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 Faculties and Schools > Faculty of Science > School of Natural Sciences |
| Research Centres and Institutes: | Bioinformatics, Bloomsbury Centre for (Closed), Structural Molecular Biology, Institute of (ISMB) |
| Depositing User: | Administrator |
| Date Deposited: | 24 Apr 2013 11:13 |
| Last Modified: | 02 Aug 2023 17:03 |
| URI: | https://eprints.bbk.ac.uk/id/eprint/6482 |
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