Apo chicken liver bile acid-binding protein has been structurally characterized by NMR. The dynamic behavior of the protein in its apo- and holo-forms, complexed with chenodeoxycholate, has been determined via N-15 relaxation and steady state heteronuclear N-15(H-1) nuclear Overhauser effect measurements. The dynamic parameters were obtained at two pH values (5.6 and 7.0) for the apoprotein and at pH 7.0 for the holoprotein, using the model free approach. Relaxation studies, performed at three different magnetic fields, revealed a substantial conformational flexibility on the microsecond to millisecond time scales, mainly localized in the C-terminal face of the beta-barrel. The observed dynamics are primarily caused by the protonation/deprotonation of a buried histidine residue, His(98), located on this flexible face. A network of polar buried side chains, defining a spine going from the E to J strand, is likely to provide the long range connectivity needed to communicate motion from His(98) to the EF loop region. NMR data are accompanied by molecular dynamics simulations, suggesting that His(98) protonation equilibrium is the triggering event for the modulation of a functionally important motion, i.e. the opening/closing at the protein open end, whereas ligand binding stabilizes one of the preexisting conformations ( the open form). The results presented here, complemented with an analysis of proteins belonging to the intracellular lipid-binding protein family, are consistent with a model of allosteric activation governing the binding mechanism. The functional role of this mechanism is thoroughly discussed within the framework of the mechanism for the enterohepatic circulation of bile acids.

Ragona, L., Catalano, M., Luppi, M., Cicero, D.o., Eliseo, T., Foote, J., et al. (2006). NMR dynamic studies suggest that allosteric activation regulates ligand binding in chicken liver bile acid-binding protein. THE JOURNAL OF BIOLOGICAL CHEMISTRY, 281(14), 9697-9709 [10.1074/jbc.M513003200].

NMR dynamic studies suggest that allosteric activation regulates ligand binding in chicken liver bile acid-binding protein

CICERO, DANIEL OSCAR;
2006-01-01

Abstract

Apo chicken liver bile acid-binding protein has been structurally characterized by NMR. The dynamic behavior of the protein in its apo- and holo-forms, complexed with chenodeoxycholate, has been determined via N-15 relaxation and steady state heteronuclear N-15(H-1) nuclear Overhauser effect measurements. The dynamic parameters were obtained at two pH values (5.6 and 7.0) for the apoprotein and at pH 7.0 for the holoprotein, using the model free approach. Relaxation studies, performed at three different magnetic fields, revealed a substantial conformational flexibility on the microsecond to millisecond time scales, mainly localized in the C-terminal face of the beta-barrel. The observed dynamics are primarily caused by the protonation/deprotonation of a buried histidine residue, His(98), located on this flexible face. A network of polar buried side chains, defining a spine going from the E to J strand, is likely to provide the long range connectivity needed to communicate motion from His(98) to the EF loop region. NMR data are accompanied by molecular dynamics simulations, suggesting that His(98) protonation equilibrium is the triggering event for the modulation of a functionally important motion, i.e. the opening/closing at the protein open end, whereas ligand binding stabilizes one of the preexisting conformations ( the open form). The results presented here, complemented with an analysis of proteins belonging to the intracellular lipid-binding protein family, are consistent with a model of allosteric activation governing the binding mechanism. The functional role of this mechanism is thoroughly discussed within the framework of the mechanism for the enterohepatic circulation of bile acids.
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore BIO/10
English
Conformations; Molecular dynamics; Nuclear magnetic resonance; pH effects; Bile acids; Enterohepatic circulation; Holoprotein; Lipid-binding protein; Proteins; apoprotein; bile acid binding protein; binding protein; chenodeoxycholic acid; histidine; unclassified drug; apolipoprotein; bile acid; bile acid binding proteins; carrier protein; ligand; membrane protein; allosterism; article; carboxy terminal sequence; conformation; controlled study; ligand binding; molecular dynamics; nitrogen nuclear magnetic resonance; nonhuman; nuclear magnetic resonance; nuclear Overhauser effect; pH; priority journal; protein binding; protein motif; protein structure; proton transport; steady state; validation study; amino acid sequence; animal; binding site; chemistry; chicken; enzymology; liver; metabolism; molecular genetics; protein conformation; Allosteric Regulation; Amino Acid Sequence; Animals; Apolipoproteins; Bile Acids and Salts; Binding Sites; Carrier Proteins; Chickens; Ligands; Liver; Membrane Glycoproteins; Molecular Sequence Data; Nuclear Magnetic Resonance, Biomolecular; Protein Binding; Protein Conformation
Ragona, L., Catalano, M., Luppi, M., Cicero, D.o., Eliseo, T., Foote, J., et al. (2006). NMR dynamic studies suggest that allosteric activation regulates ligand binding in chicken liver bile acid-binding protein. THE JOURNAL OF BIOLOGICAL CHEMISTRY, 281(14), 9697-9709 [10.1074/jbc.M513003200].
Ragona, L; Catalano, M; Luppi, M; Cicero, Do; Eliseo, T; Foote, J; Fogolari, F; Zetta, L; Molinari, H
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/37017
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