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-Structure paper
タイトル | Mechanosensitive channel gating by delipidation. |
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ジャーナル・号・ページ | Proc Natl Acad Sci U S A, Vol. 118, Issue 33, Year 2021 |
掲載日 | 2021年8月17日 |
著者 | Vanessa Judith Flegler / Akiko Rasmussen / Karina Borbil / Lea Boten / Hsuan-Ai Chen / Hanna Deinlein / Julia Halang / Kristin Hellmanzik / Jessica Löffler / Vanessa Schmidt / Cihan Makbul / Christian Kraft / Rainer Hedrich / Tim Rasmussen / Bettina Böttcher / |
PubMed 要旨 | The mechanosensitive channel of small conductance (MscS) protects bacteria against hypoosmotic shock. It can sense the tension in the surrounding membrane and releases solutes if the pressure in the ...The mechanosensitive channel of small conductance (MscS) protects bacteria against hypoosmotic shock. It can sense the tension in the surrounding membrane and releases solutes if the pressure in the cell is getting too high. The membrane contacts MscS at sensor paddles, but lipids also leave the membrane and move along grooves between the paddles to reside as far as 15 Å away from the membrane in hydrophobic pockets. One sensing model suggests that a higher tension pulls lipids from the grooves back to the membrane, which triggers gating. However, it is still unclear to what degree this model accounts for sensing and what contribution the direct interaction of the membrane with the channel has. Here, we show that MscS opens when it is sufficiently delipidated by incubation with the detergent dodecyl-β-maltoside or the branched detergent lauryl maltose neopentyl glycol. After addition of detergent-solubilized lipids, it closes again. These results support the model that lipid extrusion causes gating: Lipids are slowly removed from the grooves and pockets by the incubation with detergent, which triggers opening. Addition of lipids in micelles allows lipids to migrate back into the pockets, which closes the channel even in the absence of a membrane. Based on the distribution of the aliphatic chains in the open and closed conformation, we propose that during gating, lipids leave the complex on the cytosolic leaflet at the height of highest lateral tension, while on the periplasmic side, lipids flow into gaps, which open between transmembrane helices. |
リンク | Proc Natl Acad Sci U S A / PubMed:34376558 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 2.3 - 3.9 Å |
構造データ | EMDB-12996, PDB-7onj: EMDB-12997, PDB-7onl: EMDB-13003, PDB-7oo0: EMDB-13006, PDB-7oo6: EMDB-13007, PDB-7oo8: EMDB-13008, PDB-7ooa: |
化合物 | ChemComp-PEE: ChemComp-LMT: ChemComp-AV0: ChemComp-HOH: ChemComp-PCW: |
由来 |
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キーワード | MEMBRANE PROTEIN / mechanosensitive channel / LMNG stack / delipidation / DDM / LMNG |