2zy0
From Proteopedia
Crystal structure of the human RXR alpha ligand binding domain bound to a synthetic agonist compound and a coactivator peptide
Structural highlights
Disease[NCOA2_HUMAN] Note=Chromosomal aberrations involving NCOA2 may be a cause of acute myeloid leukemias. Inversion inv(8)(p11;q13) generates the KAT6A-NCOA2 oncogene, which consists of the N-terminal part of KAT6A and the C-terminal part of NCOA2/TIF2. KAT6A-NCOA2 binds to CREBBP and disrupts its function in transcription activation. 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] [NCOA2_HUMAN] Transcriptional coactivator for steroid receptors and nuclear receptors. Coactivator of the steroid binding domain (AF-2) but not of the modulating N-terminal domain (AF-1). Required with NCOA1 to control energy balance between white and brown adipose tissues.[5] 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 PubMedC/Si switch: Twofold sila-substitution (C/Si exchange) in the RXR-selective retinoids 4 a (SR11237) and 5 a leads to 4 b (disila-SR11237) and 5 b, respectively. Chemistry and biology of the C/Si pairs are reported.SR11237 (BMS649, 4 a) is a pan-RXR-selective retinoid agonist. Its silicon analogue, disila-SR11237 (4 b; twofold C/Si exchange), was prepared in a multistep synthesis by starting from 1,2-bis(ethynyldimethylsilyl)ethane. In addition, the related C/Si analogues 5 a and 5 b, with an indane (disila-indane) instead of a tetraline (disila-tetraline) skeleton, were synthesized. The C/Si pairs 4 a/4 b and 5 a/5 b were studied for their interaction with retinoid receptors and were demonstrated to be highly potent RXR-selective ("rexinoid") agonists. Interestingly, twofold C/Si exchange in the indane moiety of 5 a resulted in a 10-fold increase in biological activity of the corresponding silicon-containing rexinoid 5 b, possibly resulting from an increased receptor affinity or a divergent allosteric effect on co-regulator-binding surfaces. The crystal structures of the ternary complexes formed by 5 a and 5 b, respectively, with the ligand-binding domain of hRXRalpha and a peptide of the co-activator TIF2/GRIP1 revealed additional interactions of the disila analogue 5 b with the H7 and H11 residues, supporting the first option of increased binding affinity. This is the first demonstration of an increase in binding affinity of a ligand to a nuclear receptor by C/Si replacement, thereby adding this C/Si switch strategy to the repertoire of nuclear receptor ligand design. Silicon analogues of the RXR-selective retinoid agonist SR11237 (BMS649): chemistry and biology.,Lippert WP, Burschka C, Gotz K, Kaupp M, Ivanova D, Gaudon C, Sato Y, Antony P, Rochel N, Moras D, Gronemeyer H, Tacke R ChemMedChem. 2009 Jul;4(7):1143-52. PMID:19496083[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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