title: Distinction of the binding modes for human nuclear receptor ERRgamma between bisphenol A and 4-hydroxytamoxifen.
abstract: Bisphenol A (BPA) strongly binds to human estrogen-related receptor gamma (ERRgamma). BPA is an oestrogenic endocrine disruptor that influences various physiological functions at very low doses. BPA functions as an inverse-type antagonist of ERRgamma to retain its high basal constitutive activity by inhibiting the deactivating inverse agonist activity of 4-hydroxytamoxifen (4-OHT). We recently demonstrated that ERRgamma receptor residues Glu275 and Arg316 function as the intrinsic binding site of BPA's phenol-hydroxyl group. We also determined the chief importance of phenol-hydroxyl<-->Arg316 hydrogen bonding and the corroborative role of phenol-hydroxyl<-->Glu275 hydrogen bonding. However, there appeared to be a distinct difference between the receptor binding modes of BPA and 4-OHT. In the present study, using tritium-labelled or non-labelled BPA and 4-OHT, we evaluated in detail the receptor binding capabilities of wild-type ERRgamma and its mutants with amino acid alterations at positions 275 and 316. Both compounds exhibited a strong binding ability to wild-type ERRgamma due to the hydrogen bonding to Glu275 and Arg316. However, 4-OHT revealed significantly reduced occupancy for both wild-type and mutant receptors. The data obtained suggest that 4-OHT barely binds to ERRgamma due to the strong ability of Glu275 and Arg316 to recruit phenol compounds.
authors.affiliation: Laboratory of Structure-Function Biochemistry, Department of Chemistry, Research-Education Centre of Risk Science, Faculty and Graduate School of Sciences, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Liu
authors.forename: Ayami
authors.initials: A
authors.lastname: Matsushima
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Okada
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Shimohigashi
mesh_terms: D001559:Benzhydryl Compounds; D001665:Binding Sites; D006801:Humans; D006860:Hydrogen Bonding; D010636:Phenols / Q000378:metabolism*; D011485:Protein Binding; D011960:Receptors, Estrogen / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013629:Tamoxifen / Q000031:analogs & derivatives* / Q000378:metabolism; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D010636:Phenols; D011960:Receptors, Estrogen; D013629:Tamoxifen; C490917:ESRRG protein, human; C016601:afimoxifene; C006780:bisphenol A; D000098826:Bisphenol A Compounds