The temperature dependence of carbon-13 nuclear magnetic resonance shifts. Limiting factors and stereochemical applications

Schneider, H.‐J.; Freitag, Wolfgang

doi:10.1021/ja00418a025

Cited by 59 publications

(11 citation statements)

References 2 publications

(3 reference statements)

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“…The range in thermal dependence reflects differences in nuclear shielding among the atoms in the more populated excited rotational-vibrational states when the temperature is raised (Jameson, 1980;Schneider and Freitag, 1976). In their alanine-based peptides at low temperatures, where the helix is fully formed and stable, the thermal dependence of the carbonyl resonances is about + I 0 ppb/"C (Shalongo ct al., 1994a).…”

Section: Temperature Dependence Of the Carbonyl Chemical Shiftsmentioning

confidence: 99%

The Interactions with Solvent, Heat Stability, and ¹³C‐Labelling of Alamethicin, an Ion‐Channel‐Forming Peptide

Yee

Marat

O'Neil

1997

European Journal of Biochemistry

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The peptide alamethicin was labelled with I3C and "N by growing the fungus Trichoderma viride in a medium containing [U-"C]glucose and K"N0,. Spin-echo difference spectroscopy showed that I3C was incorporated to a level of about SO% and "N to about 98%. Incorporation of "C into the peptide provided residue-specific probes of the interactions with solvent and heat stability of this ion-channelforming peptide. All of the carbonyl carbons and the a-carbons of the a-aminoisobutyric acid [Ala(Me)J residues of alamethicin in methanol were assigned using two-dimensional and three-dimensional heteronuclear correlation experiments. Measurements of '.Ic,, revealed hydrogen bonding with solvent at residues 1 and 19 at the ends of the peptide and at Glyl 1 in the middle. The data also support the thesis [see Juranic, N., Ilich, P. K. & Macara, S. (1995) J. Am. that intramolecular hydrogen bonds in proteins and peptides are weaker than hydrogen bonds to solvent. The sensitivity of alamethicin carbonyl and proton chemical shifts to perturbation by dimethyl sulfoxide correlates well with the calculated solvent accessibilities of the carbonyls in the crystal structures and reveals residues in the middle of the peptide and at the C-terminus which interact with solvent. Taken together with the 'JC,, measurements, the data support a model in which hydrogen bonding to solvent at the GlylULeul2 amide could provide a site of hydration in the interior of the alamethicin channel structure. The temperature dependencies of the carbonyl chemical shifts support the suggestion that the peptide is flexible in the regions where solvent interacts with the backbone of the peptide. The linear temperature dependence of the carbonyl chemical shifts and molar ellipticity indicate that, due to steric constraints at the Ala(Me) residues, the peptide foldinghnfolding transition is non-cooperative and that the peptide is remarkably heat stable. Keywords:alamethicin ; "C labelling; dimethyl sulfoxide ; ion channel ; NMR.Alamethicin is a 20-amino-acid antibiotic peptide secreted by the fungus Trichoderma viride. It forms a voltage-gated conductance in lipid bilayers (Eisenberg et al., 1973;Latore et al., 1981) and is one of the most extensively studied models for vertebrate ion channels [for reviews see Sansom (1993) and Cafiso (1994)l. The peptide has eight residues of a-aminoisobutyric acid [Ala(Me)] which have a-methyl in place of the usual a-hydrogen found in the L-amino acids. The mechanism by which alamethicin inserts into membranes, forms ion channels, and is regulated by an applied voltage is unclear. You et al.(1 996) recently showed that covalent dimers of alamethicin form stabilized ion channels with a single predominant conductance state. They suggest that the channels consist of a bundle of six parallel monomers. Evidence for antiparallel interactions between monomers dissolved in methanol was obtained by North et al. (1994). Their measurements of the paramagnetic enhancements of nuclear relaxation also indicated that the peptide backbone c...

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Section: Temperature Dependence Of the Carbonyl Chemical Shiftsmentioning

confidence: 99%

The Interactions with Solvent, Heat Stability, and ¹³C‐Labelling of Alamethicin, an Ion‐Channel‐Forming Peptide

Yee

Marat

O'Neil

1997

European Journal of Biochemistry

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“…Deshieldings of 3 x 10-3 ppm/K for cyclohexane and 5 x 10-3 ppm/K for C2,6 of trans -1, 4-dimethylcyclohexane have been reported by Schnieder and Freitag. 42 Deshieldings, some nonlinear, of up to 9 X 10-3 ppm/K relative to the methyl of acetoned S have been reported by Yamamoto et al 43 for various hexachlorocyclohexane isomers. We note that due to the temperature dependence of the TMS shift reported, 42 the mean shift of C t ,2 is likely to be temperature dependent if measured with respect to a different reference.…”

Section: Resul R8-nmrmentioning

confidence: 80%

“…42 Deshieldings, some nonlinear, of up to 9 X 10-3 ppm/K relative to the methyl of acetoned S have been reported by Yamamoto et al 43 for various hexachlorocyclohexane isomers. We note that due to the temperature dependence of the TMS shift reported, 42 the mean shift of C t ,2 is likely to be temperature dependent if measured with respect to a different reference. The areas of the Lorentzian lines used to fit the low temperature data were used to compute K for the three pairs of carbons.…”

Section: Resul R8-nmrmentioning

confidence: 80%

Dielectric and NMR study of conformational dynamics in t r a n s-1,2-dichlorocyclohexane

Ehrhardt

Vaughan

1981

The Journal of Chemical Physics

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The complex dielectric permittivity of trans-I,2-dichlorocyclohexane (DCCH) in supercooled o-terphenyl at audio frequencies is reported. These data are interpreted in terms of a dynamical model involving internal site exchange coupled to a cooperative solvent controlled molecular reorientation process. Fourier transform l3C lines shapes are reported for DCCH in mixed carbon tetrachloride-;leuterochloroform solvent over a range of temperatures encompassing the coalescence region. Details of the site dynamics are extracted from these data via numerical line shape analysis. Reasonable agreement between the parameters common to both models is found.

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“…Temperature effects on 13 C NMR spectra of alkanes are variable, ranging from 0 to about 20 ppb per degree K in either direction (that is, upfield or downfield with increasing T), reflecting the change in conformation populations with temperature. 7 So in two different samples with very similar 13 C NMR spectra, the chemical shift differences caused by small changes in sample temperature could easily exceed the real differences. Clearly the spectra of the candidate samples have to be collected at the same sample temperature as the spectrum of the natural product.…”

Section: Resultsmentioning

confidence: 99%

Systematic Comparison of Sets of ¹³C NMR Spectra That Are Potentially Identical. Confirmation of the Configuration of a Cuticular Hydrocarbon from the Cane Beetle Antitrogus parvulus

et al. 2014

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A systematic process is introduced to compare 13C NMR spectra of two (or more) candidate samples of known structure to a natural product sample of unknown structure. The process is designed for the case where the spectra involved can reasonably be expected to be very similar, perhaps even identical. It is first validated by using published 13C NMR data sets for the natural product 4,6,8,10,16,18-hexamethyldocosane. Then the stereoselective total syntheses of two candidate isomers of the related 4,6,8,10,16-pentamethyldocosane natural product are described, and the process is applied to confidently assign the configuration of the natural product as (4S,6R,8R,10S,16S). This is accomplished even though the chemical shift differences between this isomer and its (16R)-epimer are only ±5–10 ppb (±0.005–0.01 ppm).

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The temperature dependence of carbon-13 nuclear magnetic resonance shifts. Limiting factors and stereochemical applications

Cited by 59 publications

References 2 publications

The Interactions with Solvent, Heat Stability, and ¹³C‐Labelling of Alamethicin, an Ion‐Channel‐Forming Peptide

The Interactions with Solvent, Heat Stability, and ¹³C‐Labelling of Alamethicin, an Ion‐Channel‐Forming Peptide

Dielectric and NMR study of conformational dynamics in t r a n s-1,2-dichlorocyclohexane

Systematic Comparison of Sets of ¹³C NMR Spectra That Are Potentially Identical. Confirmation of the Configuration of a Cuticular Hydrocarbon from the Cane Beetle Antitrogus parvulus

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The temperature dependence of carbon-13 nuclear magnetic resonance shifts. Limiting factors and stereochemical applications

Cited by 59 publications

References 2 publications

The Interactions with Solvent, Heat Stability, and 13C‐Labelling of Alamethicin, an Ion‐Channel‐Forming Peptide

The Interactions with Solvent, Heat Stability, and 13C‐Labelling of Alamethicin, an Ion‐Channel‐Forming Peptide

Dielectric and NMR study of conformational dynamics in t r a n s-1,2-dichlorocyclohexane

Systematic Comparison of Sets of 13C NMR Spectra That Are Potentially Identical. Confirmation of the Configuration of a Cuticular Hydrocarbon from the Cane Beetle Antitrogus parvulus

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The Interactions with Solvent, Heat Stability, and ¹³C‐Labelling of Alamethicin, an Ion‐Channel‐Forming Peptide

The Interactions with Solvent, Heat Stability, and ¹³C‐Labelling of Alamethicin, an Ion‐Channel‐Forming Peptide

Systematic Comparison of Sets of ¹³C NMR Spectra That Are Potentially Identical. Confirmation of the Configuration of a Cuticular Hydrocarbon from the Cane Beetle Antitrogus parvulus