An Improved Understanding of the Yariv Reagent - A Plant Proteoglycan Binding Dye

Hoshing, Raghuraj

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Year:: 2022
Contributor:: Hoshing, Raghuraj (creator); Basu, Amit (Advisor); Delaney, Sarah (Reader); Zimmt, Matthew (Reader); Brown University. Department of Chemistry (sponsor)
Genre:: theses
Subject:: Chemistry; Chemistry, Organic; Dyes
Extent:: xi, 248 p.

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Abstract:: Plant cell walls are composed mainly of carbohydrate containing molecules such as cellulose, hemi-celluloses, various pectins, and proteoglycans. The exact carbohydrate composition varies between species, within different tissues and cell types of the same plant, and at different stages of growth. Polysaccharide recognition tools such as small molecule dyes can accurately provide details about composition and spatiotemporal dynamics of cell wall polysaccharides. The Yariv reagents, a set of glycosylated tris-hydroxyazo dyes, are known for their strong specificity towards the arabinogalactan proteins (AGPs). The AGPs are proteoglycans found in plant cell walls that are integral for plant growth and development. Yariv reagents are widely utilized as imaging, purification, and quantification tools for AGPs. Our work on three aspects of the Yariv reagents is presented here- 1) Synthesis and Purification of Yariv reagents: In our attempts to synthesize the Yariv reagents we found that the isolated crude products were often contaminated with impurities and exhibited peak broadening in their NMR spectra. In this chapter the reasons for these issues which hindered complete characterization are presented in brief. Further, optimization and development of protocols that help resolve these problems are presented. 2) Characterization of Yariv reagent-AGP Binding and Yariv reagent aggregation: The ability of Yariv reagents to bind to AGPs is dependent on the structure of the terminal glycoside on the dye. This chapter presents results that help explain the reason for this selectivity. Using circular dichroism spectroscopy, we show that the Yariv reagents form supramolecular aggregates with helical chirality. More significantly, the ability of the Yariv reagent to bind AGPs is correlated with this helical chirality. The Yariv reagent aggregates are further studied using a variety of experiments such as the soldiers and sergeants phenomenon and variable temperature experiments. 3) Identification of the chromophore(s) in the Yariv reagent UV/vis spectra: The UV/vis spectra of Yariv reagents exhibit two major transitions. However, the exact chromophore(s) that give rise to these transitions have not been determined. In this chapter, we evaluate if some commonly hypothesized identities of the chromophore for hydroxy-azo dyes are applicable to the Yariv reagents.
Notes:: Thesis (Ph. D.)--Brown University, 2022

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Citation

Hoshing, Raghuraj, "An Improved Understanding of the Yariv Reagent - A Plant Proteoglycan Binding Dye" (2022). Chemistry Theses and Dissertations. Brown Digital Repository. Brown University Library. https://repository.library.brown.edu/studio/item/bdr:6vteha9q/

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Chemistry Theses and Dissertations

Theses and Dissertations for the Chemistry department.
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