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- Jonathan A. Lukin
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213; and Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
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- Georg Kontaxis
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213; and Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
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- Virgil Simplaceanu
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213; and Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
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- Yue Yuan
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213; and Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
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- Ad Bax
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213; and Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
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- Chien Ho
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213; and Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
説明
<jats:p> Many important proteins perform their physiological functions under allosteric control, whereby the binding of a ligand at a specific site influences the binding affinity at a different site. Allosteric regulation usually involves a switch in protein conformation upon ligand binding. The energies of the corresponding structures are comparable, and, therefore, the possibility that a structure determined by x-ray diffraction in the crystalline state is influenced by its intermolecular contacts, and thus differs from the solution structure, cannot be excluded. Here, we demonstrate that the quaternary structure of tetrameric human normal adult carbonmonoxy-hemoglobin can readily be determined in solution at near-physiological conditions of pH, ionic strength, and temperature by NMR measurement of <jats:sup>15</jats:sup> N- <jats:sup>1</jats:sup> H residual dipolar couplings in weakly oriented samples. The structure is found to be a dynamic intermediate between two previously solved crystal structures, known as the R and R2 states. Exchange broadening at the subunit interface points to a rapid equilibrium between different structures that presumably include the crystallographically observed states. </jats:p>
収録刊行物
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- Proceedings of the National Academy of Sciences
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Proceedings of the National Academy of Sciences 100 (2), 517-520, 2003-01-13
Proceedings of the National Academy of Sciences