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From Proteopedia
Crystal structure of the human RORalpha ligand binding domain in complex with cholesterol sulfate at 2.2A
Structural highlights
FunctionRORA_HUMAN Orphan nuclear receptor. Binds DNA as a monomer to hormone response elements (HRE) containing a single core motif half-site preceded by a short A-T-rich sequence. This isomer binds to the consensus sequence 5'-[AT][TA]A[AT][CGT]TAGGTCA-3'. Regulates a number of genes involved in lipid metabolism such as apolipoproteins AI, APOA5, CIII, CYP71 and PPARgamma, in cerebellum and photoreceptor development including PCP2, OPN1SW, OPN1SM AND ARR3, in circadian rhythm with BMAL1, and skeletal muscle development with MYOD1. Possible receptor for cholesterol or one of its derivatives.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe retinoic acid-related orphan receptor alpha (RORalpha) is an orphan member of the subfamily 1 of nuclear hormone receptors. Our recent structural and functional studies have led to the hypothesis that cholesterol or a cholesterol derivative is the natural ligand of RORalpha. We have now solved the x-ray crystal structure of the ligand binding domain of RORalpha in complex with cholesterol-3-O-sulfate following a ligand exchange experiment. In contrast to the 3-hydroxyl of cholesterol, the 3-O-sulfate group makes additional direct hydrogen bonds with three residues of the RORalpha ligand binding domain, namely NH-Gln(289), NH-Tyr(290), and NH1-Arg(370). When compared with the complex with cholesterol, seven well ordered water molecules have been displaced, and the ligand is slightly shifted toward the hydrophilic part of the ligand binding pocket, which is ideally suited for interactions with a sulfate group. These additional ligand-protein interactions result in an increased affinity of cholesterol sulfate when compared with cholesterol, as shown by mass spectrometry analysis done under native conditions and differential scanning calorimetry. Moreover, mutational studies show that the higher binding affinity of cholesterol sulfate translates into an increased transcriptional activity of RORalpha. Our findings suggest that cholesterol sulfate could play a crucial role in the regulation of RORalpha in vivo. Crystal structure of the human RORalpha Ligand binding domain in complex with cholesterol sulfate at 2.2 A.,Kallen J, Schlaeppi JM, Bitsch F, Delhon I, Fournier B J Biol Chem. 2004 Apr 2;279(14):14033-8. Epub 2004 Jan 13. PMID:14722075[11] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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