The metal-binding properties of DREAM. Evidence for calcium-mediated changes in DREAM structure

Theodore A. Craig, Linda M. Benson, Sergei Yu Venyaminov, Elena S. Klimtchuk, Zeljko Bajzer, Franklyn G. Prendergast, Stephen Naylor, Rajiv Kumar

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


DREAM, an EF-hand protein, associates with and modulates the activity of presenilins and Kv4 potassium channels in neural and cardiac tissues and represses prodynorphin and c-fos gene expression by binding to DNA response elements in these genes. Information concerning the metal-binding properties of DREAM and the consequences of metal binding on protein structure are important in understanding how this protein functions in cells. We now show that DREAM binds 1 mol of calcium/mol of protein with relatively high affinity and another 3 mol of calcium with lower affinity. DREAM binds 1 mol of magnesium/mol of protein. DREAM, pre-loaded with 1 mol of calcium, binds 1 mol of magnesium, thus demonstrating that the magnesium-binding site is distinct from the high affinity calcium-binding site. Analysis of metal binding to mutant DREAM protein constructs localizes the high affinity calcium-binding site and the magnesium-binding site to EF-hands 3 or 4. Binding of calcium but not magnesium changes the conformation, stability, and a-helical content of DREAM. Calcium, but not magnesium, reduces the affinity of apo-DREAM for specific DNA response elements in the prodynorphin and c-fos genes. We conclude that DREAM binds calcium and magnesium and that calcium, but not magnesium, modulates DREAM structure and function.

Original languageEnglish (US)
Pages (from-to)10955-10966
Number of pages12
JournalJournal of Biological Chemistry
Issue number13
StatePublished - Mar 29 2002

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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