An NMR study of ligand binding by maltodextrin binding protein

1998 ◽  
Vol 76 (2-3) ◽  
pp. 189-197 ◽  
Author(s):  
Kalle Gehring ◽  
Xiaochen Zhang ◽  
Jason Hall ◽  
Hiroshi Nikaido ◽  
David E Wemmer
Keyword(s):  
Chemical Shift ◽  
Ligand Binding ◽  
Conformational Changes ◽  
Chemical Exchange ◽  
Binding Protein ◽  
Difference Spectra ◽  
One Dimensional ◽  
Beta Cyclodextrin ◽  
Nmr Study ◽  
Maltodextrin Binding Protein

Proton NMR spectra of maltodextrin binding protein from Escherichia coli were used to monitor conformational changes that accompany ligand binding. Chemical shift changes associated with the binding of different maltodextrins to maltodextrin binding protein were studied using one-dimensional difference spectra. Line-shape analysis of an isolated upfield methyl resonance was used to measure the kinetics of maltose binding at several temperatures. Maltose and linear maltodextrins caused similar changes to the upfield protein spectrum with no detectable differences between alpha and beta sugar anomers. Binding of a cyclic ligand, beta-cyclodextrin, caused smaller chemical shift changes than binding of linear maltodextrins. Two maltodextrin derivatives were also studied. Both maltohexaitol and maltohexanoic acid gave one-dimensional difference spectra that were intermediate between those of linear maltodextrins and beta-cyclodextrin. The methyl resonances at -1 and -0.35 ppm were assigned to leucine 160 on the basis of homonuclear COSY and TOCSY experiments and theoretical chemical shift calculations using the X-ray crystal structure of maltodextrin binding protein.Key words: maltose binding protein, chemical shifts, chemical exchange, sugar anomer specificity.

scholarly journals Attractant- and Disulfide-Induced Conformational Changes in the Ligand Binding Domain of the Chemotaxis Aspartate Receptor: A 19F NMR Study

Biochemistry ◽  
1994 ◽  
Vol 33 (20) ◽  
pp. 6100-6109 ◽  
Author(s):  
Mark A. Danielson ◽  
Hans-Peter Biemann ◽  
Daniel E. Koshland ◽  
Joseph J. Falke
Keyword(s):  
Ligand Binding ◽  
Conformational Changes ◽  
Binding Domain ◽  
Ligand Binding Domain ◽  
19F Nmr ◽  
Aspartate Receptor ◽  
Nmr Study

Binding of Radiolabeled Folate and 5-Methyltetrahydrofolate to Cow's Milk Folate Binding Protein at pH 7.4 and 5.0. Relationship to Concentration and Polymerization Equilibrium of the Purified Protein

2001 ◽  
Vol 21 (6) ◽  
pp. 733-743 ◽  
Author(s):  
Jan Holm ◽  
Steen Ingemann Hansen
Keyword(s):  
Ligand Binding ◽  
Binding Affinity ◽  
Conformational Changes ◽  
Protein Conformation ◽  
Binding Protein ◽  
Cow’S Milk ◽  
Folate Binding Protein ◽  
Cow's Milk ◽  
Polymerization Equilibrium ◽  
Methyl Tetrahydrofolate

Binding of folate (pteroylglutamate) and 5-methyltetrahydrofolate, the major endogenous form of folate, to folate binding protein purified from cow's milk was studied at 7°C to avoid degradation of 5-methyltetrahydrofolate. Both folates dissociate rapidly from the protein at pH 3.5, but extremely slowly at pH 7.4, most likely due to drastic changes in protein conformation occurring after folate binding. Dissociation of 5-methyltetrahydrofolate showed no increase at 37°C suggesting that protein-bound-5-methyltetrahydrofolate is protected against degradation. Binding displayed two characteristics, positive cooperativity and a binding affinity that increased with decreasing concentrations of the protein. The binding affinity of folate was somewhat greater than that of 5-methyl tetrahydrofolate, in particular at pH 5.0. Ligand-bound protein exhibited concentration-dependent polymerization (8-mers formed at 13 μM) at pH 7.4. At pH 5.0, only folate-bound forms showed noticeable polymerization. The fact that folate at pH 5.0 surpasses 5-methyltetrahydrofolate both with regard to binding affinity and ability to induce polymerization suggests that ligand binding is associated with conformational changes of the protein which favor polymerization.

109Ag NMR-Study of the Selective Solvation of the Ag+ Ion in Solvent Mixtures of Water and the Organic Solvents: Pyridine, Acetonitrile, and Dimethyl Sulfoxide

1984 ◽  
Vol 39 (1) ◽  
pp. 83-94 ◽  
Author(s):  
L. Guinand. K. L. Hobt. E. Mittermaier ◽  
E. Rößler ◽  
A. Schwenk ◽  
H. Schneider
Keyword(s):  
Chemical Shift ◽  
Dimethyl Sulfoxide ◽  
Organic Solvents ◽  
Mole Fraction ◽  
Chemical Exchange ◽  
Chemical Shifts ◽  
Equilibrium Constants ◽  
Solvent Mixtures ◽  
Nmr Study ◽  
Solvent Molecules

In mixtures of water (W) and one of the organic solvents pyridine, acetonitrile, and dimethyl sulfoxide (O), the silver ion forms the following solvate complexes: AgW2, AgWO, and Ag02. The chemical shift of 109Ag is strongly affected by the ligating solvent molecules, and replacing the ligand W by one of the three organic ligands yields a higher Larmor frequency. In solvent mixtures, only a single resonance line has been observed because of rapid chemical exchange. The measured chemical shifts in the range up to 400 ppm are mean values of the chemical shifts of the different solvate species in a given mixture, weighted with their relative concentrations. The 109Ag chemical shifts were determined for 0.05 to 0.15 molal solutions of AgNO3, as functions of the mole fractions of the solvent components. Using a Gaussian least squares fitting routine, the individual chemical shifts of the Ag+ solvate complexes and the corresponding equilibrium constants were determined. This fit was successful for the whole mole fraction range of DMSO, while in the solvent systems with acetonitrile and with pyridine at higher concentrations of the organic component the chemical shift is influenced by more than two solvent molecules. In these cases equilibrium constants were calculated from chemical shift data for solutions of low mole fraction of acetonitrile and pyridine.

scholarly journals Cross-Peaks in Simple 2D NMR Experiments from Chemical Exchange of Transverse Magnetization

2019 ◽  
Author(s):  
Chris Waudby ◽  
Tom Frenkiel ◽  
John Christodoulou
Keyword(s):  
Chemical Shift ◽  
Chemical Exchange ◽  
Exchange Process ◽  
2D Nmr ◽  
Two Dimensional ◽  
One Dimensional ◽  
Exchange Processes ◽  
Rich Information ◽  
Multiple Chemical

Two-dimensional correlation measurements such as COSY, NOESY, HMQC and HSQC experiments are central to small molecule and biomolecular NMR spectroscopy, and commonly form the basis of more complex experiments designed to study chemical exchange occurring during additional mixing periods. However, exchange occurring during chemical shift evolution periods can also influence the appearance of such spectra. While this is often exploited through one-dimensional lineshape analysis ('dynamic NMR'), the analysis of exchange across multiple chemical shift evolution periods has received less attention. Here we report that chemical exchange-induced cross-peaks can arise in even the simplest two-dimensional NMR experiments. These cross-peaks can have highly distorted phases that contain rich information about the underlying exchange process. The quantitative analysis of such peaks, from a single 2D spectrum, can provide a highly accurate characterization of underlying exchange processes.

1 H nuclear magnetic resonance studies of the tyrosine residues of selectively deuterated Lactobacillus casei dihydrofolate reductase

1977 ◽  
Vol 196 (1124) ◽  
pp. 267-290 ◽  
Keyword(s):  
Chemical Shift ◽  
Ligand Binding ◽  
Dihydrofolate Reductase ◽  
Conformational Changes ◽  
Lactobacillus Casei ◽  
Inhibitor Binding ◽  
Tyrosine Residues ◽  
Coenzyme Binding ◽  
Binary Complexes ◽  
Significant Difference

A selectively deuterated dihydrofolate reductase, in which all the aro­matic protons except the 2, 6-protons of the tyrosine residues have been replaced by deuterium, has been prepared from Lactobacillus casei grown on a mixture of normal and deuterated amino acids. The aromatic region of the 1 H n. m. r. spectrum of this enzyme contains only resonances from the five tyrosine residues. For each tyrosine, the 2- and 6-protons have the same chemical shift, indicating rapid interconversion of the two conformers related by 180° rotation about the C β -C γ bond. The effects of sub­strate, inhibitor and coenzyme binding on the tyrosine residues have been investigated; four of the five residues are affected by ligand binding. Using the weakly binding ligands 2, 4-diaminopyrimidine and p -nitrobenzoyl-l-glutamate to connect the spectra of the free enzyme with those of the complexes, it is possible to give a detailed description of the effects of ligand binding on individual residues. In the binary complexes, methotrexate affects three tyrosine residues, only one of which is affected by folate, indicating a significant difference in the mode of binding of substrates and inhibitors. The co-enzymes NADP + and NADPH lead to broadly similar changes in the spectrum, except for one resonance which is shifted in opposite directions by the two co-enzymes. The oxidized and reduced co­enzymes also differ in their effects on the changes produced by inhibitor binding; the spectrum of the enzyme-NADPH-methotrexate complex is similar to that of the enzyme-methotrexate complex, while that of the enzyme-NADP + -methotrexate complex is not. In contrast to the be­haviour seen in the binary complexes, the spectrum of the enzyme-NADP + -folate complex is very similar to that of enzyme-NADP + -methotrexate. Evidence is presented that some, at least, of the changes in chemical shift of the tyrosine residues are due to ligand-induced conformational changes. The binding of p -nitrobenzoyl-l-glutamate to the enzyme-2, 4-diamino-pyrimidine complex is found to be tighter than that to the enzyme alone.

scholarly journals Cross-Peaks in Simple 2D NMR Experiments from Chemical Exchange of Transverse Magnetization

2019 ◽  
Author(s):  
Chris Waudby ◽  
Tom Frenkiel ◽  
John Christodoulou
Keyword(s):  
Chemical Shift ◽  
Chemical Exchange ◽  
Exchange Process ◽  
2D Nmr ◽  
Two Dimensional ◽  
One Dimensional ◽  
Exchange Processes ◽  
Rich Information ◽  
Multiple Chemical

Two-dimensional correlation measurements such as COSY, NOESY, HMQC and HSQC experiments are central to small molecule and biomolecular NMR spectroscopy, and commonly form the basis of more complex experiments designed to study chemical exchange occurring during additional mixing periods. However, exchange occurring during chemical shift evolution periods can also influence the appearance of such spectra. While this is often exploited through one-dimensional lineshape analysis ('dynamic NMR'), the analysis of exchange across multiple chemical shift evolution periods has received less attention. Here we report that chemical exchange-induced cross-peaks can arise in even the simplest two-dimensional NMR experiments. These cross-peaks can have highly distorted phases that contain rich information about the underlying exchange process. The quantitative analysis of such peaks, from a single 2D spectrum, can provide a highly accurate characterization of underlying exchange processes.

Refined 1.8-.ANG. structure reveals the mode of binding of .beta.-cyclodextrin to the maltodextrin binding protein

Biochemistry ◽  
1993 ◽  
Vol 32 (40) ◽  
pp. 10553-10559 ◽  
Author(s):  
Andrew J. Sharff ◽  
Lynn E. Rodseth ◽  
Florante A. Quiocho
Keyword(s):  
Binding Protein ◽  
Beta Cyclodextrin ◽  
Maltodextrin Binding Protein
Sign in / Sign up

Export Citation Format

Share Document