1k4d: Difference between revisions
No edit summary |
No edit summary |
||
| Line 4: | Line 4: | ||
==Overview== | ==Overview== | ||
Ion transport proteins must remove an ion's hydration shell to coordinate | 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. | ||
==About this Structure== | ==About this Structure== | ||
| Line 16: | Line 16: | ||
[[Category: Kaufman, A.]] | [[Category: Kaufman, A.]] | ||
[[Category: MacKinnon, R.]] | [[Category: MacKinnon, R.]] | ||
[[Category: Morais-Cabral, J | [[Category: Morais-Cabral, J H.]] | ||
[[Category: Zhou, Y.]] | [[Category: Zhou, Y.]] | ||
[[Category: DGA]] | [[Category: DGA]] | ||
| Line 25: | Line 25: | ||
[[Category: protein-antibody fab complex]] | [[Category: protein-antibody fab complex]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:30:00 2008'' | ||
Revision as of 11:30, 21 February 2008
|
Potassium Channel KcsA-Fab complex in low concentration of K+
Overview
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.
About this Structure
1K4D is a Single protein structure of sequence from Mus musculus and Streptomyces lividans with K, NA, DGA and F09 as ligands. Full crystallographic information is available from OCA.
Reference
Chemistry of ion coordination and hydration revealed by a K+ channel-Fab complex at 2.0 A resolution., Zhou Y, Morais-Cabral JH, Kaufman A, MacKinnon R, Nature. 2001 Nov 1;414(6859):43-8. PMID:11689936
Page seeded by OCA on Thu Feb 21 13:30:00 2008
