An Investigation of Carbohydrate – Carbohydrate Interactions Using Glycopolymers and Supramolecular Glycoconjugates as Multivalent Model Systems

Leeber, Blaise William

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Year:: 2018
Contributor:: Leeber, Blaise William (creator); Basu, Amit (Advisor); Delaney, Sarah (Reader); Sello, Jason (Reader); Brown University. Department of Chemistry (sponsor)
Genre:: theses
Subject:: Polymers; Carbohydrates; Supramolecular chemistry; Carbohydrate-carbohydrate interactions; Self-assembly
Extent:: xiv, 321 p.
DOI: https://doi.org/10.26300/7n2m-1r51

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Abstract:: Carbohydrate-carbohydrate interactions (CCIs) between cell surface carbohydrates play an important role in cell adhesion and cell surface signaling. Glycopolymers, synthetic polymers functionalized with carbohydrate pendant groups, can mimic the natural multivalent presentation of glycans and are useful probes for CCI. In this research, we report the synthesis and characterization of glycopolymers synthesized via ring-opening metathesis polymerization (ROMP) of a norbornene NHS-ester monomer, followed by alkyne functionalization of the polymer and finally addition of 1-deoxy-1-azido sugars via a “click” reaction. Fluorescent well-binding assays and isothermal titration calorimetry (ITC) experiments were performed using the glycopolymers to study a CCI that is associated with myelin compaction. Yariv reagents are a class of glycosylated phenyl-azo dyes which bind to arabinogalactan polysaccharides (AGs) in an apparent CCI. Yariv reagents are commonly used to detect and purify AGs from biological samples. Prior studies have shown that Yariv reagents self-associate to form aggregates in aqueous solution, and that the assembly of these aggregates can be disrupted by the presence of additives such as organic solvents. The AG binding ability of a Yariv reagent is dependent on the identity of the sugar present on the dye. Recent data suggests that the AG moiety that binds Yariv adopts a helical conformation in aqueous solution. In this study, circular dichroism (CD) spectroscopy was used to show that Yariv reagents form helical aggregates in aqueous solution, and that only those reagents forming right-handed helices bind to AG. CD spectroscopy was used to detect Yariv-AG binding. Additionally, Yariv aggregates dissolved in alcohol-water mixtures were found to form higher order aggregates at low temperatures. The extent of this transformation is dependent on the fraction of alcohol in solution and is related to the excess enthalpy of mixing for the solution.
Notes:: Thesis (Ph. D.)--Brown University, 2018

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Leeber, Blaise William, "An Investigation of Carbohydrate – Carbohydrate Interactions Using Glycopolymers and Supramolecular Glycoconjugates as Multivalent Model Systems" (2018). Chemistry Theses and Dissertations. Brown Digital Repository. Brown University Library. https://doi.org/10.26300/7n2m-1r51

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Chemistry Theses and Dissertations

Theses and Dissertations for the Chemistry department.
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