Related ArticlesThe importance of binding energy in catalysis of hydride transfer by UDP-galactose 4-epimerase: a 13C and 15N NMR and kinetic study.
Biochemistry. 1993 Dec 7;32(48):13220-30
Authors: Burke JR, Frey PA
UDP-galactose 4-epimerase contains NAD+ irreversibly but noncovalently bound to the active site. Uridine nucleotides bind to the substrate site and induce a protein conformational change that increases the chemical reactivity of NAD+ at the coenzyme site. Activation of NAD+ by uridine nucleotides perturbs the 15N and 13C NMR chemical shifts of selectively enriched NAD+ bound to the coenzyme site. The proton-decoupled 15N NMR signal for enzyme-bound [carboxamide-15N]NAD+ does not change upon addition of UDP, indicating that activation is not brought about by a change in the binding of the carboxamide group. The 15N NMR signal of enzyme-bound [nicotinamide-1-15N]NAD+ is shifted upfield 3.0 ppm and the 13C NMR signal for [nicotinamide-4-13C]NAD+ is shifted downfield 3.4 ppm downfield by the binding of UDP at the substrate site. These changes are consistent with the induction of a distortion into the nicotinamide ring, in which positive charge is transferred from N-1 to C-4. The kinetic and thermodynamic effects of these perturbations are significant, as indicated by the nonenzymatic chemical reactivities of a series of N-alkyl nicotinamides differing in the inductive electron withdrawing effects of the alkyl substituents. A downfield change of 3.4 ppm in the 4-13C chemical shifts brought about by electron withdrawal in the model compounds corresponds to a 3200-fold increase in the rate of reduction by NaBH3CN in water, a 15,000-fold increase in 86% ethanol, and a 152 mV more positive reduction potential in this series. The distortion of NAD+ by the binding of UDP is a long-range effect that is transmitted from the substrate binding site to the coenzyme through the protein conformational change. This apparently distorts the pi-electron distribution in the nicotinamide ring and reduces the activation energy for its reduction. Activation of enzyme-bound NAD+ toward reduction apparently arises from a destabilization in the nicotinamide ring structure rather than from a stabilization of the transition state through attractive interactions between the nicotinamide ring and the enzyme.
[Question from NMRWiki Q&A forum] 13C NMR of sulfated galactose
13C NMR of sulfated galactose
Hi everybody, Has anyone ever seen a C-6 at 64 ppm in the 13C NMR spectrum of a sulfated galactose?
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01-17-2012 12:11 PM
Site-specific free energy changes in proteins upon ligand binding by NMR: Ca(2+) -displacement by Ln(3+) in a Ca(2+) -binding protein from Entamoeba histolytica.
Site-specific free energy changes in proteins upon ligand binding by NMR: Ca(2+) -displacement by Ln(3+) in a Ca(2+) -binding protein from Entamoeba histolytica.
Site-specific free energy changes in proteins upon ligand binding by NMR: Ca(2+) -displacement by Ln(3+) in a Ca(2+) -binding protein from Entamoeba histolytica.
Chem Biol Drug Des. 2011 Jan 14;
Authors: Chandra K, Mustafi SM, Muthukumar S, Chary KV
The study of protein-ligand interaction has been of a great interest in contemporary structural biology. The understanding of the nature...
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01-18-2011 10:22 PM
[NMRpipe Yahoo group] importance of -di command
importance of -di command
Dear All, We know that in nmrDraw -di command deletes imaginary data points but we want to know why we should delete them.What is the advantage of deleting
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12-29-2010 06:06 PM
[NMR paper] Selective NMR observation of inhibitor and sugar binding to the galactose-H(+) sympor
Selective NMR observation of inhibitor and sugar binding to the galactose-H(+) symport protein GalP, of Escherichia coli.
Related Articles Selective NMR observation of inhibitor and sugar binding to the galactose-H(+) symport protein GalP, of Escherichia coli.
Biochim Biophys Acta. 2000 Dec 20;1509(1-2):55-64
Authors: Appleyard AN, Herbert RB, Henderson PJ, Watts A, Spooner PJ
The binding of the transport inhibitor forskolin, synthetically labelled with (13)C, to the galactose-H(+) symport protein GalP, overexpressed in its native inner...
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11-19-2010 08:29 PM
NMR derived topology of a GFP-photoprotein energy transfer complex.
NMR derived topology of a GFP-photoprotein energy transfer complex.
Related Articles NMR derived topology of a GFP-photoprotein energy transfer complex.
J Biol Chem. 2010 Oct 6;
Authors: Titushin MS, Feng Y, Stepanyuk GA, Li Y, Markova SV, Golz S, Wang BC, Lee J, Wang J, Vysotski ES, Liu ZJ
Forster resonance energy transfer within a protein-protein complex has previously been invoked to explain emission spectral modulation observed in several bioluminescence systems. Here we present a spatial structure of a complex of the Ca2+-regulated...
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10-12-2010 02:52 PM
[NMR paper] 19F-NMR studies of retinol transfer between cellular retinol binding proteins and pho
19F-NMR studies of retinol transfer between cellular retinol binding proteins and phospholipid vesicles.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--linkinghub.elsevier.com-ihub-images-PubMedLink.gif Related Articles 19F-NMR studies of retinol transfer between cellular retinol binding proteins and phospholipid vesicles.
FEBS Lett. 1997 Feb 3;402(2-3):116-20
Authors: Rong D, Lin CL, d'Avignon DA, Lovey AJ, Rosenberger M, Li E
The cellular retinol binding proteins, CRBP and CRBP II, are implicated in the cellular uptake of retinol...
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08-22-2010 03:31 PM
[NMR paper] 19F-NMR studies of retinol transfer between cellular retinol binding proteins and pho
19F-NMR studies of retinol transfer between cellular retinol binding proteins and phospholipid vesicles.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--linkinghub.elsevier.com-ihub-images-PubMedLink.gif Related Articles 19F-NMR studies of retinol transfer between cellular retinol binding proteins and phospholipid vesicles.
FEBS Lett. 1997 Feb 3;402(2-3):116-20
Authors: Rong D, Lin CL, d'Avignon DA, Lovey AJ, Rosenberger M, Li E
The cellular retinol binding proteins, CRBP and CRBP II, are implicated in the cellular uptake of retinol...
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08-22-2010 03:03 PM
[NMR paper] 19F NMR studies of the D-galactose chemosensory receptor. 1. Sugar binding yields a g
19F NMR studies of the D-galactose chemosensory receptor. 1. Sugar binding yields a global structural change.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--www.pubmedcentral.nih.gov-corehtml-pmc-pmcgifs-pubmed-pmc-MS.gif Related Articles 19F NMR studies of the D-galactose chemosensory receptor. 1. Sugar binding yields a global structural change.
Biochemistry. 1991 Apr 30;30(17):4248-56
Authors: Luck LA, Falke JJ
The Escherichia coli D-galactose and D-glucose receptor is an aqueous sugar-binding protein and the first component in the...