2fsz
From Proteopedia
A second binding site for hydroxytamoxifen within the coactivator-binding groove of estrogen receptor beta
Structural highlights
Function[ESR2_HUMAN] Nuclear hormone receptor. Binds estrogens with an affinity similar to that of ESR1, and activates expression of reporter genes containing estrogen response elements (ERE) in an estrogen-dependent manner. Isoform beta-cx lacks ligand binding ability and has no or only very low ere binding activity resulting in the loss of ligand-dependent transactivation ability. DNA-binding by ESR1 and ESR2 is rapidly lost at 37 degrees Celsius in the absence of ligand while in the presence of 17 beta-estradiol and 4-hydroxy-tamoxifen loss in DNA-binding at elevated temperature is more gradual. 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 PubMedEvidence is presented that the estrogen antagonist 4-hydroxytamoxifen (HT) can occupy not only the core binding pocket within the ligand-binding domain of estrogen receptor (ER) beta but also a second site on its surface. The crystal structure of the ligand-binding domain (LBD) associated with HT was determined to 2.2 A and revealed two molecules of HT bound to the protein. One was located in the consensus ligand-binding pocket, whereas the other bound to a site that overlaps with the hydrophobic groove of the coactivator recognition surface. Relative to the ERalpha-tamoxifen structure, helix 12 has been displaced from the coactivator recognition surface and occupies a unique position. Although it has been demonstrated that association of the antagonist with the core ligand-binding pocket is sufficient to induce an antagonist ligand-binding domain conformation, this structure suggests that small molecules may directly antagonize receptor-coactivator interactions. These results provide a direct demonstration of two binding sites for HT in ERbeta, as has been previously suggested for ERalpha by using biochemical methods, and represent a crystal structure of a small nonpeptide molecule occupying the coactivator recognition site. A second binding site for hydroxytamoxifen within the coactivator-binding groove of estrogen receptor beta.,Wang Y, Chirgadze NY, Briggs SL, Khan S, Jensen EV, Burris TP Proc Natl Acad Sci U S A. 2006 Jun 27;103(26):9908-11. Epub 2006 Jun 16. PMID:16782818[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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