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| | ==Structure of KcsA with E118A mutation== | | ==Structure of KcsA with E118A mutation== |
| - | <StructureSection load='4lcu' size='340' side='right' caption='[[4lcu]], [[Resolution|resolution]] 2.75Å' scene=''> | + | <StructureSection load='4lcu' size='340' side='right'caption='[[4lcu]], [[Resolution|resolution]] 2.75Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[4lcu]] 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/Lk3_transgenic_mice Lk3 transgenic mice]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4LCU OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4LCU FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[4lcu]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Mus_musculus Mus musculus] and [https://en.wikipedia.org/wiki/Streptomyces_lividans Streptomyces lividans]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4LCU OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4LCU FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=DGA:DIACYL+GLYCEROL'>DGA</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</scene></td></tr> | + | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=DGA:DIACYL+GLYCEROL'>DGA</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</scene></td></tr> |
| - | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[4lbe|4lbe]]</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=4lcu FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4lcu OCA], [https://pdbe.org/4lcu PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4lcu RCSB], [https://www.ebi.ac.uk/pdbsum/4lcu PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4lcu ProSAT]</span></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://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4lcu FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4lcu OCA], [http://pdbe.org/4lcu PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4lcu RCSB], [http://www.ebi.ac.uk/pdbsum/4lcu PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=4lcu 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> |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
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| | </div> | | </div> |
| | <div class="pdbe-citations 4lcu" style="background-color:#fffaf0;"></div> | | <div class="pdbe-citations 4lcu" style="background-color:#fffaf0;"></div> |
| | + | |
| | + | ==See Also== |
| | + | *[[Potassium channel 3D structures|Potassium channel 3D structures]] |
| | == References == | | == References == |
| | <references/> | | <references/> |
| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Actinomyces lividans krasil'nikov et al. 1965]] | + | [[Category: Large Structures]] |
| - | [[Category: Lk3 transgenic mice]] | + | [[Category: Mus musculus]] |
| - | [[Category: McCoy, J M]] | + | [[Category: Streptomyces lividans]] |
| - | [[Category: Nimigean, C M]] | + | [[Category: McCoy JM]] |
| - | [[Category: Posson, D J]] | + | [[Category: Nimigean CM]] |
| - | [[Category: Membrane protein]] | + | [[Category: Posson DJ]] |
| - | [[Category: Ph-gated potassium channel]]
| + | |
| - | [[Category: Potassium channel]]
| + | |
| - | [[Category: Transport protein]]
| + | |
| - | [[Category: Voltage gated potassium channel]]
| + | |
| 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 PubMed
The bacterial potassium channel KcsA is gated open by the binding of protons to amino acids on the intracellular side of the channel. We have identified, via channel mutagenesis and x-ray crystallography, two pH-sensing amino acids and a set of nearby residues involved in molecular interactions that influence gating. We found that the minimal mutation of one histidine (H25) and one glutamate (E118) near the cytoplasmic gate completely abolished pH-dependent gating. Mutation of nearby residues either alone or in pairs altered the channel's response to pH. In addition, mutations of certain pairs of residues dramatically increased the energy barriers between the closed and open states. We proposed a Monod-Wyman-Changeux model for proton binding and pH-dependent gating in KcsA, where H25 is a "strong" sensor displaying a large shift in pKa between closed and open states, and E118 is a "weak" pH sensor. Modifying model parameters that are involved in either the intrinsic gating equilibrium or the pKa values of the pH-sensing residues was sufficient to capture the effects of all mutations.
Molecular interactions involved in proton-dependent gating in KcsA potassium channels.,Posson DJ, Thompson AN, McCoy JG, Nimigean CM J Gen Physiol. 2013 Dec;142(6):613-24. doi: 10.1085/jgp.201311057. Epub 2013 Nov , 11. PMID:24218397[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
- ↑ Posson DJ, Thompson AN, McCoy JG, Nimigean CM. Molecular interactions involved in proton-dependent gating in KcsA potassium channels. J Gen Physiol. 2013 Dec;142(6):613-24. doi: 10.1085/jgp.201311057. Epub 2013 Nov , 11. PMID:24218397 doi:http://dx.doi.org/10.1085/jgp.201311057
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