1zry
From Proteopedia
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NMR structural analysis of apo chicken liver bile acid binding protein
Overview
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, (15)N relaxation and steady state heteronuclear (15)N((1)H) 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.
About this Structure
1ZRY is a Single protein structure of sequence from Gallus gallus. Full crystallographic information is available from OCA.
Reference
NMR dynamic studies suggest that allosteric activation regulates ligand binding in chicken liver bile acid-binding protein., Ragona L, Catalano M, Luppi M, Cicero D, Eliseo T, Foote J, Fogolari F, Zetta L, Molinari H, J Biol Chem. 2006 Apr 7;281(14):9697-709. Epub 2006 Jan 26. PMID:16439356
Page seeded by OCA on Wed Nov 21 07:37:57 2007
