Conformational Dynamics and Stability Associated with Magnesium or Calcium Binding to DREAM in the Regulation of Interactions between DREAM and DNA or Presenilins
Doctor of Philosophy (PhD)
First Advisor's Name
First Advisor's Committee Title
Second Advisor's Name
Second Advisor's Committee Title
Third Advisor's Name
Third Advisor's Committee Title
Fourth Advisor's Name
John P. Berry
Fourth Advisor's Committee Title
Fifth Advisor's Name
Prem P. Chapagain
Fifth Advisor's Committee Title
DREAM, KChIP3, casenilin, presenilin, Alzheimer’s disease, pain modulation, fluorescence spectroscopy, circular dichroism, isothermal titration calorimetry, photothermal spectroscopy, computational MD simulation, dynamics network analysis, binding interface, drug discovery
Date of Defense
Downstream regulatory element antagonist modulator (DREAM) is involved in various interactions with targets both inside and outside of the nucleus. In the cytoplasm, DREAM interacts with the C-terminal fragments of presenilins to facilitate the production of β-amyloid plaques in Alzheimer’s disease. In the nucleus, Ca2+ free DREAM directly binds to specific downstream regulatory elements of prodynorphin/c-fos gene to repress the gene transcription in pain modulation. These interactions are regulated by Ca2+ and/or Mg2+ association at the EF-hands in DREAM. Therefore, understanding the conformational dynamics and stability associated with Ca2+ and/or Mg2+ binding to DREAM is crucial for elucidating the mechanisms of interactions of DREAM with DNA or presenilins. The critical barrier for envisioning the mechanisms of these interactions lies in the lack of NMR/crystal structures of Apo and Mg2+DREAM.
Using a combination of fluorescence spectroscopy, circular dichroism, isothermal titration calorimetry, photothermal spectroscopy, and computational approaches, I showed that Mg2+ association at the EF-hand 2 structurally stabilizes the N-terminal alpha-helices 1, 2, and 5, facilitating the interaction with DNA. Binding of Ca2+ at the EF-hand 3 induces significant structural changes in DREAM, mediated by several hydrophobic residues in both the N- and C-domains. These findings illustrate the critical role of EF-hand 3 for Ca2+ signal transduction from the C- to N-terminus in DREAM. The Ca2+ association at the EF-hand 4 stabilizes the C-terminus by forming a cluster consisting of several hydrophobic residues in C-terminal domain. I also demonstrated that association of presenilin-1 carboxyl peptide with DREAM is Ca2+ dependent and the complex is stabilized by aromatic residues F462 and F465 from presenilin-1 and F252 from DREAM. Stabilization is also provided by residues R200 and R207 in the loop connecting a7 and a8 in DREAM and the residues D450 and D458 in presenilin-1.
These findings provide a structural basis for the development of new drugs for chronic pain and Alzheimer’s disease treatments.
Pham, Khoa Ngoc, "Conformational Dynamics and Stability Associated with Magnesium or Calcium Binding to DREAM in the Regulation of Interactions between DREAM and DNA or Presenilins" (2016). FIU Electronic Theses and Dissertations. 2589.
Amino Acids, Peptides, and Proteins Commons, Biochemistry Commons, Biophysics Commons, Complex Mixtures Commons, Medicinal-Pharmaceutical Chemistry Commons, Molecular Biology Commons, Physical Chemistry Commons
In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/
This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).