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| Article Authors: | Y Zhou; J H Morais-Cabral; A Kaufman; R MacKinnon |
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| Article Title: | Chemistry of ion coordination and hydration revealed by a K+ channel-Fab complex at 2.0 A resolution. |
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| Reference ID: | 1001553 |
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| Abstract: | Ion transport proteins must remove an ion's hydration shell to coordinate the ion selectively on the basis of its size and charge. To discover how the K+ channel solves this fundamental aspect of ion conduction, we solved the structure of the KcsA K+ channel in complex with a monoclonal Fab antibody fragment at 2.0 A resolution. Here we show how the K+ channel displaces water molecules around an ion at its extracellular entryway, and how it holds a K+ ion in a square antiprism of water molecules in a cavity near its intracellular entryway. Carbonyl oxygen atoms within the selectivity filter form a very similar square antiprism around each K+ binding site, as if to mimic the waters of hydration. The selectivity filter changes its ion coordination structure in low K+ solutions. This structural change is crucial to the operation of the selectivity filter in the cellular context, where the K+ ion concentration near the selectivity filter varies in response to channel gating. |
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| Affiliations: | Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, New Haven, Connecticut 06520, USA. |
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| Date: | 2001 |
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| Reference Type: | Literature |
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| PubMed ID: | 11689936 |
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| Journal: | Nature |
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| Journal Volume: | 414 |
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| Article Pages: | 43-8 |
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| Journal ISSN: | 1476-4687 |
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| Article Chemical List: | Antibodies, Monoclonal;Bacterial Proteins;Immunoglobulin Fab Fragments;Potassium Channels;Solutions;prokaryotic potassium channel;Potassium;Water |
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| Article MeSH List: | Animals; Antibodies, Monoclonal(chemistry; immunology; metabolism); Bacterial Proteins; Crystallography, X-Ray; Electrochemistry; Immunoglobulin Fab Fragments(chemistry; immunology; metabolism); Mice; Models, Biological; Models, Molecular; Particle Size; Potassium(chemistry; metabolism); Potassium Channels(chemistry; immunology; metabolism); Protein Conformation; Solutions; Water(chemistry) |
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| Curation Last Updated: | 2013-05-28 20:20:56 |
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