Dissertations, Theses, and Capstone Projects
Date of Degree
2-2019
Document Type
Dissertation
Degree Name
Ph.D.
Program
Biochemistry
Advisor
Ranajeet Ghose
Committee Members
Kevin Dalby
David Jeruzalmi
Reza Khayat
Ming-Ming Zhou
Subject Categories
Biochemistry | Biophysics | Structural Biology
Keywords
calmodulin, eEF-2K, NMR, ITC, Structural biology, Biochemistry, Biophysics
Abstract
Eukaryotic elongation factor 2 kinase (eEF-2K) is a key modulator of the rate of protein synthesis. Activated by calcium-loaded calmodulin (Ca2+-CaM), eEF-2K phosphorylates its only known physiological substrate, eEF-2, on a specific threonine residue (Thr-56). Phosphorylated eEF-2 has reduced affinity for the ribosome, and results in a significant decrease in the rate of translation elongation. Modulation of the rate of translation elongation plays a crucial role in proteostasis – adequate regulation of protein synthesis, protein folding, and protein degradation that greatly influences cellular growth and survival. Binding of Ca2+-CaM triggers activation of eEF-2K and remains intact to facilitate the substrate phosphorylation, acting as a cofactor of the enzyme. Despite its importance, how the binding of Ca2+-CaM leads to activation remains poorly understood.
We employed various biophysical tools, such as nuclear magnetic resonance (NMR) spectroscopy and isothermal titration calorimetry (ITC), coupled with mutational strategies to characterize structural and thermodynamic nature of the binding of Ca2+-CaM onto eEF-2K. Our data clarify the roles of Ca2+ and each lobe of CaM that provide mechanistic insight into the structural regulation of eEF-2K mediated by the binding of Ca2+-CaM.
Recommended Citation
Lee, Kwangwoon, "Structural Studies on Calcium/calmodulin-dependent Activation of Eukaryotic Elongation Factor 2 Kinase" (2019). CUNY Academic Works.
https://academicworks.cuny.edu/gc_etds/3037
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