Structural and thermodynamic consequences of the replacement of zinc with environmental metals on estrogen receptor α-DNA interactions

Brian J. Deegan, Anna M. Bona, Vikas Bhat, David C. Mikles, Caleb B. McDonald, Kenneth L. Seldeen, Amjad Farooq

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

Estrogen receptor α (ERα) acts as a transcription factor by virtue of the ability of its DNA-binding (DB) domain, comprised of a tandem pair of zinc fingers, to recognize the estrogen response element within the promoters of target genes. Herein, using an array of biophysical methods, we probe the structural consequences of the replacement of zinc within the DB domain of ERα with various environmental metals and their effects on the thermodynamics of binding to DNA. Our data reveal that whereas the DB domain reconstituted with divalent ions of zinc, cadmium, mercury, and cobalt binds to DNA with affinities in the nanomolar range, divalent ions of barium, copper, iron, lead, manganese, nickel, and tin are unable to regenerate DB domain with DNA-binding potential, although they can compete with zinc for coordinating the cysteine ligands within the zinc fingers. We also show that the metal-free DB domain is a homodimer in solution and that the binding of various metals only results in subtle secondary and tertiary structural changes, implying that metal coordination may only be essential for binding to DNA. Collectively, our findings provide mechanistic insights into how environmental metals may modulate the physiological function of a key nuclear receptor involved in mediating a plethora of cellular functions central to human health and disease.

Original languageEnglish (US)
Pages (from-to)1007-1017
Number of pages11
JournalJournal of Molecular Recognition
Volume24
Issue number6
DOIs
StatePublished - Nov 1 2011

    Fingerprint

Keywords

  • analytical light scattering
  • circular dichroism
  • environmental metals
  • estrogen receptor α
  • isothermal titration calorimetry
  • steady-state absorbance
  • steady-state fluorescence
  • zinc fingers

ASJC Scopus subject areas

  • Molecular Biology
  • Structural Biology

Cite this