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1cbr
From Proteopedia
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CRYSTAL STRUCTURE OF CELLULAR RETINOIC-ACID-BINDING PROTEINS I AND II IN COMPLEX WITH ALL-TRANS-RETINOIC ACID AND A SYNTHETIC RETINOID
Overview
BACKGROUND: Retinoic acid (RA) plays a fundamental role in diverse, cellular activities. Cellular RA binding proteins (CRABPs) are thought to, act by modulating the amount of RA available to nuclear RA receptors., CRABPs and cellular retinol-binding proteins (CRBPs) share a unique fold, of two orthogonal beta-sheets that encapsulate their ligands. It has been, suggested that a trio of residues are the prime determinants defining the, high specificity of CRBPs and CRABPs for their physiological ligands., RESULTS: Bovine/murine CRABP I and human CRABP II have been crystallized, in complex with their natural ligand, all-trans-RA. Human CRABP II has, also been crystallized in complex with a synthetic retinoid, 'compound, 19'. Their structures have been determined and refined at resolutions of, 2.9 A, 1.8 A and 2.2 A, respectively. CONCLUSIONS: The retinoid-binding, site in CRABPs differs significantly from that observed in CRBP., Structural changes in three juxtaposed areas of the protein create a new, displaced binding site for RA. The carboxylate of the ligand interacts, with the expected trio of residues (Arg132, Tyr134 and Arg111; CRABP II, numbering). The RA ligand is almost flat with the beta-ionone ring showing, a significant deviation (-33 degrees) from a cis conformation relative to, the isoprene tail. The edge atoms of the beta-ionone ring are accessible, to solvent in a suitable orientation for presentation to metabolizing, enzymes. The bulkier synthetic retinoid causes small conformational, changes in the protein structure.
About this Structure
1CBR is a Single protein structure of sequence from Mus musculus with REA as ligand. Full crystallographic information is available from OCA.
Reference
Crystal structures of cellular retinoic acid binding proteins I and II in complex with all-trans-retinoic acid and a synthetic retinoid., Kleywegt GJ, Bergfors T, Senn H, Le Motte P, Gsell B, Shudo K, Jones TA, Structure. 1994 Dec 15;2(12):1241-58. PMID:7704533
Page seeded by OCA on Tue Nov 20 12:19:36 2007
