Electronic Resource
    Cooperation of a “Reactive Oxygen Cycle” with The Q Cycle and The Proton Cycle in the Respiratory Chain—Superoxide Generating and Cycling Mechanisms in Mitochondria (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 367-376 
    Details
    ISSN: 1573-6881
    Keywords: Superoxide generation ; protonmotive force dependent ; protonophore ; proton leak ; heat production ; ROS cycle ; mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Based on our recent findings concerning the generating, partitioning, targeting, and functioningof superoxide in mitochondria, a hypothetical model involving a “reactive oxygen cycle” inthe respiratory chain has been proposed (Liu and Huang, 1991, 1996; Liu et al., 1996; Liu,1997, 1998) This model emphasizes that during State 4 respiration, an interaction between anelectron leak (a branch of electron transfer directly from the respiratory chain to form O•- 2,but not H2O) and a proton leak (a branch pathway which utilizes $$\Delta \mu _{{\text{H}}^{\text{ + }} } $$ to produce heat, butnot ATP) may take place in cooperation with the Q and proton cycles in mitochondria throughthe consumption of H+ by O•- 2 anions to form a protonated perhydroxyl radical, HO2, whichis directly permeable across the inner mitochondrial membrane and induces proton leakageand a decrease of $$\Delta \mu _{{\text{H}}^{\text{ + }} } $$ . O•- 2 generation in the mitochondrial respiratory chain and its cyclingacross the inner membrane may have the role of an endogenous protonophore in regulating andpartitioning energy transduction and heat production, as well as in pathogenesis of mitochondrialdiseases, aging, and apoptosis. The present article summarizes the supporting experimentalevidence obtained in this laboratory and presents a brief description of the theoretical basisof this model
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018650103259
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