Structural basis of the gating mechanism of the large-conductance mechanosensitive channel from Escherichia coli

Structural basis of the gating mechanism of the large-conductance mechanosensitive channel from Escherichia coli | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Structural basis of the gating mechanism of the large-conductance mechanosensitive channel from Escherichia coli Christos Pliotas, Katie Hardman, Joshua Wort, Qaiser Waheed, Xinyu Liu, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8844336/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract The mechanosensitive channel of large conductance (MscL) is a tension-gated, pore-forming protein that acts as a safety valve to protect bacteria from osmotic lysis. Escherichia coli MscL (EcMscL) was the first mechanosensitive channel discovered and subsequently served as a model system for understanding mechanical sensing, becoming one of the most decorated and well-studied systems. Despite extensive biophysical and functional characterisation spanning several decades, the precise mechanism of EcMscL gating has been poorly understood due to the lack of high-resolution structural information. Herein, we solved two EcMscL structures by cryoEM in the closed conformation in DMPC and DOPC lipid nanodiscs. Using PELDOR spectroscopy, we screened conditions and identified that in DSPC lipids, EcMscL open-like states are present within its conformational ensemble. We solved the structure in an expanded state by cryoEM, revealing an architecture with pore properties consistent with previous electrophysiology reports. By combining hydrogen-deuterium exchange mass spectrometry and molecular dynamics simulations, we investigated the dynamics of EcMscL gating in lipid bilayers, identifying sites involved in the closed-open transition. Combined, this has enabled us to inform on the elusive structural mechanism of EcMscL mechanosensitive channel function. Biological sciences/Structural biology/Electron microscopy/Cryoelectron microscopy Biological sciences/Biophysics/Membrane biophysics Full Text Additional Declarations There is NO Competing Interest. Supplementary Files VideoS1.mp4 Supplementary Video 1 - Gating transitions of EcMscL Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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