Document Type



Doctor of Philosophy (PhD)



First Advisor's Name

Jaroslava Miksovska

First Advisor's Committee Title

Committee chair

Second Advisor's Name

Xiaotang Wang

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Francisco Fernadez-Lima

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Fenfei Leng

Fourth Advisor's Committee Title

Committee member

Fifth Advisor's Name

Prem Chapagain

Fifth Advisor's Committee Title

Committee member


Neuronal Calcium Sensors, DREAM, calsenilin, potassium channels, divalent metals interactions, allostery

Date of Defense



DREAM belongs to the NCS family, and it is involved in several physiological processes mediated by Ca2+ association, which produces changes in its oligomerization state. The mechanism of how Ca2+ binds to DREAM remains unknown. A kinetic study of the binding of Ca2+ to DREAM suggested that DREAM dimerization is a two-step process, the first step( τ1= 8±0.1ms) is associated with the binding of Ca2+ to the monomer, while the second step (τ2 = 3.6 ±0.4 s ) corresponds to a conformation relaxation that leads to the dimerization. Furthermore, by analyzing the fast kinetic k obsvs[L] , an inverse hyperbolic dependance was observed , which corresponds to the conformational selection mechanism providing crucial information on the binding of Ca2+ to DREAM.

Previous MD studies has shown that a network of hydrophobic residues in DREAM participate in the transmission of the interdomain allosteric signal. The Trp169 is part of this network, MD analysis were performed to determine its role in allosteric signal transmission. The mutation of Trp to Ala lead to a loss of structural rearrangement previously observed upon Ca2+ binding. For instance, in the case of DREAMW169A the stabilizing salt bridge K87-E165 was not present , the EF hands in the mutant did not undergo the reorientation observed in DREAMWT and the dimer divided into two monomers in the presence of Ca2+. These findings suggest the Trp169 is involved in the interdomain communication in DREAM, and it is crucial for the protein proper functioning.

Zn2+ is involved in several physiological processes and interacts with a wide variety of proteins , including other NCS proteins. DREAM also interacts with divalent metals with relatively high affinity . The presence of Zn2+ produces changes in DREM’s tertiary structure , and it is able to bind to DREAM in the presence(Kd=10.76± 1.46 and µM) and absence of Ca2+ (Kd=6.9 ± 0.6 µM). For the MD studies in the presence and absence of Ca2+, Zn2+ was found to bind to the protein involving amino acids located in EFH2. These findings suggest that Zn2+ may be involved in processes possibly involving DREAM and other NCS.





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