Skip to content
University of Maryland LibrariesDigital Repository at the University of Maryland
    • Login
    View Item 
    •   DRUM
    • Theses and Dissertations from UMD
    • UMD Theses and Dissertations
    • View Item
    •   DRUM
    • Theses and Dissertations from UMD
    • UMD Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Allostery and GroEL: Exploring the Tenets of Nested Cooperativity

    Thumbnail
    View/Open
    umi-umd-1675.pdf (2.220Mb)
    No. of downloads: 1749

    Date
    2004-06-24
    Author
    Gresham, Jennifer Suzanne
    Advisor
    Lorimer, George H
    Metadata
    Show full item record
    Abstract
    Despite a wealth of structural and biochemical studies on the functional cycle of the <i>E. coli</i> chaperonins GroEL and GroES, no model proposed to date accounts for all the effects seen experimentally by the various allosteric ligands: ATP, ADP, SP, GroES, and K+. The work in this dissertation explores the various allosteric transitions in the GroEL reaction cycle and offers a refined model for nested cooperativity that successfully accounts for the effects of these ligands. Initial studies take advantage of a single ring variant, termed SR1, to examine the allosteric properties of GroEL in the absence of complicating interactions arising from negative cooperativity. Initial rates of ATP hydrolysis by GroEL and SR1 as a function of ATP concentration were fit to an equation that makes no arbitrary assumptions. A novel role for K+ and SP is proposed, which suggests they help regulate the negative cooperativity and control the timing of the chaperonin cycle. The kinetics of association of GroES to the trans ring of the asymmetric complex were also studied, using stopped flow fluorescence energy transfer (FRET), revealing that conditions which accelerate dissociation of the cis ligands also accelerate association to the trans ring. This, along with previous work obtained by our lab, suggests that the allosteric signal transmitted between the rings for cis ligand release is the binding of ATP to the T state of the trans ring. A mechanism for the formation of symmetrical particles, termed "footballs," is suggested.
    URI
    http://hdl.handle.net/1903/1695
    Collections
    • Chemistry & Biochemistry Theses and Dissertations
    • UMD Theses and Dissertations

    DRUM is brought to you by the University of Maryland Libraries
    University of Maryland, College Park, MD 20742-7011 (301)314-1328.
    Please send us your comments.
    Web Accessibility
     

     

    Browse

    All of DRUMCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    LoginRegister
    Pages
    About DRUMAbout Download Statistics

    DRUM is brought to you by the University of Maryland Libraries
    University of Maryland, College Park, MD 20742-7011 (301)314-1328.
    Please send us your comments.
    Web Accessibility