A 139La NMR study of the interactions between the La(III) cation and D-ribose in aqueous solution

1994 ◽  
Vol 72 (7) ◽  
pp. 1753-1757 ◽  
Author(s):  
Zhigang Chen ◽  
Nicole Morel-Desrosiers ◽  
Jean-Pierre Morel ◽  
Christian Detellier
Keyword(s):  
Aqueous Solution ◽  
Nmr Spectroscopy ◽  
Chemical Shift ◽  
Stability Constant ◽  
Chemical Shifts ◽  
Similar Treatment ◽  
Calorimetric Measurements ◽  
Nmr Study ◽  
The Stability ◽  
Good Agreement

The interactions of the La(III) cation with D-ribose and with D-arabinose in aqueous solution were investigated by 139La NMR spectroscopy. In the case of D-ribose, the formation of a La(III)-sugar complex was indicated by variations of the 139La chemical shift and linewidth with an increase of the sugar concentration in solution. In contrast, the complexation of La(III) by arabinose is very weak and almost undetectable by 139La NMR. On the basis of a 1:1 stoichiometry, the stability constant for the complex of La(III) with D-ribose was calculated from the observed 139La chemical shift values. A similar treatment was done for the viscosity corrected 139La linewidths using arabinose as an uninteractive reference. The stability constants, K, obtained independently from 139La chemical shifts and linewidths are in good agreement, 2.8 ± 0.5 and 2.2 ± 0.6 M−1 respectively at 299.0 ± 0.5 K. The thermodynamic parameters for the complexation of La(III) by D-ribose could also be obtained: ΔH0 = −12 ± 2 kJ mol−1, and ΔS0 = −31 ± 5 J K−1 mol−1. These values are in very good agreement with those obtained by calorimetric measurements.

scholarly journals Structure of Nanobody Nb23

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3567
Author(s):  
Mathias Percipalle ◽  
Yamanappa Hunashal ◽  
Jan Steyaert ◽  
Federico Fogolari ◽  
Gennaro Esposito
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Shift ◽  
Solution Structure ◽  
Chemical Shifts ◽  
Molecular Size ◽  
Side Chain ◽  
3D Nmr ◽  
Target Antigen ◽  
Internuclear Distances ◽  
2D And 3D

Background: Nanobodies, or VHHs, are derived from heavy chain-only antibodies (hcAbs) found in camelids. They overcome some of the inherent limitations of monoclonal antibodies (mAbs) and derivatives thereof, due to their smaller molecular size and higher stability, and thus present an alternative to mAbs for therapeutic use. Two nanobodies, Nb23 and Nb24, have been shown to similarly inhibit the self-aggregation of very amyloidogenic variants of β2-microglobulin. Here, the structure of Nb23 was modeled with the Chemical-Shift (CS)-Rosetta server using chemical shift assignments from nuclear magnetic resonance (NMR) spectroscopy experiments, and used as prior knowledge in PONDEROSA restrained modeling based on experimentally assessed internuclear distances. Further validation was comparatively obtained with the results of molecular dynamics trajectories calculated from the resulting best energy-minimized Nb23 conformers. Methods: 2D and 3D NMR spectroscopy experiments were carried out to determine the assignment of the backbone and side chain hydrogen, nitrogen and carbon resonances to extract chemical shifts and interproton separations for restrained modeling. Results: The solution structure of isolated Nb23 nanobody was determined. Conclusions: The structural analysis indicated that isolated Nb23 has a dynamic CDR3 loop distributed over different orientations with respect to Nb24, which could determine differences in target antigen affinity or complex lability.

Evaluation of the stability constant of Cl2˙–in neutral aqueous solution

1995 ◽  
Vol 91 (18) ◽  
pp. 3303-3305 ◽  
Author(s):  
David J. Adams ◽  
Susan Barlow ◽  
George V. Buxton ◽  
Treena M. Malone ◽  
G. Arthur Salmon
Keyword(s):  
Aqueous Solution ◽  
Stability Constant ◽  
Neutral Aqueous Solution ◽  
The Stability

109Ag NMR-Study of the Selective Solvation of the Ag+ Ion in Solvent Mixtures of Water and the Organic Solvents: Pyridine, Acetonitrile, and Dimethyl Sulfoxide

1984 ◽  
Vol 39 (1) ◽  
pp. 83-94 ◽  
Author(s):  
L. Guinand. K. L. Hobt. E. Mittermaier ◽  
E. Rößler ◽  
A. Schwenk ◽  
H. Schneider
Keyword(s):  
Chemical Shift ◽  
Dimethyl Sulfoxide ◽  
Organic Solvents ◽  
Mole Fraction ◽  
Chemical Exchange ◽  
Chemical Shifts ◽  
Equilibrium Constants ◽  
Solvent Mixtures ◽  
Nmr Study ◽  
Solvent Molecules

In mixtures of water (W) and one of the organic solvents pyridine, acetonitrile, and dimethyl sulfoxide (O), the silver ion forms the following solvate complexes: AgW2, AgWO, and Ag02. The chemical shift of 109Ag is strongly affected by the ligating solvent molecules, and replacing the ligand W by one of the three organic ligands yields a higher Larmor frequency. In solvent mixtures, only a single resonance line has been observed because of rapid chemical exchange. The measured chemical shifts in the range up to 400 ppm are mean values of the chemical shifts of the different solvate species in a given mixture, weighted with their relative concentrations. The 109Ag chemical shifts were determined for 0.05 to 0.15 molal solutions of AgNO3, as functions of the mole fractions of the solvent components. Using a Gaussian least squares fitting routine, the individual chemical shifts of the Ag+ solvate complexes and the corresponding equilibrium constants were determined. This fit was successful for the whole mole fraction range of DMSO, while in the solvent systems with acetonitrile and with pyridine at higher concentrations of the organic component the chemical shift is influenced by more than two solvent molecules. In these cases equilibrium constants were calculated from chemical shift data for solutions of low mole fraction of acetonitrile and pyridine.

scholarly journals Determination of the protonation state of [H3PW11O39]4− and the stability constant of [Ag(H2O)(H3PW11O39)]3− in aqueous solution

2016 ◽  
Vol 69 (17) ◽  
pp. 2525-2531 ◽  
Author(s):  
Jidan Wang ◽  
Jiansheng Li ◽  
Wansheng You ◽  
Chunxiang He ◽  
Zaiming Zhu
Keyword(s):  
Aqueous Solution ◽  
Stability Constant ◽  
Protonation State ◽  
The Stability

The coordination of β-amino ketoximes with divalent iron, cobalt, nickel and zinc

1978 ◽  
Vol 31 (11) ◽  
pp. 2409 ◽  
Author(s):  
HKJ Powell ◽  
JM Russell
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Bonding ◽  
Stability Constant ◽  
Methyl Ether ◽  
Infrared Spectra ◽  
Iron Cobalt ◽  
Divalent Iron ◽  
Cobalt Nickel ◽  
Stability Order ◽  
The Stability

The iron(II), nickel(II) and zinc(II) complexes of the diamine dioxime ligand 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-dione dioxime (H2dddo) and the cobalt(II), nickel(II) and zinc(II) complexes of its O-methyl ether (Hddmo) have been studied potentiometrically at 25°C, I 0.10M NaCl. Stability constant data are compared with those obtained for the copper(II) and cobalt(II) complexes of H2dddo and the copper(II) complexes of Hddmo. H2dddo coordinates in the oxime-oximato form [M(Hdddo)]+ with iron(II), cobalt(II), nickel(II) and zinc(II) Hddmo forms complexes with the ligand coordinated in the oxime form [M(Hddmo)]2+ and the oximato form [M(ddmo)]+. The complexes [Zn(Hddmo)2]2+, [Zn(Hddmo)(ddmo)]+ and [Co(ddmo)(OH)] were also characterized in aqueous solution. The stability order FeII < CoII < NiII < CuII > ZnII was observed for the formation of 1 : 1 complexes with the ligands Hdddo- (log K = 8.8, 11.7, 15.2, 23.3, 12.0 for Fe to Zn respectively) and Hddmo (5.7, 6.6, 12.1, 5.3 for Co to Zn). The infrared spectra of the complexes [Ni(Hdddo)] ClO4,H2O and [Zn(Hdddo)] ClO4 are discussed in terms of oxime-oximato hydrogen bonding.

A nuclear magnetic resonance investigation of the micellar properties of a series of sodium cyclohexylalkanoates

1999 ◽  
Vol 77 (11) ◽  
pp. 1994-2000 ◽  
Author(s):  
Judith A MacInnis ◽  
R Palepu ◽  
D Gerrard Marangoni
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Shift ◽  
Conformational Changes ◽  
Chemical Shifts ◽  
Micelle Formation ◽  
Counterion Binding ◽  
Micellar Properties ◽  
Aggregation Numbers ◽  
Multinuclear Nmr Spectroscopy ◽  
Magnetic Resonance Investigation

The micellar properties of a family of surfactants, the sodium cyclohexylalkanoates, have been investigated in aqueous solution using multinuclear NMR spectroscopy. C-13 chemical shift measurements have been used to determine both the cmc values and the micellar aggregation numbers (Ns values) of these surfactants. The cmc values and the degrees of counterion binding were estimated from 23Na chemical shift measurements. The critical micelle concentrations (cmc's) and the aggregation numbers determined from the NMR experiments indicate that these amphiphiles have high cmc's and low aggregation numbers when compared to other single-headed surfactants (most notably the sodium alkanoates). The conformational changes incurred by the carbon atoms upon micelle formation have been deduced from the 13C chemical shift differences (δsurf,mic - δsurf,aq). These results are used to discuss the formation of the aggregates of the sodium cyclohexylalkanoate surfactants as a function of the length of the alkanoate side chain.Key words: micelles, surfactants, NMR spectroscopy, chemical shifts, aggregation numbers, degree of counterion binding, conformational changes.

CORE LEVEL CHEMICAL SHIFTS AND LINE SHAPES FOR SYSTEMS WITH DIFFERENT VALENCIES AND Cu-O NETWORKS

2000 ◽  
Vol 14 (32) ◽  
pp. 3791-3830 ◽  
Author(s):  
K. KARLSSON ◽  
O. GUNNARSSON ◽  
O. JEPSEN
Keyword(s):  
Chemical Shift ◽  
Chemical Shifts ◽  
Core Level ◽  
Photoemission Spectrum ◽  
Main Peak ◽  
Model Compounds ◽  
Line Shapes ◽  
Impurity Model ◽  
Anderson Impurity Model ◽  
Good Agreement

We have studied the Cu -2p core level photoemission spectrum of a variety of cuprates, mainly focusing on the chemical shift and the shape of the leading peak. The spectra are calculated using the Anderson impurity model and we obtain a very good agreement with the experimental data. We find that the shape of the leading peak depends crucially on the structure of the Cu - O network. The main peak turns out to be quite narrow if the network consists of Cu - O - Cu bond angels of the order of 90°. On the other hand, if the Cu - O atoms are arranged with bond angles of approximately 180°, the main peak becomes substantially broader and contains a rather complicated structure. However, in some cases it is not sufficient only to consider the Cu - O network because interactions with other atoms are also important. In the model compounds Cu 2 O , CuO and NaCuO 2, where Cu is formally monovalent, divalent and trivalent, respectively, we find that the number of 3d electrons is rather similar. Nevertheless, the binding energy increases with the valence as expected from chemical intuition. The spectra exhibit a large variation in the strength of the d9-like satellite and in the width of the main line. We, furthermore, study the chemical shift of three inequivalent Cu atoms in YBa 2 Cu 3 O 6.5, and compare the results with the model compounds, which suggests that the different Cu atoms in YBa 2 Cu 3 O 6.5 have formal valences of approximately one, two and three. These findings are analyzed and related to the formal valence.

SUBSTITUTIONAL AND CONFIGURATIONAL EFFECTS ON CHEMICAL SHIFT IN PYRANOID CARBOHYDRATE DERIVATIVES

1965 ◽  
Vol 43 (7) ◽  
pp. 2059-2070 ◽  
Author(s):  
R. U. Lemieux ◽  
J. D. Stevens
Keyword(s):  
Chemical Shift ◽  
Long Range ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Equatorial Orientation ◽  
Free Energies ◽  
Bonding Interaction ◽  
Conformational Properties ◽  
Good Agreement ◽  
Shielding Effects

The effects of long-range and virtual long-range coupling on the observed spectra of acetylated hexopyranoses and pentopyranoses are examined. Use is made of both spin decoupling and specific deuteration for the assignment of signals. It is seen that specific solvent effects on chemical shift can be superior to increasing the applied magnetic field for the resolution of the signals of closely related protons. The alteration of virtual long-range coupling effects in these ways can be useful in the diagnosis of spectra. Empirical rules are derived for estimating the long-range shielding effects which occur on changing configurations. It is seen that the inversion of a center can lead to deshielding of axial protons and to shielding of equatorial protons at other centers relative to the chemical shifts observed in reference compounds wherein all the acetoxy groups are in equatorial orientation. The effects in several cases result in equatorial protons giving their signal to higher field than chemically similar but axial protons. The conformational properties of pentopyranose tetraacetates as estimated from chemical shifts and coupling constants are seen to be in good agreement with expectations based on non-bonding interaction free energies. As expected, 2-deoxy-β-D-ribopyranose triacetate has the 1C-conformation when dissolved in chloroform.

Chemical shift correlated two-dimensional nmr spectroscopy and its application to solving the proton nmr spectra of oligoribonucleotides

1980 ◽  
Vol 58 (18) ◽  
pp. 1947-1956 ◽  
Author(s):  
Alex D. Bain ◽  
Russell A. Bell ◽  
Jeremy R. Everett ◽  
Donald W. Hughes
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Shift ◽  
Nmr Spectra ◽  
Pulse Sequence ◽  
Chemical Shifts ◽  
Proton Nmr ◽  
Two Dimensional

An alternative two-dimensional nmr pulse sequence, (90°–t1/2–90°–t1/2–FID),correlates the chemical shifts of coupled nuclei. The application of this technique to the solution of the complicated proton nmr spectra of oligoribonucleotides is discussed.

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