scholarly journals Oxidative phosphorylation. The relation between the specific binding of trimethlytin and triethyltin to mitochondria and their effects on various mitochondrial functions

1971 ◽  
Vol 124 (1) ◽  
pp. 221-234 ◽  
Author(s):  
W. N. Aldridge ◽  
B. W. Street
Keyword(s):  
Oxygen Uptake ◽  
Binding Site ◽  
Atp Hydrolysis ◽  
Specific Binding ◽  
Atp Synthesis ◽  
Low Concentrations ◽  
Mitochondrial Functions ◽  
Biological Specificity ◽  
Approach Zero ◽  
A Site

1. A binding site (site 1) is present in mitochondria with affinity for trimethyltin and triethyltin adequate for a site to which they could be attached when the processes of energy conservation are inhibited. 2. The quantitative relationships between the binding of trimethyltin and triethyltin to site 1 and their effects on various mitochondrial functions have been examined. 3. ATP synthesis linked to the oxidation of pyruvate, succinate and intramitochondrial substrate, ATP synthesis and oxygen uptake (succinate or pyruvate as substrate) stimulated by uncoupling agents are all inhibited by trimethyltin and triethyltin; when inhibition is less than 50% the ratio (percentage inhibition)/(percentage of binding site 1 complexed) is approx. 10:1. 4. ATP synthesis linked to the oxidation of reduced cytochrome c (ascorbate+NNN′N′-tetramethyl-p-phenylenediamine), ATP hydrolysis and oxygen uptake in the presence of low concentrations of trimethyltin and triethyltin approach zero activity as the proportion of binding site 1 complexed approaches 100%. 5. Possible interpretations of these findings are discussed with reference to published arrangements for coupling of electron transport to ATP synthesis and also to our present knowledge of the chemical and biological specificity of trialkyltin compounds.

scholarly journals Oxidative phosphorylation. The effect of anions on the inhibition by triethyltin of various mitochondrial functions, and the relationship between this inhibition and binding of triethyltin

1972 ◽  
Vol 127 (1) ◽  
pp. 51-59 ◽  
Author(s):  
M. S. Rose ◽  
W. N. Aldridge
Keyword(s):  
Electron Transport ◽  
Oxygen Uptake ◽  
Atp Hydrolysis ◽  
Atp Synthesis ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Hydroxide Ion ◽  
Mitochondrial Functions ◽  
Relationship Of ◽  
The Relationship

1. The binding of triethyltin to rat liver mitochondria is unaffected by the nature of the predominant anion in the incubation medium. 2. With chloride, bromide or iodide as the predominant anion, ATP synthesis linked to the oxidation of pyruvate or succinate and ATP hydrolysis stimulated by 2,4-dinitrophenol are much more sensitive to triethyltin than they are when nitrate or isethionate is the predominant anion. 3. When nitrate or isethionate is the predominant anion, oxygen uptake stimulated by 2,4-dinitrophenol is not inhibited by triethyltin. 4. In the presence of nitrate or isethionate anions, inhibition of ATP synthesis is directly related to the binding of triethyltin to mitochondria. 5. The relationship of the above effects to the anion–hydroxide ion exchange mediated by triethyltin and the relevance of this to published arrangements for coupling of electron transport to ATP synthesis are discussed.

scholarly journals Identification of an octamer-binding site in the mouse kappa light-chain immunoglobulin enhancer.

1989 ◽  
Vol 9 (10) ◽  
pp. 4239-4247 ◽  
Author(s):  
R A Currie ◽  
R G Roeder
Keyword(s):  
B Cell ◽  
Binding Site ◽  
Light Chain ◽  
Specific Binding ◽  
Specific Factor ◽  
Immunoglobulin Gene ◽  
Kappa Light Chain ◽  
Nf Kappa B ◽  
Light Chain Immunoglobulin ◽  
A Site

A 215-base-pair (bp) region of the mouse MOPC 41 kappa light-chain immunoglobulin gene enhancer has been analyzed for specific binding of lymphoid and nonlymphoid nuclear factors. Mobility shift assays with a series of overlapping DNA fragments have mapped DNA-binding sites for three unique factors. The B-cell-specific (OTF-2) and ubiquitous (OTF-1) octamer-binding transcription factors specifically bound to a site centered about 136 bp 5' of the nuclear factor NF-kappa B site. A third specific factor, NF-kappa E, bound to a site that was about 75 bp 5' of the NF-kappa B site and within a region important for enhancer function. This novel factor was found in both mature B and HeLa cell nuclei. B-cell OTF-2, B-cell OTF-1, and HeLa OTF-1 bound to the kappa enhancer and kappa promoter octamer sites with similar affinities despite a 2-bp difference in the kappa enhancer octamer sequence. However, DNase I footprint analyses indicated that affinity-purified OTF-2 bound both to the enhancer OTF site and, surprisingly, to 80 bp of A + T-rich flanking sequence. Moreover, methylation interference studies demonstrated distinct differences in OTF interactions between the consensus octamer in the kappa promoter and the nonconsensus octamer identified in the enhancer. This novel observation of an OTF-binding site in the kappa enhancer provides a common link with the OTF sites in the promoter-proximal regions of all kappa promoters and thus mirrors the structural arrangement of OTF sites found in the promoters and enhancers of immunoglobulin heavy-chain genes.

Identification of an octamer-binding site in the mouse kappa light-chain immunoglobulin enhancer

1989 ◽  
Vol 9 (10) ◽  
pp. 4239-4247
Author(s):  
R A Currie ◽  
R G Roeder
Keyword(s):  
B Cell ◽  
Binding Site ◽  
Light Chain ◽  
Specific Binding ◽  
Specific Factor ◽  
Immunoglobulin Gene ◽  
Kappa Light Chain ◽  
Nf Kappa B ◽  
Light Chain Immunoglobulin ◽  
A Site

A 215-base-pair (bp) region of the mouse MOPC 41 kappa light-chain immunoglobulin gene enhancer has been analyzed for specific binding of lymphoid and nonlymphoid nuclear factors. Mobility shift assays with a series of overlapping DNA fragments have mapped DNA-binding sites for three unique factors. The B-cell-specific (OTF-2) and ubiquitous (OTF-1) octamer-binding transcription factors specifically bound to a site centered about 136 bp 5' of the nuclear factor NF-kappa B site. A third specific factor, NF-kappa E, bound to a site that was about 75 bp 5' of the NF-kappa B site and within a region important for enhancer function. This novel factor was found in both mature B and HeLa cell nuclei. B-cell OTF-2, B-cell OTF-1, and HeLa OTF-1 bound to the kappa enhancer and kappa promoter octamer sites with similar affinities despite a 2-bp difference in the kappa enhancer octamer sequence. However, DNase I footprint analyses indicated that affinity-purified OTF-2 bound both to the enhancer OTF site and, surprisingly, to 80 bp of A + T-rich flanking sequence. Moreover, methylation interference studies demonstrated distinct differences in OTF interactions between the consensus octamer in the kappa promoter and the nonconsensus octamer identified in the enhancer. This novel observation of an OTF-binding site in the kappa enhancer provides a common link with the OTF sites in the promoter-proximal regions of all kappa promoters and thus mirrors the structural arrangement of OTF sites found in the promoters and enhancers of immunoglobulin heavy-chain genes.

scholarly journals Oxidative phosphorylation. Halide-dependent and halide-independent effects of triorganotin and trioganolead compounds on mitochondrial functions

1977 ◽  
Vol 168 (3) ◽  
pp. 353-364 ◽  
Author(s):  
W N Aldridge ◽  
B W Street ◽  
D N Skilleter
Keyword(s):  
Maximum Rate ◽  
Atp Hydrolysis ◽  
Atp Synthesis ◽  
O2 Uptake ◽  
Structure Activity ◽  
Triethyl Lead ◽  
Mitochondrial Functions ◽  
Independent Effects ◽  
Beta Hydroxybutyrate ◽  
Rate Limiting

1. Each of five triorganotin and five triorganolead compounds was shown to perturb mithochondrial functions in three different ways. One is dependent and two are independent of Cl- in the medium. 2. Structure-activity relationships for the three interactions are described, and compounds suitable as tools for the separate study of each process are defined. 3. In a Cl- -containing medium trimethyltin, triethyltin, trimethyl-lead, triethyl-lead and tri-n-propyl-lead all produce the same maximum rate of ATP hydrolysis and O2 uptake; this rate is much less than that produced by uncoupling agents such as 2,4-dinitrophenol. 4. Increase in ATP hydrolysis and O2 uptake are measures on energy ultilization when triogranotin and triorganolead compounds bring about an exchange of external C1- for intramitochondrial OH- ions. Possible rate-limiting steps in this process are discussed. 5. In a C1- -containing medium ATP synthesis linked to the oxidation of beta-hydroxybutyrate or reduced cytochrone c is less inhibited by triethyltin or triethyl-lead than is ATP synthesis linked to the oxidation of succinate, pyruvate or L-glutamate. 6. The inhibition of ATP synthesis linked to the oxidation of both beta-hydroxybutyrate and reduced cytochrome c consists of two processes: one is a limited uncoupling and is C1- -dependent and the other is a C1- -independent inhibition of the energy-conservation system. 7. The different sensitivities to inhibition by triethyltin of mitochondrial functions involving the oxidation of beta-hydroxybutyrate and succinate are compared and discussed.

scholarly journals The second metal-binding site of 70 kDa heat-shock protein is essential for ADP binding, ATP hydrolysis and ATP synthesis

2004 ◽  
Vol 378 (3) ◽  
pp. 793-799 ◽  
Author(s):  
Xueji WU ◽  
Mihiro YANO ◽  
Hiroyo WASHIDA ◽  
Hiroshi KIDO
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Binding Site ◽  
Metal Binding ◽  
Atp Hydrolysis ◽  
Atp Synthesis ◽  
Site Directed Mutagenesis ◽  
Atp Binding ◽  
Binding Motif ◽  
Metal Binding Site

The chaperone activity of Hsp70 (70 kDa heat-shock protein) in protein folding and its conformational switch, including oligomeric and monomeric interconversion, are regulated by the hydrolysis of ATP and the ATP–ADP exchange cycle. The crystal structure of human ATPase domain shows two metal-binding sites, the first for ATP binding and a second, in close proximity to the first, whose function remains unknown [Sriram, Osipiuk, Freeman, Morimoto and Joachimiak (1997) Structure 5, 403–414]. In this study, we have characterized the second metal-binding motif by site-directed mutagenesis and the kinetics of ATP and ADP binding, and found that the second metal-binding site, comprising a loop co-ordinated by His-227, Glu-231 and Asp-232, participates both in ATP hydrolysis and ATP-synthetic activities, in co-operation with the first metal-binding site. The first metal-binding site, a catalytic centre, is essential for ATP binding and the second site for ADP binding in the reactions of ATP hydrolysis and ATP synthesis.

Effects of Diphenylether Herbicides on Reactions of Mitochondria and Chloroplasts

Weed Science ◽  
1970 ◽  
Vol 18 (5) ◽  
pp. 636-642 ◽  
Author(s):  
D. E. Moreland ◽  
W. J. Blackmon ◽  
H. G. Todd ◽  
F. S. Farmer
Keyword(s):  
Electron Transport ◽  
Oxygen Uptake ◽  
Spinacia Oleracea ◽  
White Potato ◽  
Light Reaction ◽  
Site Of Action ◽  
Transport Inhibitors ◽  
Atp Generation ◽  
A Site ◽  
Limited Oxygen

Effects of three diphenylether herbicides [2,4-dichlorophenyl-p-nitrophenyl ether (nitrofen); 2,4,6-trichlorophenyl-4′-nitrophenyl ether (hereinafter referred to as MC-1478); and 2,4′-dinitro-4-trifluoromethyl-diphenylether (hereinafter referred to as C-6989)] were measured on phosphorylation and electron transport in spinach(Spinacia oleraceaL.) chloroplasts, and mung bean(Phaseolus aureusL., var. Jumbo) and white potato tuber(Solarium tuberosumL.) mitochondria. All of the diphenylethers acted primarily as inhibitors of chloroplast noncyclic electron transport, and the coupled photophosphorylation. The compounds ranked in the following decreasing order of inhibitory effectiveness: MC-1478 ≥ C-6989 >> nitrofen. A site of action close to light reaction II was suggested. At high molar concentrations, marginal interference with cyclic electron transport or phosphorylation was obtained. In mitochondria, MC-1478 and nitrofen acted primarily as electron transport inhibitors with malate, NADH, and succinate as substrates. MC-1478 was a slightly stronger inhibitor than nitrofen. Only slight stimulation of ADP-limited oxygen uptake was obtained during the oxidation of NADH and succinate; whereas, strong inhibition of oxygen uptake was obtained with malate. C-6989 also weakly stimulated ADP-limited oxygen uptake with NADH and succinate but differed from the two chlorinated diphenylethers in that electron transport was not inhibited when ADP was present in excess. Interference with ATP generation could be one of the mechanisms through which the phytotoxicity of diphenylether herbicides is expressed.

scholarly journals Novel proliferative effect of phospholipase A2 in Swiss 3T3 cells via specific binding site.

1991 ◽  
Vol 266 (29) ◽  
pp. 19139-19141
Author(s):  
H. Arita ◽  
K. Hanasaki ◽  
T. Nakano ◽  
S. Oka ◽  
H. Teraoka ◽  
...  
Keyword(s):  
Phospholipase A2 ◽  
Binding Site ◽  
Specific Binding ◽  
3T3 Cells ◽  
Proliferative Effect ◽  
Swiss 3T3

scholarly journals Electron-paramagnetic-resonance studies on nitrogenase of Klebsiella pneumoniae. Evidence for acetylene- and ethylene-nitrogenase transient complexes

1978 ◽  
Vol 173 (1) ◽  
pp. 277-290 ◽  
Author(s):  
D J Lowe ◽  
R R Eady ◽  
R N F Thorneley
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Klebsiella Pneumoniae ◽  
Binding Site ◽  
Dissociation Constants ◽  
Paramagnetic Resonance ◽  
Fe Protein ◽  
Low Concentrations ◽  
Direct Binding ◽  
Electron Paramagnetic ◽  
Single Binding Site

Klebsiella pneumoniae nitrogenase exhibited four new electron-paramagnetic-resonance signals during turnover at 10 degrees C, pH7.4, which were assigned to intermediates present in low concentrations in the steady state. 57Fe-substituted Mo–Fe protein showed that they arose from Fe–S clusters in the Mo–Fe protein of nitrogenase. The new signals are designated: Ic, g values at 4.67, 3.37 and approx. 2.0; VI, g values at 2.125, 2.000 and 2.000; VII, g values at 5.7 and 5.4; VIII, g values at 2.092, 1.974 and 1.933. The sharp axial signal VI arises from a Fe4S4 cluster at the −1 oxidation level. This signal was only detected in the presence of ethylene and provides the first evidence of an enzyme–product complex for nitrogenase. [13C]Acetylene and [13C]ethylene provided no evidence for direct binding of this substrate and product to the Fe–S clusters giving rise to these signals. The dependence of signal intensities on acetylene concentration indicated two types of binding site, with apparent dissociation constants K less than 16 micron and K approximately 13mM. A single binding site for ethylene (K=1.5mM) was detected. A scheme is proposed for the mechanism of reduction of acetylene to ethylene and inhibition of this reaction by CO.

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