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
Fourth Advisor's Committee Title
Fifth Advisor's Name
Fifth Advisor's Committee Title
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.
Santiago Estevez, Maria D., "Allosteric Mechanism on DREAM Dimerization and Impact on Its Interactions with Divalent Metal Zn2+" (2022). FIU Electronic Theses and Dissertations. 5033.
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).