Cation Binding in Na,K-ATPase, Investigated by <sup>205</sup>Tl Solid-State NMR Spectroscopy

Jakobsen, Louise Odgaard; Malmendal, Anders; Nielsen, Niels Chr.; Esmann, Mikael

doi:10.1021/bi060642k

Cited by 4 publications

(4 citation statements)

References 37 publications

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“…A low chemical shift also suggested that occlusion site geometries have a relatively small contribution from carboxylate and hydroxyl groups. The non-specific binding of thallium ions were characterised by rapid chemical exchange, in agreement with an observed low binding affinity [363].…”

Section: Thalliumsupporting

confidence: 74%

NMR-Active Nuclei for Biological and Biomedical Applications

Patching¹

2016

J Diagn Imaging Ther

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Nuclear magnetic resonance (NMR) spectroscopy is a principal well-established technique for analysis of chemical, biological, food and environmental samples. This article provides an overview of the properties and applications of NMR-active nuclei (39 nuclei of 33 different elements) used in NMR measurements (solution-and solid-state NMR, magnetic resonance spectroscopy, magnetic resonance imaging) with biological and biomedical systems and samples. The samples include biofluids, cells, tissues, organs or whole body from different organisms (humans, animals, bacteria, fungi, plants) for detecting and quantifying metabolites or environmental samples (water, soils, sediments). Isolated biomolecules (peptides, proteins, nucleic acids) can be analysed for elucidation of atomic-resolution structure, conformation and dynamics and for characterisation of ligand and drug binding, and of protein-ligand, protein-protein and protein-nucleic acid interactions. NMR can be used for drug screening and pharmacokinetics and to provide information in the design and discovery of new drugs. NMR can also measure translocation of ions and small molecules across lipid bilayers and membranes, characterise structure, phase behaviour and dynamics of membranes and elucidate atomic-resolution structure, orientation and dynamics of membrane-embedded peptides and proteins.Keywords: biological and biomedical applications; drug screening; dynamics; magnetic resonance imaging; membrane proteins; metabolomics; MRI; NMR-active nuclei; nuclear magnetic resonance; protein structure INTRODUCTION1 UCLEAR magnetic resonance (NMR) spectroscopy is one of the principal techniques used for analysis of biological and biomedical systems and samples. This can include the identification, quantification and monitoring of ions, small molecules and biomolecules in studies of metabolism and biological function in human and animal cells and tissues, bacterial cells and spores, fungi and plants. Similar types of measurements can be performed on environmental samples such as water, soils and sediment. NMR is able to elucidate atomic-resolution structure, conformation, molecular mechanism, dynamics and exchange processes (on timescales of picoseconds to seconds) in biomolecules, especially peptides, proteins and nucleic acids. NMR can be used for the observation, quantification and characterisation of ligand and drug binding to biomolecules, and for characterisation of ligandprotein, protein-protein and protein-nucleic acid interactions. NMR can be used for drug screening and it can acquire structural, binding and kinetic information for the design and discovery of new drugs. It can then monitor the absorption, distribution, metabolism and excretion (ADME) of administered drugs in pharmacokinetics studies. OPEN ACCESS PEER-REVIEWED*NMR can be used for the observation, quantification and kinetic characterisation of ion and smallmolecule translocation across lipid bilayers and biological membranes, including those of cells, tissues and vesicles. Solid-state NM...

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Section: Thalliumsupporting

confidence: 74%

NMR-Active Nuclei for Biological and Biomedical Applications

Patching¹

2016

J Diagn Imaging Ther

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“…It is possible that the errors in the determination of Tl 1 bound at high concentrations in the filter experiments obscure the nonspecific component. Using the data for nonspecific binding to shark enzyme from Jakobsen et al (35), we estimate this to be ;2.5 nmol/mg at 30 mM Tl 1 , which corresponds to almost one Tl 1 per nucleotide binding site. To within experimental uncertainty, the Tl 1 occlusion capacity in the presence of 50% glycerol or 20% PEG is similar to that of the control enzyme, but precision is severely limited by the differential retention of the protein on the filters.…”

Section: Tl 1 Binding At Equilibriummentioning

confidence: 96%

“…We have previously observed ;2 Tl 1 ions occluded per nucleotide site by using a centrifugation technique, which allows a larger range of Tl 1 concentrations to be tested. But in addition, the data indicated a large nonspecific low-affinity binding of Tl 1 to the membranes (28,35). It is possible that the errors in the determination of Tl 1 bound at high concentrations in the filter experiments obscure the nonspecific component.…”

Section: Tl 1 Binding At Equilibriummentioning

confidence: 99%

Osmotic Stress and Viscous Retardation of the Na,K-ATPase Ion Pump

Esmann

Fedosova

Marsh

2008

Biophysical Journal

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The transport function of the Na pump (Na,K-ATPase) in cellular ion homeostasis involves both nucleotide binding reactions in the cytoplasm and alternating aqueous exposure of inward- and outward-facing ion binding sites. An osmotically active, nonpenetrating polymer (poly(ethyleneglycol); PEG) and a modifier of the aqueous viscosity (glycerol) were used to probe the overall and partial enzymatic reactions of membranous Na,K-ATPase from shark salt glands. Both inhibit the steady-state Na,K-ATPase as well as Na-ATPase activity, whereas the K(+)-dependent phosphatase activity is little affected by up to 50% of either. Both Na,K-ATPase and Na-ATPase activities are inversely proportional to the viscosity of glycerol solutions in which the membranes are suspended, in accordance with Kramers' theory for strong coupling of fluctuations at the active site to solvent mobility in the aqueous environment. PEG decreases the affinity for Tl(+) (a congener for K(+)), whereas glycerol increases that for the nucleotides ATP and ADP in the presence of NaCl but has little effect on the affinity for Tl(+). From the dependence on osmotic stress induced by PEG, the aqueous activation volume for the Na,K-ATPase reaction is estimated to be approximately 5-6 nm(3) (i.e., approximately 180 water molecules), approximately half this for Na-ATPase, and essentially zero for p-nitrophenol phosphatase. The change in aqueous hydrated volume associated with the binding of Tl(+) is in the region of 9 nm(3). Analysis of 15 crystal structures of the homologous Ca-ATPase reveals an increase in PEG-inaccessible water space of approximately 22 nm(3) between the E(1)-nucleotide bound forms and the E(2)-thapsigargin forms, showing that the experimental activation volumes for Na,K-ATPase are of a magnitude comparable to the overall change in hydration between the major E(1) and E(2) conformations of the Ca-ATPase.

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“…Tl + cannot be regarded as a perfect K + ‐analogue, but a large number of studies in very different fields indicate that it mimics K + quite well. Tl + can replace, for instance, K + in studies of K + ‐binding to the Na,K‐ATPase (Jakobsen et al. 2006) or K + ‐binding to nucleic acids (Gill et al.…”

Section: Discussionmentioning

confidence: 99%

The use of thallium diethyldithiocarbamate for mapping CNS potassium metabolism and neuronal activity: Tl⁺‐redistribution, Tl⁺‐kinetics and Tl⁺‐equilibrium distribution

Wanger

Scheich

Ohl

et al. 2012

Journal of Neurochemistry

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J. Neurochem. (2012) 122, 106–114. Abstract The potassium (K+) analogue thallium (Tl+) can be used as a tracer for mapping neuronal activity. However, because of the poor blood–brain barrier (BBB) K+‐permeability, only minute amounts of Tl+ enter the brain after systemic injection of Tl+‐salts like thallium acetate (TlAc). We have recently shown that it is possible to overcome this limitation by injecting animals with the lipophilic chelate complex thallium diethyldithiocarbamate (TlDDC), that crosses the BBB and releases Tl+ prior to neuronal or glial uptake. TlDDC can thus be used for mapping CNS K+ metabolism and neuronal activity. Here, we analyze Tl+‐kinetics in the rodent brain both experimentally and using simple mathematical models. We systemically injected animals either with TlAc or with TlDDC. Using an autometallographic method we mapped the brain Tl+‐distribution at various time points after injection. We show that the patterns and kinetics of Tl+‐redistribution in the brain are essentially the same irrespective of whether animals have been injected with TlAc or TlDDC. Data from modeling and experiments indicate that transmembrane Tl+‐fluxes in cells within the CNS in vivo equilibrate at similar rates as K+‐fluxes in vitro. This equilibration is much faster than and largely independent of the equilibration of Tl+‐fluxes across the BBB. The study provides further proof‐of‐concept for the use of TlDDC for mapping neuronal activity and CNS K+‐metabolism. A theoretical guideline is given for the use of K+‐analogues for imaging neuronal activity with general implications for the use of metal ions in neuroimaging.

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Cation Binding in Na,K-ATPase, Investigated by ²⁰⁵Tl Solid-State NMR Spectroscopy

Cited by 4 publications

References 37 publications

NMR-Active Nuclei for Biological and Biomedical Applications

NMR-Active Nuclei for Biological and Biomedical Applications

Osmotic Stress and Viscous Retardation of the Na,K-ATPase Ion Pump

The use of thallium diethyldithiocarbamate for mapping CNS potassium metabolism and neuronal activity: Tl⁺‐redistribution, Tl⁺‐kinetics and Tl⁺‐equilibrium distribution

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Cation Binding in Na,K-ATPase, Investigated by 205Tl Solid-State NMR Spectroscopy

Cited by 4 publications

References 37 publications

NMR-Active Nuclei for Biological and Biomedical Applications

NMR-Active Nuclei for Biological and Biomedical Applications

Osmotic Stress and Viscous Retardation of the Na,K-ATPase Ion Pump

The use of thallium diethyldithiocarbamate for mapping CNS potassium metabolism and neuronal activity: Tl+‐redistribution, Tl+‐kinetics and Tl+‐equilibrium distribution

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Cation Binding in Na,K-ATPase, Investigated by ²⁰⁵Tl Solid-State NMR Spectroscopy

The use of thallium diethyldithiocarbamate for mapping CNS potassium metabolism and neuronal activity: Tl⁺‐redistribution, Tl⁺‐kinetics and Tl⁺‐equilibrium distribution