Solid state 19F NMR parameters of fluorine-labeled amino acids. Part II: Aliphatic substituents

Dürr, U.; Grage, Stephan L.; Witter, Raiker; Ulrich, Anne S.

doi:10.1016/j.jmr.2007.11.016

Cited by 67 publications

(53 citation statements)

References 20 publications

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“…S2) were analyzed in quantitative detail and indicate that at 240 K and 250 K, the 19 F chemical-shift anisotropy is 48 5 2 ppm and 47 5 2 ppm (asymmetry parameter h ¼ 0). These values are similar to the static powder limit for this label (56), whereas at temperatures of >262 K the 19 F chemical-shift anisotropy is reduced due to motional averaging. The change in anisotropy correlates with the freezing of membrane-associated water (57) concomitantly with the slowing down of motions of the side chains and the peptides as a whole.…”

Section: Solid-state Nmr Spectroscopy Of An Alm Oligomersupporting

confidence: 78%

Alamethicin Supramolecular Organization in Lipid Membranes from 19F Solid-State NMR

Salnikov

Raya

Zotti

et al. 2016

Biophysical Journal

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Alamethicins (ALMs) are antimicrobial peptides of fungal origin. Their sequences are rich in hydrophobic amino acids and strongly interact with lipid membranes, where they cause a well-defined increase in conductivity. Therefore, the peptides are thought to form transmembrane helical bundles in which the more hydrophilic residues line a water-filled pore. Whereas the peptide has been well characterized in terms of secondary structure, membrane topology, and interactions, much fewer data are available regarding the quaternary arrangement of the helices within lipid bilayers. A new, to our knowledge, fluorine-labeled ALM derivative was prepared and characterized when reconstituted into phospholipid bilayers. As a part of these studies, C 19 F 3 -labeled compounds were characterized and calibrated for the first time, to our knowledge, for 19 F solid-state NMR distance and oligomerization measurements by centerband-only detection of exchange (CODEX) experiments, which opens up a large range of potential labeling schemes. The 19 F-19 F CODEX solid-state NMR experiments performed with ALM in POPC lipid bilayers and at peptide/lipid ratios of 1:13 are in excellent agreement with molecular-dynamics calculations of dynamic pentameric assemblies. When the peptide/lipid ratio was lowered to 1:30, ALM was found in the dimeric form, indicating that the supramolecular organization is tuned by equilibria that can be shifted by changes in environmental conditions.

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Section: Solid-state Nmr Spectroscopy Of An Alm Oligomersupporting

confidence: 78%

Alamethicin Supramolecular Organization in Lipid Membranes from 19F Solid-State NMR

Salnikov

Raya

Zotti

et al. 2016

Biophysical Journal

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“…The chemical shift values amongst these preparations were more homogeneous than within the polycrystalline amino acids, suggesting that it is better to use the tabulated values (or newly acquired parameters) of the lyophilized peptide samples than of the polycrystalline amino acids, in contrast to the aliphatic amino acids discussed in Part II [43]. Nonetheless, the chemical shift anisotropies D of the pure aromatic amino acids give some clues for biological samples, taking into account differences due to residual molecular motion in the peptide samples.…”

Section: Discussionmentioning

confidence: 99%

“…This set of data includes most of the amino acids that are suitable for biosynthetic labeling. Part II then characterizes amino acids containing aliphatic 19 F-labels, with an emphasis on CF 3 -groups [43].…”

Section: Introductionmentioning

confidence: 99%

Solid state 19F NMR parameters of fluorine-labeled amino acids. Part I: Aromatic substituents

Dürr

Grage²,

Witter³

et al. 2008

Journal of Magnetic Resonance

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111

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Structural parameters of peptides and proteins in biomembranes can be directly measured by solid state NMR of selectively labeled amino acids. The 19F nucleus is a promising label to overcome the low sensitivity of 2H, 13C or 15N, and to serve as a background-free reporter group in biological compounds. To make the advantages of solid state 19F NMR fully available for structural studies of polypeptides, we have systematically measured the chemical shift anisotropies and relaxation properties of the most relevant aromatic and aliphatic 19F-labeled amino acids. In this first part of two consecutive contributions, six different 19F-substituents on representative aromatic side chains were characterized as polycrystalline powders by static and MAS experiments. The data are also compared with results on the same amino acids incorporated in synthetic peptides. The spectra show a wide variety of lineshapes, from which the principal values of the CSA tensors were extracted. In addition, temperature-dependent T(1) and T(2) relaxation times were determined by 19F NMR in the solid state, and isotropic chemical shifts and scalar couplings were obtained in solution.

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“…The CSA and inter-nuclear DD contributions may safely be ignored for two reasons. Firstly, on theoretical grounds, the 19 F CSA in the trifluoromethyl group is quite small [41,42] and inter-nuclear DD interaction is swamped by the much stronger electron-nuclear interactions. Secondly, from experimental observations, the fluorine T 1 time in diamagnetic Y 3 + and La 3 + complexes is about 1 s, so CSA and inter-nuclear DD cannot account for more than around 1 Hz in the measured paramagnetic relaxation rates, which are all of the order of 100 Hz.…”

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confidence: 99%

Design Principles and Theory of Paramagnetic Fluorine‐Labelled Lanthanide Complexes as Probes for ¹⁹F Magnetic Resonance: A Proof‐of‐Concept Study

Chalmers

Luca

Hogg

et al. 2009

Chemistry A European J

143

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The synthesis and spectroscopic properties of a series of CF(3)-labelled lanthanide(III) complexes (Ln=Gd, Tb, Dy, Ho, Er, Tm) with amide-substituted ligands based on 1,4,7,10-tetraazacyclododecane are described. The theoretical contributions of the (19)F magnetic relaxation processes in these systems are critically assessed and selected volumetric plots are presented. These plots allow an accurate estimation of the increase in the rates of longitudinal and transverse relaxation as a function of the distance between the Ln(III) ion and the fluorine nucleus, the applied magnetic field, and the re-rotational correlation time of the complex, for a given Ln(III) ion. Selected complexes exhibit pH-dependent chemical shift behaviour, and a pK(a) of 7.0 was determined in one example based on the holmium complex of an ortho-cyano DO3A-monoamide ligand, which allowed the pH to be assessed by measuring the difference in chemical shift (varying by over 14 ppm) between two (19)F resonances. Relaxation analyses of variable-temperature and variable-field (19)F, (17)O and (1)H NMR spectroscopy experiments are reported, aided by identification of salient low-energy conformers by using density functional theory. The study of fluorine relaxation rates, over a field range of 4.7 to 16.5 T allowed precise computation of the distance between the Ln(III) ion and the CF(3) reporter group by using global fitting methods. The sensitivity benefits of using such paramagnetic fluorinated probes in (19)F NMR spectroscopic studies are quantified in preliminary spectroscopic and imaging experiments with respect to a diamagnetic yttrium(III) analogue.

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Solid state 19F NMR parameters of fluorine-labeled amino acids. Part II: Aliphatic substituents

Cited by 67 publications

References 20 publications

Alamethicin Supramolecular Organization in Lipid Membranes from 19F Solid-State NMR

Alamethicin Supramolecular Organization in Lipid Membranes from 19F Solid-State NMR

Solid state 19F NMR parameters of fluorine-labeled amino acids. Part I: Aromatic substituents

Design Principles and Theory of Paramagnetic Fluorine‐Labelled Lanthanide Complexes as Probes for ¹⁹F Magnetic Resonance: A Proof‐of‐Concept Study

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Solid state 19F NMR parameters of fluorine-labeled amino acids. Part II: Aliphatic substituents

Cited by 67 publications

References 20 publications

Alamethicin Supramolecular Organization in Lipid Membranes from 19F Solid-State NMR

Alamethicin Supramolecular Organization in Lipid Membranes from 19F Solid-State NMR

Solid state 19F NMR parameters of fluorine-labeled amino acids. Part I: Aromatic substituents

Design Principles and Theory of Paramagnetic Fluorine‐Labelled Lanthanide Complexes as Probes for 19F Magnetic Resonance: A Proof‐of‐Concept Study

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Design Principles and Theory of Paramagnetic Fluorine‐Labelled Lanthanide Complexes as Probes for ¹⁹F Magnetic Resonance: A Proof‐of‐Concept Study