ASU Electronic Theses and Dissertations
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Nucleosomes are the basic repetitive unit of eukaryotic chromatin and are responsible for packing DNA inside the nucleus of the cell. They consist of a complex of eight histone proteins (two copies of four proteins H2A, H2B, H3 and H4) around which 147 base pairs of DNA are wrapped in ~1.67 superhelical turns. Although the nucleosomes are stable protein-DNA complexes, they undergo spontaneous conformational changes that occur in an asynchronous fashion. This conformational dynamics, defined by the "site-exposure" model, involves the DNA unwrapping from the protein core and exposing itself transiently before wrapping back. Physiologically, this allows regulatory proteins to …
- Gurunathan, Kaushik, Levitus, Marcia, Lindsay, Stuart, et al.
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The fundamental photophysics of fluorescent probes must be understood when the probes are used in biological applications. The photophysics of BODIPY dyes inside polymeric micelles and rhodamine dyes covalently linked to proteins were studied. Hydrophobic boron-dipyrromethene (BODIPY) dyes were noncovalently encapsulated inside polymeric micelles. Absorbance and fluorescence measurements were employed to study the photophysics of these BODIPY dyes in the micellar environments. Amphiphilic polymers with a hydrophobic character and low Critical Micelle Concentration (CMC) protected BODIPYS from the aqueous environment. Moderate dye loading conditions did not result in ground-state dimerization, and only fluorescence lifetimes and brightnesses were affected. However, amphiphilic …
- Donaphon, Bryan Matthew, Levitus, Marcia, Van Horn, Wade, et al.
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