title: Genetic variations within the ERE motif modulate plasticity and energetics of binding of DNA to the ERα nuclear receptor.
abstract: Upon binding to estrogens, the ERα nuclear receptor acts as a transcription factor and mediates a multitude of cellular functions central to health and disease. Herein, using isothermal titration calorimetry (ITC) and circular dichroism (CD) in conjunction with molecular modeling (MM), we analyze the effect of symmetric introduction of single nucleotide variations within each half-site of the estrogen response element (ERE) on the binding of ERα nuclear receptor. Our data reveal that ERα exudes remarkable tolerance and binds to all genetic variants in the physiologically relevant nanomolar-micromolar range with the consensus ERE motif affording the highest affinity. We provide rationale for how genetic variations within the ERE motif may reduce its affinity for ERα by orders of magnitude at atomic level. Our data also suggest that the introduction of genetic variations within the ERE motif allows it to sample a much greater conformational space. Surprisingly, ERα displays no preference for binding to ERE variants with higher AT content, implying that any advantage due to DNA plasticity may be largely compensated by unfavorable entropic factors. Collectively, our study bears important consequences for how genetic variations within DNA promoter elements may fine-tune the physiological action of ERα and other nuclear receptors.
authors.affiliation: Department of Biochemistry and Molecular Biology and USylvester Braman Family Breast Cancer Institute, Leonard Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Deegan
authors.forename: Vikas
authors.initials: V
authors.lastname: Bhat
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Seldeen
authors.forename: Caleb B
authors.initials: CB
authors.lastname: McDonald
authors.forename: Amjad
authors.initials: A
authors.lastname: Farooq
mesh_terms: D001482:Base Composition; D001483:Base Sequence; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019277:Entropy; D047628:Estrogen Receptor alpha / Q000737:chemistry / Q000378:metabolism*; D004967:Estrogens / Q000235:genetics*; D006801:Humans; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D020641:Polymorphism, Single Nucleotide; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D020218:Response Elements / Q000235:genetics*
chemical_list: D047628:Estrogen Receptor alpha; D004967:Estrogens; D004247:DNA