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| | ==Mechanosensitive Channel of Small Conductance (MscS)== | | ==Mechanosensitive Channel of Small Conductance (MscS)== |
| - | <StructureSection load='2oau' size='340' side='right' caption='[[2oau]], [[Resolution|resolution]] 3.70Å' scene=''> | + | <StructureSection load='2oau' size='340' side='right'caption='[[2oau]], [[Resolution|resolution]] 3.70Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[2oau]] is a 7 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_coli"_migula_1895 "bacillus coli" migula 1895]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=1mxm 1mxm]. The November 2008 RCSB PDB [http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/index.html Molecule of the Month] feature on ''Mechanosensitive Channels'' by David Goodsell is [http://dx.doi.org/10.2210/rcsb_pdb/mom_2008_11 10.2210/rcsb_pdb/mom_2008_11]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2OAU OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2OAU FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[2oau]] is a 7 chain structure with sequence from [https://en.wikipedia.org/wiki/"bacillus_coli"_migula_1895 "bacillus coli" migula 1895]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=1mxm 1mxm]. The November 2008 RCSB PDB [https://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/index.html Molecule of the Month] feature on ''Mechanosensitive Channels'' by David Goodsell is [https://dx.doi.org/10.2210/rcsb_pdb/mom_2008_11 10.2210/rcsb_pdb/mom_2008_11]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2OAU OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2OAU FirstGlance]. <br> |
| - | </td></tr><tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">mscS ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 "Bacillus coli" Migula 1895])</td></tr> | + | </td></tr><tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">mscS ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 "Bacillus coli" Migula 1895])</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=2oau FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2oau OCA], [http://pdbe.org/2oau PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=2oau RCSB], [http://www.ebi.ac.uk/pdbsum/2oau PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=2oau 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=2oau FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2oau OCA], [https://pdbe.org/2oau PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2oau RCSB], [https://www.ebi.ac.uk/pdbsum/2oau PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2oau ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/MSCS_ECOLI MSCS_ECOLI]] Mechanosensitive channel that participates in the regulation of osmotic pressure changes within the cell, opening in response to stretch forces in the membrane lipid bilayer, without the need for other proteins. Forms an ion channel of 1.0 nanosiemens conductance with a slight preference for anions. The channel is sensitive to voltage; as the membrane is depolarized, less tension is required to open the channel and vice versa. The channel is characterized by short bursts of activity that last for a few seconds. The channel pore is formed by TM3 and the loop between TM2 and TM3. After a sharp turn at Gly-113, an alpha-helix (residues 114-127) is oriented nearly parallel to the plane of the putative lipid bilayer. On the intracellular side of the channel, the permeation pathway of MscS does not connect directly to the cytoplasm but instead opens to a large chamber that is connected to the cytoplasm. This chamber resembles a molecular filter that could serve to prescreen large molecules before they are allowed passage to the transmembrane pore. The TM1 and TM2 helices appear to be likely candidates for mediating the tension and voltage sensitivities of MscS. Gating requires large rearrangements of at least the C-terminus. | + | [[https://www.uniprot.org/uniprot/MSCS_ECOLI MSCS_ECOLI]] Mechanosensitive channel that participates in the regulation of osmotic pressure changes within the cell, opening in response to stretch forces in the membrane lipid bilayer, without the need for other proteins. Forms an ion channel of 1.0 nanosiemens conductance with a slight preference for anions. The channel is sensitive to voltage; as the membrane is depolarized, less tension is required to open the channel and vice versa. The channel is characterized by short bursts of activity that last for a few seconds. The channel pore is formed by TM3 and the loop between TM2 and TM3. After a sharp turn at Gly-113, an alpha-helix (residues 114-127) is oriented nearly parallel to the plane of the putative lipid bilayer. On the intracellular side of the channel, the permeation pathway of MscS does not connect directly to the cytoplasm but instead opens to a large chamber that is connected to the cytoplasm. This chamber resembles a molecular filter that could serve to prescreen large molecules before they are allowed passage to the transmembrane pore. The TM1 and TM2 helices appear to be likely candidates for mediating the tension and voltage sensitivities of MscS. Gating requires large rearrangements of at least the C-terminus. |
| | == Evolutionary Conservation == | | == Evolutionary Conservation == |
| | [[Image:Consurf_key_small.gif|200px|right]] | | [[Image:Consurf_key_small.gif|200px|right]] |
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| | ==See Also== | | ==See Also== |
| - | *[[Ion channels|Ion channels]] | + | *[[Ion channels 3D structures|Ion channels 3D structures]] |
| - | *[[Mechanosensitive channels: opening and closing|Mechanosensitive channels: opening and closing]]
| + | |
| | == References == | | == References == |
| | <references/> | | <references/> |
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| | </StructureSection> | | </StructureSection> |
| | [[Category: Bacillus coli migula 1895]] | | [[Category: Bacillus coli migula 1895]] |
| | + | [[Category: Large Structures]] |
| | [[Category: Mechanosensitive Channels]] | | [[Category: Mechanosensitive Channels]] |
| | [[Category: RCSB PDB Molecule of the Month]] | | [[Category: RCSB PDB Molecule of the Month]] |
| Structural highlights
Function
[MSCS_ECOLI] Mechanosensitive channel that participates in the regulation of osmotic pressure changes within the cell, opening in response to stretch forces in the membrane lipid bilayer, without the need for other proteins. Forms an ion channel of 1.0 nanosiemens conductance with a slight preference for anions. The channel is sensitive to voltage; as the membrane is depolarized, less tension is required to open the channel and vice versa. The channel is characterized by short bursts of activity that last for a few seconds. The channel pore is formed by TM3 and the loop between TM2 and TM3. After a sharp turn at Gly-113, an alpha-helix (residues 114-127) is oriented nearly parallel to the plane of the putative lipid bilayer. On the intracellular side of the channel, the permeation pathway of MscS does not connect directly to the cytoplasm but instead opens to a large chamber that is connected to the cytoplasm. This chamber resembles a molecular filter that could serve to prescreen large molecules before they are allowed passage to the transmembrane pore. The TM1 and TM2 helices appear to be likely candidates for mediating the tension and voltage sensitivities of MscS. Gating requires large rearrangements of at least the C-terminus.
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
The mechanosensitive channel of small conductance (MscS) responds both to stretching of the cell membrane and to membrane depolarization. The crystal structure at 3.9 angstroms resolution demonstrates that Escherichia coli MscS folds as a membrane-spanning heptamer with a large cytoplasmic region. Each subunit contains three transmembrane helices (TM1, -2, and -3), with the TM3 helices lining the pore, while TM1 and TM2, with membrane-embedded arginines, are likely candidates for the tension and voltage sensors. The transmembrane pore, apparently captured in an open state, connects to a large chamber, formed within the cytoplasmic region, that connects to the cytoplasm through openings that may function as molecular filters. Although MscS is likely to be structurally distinct from other ion channels, similarities in gating mechanisms suggest common structural elements.
Crystal structure of Escherichia coli MscS, a voltage-modulated and mechanosensitive channel.,Bass RB, Strop P, Barclay M, Rees DC Science. 2002 Nov 22;298(5598):1582-7. PMID:12446901[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Bass RB, Strop P, Barclay M, Rees DC. Crystal structure of Escherichia coli MscS, a voltage-modulated and mechanosensitive channel. Science. 2002 Nov 22;298(5598):1582-7. PMID:12446901 doi:10.1126/science.1077945
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