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

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Abstract

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
Volume277
Issue number13
DOIs
StatePublished - Mar 29 2002

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ASJC Scopus subject areas

  • Biochemistry

Cite this

Craig, T. A., Benson, L. M., Venyaminov, S. Y., Klimtchuk, E. S., Bajzer, Z., Prendergast, F. G., Naylor, S., & Kumar, R. (2002). The metal-binding properties of DREAM. Evidence for calcium-mediated changes in DREAM structure. Journal of Biological Chemistry, 277(13), 10955-10966. https://doi.org/10.1074/jbc.M109660200