Site-directed spin-labeling analysis of reconstituted MscL in the closed state

Perozo, E., Kloda, A., Cortes, D. M. and Martinac, B. (2001) Site-directed spin-labeling analysis of reconstituted MscL in the closed state. Journal of General Physiology, 118 2: 193-205. doi:10.1085/jgp.118.2.193

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Author Perozo, E.
Kloda, A.
Cortes, D. M.
Martinac, B.
Title Site-directed spin-labeling analysis of reconstituted MscL in the closed state
Journal name Journal of General Physiology   Check publisher's open access policy
ISSN 0022-1295
Publication date 2001
Sub-type Article (original research)
DOI 10.1085/jgp.118.2.193
Open Access Status File (Publisher version)
Volume 118
Issue 2
Start page 193
End page 205
Total pages 13
Place of publication New York
Publisher Rockefeller Univ Press
Language eng
Abstract The mechanosensitive channel fi-om Escherichia coli (Eco-MscL) responds to membrane lateral tension by opening a large, water-filled pore that serves as an osmotic safety valve. In an attempt to understand the structural dynamics of MscL in the closed state and under physiological conditions, we have performed a systematic site-directed spin labeling study of this channel reconstituted in a membrane bilayer. Structural information was derived from an analysis of probe mobility, residue accessibility to O-2 or NiEdda and overall intersubunit proximity. For the majority of the residues studied, mobility, and accessibility data showed a remarkable agreement with the Mycobacterium tuberculosis crystal structure, clearly identifying residues facing the large water-filled vestibule at the extracellular face of the molecule, the narrowest point along the permeation pathway (residues 21-26 of Eco-MscL), and the lipid-exposed residues in the peripheral transmembrane segments (TM2). Overall, the present dataset demonstrates that the transmembrane regions of the MscL crystal structure (obtained in detergent and at low pH) are, in general, an accurate representation of its structure in a membrane bilayer under physiological conditions. However, significant differences between the EPR data and the crystal structure were found toward the COOH-terminal end of TM2.
Keyword Physiology
mechanosensitive channel
solvent accessibility
dipolar coupling
transmembrane segments
Mechanosensitive Ion-channel
Functional Reconstitution
Lipid Bilayers
K+ Channel
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Biomedical Sciences Publications
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Citation counts: TR Web of Science Citation Count  Cited 70 times in Thomson Reuters Web of Science Article | Citations
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Created: Wed, 19 Sep 2007, 15:54:07 EST