1kgl
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Solution structure of cellular retinol binding protein type-I in complex with all-trans-retinol
OverviewOverview
Retinoid-binding proteins play an important role in regulating transport, storage, and metabolism of vitamin A and its derivatives. The solution, structure and backbone dynamics of rat cellular retinol-binding protein, type I (CRBP) in the apo- and holo-form have been determined and compared, using multidimensional high resolution NMR spectroscopy. The global fold, of the protein is consistent with the common motif described for members, of the intracellular lipid-binding protein family. The most relevant, difference between the NMR structure ensembles of apo- and holoCRBP is the, higher backbone disorder, in the ligand-free form, of some segments that, frame the putative entrance to the ligand-binding site. These comprise, alpha-helix II, the subsequent linker to beta-strand B, the hairpin turn, between beta-strands C and D, and the betaE-betaF turn. The internal, backbone dynamics, obtained from 15N relaxation data (T1, T2, and, heteronuclear nuclear Overhauser effect) at two different fields, indicate, several regions with significantly higher backbone mobility in the, apoprotein, including the betaC-betaD and betaE-betaF turns. Although, apoCRBP contains a binding cavity more shielded than that of any other, retinoid carrier, conformational flexibility in the portal region may, assist retinol uptake. The stiffening of the backbone in the holoprotein, guarantees the stability of the complex during retinol transport and, suggests that targeted retinol release requires a transiently open state, that is likely to be promoted by the acceptor or the local environment.
About this StructureAbout this Structure
1KGL is a Single protein structure of sequence from Rattus norvegicus with RTL as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Structure and backbone dynamics of Apo- and holo-cellular retinol-binding protein in solution., Franzoni L, Lucke C, Perez C, Cavazzini D, Rademacher M, Ludwig C, Spisni A, Rossi GL, Ruterjans H, J Biol Chem. 2002 Jun 14;277(24):21983-97. Epub 2002 Apr 4. PMID:11934897
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