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| | ==KcsA E71A variant in presence of Na+== | | ==KcsA E71A variant in presence of Na+== |
| - | <StructureSection load='3ogc' size='340' side='right' caption='[[3ogc]], [[Resolution|resolution]] 3.80Å' scene=''> | + | <StructureSection load='3ogc' size='340' side='right'caption='[[3ogc]], [[Resolution|resolution]] 3.80Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[3ogc]] 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=3OGC OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3OGC FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[3ogc]] 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=3OGC OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3OGC FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=NA:SODIUM+ION'>NA</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]] 3.8Å</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=NA:SODIUM+ION'>NA</scene></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=3ogc FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ogc OCA], [http://pdbe.org/3ogc PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3ogc RCSB], [http://www.ebi.ac.uk/pdbsum/3ogc PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=3ogc 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=3ogc FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ogc OCA], [https://pdbe.org/3ogc PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3ogc RCSB], [https://www.ebi.ac.uk/pdbsum/3ogc PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3ogc 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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| | ==See Also== | | ==See Also== |
| - | *[[3D structures of antibody|3D structures of antibody]] | + | *[[Antibody 3D structures|Antibody 3D structures]] |
| | + | *[[3D structures of non-human antibody|3D structures of non-human antibody]] |
| | == 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 G]] | + | [[Category: Streptomyces lividans]] |
| - | [[Category: Nimigean, C M]] | + | [[Category: McCoy JG]] |
| - | [[Category: Antibody fab complex]] | + | [[Category: Nimigean CM]] |
| - | [[Category: Membrane protein]]
| + | |
| - | [[Category: Voltage-gated 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
Structures of the prokaryotic K(+) channel, KcsA, highlight the role of the selectivity filter carbonyls from the GYG signature sequence in determining a highly selective pore, but channels displaying this sequence vary widely in their cation selectivity. Furthermore, variable selectivity can be found within the same channel during a process called C-type inactivation. We investigated the mechanism for changes in selectivity associated with inactivation in a model K(+) channel, KcsA. We found that E71A, a noninactivating KcsA mutant in which a hydrogen-bond behind the selectivity filter is disrupted, also displays decreased K(+) selectivity. In E71A channels, Na(+) permeates at higher rates as seen with and flux measurements and analysis of intracellular Na(+) block. Crystal structures of E71A reveal that the selectivity filter no longer assumes the "collapsed," presumed inactivated, conformation in low K(+), but a "flipped" conformation, that is also observed in high K(+), high Na(+), and even Na(+) only conditions. The data reveal the importance of the E71-D80 interaction in both favoring inactivation and maintaining high K(+) selectivity. We propose a molecular mechanism by which inactivation and K(+) selectivity are linked, a mechanism that may also be at work in other channels containing the canonical GYG signature sequence.
Mechanism for selectivity-inactivation coupling in KcsA potassium channels.,Cheng WW, McCoy JG, Thompson AN, Nichols CG, Nimigean CM Proc Natl Acad Sci U S A. 2011 Mar 29;108(13):5272-7. Epub 2011 Mar 14. PMID:21402935[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
- ↑ Cheng WW, McCoy JG, Thompson AN, Nichols CG, Nimigean CM. Mechanism for selectivity-inactivation coupling in KcsA potassium channels. Proc Natl Acad Sci U S A. 2011 Mar 29;108(13):5272-7. Epub 2011 Mar 14. PMID:21402935 doi:10.1073/pnas.1014186108
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