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| <StructureSection load='6w0b' size='340' side='right'caption='[[6w0b]], [[Resolution|resolution]] 3.60Å' scene=''> | | <StructureSection load='6w0b' size='340' side='right'caption='[[6w0b]], [[Resolution|resolution]] 3.60Å' scene=''> |
| == Structural highlights == | | == Structural highlights == |
| <table><tr><td colspan='2'>[[6w0b]] is a 3 chain structure with sequence from [http://en.wikipedia.org/wiki/"actinomyces_lividans"_krasil'nikov_et_al._1965 "actinomyces lividans" krasil'nikov et al. 1965] and [http://en.wikipedia.org/wiki/Buffalo_rat Buffalo rat]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6W0B OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=6W0B FirstGlance]. <br> | | <table><tr><td colspan='2'>Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6W0B OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6W0B FirstGlance]. <br> |
| </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BA:BARIUM+ION'>BA</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</scene></td></tr> | | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 3.604Å</td></tr> |
| <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">kcsA, skc1 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1916 "Actinomyces lividans" Krasil'nikov et al. 1965])</td></tr> | | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BA:BARIUM+ION'>BA</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</scene></td></tr> |
| <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=6w0b FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6w0b OCA], [http://pdbe.org/6w0b PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6w0b RCSB], [http://www.ebi.ac.uk/pdbsum/6w0b PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6w0b ProSAT]</span></td></tr> | | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=6w0b FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6w0b OCA], [https://pdbe.org/6w0b PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6w0b RCSB], [https://www.ebi.ac.uk/pdbsum/6w0b PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6w0b ProSAT]</span></td></tr> |
| </table> | | </table> |
| == Function ==
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| [[http://www.uniprot.org/uniprot/KCSA_STRLI KCSA_STRLI]] Acts as a pH-gated potassium ion channel; changing the cytosolic pH from 7 to 4 opens the channel, although it is not clear if this is the physiological stimulus for channel opening. Monovalent cation preference is K(+) > Rb(+) > NH4(+) >> Na(+) > Li(+).<ref>PMID:7489706</ref>
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| <div style="background-color:#fffaf0;">
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| == Publication Abstract from PubMed ==
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| Barium (Ba(2+)) is a classic permeant blocker of potassium (K(+)) channels. The "external lock-in effect" in barium block experiments, whereby the binding of external K(+) impedes the forward translocation of the blocker, provides a powerful avenue to investigate the selectivity of the binding sites along the pore of potassium channels. Barium block experiments show that the external lock-in site is highly selective for K(+) over Na(+). Wild-type KcsA was crystallized in low K(+) conditions, and the crystals were soaked in solutions containing various concentrations of barium. Structural analysis reveals open and closed gate conformations of the KcsA channel. Anomalous diffraction experiments show that Ba(2+) primarily binds to the innermost site S4 of the selectivity filter of the open-gate conformation and also the site S2, but no binding is detected with the closed-gate conformation. Alchemical free-energy perturbation calculations indicate that the presence of a Ba(2+) ion in the selectivity filter boosts the specificity of K(+) binding relative to Na(+) in the external sites S0-S2.
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| Open and Closed Structures of a Barium-Blocked Potassium Channel.,Rohaim A, Gong L, Li J, Rui H, Blachowicz L, Roux B J Mol Biol. 2020 Aug 7;432(17):4783-4798. doi: 10.1016/j.jmb.2020.06.012. Epub, 2020 Jun 29. PMID:32615129<ref>PMID:32615129</ref>
| | ==See Also== |
| | | *[[Potassium channel 3D structures|Potassium channel 3D structures]] |
| From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
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| </div>
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| <div class="pdbe-citations 6w0b" style="background-color:#fffaf0;"></div>
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| == References == | |
| <references/>
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| __TOC__ | | __TOC__ |
| </StructureSection> | | </StructureSection> |
| [[Category: Actinomyces lividans krasil'nikov et al. 1965]]
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| [[Category: Buffalo rat]]
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| [[Category: Large Structures]] | | [[Category: Large Structures]] |
| [[Category: Gong, L]] | | [[Category: Gong L]] |
| [[Category: Li, J]] | | [[Category: Li J]] |
| [[Category: Rohaim, A]] | | [[Category: Rohaim A]] |
| [[Category: Ion channel]]
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| [[Category: Membrane protein]]
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