Crystal structure of human retinoic X receptor alpha complexed with bigelovin and coactivator SRC-1Crystal structure of human retinoic X receptor alpha complexed with bigelovin and coactivator SRC-1

Structural highlights

3ozj is a 4 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.1Å
Ligands:
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

RXRA_HUMAN Receptor for retinoic acid. Retinoic acid receptors bind as heterodimers to their target response elements in response to their ligands, all-trans or 9-cis retinoic acid, and regulate gene expression in various biological processes. The RAR/RXR heterodimers bind to the retinoic acid response elements (RARE) composed of tandem 5'-AGGTCA-3' sites known as DR1-DR5. The high affinity ligand for RXRs is 9-cis retinoic acid. RXRA serves as a common heterodimeric partner for a number of nuclear receptors. The RXR/RAR heterodimers bind to the retinoic acid response elements (RARE) composed of tandem 5'-AGGTCA-3' sites known as DR1-DR5. In the absence of ligand, the RXR-RAR heterodimers associate with a multiprotein complex containing transcription corepressors that induce histone acetylation, chromatin condensation and transcriptional suppression. On ligand binding, the corepressors dissociate from the receptors and associate with the coactivators leading to transcriptional activation. The RXRA/PPARA heterodimer is required for PPARA transcriptional activity on fatty acid oxidation genes such as ACOX1 and the P450 system genes.[1] [2] [3] [4]

Publication Abstract from PubMed

The nuclear receptor retinoid X receptor (RXR) functions potently in the regulation of homeostasis and cell development, while rexinoids as RXR agonists have proved their therapeutic potential in the treatment of metabolic diseases and cancer. Here, the natural product bigelovin was identified as a selective RXRalpha agonist. Interestingly, this compound could not transactivate RXRalpha:RXRalpha homodimer but could enhance the transactivation of RXRalpha:peroxisome proliferator-activated receptor gamma heterodimer and repress that of RXRalpha:liver X receptor (LXR) alpha heterodimer, while it had no effects on RXRalpha:farnesoid X receptor heterodimer. Considering that the effective role of LXR response element involved transactivation of sterol regulatory element-binding protein-1c mediated by RXRalpha:LXRalpha in triglyceride elevation, such LXR response element repressing by bigelovin has obviously addressed its potency for further research. Moreover, our determined crystal structure of the bigelovin-activated RXRalpha ligand-binding domain with the coactivator human steroid receptor coactivator-1 peptide revealed that bigelovin adopted a distinct binding mode. Compared with the known RXR ligands, bigelovin lacks the acidic moiety in structure, which indicated that the acidic moiety rendered little effects on RXR activation. Our results have thereby provided new insights into the structure-based selective rexinoids design with bigelovin as a potential lead compound.

Structure basis of bigelovin as a selective RXR agonist with a distinct binding mode.,Zhang H, Li L, Chen L, Hu L, Jiang H, Shen X J Mol Biol. 2011 Mar 18;407(1):13-20. Epub 2011 Jan 22. PMID:21262235[5]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Gorla-Bajszczak A, Juge-Aubry C, Pernin A, Burger AG, Meier CA. Conserved amino acids in the ligand-binding and tau(i) domains of the peroxisome proliferator-activated receptor alpha are necessary for heterodimerization with RXR. Mol Cell Endocrinol. 1999 Jan 25;147(1-2):37-47. PMID:10195690
  2. Harish S, Ashok MS, Khanam T, Rangarajan PN. Serine 27, a human retinoid X receptor alpha residue, phosphorylated by protein kinase A is essential for cyclicAMP-mediated downregulation of RXRalpha function. Biochem Biophys Res Commun. 2000 Dec 29;279(3):853-7. PMID:11162439 doi:10.1006/bbrc.2000.4043
  3. Tsutsumi T, Suzuki T, Shimoike T, Suzuki R, Moriya K, Shintani Y, Fujie H, Matsuura Y, Koike K, Miyamura T. Interaction of hepatitis C virus core protein with retinoid X receptor alpha modulates its transcriptional activity. Hepatology. 2002 Apr;35(4):937-46. PMID:11915042 doi:10.1053/jhep.2002.32470
  4. Santos NC, Kim KH. Activity of retinoic acid receptor-alpha is directly regulated at its protein kinase A sites in response to follicle-stimulating hormone signaling. Endocrinology. 2010 May;151(5):2361-72. doi: 10.1210/en.2009-1338. Epub 2010 Mar , 9. PMID:20215566 doi:10.1210/en.2009-1338
  5. Zhang H, Li L, Chen L, Hu L, Jiang H, Shen X. Structure basis of bigelovin as a selective RXR agonist with a distinct binding mode. J Mol Biol. 2011 Mar 18;407(1):13-20. Epub 2011 Jan 22. PMID:21262235 doi:10.1016/j.jmb.2011.01.032

3ozj, resolution 2.10Å

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