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| | <SX load='6rld' size='340' side='right' viewer='molstar' caption='[[6rld]], [[Resolution|resolution]] 2.93Å' scene=''> | | <SX load='6rld' size='340' side='right' viewer='molstar' caption='[[6rld]], [[Resolution|resolution]] 2.93Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[6rld]] is a 7 chain structure with sequence from [http://en.wikipedia.org/wiki/Escherichia_coli_k-12 Escherichia coli k-12]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6RLD OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=6RLD FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[6rld]] is a 7 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_K-12 Escherichia coli K-12]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6RLD OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6RLD FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=PCW:1,2-DIOLEOYL-SN-GLYCERO-3-PHOSPHOCHOLINE'>PCW</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 2.93Å</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=6rld FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6rld OCA], [http://pdbe.org/6rld PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6rld RCSB], [http://www.ebi.ac.uk/pdbsum/6rld PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6rld ProSAT]</span></td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=PCW:1,2-DIOLEOYL-SN-GLYCERO-3-PHOSPHOCHOLINE'>PCW</scene></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=6rld FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6rld OCA], [https://pdbe.org/6rld PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6rld RCSB], [https://www.ebi.ac.uk/pdbsum/6rld PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6rld 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. |
| | <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 6rld" style="background-color:#fffaf0;"></div> | | <div class="pdbe-citations 6rld" style="background-color:#fffaf0;"></div> |
| | + | |
| | + | ==See Also== |
| | + | *[[Ion channels 3D structures|Ion channels 3D structures]] |
| | == References == | | == References == |
| | <references/> | | <references/> |
| | __TOC__ | | __TOC__ |
| | </SX> | | </SX> |
| - | [[Category: Escherichia coli k-12]] | + | [[Category: Escherichia coli K-12]] |
| | [[Category: Large Structures]] | | [[Category: Large Structures]] |
| - | [[Category: Boettcher, B]] | + | [[Category: Boettcher B]] |
| - | [[Category: Flegler, V J]] | + | [[Category: Flegler VJ]] |
| - | [[Category: Rasmussen, A]] | + | [[Category: Rasmussen A]] |
| - | [[Category: Rasmussen, T]] | + | [[Category: Rasmussen T]] |
| - | [[Category: Channel]]
| + | |
| - | [[Category: Mechanosensitive]]
| + | |
| - | [[Category: Membrane protein]]
| + | |
| 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.
Publication Abstract from PubMed
Since life has emerged, gradients of osmolytes over the cell membrane cause pressure changes in the cell and require tight regulation to prevent cell rupture. The mechanosensitive channel of small conductance (MscS) releases solutes and water when a hypo-osmotic shock raises the pressure in the cell. It is a member of a large family of MscS-like channels found in bacteria, archaea, fungi and plants and model for mechanosensation. MscS senses the increase of tension in the membrane directly by the force from the lipids, but the molecular mechanism is still elusive. We determined the lipid interactions of MscS by resolving the structure of Escherichia coli MscS embedded in membrane discs to 2.9-A resolution using cryo-electron microscopy. The membrane is attached only to parts of the sensor paddles of MscS, but phospholipid molecules move through grooves into remote pockets on the cytosolic side. On the periplasmic side, a lipid bound by R88 at the pore entrance is separated from the membrane by TM1 helices. The N-terminus interacts with the periplasmic membrane surface. We demonstrate that the unique membrane domain of MscS promotes deep penetration of lipid molecules and shows multimodal interaction with the membrane to fine-tune tension sensing.
Structure of the Mechanosensitive Channel MscS Embedded in the Membrane Bilayer.,Rasmussen T, Flegler VJ, Rasmussen A, Bottcher B J Mol Biol. 2019 Jul 7. pii: S0022-2836(19)30427-9. doi:, 10.1016/j.jmb.2019.07.006. PMID:31291591[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Rasmussen T, Flegler VJ, Rasmussen A, Bottcher B. Structure of the Mechanosensitive Channel MscS Embedded in the Membrane Bilayer. J Mol Biol. 2019 Jul 7. pii: S0022-2836(19)30427-9. doi:, 10.1016/j.jmb.2019.07.006. PMID:31291591 doi:http://dx.doi.org/10.1016/j.jmb.2019.07.006
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