Nuclear magnetic resonance spectroscopy. Spin-lattice relaxation of the acetic acid carboxyl carbon

Gust, Devens; Pearson, Harry; Armitage, Ian M.; Roberts, John D.

doi:10.1021/ja00426a008

Cited by 13 publications

(4 citation statements)

References 2 publications

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“…The a carbons can be safely assumed to be immobilized in the protein, with each one being exclusively relaxed by dipolar interaction with its single bonded proton 1.09 Á away. Using eq 1, the measured R i value results in two solutions for re, the larger one of ( 304 Paramagnetic ion contaminants have plagued studies of carboxyl relaxation in small molecules (T") ~50-100 s), especially since their effects are pH dependent (Gust et al, 1976;Cohen et al, 1975).…”

Section: Resultsmentioning

confidence: 99%

Carbon-13 magnetic resonance of carboxymethylated human carbonic anhydrase B. Chemical shift and spin-lattice relaxation studies

Jeffers¹,

Sutherland²,

Khalifah³

1978

Biochemistry

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We have previously prepared Ntau-carbosymethylhistidine-200 human carbonic anhydrase B using 90% [1-13C]bromoacetate and have observed the 13C NMR resonance of the enriched carboxylate now covalently attached in the active site. We report here chemical shift studies of the zinc-free carboxymethylated enzyme and its Co2+-substituted form, as well as relaxation studies of the resonance in the zinc enzyme at three frequencies (15.04, 25.15, and 90.5 MHz). The chemical shift and relaxation data are both consistent with the immobilization of the carboxylate at pH 8 and its approach or coordination to the zinc. The relaxation data indicate that lowering the pH to 5.5 leads to internal motion of the carboxymethyl moiety, consistent with the chemical shift evidence for the disruption of the proposed zinc--carboxylate coordination. Inhibitor binding at either pH 5.5 or 8.0 eliminates whatever internal motion might be present. The relaxation data have been interpreted using theoretical calculations on dipolar and chemical shift anisotropy contributions. The combined results indicate that the catalytic consequences of the carboxymethylation may be due to the proposed zinc--carboxylate coordination and need not result from the disruption of any role that histidine-200 might play in the catalytic mechanism.

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Section: Resultsmentioning

confidence: 99%

Carbon-13 magnetic resonance of carboxymethylated human carbonic anhydrase B. Chemical shift and spin-lattice relaxation studies

Jeffers¹,

Sutherland²,

Khalifah³

1978

Biochemistry

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“…The inter-and intramolecular behavior of molecules in solution, as they participate in various types of non-covalent bonding, has been examined by 13 C and 15 N NMR. Using T1 measurements, non-covalent interactions, such as hydrogen bonding of carboxylic acids (15,16), cyclic alcohols, methoxy derivatives, cycloalkanones (17,18), phenols (19), anilines (19), aminobenzoic acids and substituted anilines (20), and aromatic and substituted aromatic compounds (21), with various solvents and solutes have been examined as a function of pH, ionic strength, and concentration. Likewise, 7 Li and 13 C NMR T1 measurements have been employed to characterize and examine the structure of lithoisobutyrophenone aggregates in ether solvents (22).…”

Section: Introductionmentioning

confidence: 99%

Noncovalent Interactions between Acenaphthenone and Dissolved Fulvic Acid As Determined by ¹³C NMR T₁ Relaxation Measurements

Nanny

Bortiatynski

Hatcher

1997

Environ. Sci. Technol.

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Non-covalent interactions between 13 C-labeled acenaphthenone ( 13 C-labeled in the carbonyl position) and Suwannee River fulvic acid in a methanol/D 2 O solvent have been examined using 13 C NMR T 1 relaxation measurements. The influence of solvents upon the non-covalent interactions were assessed by examining acenaphthenone in pure solvents of varying solvation capacity (chloroform, methanol, methanol/D 2 O). Interactions with fulvic acid were examined as a function of acenaphthenone and fulvic acid concentrations, fulvic acid counter-cation (H + or Na + ), and pH. In the presence of fulvic acid in a methanol/D 2 O solvent, three non-covalent interactions were identified: a weak sorption interaction between acenaphthenone and fulvic acid, an enhanced solubilization of acenaphthenone by fulvic acid, and an interaction between just the solvent and acenaphthenone. The enhanced solubilization is hypothesized to arise from fulvic acid forming hydrophobic regions that are predominantly solvated with methanol and have excluded water. Acenaphthenone in these hydrophobic regions displays similar behavior to when it is dissolved in pure methanol. The ability of fulvic acid to form hydrophobic regions was found to be dependent upon the identity of the fulvic acid counter-cation and upon pH.

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“…We then estimated the 1 H-13 C R 1DD contributions of g-Glu-[1-13 C]Gly and g-Glu-[1-13 C]Gly-d 2 using the nuclear Overhauser effect. 19,[26][27][28][29][30] We found that 37% of the total R 1 of g-Glu-[1-13 C]Gly was responsible for DD relaxation at 9.4 T, whereas only 6% of that of g-Glu-[1-13 C]Gly-d 2 was responsible for DD. Because the R 1DD of g-Glu-[1-13 C]Gly-d 2 , in which only the a-1 Hs of the Gly residue were deuterated, decreased to 6%, most of the DD relaxation of g-Glu-[1-13 C]Gly was caused by the a-1 H of the Gly residue.…”

Section: Resultsmentioning

confidence: 71%

Evaluation of enzymatic and magnetic properties of γ-glutamyl-[1-¹³C]glycine and its deuteration toward longer retention of the hyperpolarized state

et al. 2021

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Nuclear magnetic resonance spectroscopy. Spin-lattice relaxation of the acetic acid carboxyl carbon

Cited by 13 publications

References 2 publications

Carbon-13 magnetic resonance of carboxymethylated human carbonic anhydrase B. Chemical shift and spin-lattice relaxation studies

Carbon-13 magnetic resonance of carboxymethylated human carbonic anhydrase B. Chemical shift and spin-lattice relaxation studies

Noncovalent Interactions between Acenaphthenone and Dissolved Fulvic Acid As Determined by ¹³C NMR T₁ Relaxation Measurements

Evaluation of enzymatic and magnetic properties of γ-glutamyl-[1-¹³C]glycine and its deuteration toward longer retention of the hyperpolarized state

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Nuclear magnetic resonance spectroscopy. Spin-lattice relaxation of the acetic acid carboxyl carbon

Cited by 13 publications

References 2 publications

Carbon-13 magnetic resonance of carboxymethylated human carbonic anhydrase B. Chemical shift and spin-lattice relaxation studies

Carbon-13 magnetic resonance of carboxymethylated human carbonic anhydrase B. Chemical shift and spin-lattice relaxation studies

Noncovalent Interactions between Acenaphthenone and Dissolved Fulvic Acid As Determined by 13C NMR T1 Relaxation Measurements

Evaluation of enzymatic and magnetic properties of γ-glutamyl-[1-13C]glycine and its deuteration toward longer retention of the hyperpolarized state

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Product

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Noncovalent Interactions between Acenaphthenone and Dissolved Fulvic Acid As Determined by ¹³C NMR T₁ Relaxation Measurements

Evaluation of enzymatic and magnetic properties of γ-glutamyl-[1-¹³C]glycine and its deuteration toward longer retention of the hyperpolarized state