Related Articles1H-NMR measurement of fractional dissociation of imidazole in intact animals.
Am J Physiol. 1994 Mar;266(3 Pt 2):R1008-15
Authors: Hitzig BM, Perng WC, Burt T, Okunieff P, Johnson DC
The alphastat hypothesis states that intracellular acid-base status is regulated to maintain constancy of the fractional dissociation of intracellular protein and enzyme imidazole-histidine (alpha-imidazole). A major drawback of this theory has been the lack of a means to directly measure alpha-imidazole in intact animals. We developed a method for directly measuring alpha-imidazole in intact unanesthetized animals using 1H-nuclear magnetic resonance spectroscopy (NMR). We measured carnosine alpha-imidazole of white skeletal muscle from intact unanesthetized newts at three body temperatures (10, 20, and 30 degrees C). alpha-Imidazole remained constant, approximately 0.56, with alterations in body temperature, whereas intracellular pH (pHi) changed significantly (-0.015 U/degrees C), affirming the validity of the imidazole alphastat hypothesis for this tissue. This method was also used to determine the pK values of the imidazole moiety of carnosine and the imidazole moiety alone over a temperature (T) range 4-40 degrees C. The pK values of carnosine differed from those of imidazole, but the delta pK/delta T was the same. pHi was also determined using 31P-NMR and found to be the same as that calculated from carnosine alpha-imidazole values. Therefore Pi and carnosine share a similar pHi environment. We describe a novel technique to directly measure alpha-imidazole in intact tissue.
NMR insights into the core of GED assembly by H/D exchange coupled with DMSO dissociation and analysis of the denatured state.
NMR insights into the core of GED assembly by H/D exchange coupled with DMSO dissociation and analysis of the denatured state.
NMR insights into the core of GED assembly by H/D exchange coupled with DMSO dissociation and analysis of the denatured state.
J Mol Biol. 2011 Feb 4;405(5):1202-14
Authors: Chakraborty S, Hosur RV
GTPase effector domain (GED) of dynamin forms megadalton-sized assembly in vitro, rendering its structural characterization highly challenging. To probe the core of the GED assembly, we performed H/D exchange in native...
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[NMR paper] Identification of regioisomers in a series of N-substituted pyridin-4-yl imidazole de
Identification of regioisomers in a series of N-substituted pyridin-4-yl imidazole derivatives by regiospecific synthesis, GC/MS, and 1H NMR.
Related Articles Identification of regioisomers in a series of N-substituted pyridin-4-yl imidazole derivatives by regiospecific synthesis, GC/MS, and 1H NMR.
J Org Chem. 2003 May 30;68(11):4527-30
Authors: Wagner GK, Kotschenreuther D, Zimmermann W, Laufer SA
The regiospecific synthesis of 2a (Scheme 3), a novel and potent pyridinyl imidazole inhibitor of p38 MAP (mitogen-activated protein) kinase, and...
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[NMR paper] NMR methods for the determination of protein-ligand dissociation constants.
NMR methods for the determination of protein-ligand dissociation constants.
Related Articles NMR methods for the determination of protein-ligand dissociation constants.
Curr Top Med Chem. 2003;3(1):39-53
Authors: Fielding L
This article is a review with 83 references of the application of NMR to the measurement of the dissociation constants of protein-ligand complexes. After briefly discussing some general concepts of molecular stability, the text turns to consider which NMR parameters are reporters of complex formation. The available data...
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Optimizing 19F NMR protein spectroscopy by fractional biosynthetic labeling
Abstract In protein NMR experiments which employ nonnative labeling, incomplete enrichment is often associated with inhomogeneous line broadening due to the presence of multiple labeled species. We investigate the merits of fractional enrichment strategies using a monofluorinated phenylalanine species, where resolution is dramatically improved over that achieved by complete enrichment. In NMR studies of calmodulin, a 148 residue calcium binding protein, 19F and 1H-15N HSQC spectra reveal a significant extent of line broadening and the appearance of minor conformers in the presence of...
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Optimizing (19)F NMR protein spectroscopy by fractional biosynthetic labeling.
Optimizing (19)F NMR protein spectroscopy by fractional biosynthetic labeling.
Related Articles Optimizing (19)F NMR protein spectroscopy by fractional biosynthetic labeling.
J Biomol NMR. 2010 Aug 24;
Authors: Kitevski-Leblanc JL, Evanics F, Scott Prosser R
In protein NMR experiments which employ nonnative labeling, incomplete enrichment is often associated with inhomogeneous line broadening due to the presence of multiple labeled species. We investigate the merits of fractional enrichment strategies using a monofluorinated phenylalanine species,...
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[NMR paper] 1H-NMR and EPR studies on met-azido and met-imidazole Dolabella auricularia myoglobin
1H-NMR and EPR studies on met-azido and met-imidazole Dolabella auricularia myoglobin.
Related Articles 1H-NMR and EPR studies on met-azido and met-imidazole Dolabella auricularia myoglobin.
Biochim Biophys Acta. 1995 Apr 27;1248(2):149-58
Authors: Yamamoto Y, Suzuki T, Hori H
Met-azido and met-imidazole forms of the myoglobin from the mollusc Dolabella auricularia have been studied by 1H-NMR and EPR spectroscopy. In the mollusc myoglobin, in which His-E7 is replaced by Val, the guanidino group of Arg-E10 serves as an alternative hydrogen-bond...
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[NMR paper] 1H-NMR measurement of fractional dissociation of imidazole in intact animals.
1H-NMR measurement of fractional dissociation of imidazole in intact animals.
Related Articles 1H-NMR measurement of fractional dissociation of imidazole in intact animals.
Am J Physiol. 1994 Mar;266(3 Pt 2):R1008-15
Authors: Hitzig BM, Perng WC, Burt T, Okunieff P, Johnson DC
The alphastat hypothesis states that intracellular acid-base status is regulated to maintain constancy of the fractional dissociation of intracellular protein and enzyme imidazole-histidine (alpha-imidazole). A major drawback of this theory has been the lack of a means...
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08-22-2010 03:33 AM
[NMR paper] Support of 1H NMR assignments in proteins by biosynthetically directed fractional 13C
Support of 1H NMR assignments in proteins by biosynthetically directed fractional 13C-labeling.
Related Articles Support of 1H NMR assignments in proteins by biosynthetically directed fractional 13C-labeling.
J Biomol NMR. 1992 Jul;2(4):323-34
Authors: Szyperski T, Neri D, Leiting B, Otting G, Wüthrich K
Biosynthetically directed fractional incorporation of 13C into proteins results in nonrandom 13C-labeling patterns that can be investigated by analysis of the 13C-13C scalar coupling fine structures in heteronuclear 13C-1H or homonuclear...
1H-NMR measurement of fractional dissociation of imidazole in intact animals.
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