Date of Award
2016
Document Type
Thesis
Degree Name
M.S. in Chemistry
Department
Chemistry and Biochemistry
First Advisor
Susan D. Pedigo
Second Advisor
Davita L. Watkins
Third Advisor
Walter Cleland
Relational Format
dissertation/thesis
Abstract
Cadherins are calcium dependent glycoproteins whose homophilic interactions mediate cell-cell adhesion in solid tissues. They are comprised of an extracellular region, a transmembrane region and a cytoplasmic region. The extracellular region plays a critical role in cadherin-mediated cell adhesion, and has five tandemly repeated ectodomains (ec1-ec5), with three calcium binding sites situated in each interface between the domains. Dimerization of cadherin occurs through formation of adhesive interactions between extracellular domains of cadherins from neighboring cells. Adhesive interaction occurs at the interfaces of ec1 domains of two molecules originating from different cell surfaces. Dimerization is critically dependent on the binding of calcium. Neural and epithelial cadherin (ncad and ecad) are very similar in sequence comparison, but differ in kinetics of dimer assembly and dimer affinity in the presence or absence of calcium. The single most obvious difference in the strand swapped interface is a proline in ncad and a glutamate in ecad in position 16. Our hypothesis is that the slow kinetics of dimer disassembly of ncad is due to the steric restrictions of proline in position 16 of ncad. The purpose of this research is to mutate the proline, in position 16 to alanine (p16a), in ncad to decrease the steric hindrance and study the effects of the mutation. Stability studies assess the effect the mutation has on the folding properties of the protein. Calcium binding experiments demonstrate whether the mutation affects the binding affinity of calcium. From the results, p16a lowers the stability of the protein, ca2+ binding affinity, and dimerization kinetics of ncad.
Recommended Citation
Dykes, Keshia S., "Biophysical Characterization Of A Proline Mutant Of Neural Cadherin" (2016). Electronic Theses and Dissertations. 921.
https://egrove.olemiss.edu/etd/921