3LDC
High resolution open MthK pore structure crystallized in 100 mM K+
Summary for 3LDC
| Entry DOI | 10.2210/pdb3ldc/pdb |
| Related | 1LNQ 2FY8 3LDD 3LDE |
| Descriptor | Calcium-gated potassium channel mthK, POTASSIUM ION (3 entities in total) |
| Functional Keywords | transmembrane, ion channel, open conformation, potassium, ion transport, alternative initiation, cell membrane, ionic channel, membrane, metal-binding, potassium transport, transport protein |
| Biological source | Methanothermobacter thermautotrophicus |
| Cellular location | Cell membrane; Multi-pass membrane protein: O27564 |
| Total number of polymer chains | 1 |
| Total formula weight | 9230.07 |
| Authors | |
| Primary citation | Ye, S.,Li, Y.,Jiang, Y. Novel insights into K(+) selectivity from high-resolution structures of an open K(+) channel pore. Nat.Struct.Mol.Biol., 17:1019-1023, 2010 Cited by PubMed Abstract: K+ channels are highly selective for K+ over Na+. Here we present several crystal structures of the MthK K+ channel pore at up to 1.45-A resolution. The MthK selectivity filter maintains a conductive conformation even in the absence of K+, allowing the channel to conduct Na+. The high-resolution structures, along with single-channel recordings, allow for an accurate analysis of how K+ competes with Na+ in a conductive selectivity filter. At high K+ concentrations, two K+ ions equivalently occupy the four sites in the selectivity filter, whereas at low K+/high Na+ concentrations, a single K+ ion remains bound in the selectivity filter, preferably at site 1 or site 3. This single K+ binding at low concentration effectively blocks the permeation of Na+, providing a structural basis for the anomalous mole-fraction effect, a key property of multi-ion pores. PubMed: 20676101DOI: 10.1038/nsmb.1865 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.45 Å) |
Structure validation
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