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5aji

From Proteopedia

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Current revision

MscS D67R1 high resolution

Structural highlights

5aji is a 7 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.99Å
Ligands:	, , ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

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

The ability of proteins to sense membrane tension is pervasive in biology. A higher-resolution structure of the Escherichia coli small-conductance mechanosensitive channel MscS identifies alkyl chains inside pockets formed by the transmembrane helices (TMs). Purified MscS contains E. coli lipids, and fluorescence quenching demonstrates that phospholipid acyl chains exchange between bilayer and TM pockets. Molecular dynamics and biophysical analyses show that the volume of the pockets and thus the number of lipid acyl chains within them decreases upon channel opening. Phospholipids with one acyl chain per head group (lysolipids) displace normal phospholipids (with two acyl chains) from MscS pockets and trigger channel opening. We propose that the extent of acyl-chain interdigitation in these pockets determines the conformation of MscS. When interdigitation is perturbed by increased membrane tension or by lysolipids, the closed state becomes unstable, and the channel gates.

The role of lipids in mechanosensation.,Pliotas C, Dahl AC, Rasmussen T, Mahendran KR, Smith TK, Marius P, Gault J, Banda T, Rasmussen A, Miller S, Robinson CV, Bayley H, Sansom MS, Booth IR, Naismith JH Nat Struct Mol Biol. 2015 Nov 9. doi: 10.1038/nsmb.3120. PMID:26551077^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Pliotas C, Dahl AC, Rasmussen T, Mahendran KR, Smith TK, Marius P, Gault J, Banda T, Rasmussen A, Miller S, Robinson CV, Bayley H, Sansom MS, Booth IR, Naismith JH. The role of lipids in mechanosensation. Nat Struct Mol Biol. 2015 Nov 9. doi: 10.1038/nsmb.3120. PMID:26551077 doi:http://dx.doi.org/10.1038/nsmb.3120

1 Structural highlights
2 Function
3 Publication Abstract from PubMed
4 See Also
5 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/5aji"

Categories: Escherichia coli | Large Structures | Naismith JH | Pliotas C

@@ Line 4: / Line 4: @@
 == Structural highlights ==
 <table><tr><td colspan='2'>[[5aji]] is a 7 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5AJI OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5AJI FirstGlance]. <br>
-</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=D10:DECANE'>D10</scene>, <scene name='pdbligand=HEX:HEXANE'>HEX</scene>, <scene name='pdbligand=OCT:N-OCTANE'>OCT</scene>, <scene name='pdbligand=R1A:3-{[(2,2,5,5-TETRAMETHYL-1-OXO-2,5-DIHYDRO-1H-PYRROLIUM-3-YL)METHYL]DISULFANYL}-D-ALANINE'>R1A</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]] 2.99&#8491;</td></tr>
+<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=D10:DECANE'>D10</scene>, <scene name='pdbligand=HEX:HEXANE'>HEX</scene>, <scene name='pdbligand=OCT:N-OCTANE'>OCT</scene>, <scene name='pdbligand=R1A:3-{[(2,2,5,5-TETRAMETHYL-1-OXO-2,5-DIHYDRO-1H-PYRROLIUM-3-YL)METHYL]DISULFANYL}-D-ALANINE'>R1A</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=5aji FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5aji OCA], [https://pdbe.org/5aji PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5aji RCSB], [https://www.ebi.ac.uk/pdbsum/5aji PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5aji ProSAT]</span></td></tr>
 </table>

5aji

From Proteopedia

Current revision

MscS D67R1 high resolution

Structural highlights

Function

Publication Abstract from PubMed

See Also

References

Contents

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