Downstream Regulatory Element Antagonist Modulator (DREAM)/Calsenilin/KchIP3 is a multifunctional calcium binding protein belonging to the EF-hand branch of Neuronal Calcium Sensor family. DREAM associates to DRE of prodynorphin and c-fos genes and blocks their transcription in a calcium-regulated manner. Recently, we have investigated the contribution of individual EF hands (EF-2, EF-3, and EF-4) to Ca2+ triggered conformational transitions in DREAM by characterizing fluorescence properties of D150N, E186Q, and E234Q mutants. The tryptophan 169 emission and lifetime properties are strongly influenced by Ca2+ association to EF-3 whereas the ligand association to EF-2 and/or EF-4 has a minor impact suggesting that Ca2+ association to EF-3 is crucial to induced structural changes within the hydrophobic pocket between EF-2 and EF-3. In addition, ITC data show that ApoDREAM binds strongly to DynDRE (Kd = 206 nM) whereas very weak binding (Kd = 200 �M) was observed in the presence of Ca2+. These results support the mechanism that ApoDREAM strongly binds to prodynorphin DRE and blocks its transcription and the DREAM-DRE complex reversibly dissociates upon Ca2+ binding.

Spectroscopic study Ca<sup>2+</sup> induced changes in the structure, dynamics, and stability of DREAM protein and its mechanism of DNA interaction

245th National Meeting (2013)

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Spectroscopic study Ca2+ induced changes in the structure, dynamics, and stability of DREAM protein and its mechanism of DNA interaction

Spectroscopic study Ca²⁺ induced changes in the structure, dynamics, and stability of DREAM protein and its mechanism of DNA interaction