Correlating a protein structure with function of a bacterial mechanosensitive channel

Paul C. Moe, Gal Levin, Paul Blount

Research output: Contribution to journalArticle

78 Citations (Scopus)

Abstract

MscL, a mechanosensitive channel found in many bacteria, protects cells from hypotonic shock by reducing intracellular pressure through release of cytoplasmic osmolytes. First isolated from Escherichia coli, this protein has served as a model for how a protein senses and responds to membrane tension. Recently the structure of a functionally uncharacterized MscL homologue from Mycobacterium tuberculosis was solved by x-ray diffraction to a resolution of 3.5 Å. Here we demonstrate that the protein forms a functional MscL-like mechanosensitive channel in E. coli membranes and azolectin proteoliposomes. Furthermore, we show that M. tuberculosis MscL crystals, when re-solubilized and reconstituted, yield wild-type channel currents in patch clamp, demonstrating that the protein does not irreversibly change conformation upon crystallization. Finally, we apply functional clues acquired from the E. coli MscL to the M. tuberculosis channel and show a mechanistic correlation between these channels. However, the inability of the M. tuberculosis channel to gate at physiological membrane tensions, demonstrated by in vivo E. coli expression and in vitro reconstitution, suggests that the membrane environment or other additional factors influence the gating of this channel.

Original languageEnglish (US)
Pages (from-to)31121-31127
Number of pages7
JournalJournal of Biological Chemistry
Volume275
Issue number40
StatePublished - Oct 6 2000

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Mycobacterium tuberculosis
Escherichia coli
Membranes
Proteins
Escherichia coli Proteins
Osmotic Pressure
Clamping devices
Crystallization
Conformations
Bacteria
Diffraction
X-Rays
Pressure
X rays
Crystals

ASJC Scopus subject areas

  • Biochemistry

Cite this

Correlating a protein structure with function of a bacterial mechanosensitive channel. / Moe, Paul C.; Levin, Gal; Blount, Paul.

In: Journal of Biological Chemistry, Vol. 275, No. 40, 06.10.2000, p. 31121-31127.

Research output: Contribution to journalArticle

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