• Login
    View Item 
    •   Shocker Open Access Repository Home
    • Graduate Student Research
    • ETD: Electronic Theses and Dissertations
    • Dissertations
    • View Item
    •   Shocker Open Access Repository Home
    • Graduate Student Research
    • ETD: Electronic Theses and Dissertations
    • Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Understanding fluorine chemical shifts and the molecular properties of organic molecules

    View/Open
    dissertation (29.72Mb)
    Date
    2018-05
    Author
    Kasireddy, Chandana
    Advisor
    Mitchell-Koch, Katie R.
    Metadata
    Show full item record
    Abstract
    Fluorinated molecules have emerged as important probes in drug design, and as strategies for enhancing protein stability and altering physicochemical properties of biological systems. Fluorine NMR plays a crucial role in studying protein structure, dynamics and protein-ligand interactions. Histidine is an important amino acid involved in many enzymatic reactions and protein functions. 2-fluorohistidine and 4-fluorohistidine are fluorinated analogues of histidine, offering valuable tools in biophysical studies with their altered pKa values compared to the canonical amino acid. In this dissertation, the molecular properties of 2-fluorohistidine, 4- fluorohistidine, and analogues are studied with different electronic structure calculations. Among the two tautomeric states of histidine at neutral pH, it was found that 2- fluorohistidine prefers the τ-tautomeric state, whereas 4-fluorohistidine exclusively stays in the π-tautomeric state. While the 1 H signal shifts downfield in both isomers upon ring protonation, the 19F signal of 2-fluorohistidine also shifts downfield but 19F in 4- fluorohistidine shifts upfield. The reason for this unusual behavior is explained here. The effect of different environments (solvation effects, intramolecular hydrogen bonding effect, backbone effects) on tautomeric stabilities and fluorine chemical shifts are discussed. This work explains the role of histidine’s C4-H bond as a potential hydrogen bond donor. The results indicate that the C4-H bonds in histidine and 2-fluorohistidine in the τ-tautomeric states act as strong hydrogen bond donors.
    Description
    Thesis (Ph.D.)-- Wichita State University, College of Liberal Arts and Sciences, Dept. of Chemistry
    URI
    http://hdl.handle.net/10057/15415
    Collections
    • CHEM Theses and Dissertations
    • Dissertations
    • LAS Theses and Dissertations

    Browse

    All of Shocker Open Access RepositoryCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsBy TypeThis CollectionBy Issue DateAuthorsTitlesSubjectsBy Type

    My Account

    LoginRegister

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    DSpace software copyright © 2002-2023  DuraSpace
    DSpace Express is a service operated by 
    Atmire NV