A structural mechanism for MscS gating in lipid bilayers

Valeria Vásquez, Marcos Sotomayor, Julio Cordero-Morales, Klaus Schulten, Eduardo Perozo

Research output: Contribution to journalArticlepeer-review

Abstract

The mechanosensitive channel of small conductance (MscS) is a key determinant in the prokaryotic response to osmotic challenges. We determined the structural rearrangements associated with MscS activation in membranes, using functorial measurements, electron paramagnetic resonance spectroscopy, and computational analyses. MscS was trapped in its open conformation after the transbilayer pressure profile was modified through the asymmetric incorporation of lysophospholipids. The transition from the closed to the open state is accompanied by the downward tilting of the transmembrane TM1-TM2 hairpin and by the expansion, tilt, and rotation of the TM3 helices. These movements expand the permeation pathway, leading to an increase in accessibility to water around TM3. Our open MscS model is compatible with single-channel conductance measurements and supports the notion that helix tilting is associated with efficient pore widening in mechanosensitive channels.

Original languageEnglish (US)
Pages (from-to)1210-1214
Number of pages5
JournalScience
Volume321
Issue number5893
DOIs
StatePublished - Aug 29 2008

ASJC Scopus subject areas

  • General

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