Honors Theses
Date of Award
2009
Document Type
Undergraduate Thesis
Department
Chemistry and Biochemistry
First Advisor
Susan Pedigo
Relational Format
Dissertation/Thesis
Abstract
Cadherins are a family of cell adhesion receptors that are crucial for binding of mutual vertebrate cells. Cadherins are calcium-dependent, homophilic, cell-adhesive molecules that are found in varying types of cell-cell contacts. Cell-cell contacts that contain cadherins include adherens junctions, desmosomes, and synapses. Cadherins play an Important role in regulating maintenance of adult tissue structural design and integrity. tissue morphogenesis and synaptogenesis, and embryogenesis. Cadherins have an intracellular, cytoplasmic, region, a transmembrane region, and an extracellular region where calcium binding occurs. In classical cadherins, the extracellular region has five modular P-barrel domains and calcium binds to the interfaces between domains. Much effort has gone into characterizing the mechanism for cadherin cell adhesion, and it is widely accepted that the first two extracellular domains, closest to the N-terminus, are the minimal requirement for calcium binding and cell adhesion. Literature has suggested that the binding of calcium provokes conformational changes in the extracellular domain of classical cadherins by opening strand |3A and exposing an essential tryptophan in the second position, W2, which then leads to cell-cell adhesion. However, these are the first solution studies of neural cadherin that have been attempted. Although calcium binding Is known to be required in cadherin mediated cell-cell adhesion, the mechanisms behind calcium binding have been extremely hard to characterize. The purpose of these experiments is to determine calcium binding affinity for the binding pocket at the interface between extracellular domains 1 and 2. We monitored calcium titrations with circular dichroism and fluorescence spectroscopy. Binding affinities were different when spectroscopic techniques are compared to each another and a mutation to one tryptophan showed to be significantly debilitating to calcium binding.
Recommended Citation
Wood, Thomas Thayer, "Calcium Binding Affinity Properties of Neural Cadherin Domains 1 and 2" (2009). Honors Theses. 2159.
https://egrove.olemiss.edu/hon_thesis/2159
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