A5058095118- ATP Synthase and ATPases Research
- Mitochondrial Function and Pathology
- Biochemical and Molecular Research
- Drug Transport and Resistance Mechanisms
- Hybrid Renewable Energy Systems
- Sociology and Education Studies
- Photosynthetic Processes and Mechanisms
- RNA modifications and cancer
- Advanced Electron Microscopy Techniques and Applications
- Cancer, Hypoxia, and Metabolism
- Metalloenzymes and iron-sulfur proteins
- Trace Elements in Health
- Psychology, Coaching, and Therapy
- Ion Transport and Channel Regulation
- Chemical Reaction Mechanisms
- DNA and Nucleic Acid Chemistry
- RNA and protein synthesis mechanisms
- Neonatal Health and Biochemistry
- Coenzyme Q10 studies and effects
- Fuel Cells and Related Materials
- Drilling and Well Engineering
- Metabolism and Genetic Disorders
- CO2 Sequestration and Geologic Interactions
- Microbial Applications in Construction Materials
- Enhanced Oil Recovery Techniques
Texas Tech University
2011-2024
Carl von Ossietzky Universität Oldenburg
2023-2024
Martin Luther University Halle-Wittenberg
2023-2024
Texas Tech University Health Sciences Center
2009-2023
University of Lübeck
1982-2021
Baden-Wuerttemberg Cooperative State University
2017
Darmstadt University of Applied Sciences
2015
Bayer (Germany)
2014
Harvard University Press
2007
University of Rochester Medical Center
1997-2006
P-glycoprotein (Pgp or multidrug-resistance protein) shows drug-stimulated ATPase activity. The catalytic sites are known to be of low affinity and specificity for nucleotides. From the sequence, two nucleotide predicted per Pgp molecule. Using plasma membranes from a multidrug-resistant Chinese hamster ovary cell line, which highly enriched in Pgp, we show that vanadate-induced trapping at single site produces stably inhibited with <i>t</i> reactivation activity 84 min 37°C >30 h 4°C....
Purified mitochondrial ATP synthase has been shown to form Ca
Abstract Mitochondrial ATP synthase is vital not only for cellular energy production but also dissipation and cell death. c-ring was suggested to house the leak channel of mitochondrial permeability transition (mPT), which activates during excitotoxic ischemic insult. In this present study, we purified human from both eukaryotic prokaryotic hosts biophysically characterize its activity. We show that forms a large multi-conductance, voltage-gated ion inhibited by addition F 1 subcomplex....
The functional role of essential residue α-Arg-376 in the catalytic site F1-ATPase was studied. mutants αR376C, αR376Q, and αR376K were constructed, combined with mutation βY331W, to investigate nucleotide-binding parameters, assess transition state formation by measurement MgADP−fluoroaluminate binding. Each caused large impairment ATP synthesis hydrolysis. Despite apparent proximity bound nucleoside di- triphosphate published X-ray structures, mutations had little effect on MgADP or MgATP...
The fluorescence of residue Trp beta 331 in Y331W mutant Escherichia coli F1-ATPase was used as reporter probe to investigate the effects magnesium ions, inhibitors, and mutation on substrate (ATP) binding stoichiometry cooperativity. It found that Mg2+ is required for catalytic site In absence magnesium, ATP bound three independent sites, each with Kd = 76 microM. contrast, MgATP sites Kd1 < 50 nM, Kd2 0.5 microM, Kd3 25 There no significant ATPase activity Mg2+. Catalysis therefore...
Three critical residues, β-Lys-155, β-Asp-242, and β-Glu-181, situated close to the γ-phosphate of MgATP in F1-ATPase catalytic sites, were investigated. The mutations βK155Q, βD242N, βE181Q each combined with βY331W mutation; fluorescence signal β-Trp-331 was used determine MgATP, MgADP, ATP, ADP binding parameters for three sites enzyme. quantitative contribution side chains energy at all calculated. following conclusions made. major functional interaction β-Lys-155 is primary importance...
Abstract Die bekannte Umsetzung von Olefinen mit CO und NH 3 bei erhöhter Temperatur hohem Druck in Gegenwart Co führt zu einfachen Carbonsäureamiden. In Wasserstoff bilden sich dagegen vorwiegend bedeutend leichter N‐alkylierte Carbonsäureamide, z. B.: magnified image . Anwesenheit Fe im Reaktionsgemisch lenkt die zur Bildung prim.‐sek. tert. Amine, Amidbildung wird weitgehend unterdrückt. Auch Ausbeuten gehen zurück. Reaktionsprodukte werden isoliert identifiziert, es der Versuch gemacht,...
Coordination of the Mg2+ ion in Mg-nucleotide substrates by amino acid residue side chains catalytic site Escherichia coli F1-ATPase was investigated. From X-ray structure mitochondrial enzyme [Abrahams, J. P., Leslie, A. G. W., Lutter, R., and Walker, E. (1994) Nature 370, 621-628], it may be inferred that hydroxyl betaThr-156 is a direct ligand Mg2+, whereas carboxyls betaGlu-181, betaGlu-185, betaAsp-242 might contribute via intervening water molecules. Elimination each respective...
F1Fo-ATP synthase was purified from Escherichia coli βY331W mutant. The β-Trp-331 provided a specific fluorescent probe of catalytic site nucleotide binding. Physiological (mM) concentration substrate MgATP filled all three sites. With or MgADP the sites showed marked binding cooperativity and asymmetry, which dependent on Mg2+. Nucleotide fast, with kon = ∼6 × 105 M-1 s-1. Pi at physiological (5 mM) did not bind to Measurement hydrolysis under identical conditions as function revealed that...
Tryptophan was specifically inserted as the residue immediately preceding P-loop sequence in F<sub>1</sub>-ATPase catalytic sites. The mutant enzyme (βF148W) showed normal enzymatic characteristics. fluorescence responses of β-tryptophan 148 enabled us to differentiate between nucleoside di- and triphosphate bound sites; MgADP quenched at 350 nm, whereas MgAMPPNP MgADP·BeF<sub>x</sub> complex enhanced 325 nm. With MgATP, both effects were seen simultaneously. This allowed analysis site...
Tryptophan fluorescence was investigated as a tool to study the noncatalytic nucleotide-binding sites of Escherichia coli F,-ATPase.Site-directed mutagenesis, affinity labeling, and lin-benzo-ATP binding studies had shown that residues aR365 pY354 are located close base moiety bound nucleotide; here, we mutagenized each tryptophan.The new tryptophans gave signal indicating an environment high (aW365) or intermediate (pW354) polarity in unoccupied sites.aW365 completely quenched by ATP ADP,...
Escherichia coli F1-ATPase from mutant betaY331W was potently inhibited by fluoroaluminate plus MgADP but not alone. beta-Trp-331 fluorescence used to measure binding catalytic sites. Fluoroaluminate induced a very large increase in affinity at site one, smaller two, and no effect three. Mutation of either the critical residues beta-Lys-155 or beta-Glu-181 Gln abolished effects on binding. The results indicate that MgADP-fluoroaluminate complex is transition state analog independently...
Nucleotide-depleted Escherichia coli F1 was prepared by the procedure of Wise et al. (1983, Biochem. J. 215, 343–350). This enzyme had high rates steady-state ATPase and GTPase activity. When "unisite" ATP hydrolysis measured using an F1ATP concentration ratio 10, all substoichiometric became bound to high-affinity catalytic site none noncatalytic sites. The association rate constant for binding 7 × 105m−1 s−1 KdATP 7.9 10−10m, as compared values 3.8 1.9 respectively, in native (i.e.,...
A critical point of interaction between F1 and F0 in the bacterial F1F0-ATP synthase is formed by α δ subunits. Previous work has shown that N-terminal domain (residues 3−105) subunit forms a 6 α-helix bundle [Wilkens, S., Dunn, S. D., Chandler, J., Dahlquist, F. W., Capaldi, R. A. (1997) Nat. Struct. Biol. 4, 198−201] majority binding energy provided 22 residues α- [Weber, Muharemagic, A., Wilke-Mounts, Senior, E. (2003) J. Chem. 278, 13623−13626]. We have now analyzed 1:1 complex δ-subunit...