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| | <StructureSection load='1r3l' size='340' side='right'caption='[[1r3l]], [[Resolution|resolution]] 2.41Å' scene=''> | | <StructureSection load='1r3l' size='340' side='right'caption='[[1r3l]], [[Resolution|resolution]] 2.41Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[1r3l]] 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/Mus_musculus Mus musculus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1R3L OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=1R3L FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[1r3l]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/"actinomyces_lividans"_krasil'nikov_et_al._1965 "actinomyces lividans" krasil'nikov et al. 1965] and [https://en.wikipedia.org/wiki/Mus_musculus Mus musculus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1R3L OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1R3L FirstGlance]. <br> |
| | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CS:CESIUM+ION'>CS</scene>, <scene name='pdbligand=DGA:DIACYL+GLYCEROL'>DGA</scene>, <scene name='pdbligand=F09:NONAN-1-OL'>F09</scene></td></tr> | | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CS:CESIUM+ION'>CS</scene>, <scene name='pdbligand=DGA:DIACYL+GLYCEROL'>DGA</scene>, <scene name='pdbligand=F09:NONAN-1-OL'>F09</scene></td></tr> |
| | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[1k4c|1k4c]], [[1k4d|1k4d]], [[1r3i|1r3i]], [[1r3j|1r3j]], [[1r3k|1r3k]]</div></td></tr> | | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[1k4c|1k4c]], [[1k4d|1k4d]], [[1r3i|1r3i]], [[1r3j|1r3j]], [[1r3k|1r3k]]</div></td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">KCSA, SKC1, SCO7660, SC10F4.33 ([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='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">KCSA, SKC1, SCO7660, SC10F4.33 ([https://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='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=1r3l FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1r3l OCA], [http://pdbe.org/1r3l PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1r3l RCSB], [http://www.ebi.ac.uk/pdbsum/1r3l PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1r3l 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=1r3l FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1r3l OCA], [https://pdbe.org/1r3l PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1r3l RCSB], [https://www.ebi.ac.uk/pdbsum/1r3l PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1r3l ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[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> | + | [[https://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> |
| | == Evolutionary Conservation == | | == Evolutionary Conservation == |
| | [[Image:Consurf_key_small.gif|200px|right]] | | [[Image:Consurf_key_small.gif|200px|right]] |
| Structural highlights
1r3l is a 3 chain structure with sequence from "actinomyces_lividans"_krasil'nikov_et_al._1965 "actinomyces lividans" krasil'nikov et al. 1965 and Mus musculus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Ligands: | , , |
| Related: | |
| Gene: | KCSA, SKC1, SCO7660, SC10F4.33 ("Actinomyces lividans" Krasil'nikov et al. 1965) |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Function
[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(+).[1]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Potassium ions diffuse across the cell membrane in a single file through the narrow selectivity filter of potassium channels. The crystal structure of the KcsA K+ channel revealed the chemical structure of the selectivity filter, which contains four binding sites for K+. In this study, we used Tl+ in place of K+ to address the question of how many ions bind within the filter at a given time, i.e. what is the absolute ion occupancy? By refining the Tl+ structure against data to 1.9A resolution with an anomalous signal, we determined the absolute occupancy of Tl+. Then, by comparing the electron density of Tl+ with that of K+, Rb+ and Cs+, we estimated the absolute occupancy of these three ions. We further analyzed how the ion occupancy affects the conformation of the selectivity filter by analyzing the structure of KcsA at different concentrations of Tl+. Our results indicate that the average occupancy for each site in the selectivity filter is about 0.63 for Tl+ and 0.53 for K+. For K+, Rb+ and Cs+, the total number of ions contained within four sites in the selectivity filter is about two. At low concentrations of permeant ion, the number of ions drops to one in association with a conformational change in the selectivity filter. We conclude that electrostatic balance and coupling of ion binding to a protein conformational change underlie high conduction rates in the setting of high selectivity.
The occupancy of ions in the K+ selectivity filter: charge balance and coupling of ion binding to a protein conformational change underlie high conduction rates.,Zhou Y, MacKinnon R J Mol Biol. 2003 Nov 7;333(5):965-75. PMID:14583193[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Schrempf H, Schmidt O, Kummerlen R, Hinnah S, Muller D, Betzler M, Steinkamp T, Wagner R. A prokaryotic potassium ion channel with two predicted transmembrane segments from Streptomyces lividans. EMBO J. 1995 Nov 1;14(21):5170-8. PMID:7489706
- ↑ Zhou Y, MacKinnon R. The occupancy of ions in the K+ selectivity filter: charge balance and coupling of ion binding to a protein conformational change underlie high conduction rates. J Mol Biol. 2003 Nov 7;333(5):965-75. PMID:14583193
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