6w0b: Difference between revisions
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==Open-gate KcsA soaked in 2 mM BaCl2== | ==Open-gate KcsA soaked in 2 mM BaCl2== | ||
<StructureSection load='6w0b' size='340' side='right'caption='[[6w0b]]' scene=''> | <StructureSection load='6w0b' size='340' side='right'caption='[[6w0b]], [[Resolution|resolution]] 3.60Å' scene=''> | ||
== Structural highlights == | == Structural highlights == | ||
<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 [http://proteopedia.org/fgij/fg.htm?mol=6W0B FirstGlance]. <br> | <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> | ||
</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> | </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='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='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> | |||
</table> | </table> | ||
== 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> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
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. | |||
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> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 6w0b" style="background-color:#fffaf0;"></div> | |||
== References == | |||
<references/> | |||
__TOC__ | __TOC__ | ||
</StructureSection> | </StructureSection> | ||
[[Category: Actinomyces lividans krasil'nikov et al. 1965]] | |||
[[Category: Buffalo rat]] | |||
[[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]] | |||
[[Category: Membrane protein]] | |||
Revision as of 09:37, 19 August 2020
Open-gate KcsA soaked in 2 mM BaCl2Open-gate KcsA soaked in 2 mM BaCl2
Structural highlights
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] Publication Abstract from PubMedBarium (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. 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[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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