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    Stabilisation of Na,K-ATPase structure by the cardiotonic steroid ouabain

    Miles, Andrew J. and Fedosova, N.U. and Hoffmann, S.V. and Wallace, Bonnie A. and Esmann, M. (2013) Stabilisation of Na,K-ATPase structure by the cardiotonic steroid ouabain. Biochemical and Biophysical Research Communications 435 (2), pp. 300-305. ISSN 0006-291X.

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    Abstract

    Cardiotonic steroids such as ouabain bind with high affinity to the membrane-bound cation-transporting P-type Na,K-ATPase, leading to complete inhibition of the enzyme. Using synchrotron radiation circular dichroism we show that the enzyme-ouabain complex is less susceptible to thermal denaturation (unfolding) than the ouabain-free enzyme, and this protection is observed with Na,K-ATPase purified from pig kidney as well as from shark rectal glands. It is also shown that detergent-solubilised preparations of Na,K-ATPase are stabilised by ouabain, which could account for the successful crystallisation of Na,K-ATPase in the ouabain-bound form. The secondary structure is not significantly affected by the binding of ouabain. Ouabain appears however, to induce a reorganization of the tertiary structure towards a more compact protein structure which is less prone to unfolding; recent crystal structures of the two enzymes are consistent with this interpretation. These circular dichroism spectroscopic studies in solution therefore provide complementary information to that provided by crystallography.

    Metadata

    Item Type: Article
    Keyword(s) / Subject(s): Synchrotron radiation circular dichroism (SRCD) spectroscopy, Na,K-ATPase, Ouabain, Membrane protein, Thermal melt curves, Enzyme activity
    School: Birkbeck Schools and Departments > School of Science > Biological Sciences
    Research Centre: Bioinformatics, Bloomsbury Centre for, Structural Molecular Biology, Institute of (ISMB)
    Depositing User: Administrator
    Date Deposited: 24 Apr 2013 11:13
    Last Modified: 28 Jul 2019 03:14
    URI: http://eprints.bbk.ac.uk/id/eprint/6482

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