Loss-of-Function Mutations at the Rim of the Funnel of Mechanosensitive Channel MscL

Kenjiro Yoshimura, Takeshi Nomura, Masahiro Sokabe

Research output: Contribution to journalArticle

57 Citations (Scopus)

Abstract

MscL is a bacterial mechanosensitive channel that is activated directly by membrane stretch. Although the gene has been cloned and the crystal structure of the closed channel has been defined, how membrane tension causes conformational changes in MscL remains largely unknown. To identify the site where MscL senses membrane tension, we examined the function of the mutants generated by random and scanning mutagenesis. In vitro (patch-clamp) and in vivo (hypoosmotic-shock) experiments showed that when a hydrophilic amino acid replaces one of the hydrophobic residues that are thought to make contact with the membrane lipid near the periplasmic end of the M1 or M2 transmembrane domain, MscL loses the ability to open in response to membrane tension. Hydrophilic (asparagine) substitution of the other residues in the lipid-protein interface did not impair the channel's mechanosensitivity. These observations suggest that the disturbance of the hydrophobic interaction between the membrane lipid and the periplasmic rim of the channel's funnel impairs the function of MscL.

Original languageEnglish
Pages (from-to)2113-2120
Number of pages8
JournalBiophysical Journal
Volume86
Issue number4
Publication statusPublished - 2004 Apr
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics

Cite this

Loss-of-Function Mutations at the Rim of the Funnel of Mechanosensitive Channel MscL. / Yoshimura, Kenjiro; Nomura, Takeshi; Sokabe, Masahiro.

In: Biophysical Journal, Vol. 86, No. 4, 04.2004, p. 2113-2120.

Research output: Contribution to journalArticle

Yoshimura, Kenjiro ; Nomura, Takeshi ; Sokabe, Masahiro. / Loss-of-Function Mutations at the Rim of the Funnel of Mechanosensitive Channel MscL. In: Biophysical Journal. 2004 ; Vol. 86, No. 4. pp. 2113-2120.
@article{b759daa0ab4742ef93b68707c1f3a48a,
title = "Loss-of-Function Mutations at the Rim of the Funnel of Mechanosensitive Channel MscL",
abstract = "MscL is a bacterial mechanosensitive channel that is activated directly by membrane stretch. Although the gene has been cloned and the crystal structure of the closed channel has been defined, how membrane tension causes conformational changes in MscL remains largely unknown. To identify the site where MscL senses membrane tension, we examined the function of the mutants generated by random and scanning mutagenesis. In vitro (patch-clamp) and in vivo (hypoosmotic-shock) experiments showed that when a hydrophilic amino acid replaces one of the hydrophobic residues that are thought to make contact with the membrane lipid near the periplasmic end of the M1 or M2 transmembrane domain, MscL loses the ability to open in response to membrane tension. Hydrophilic (asparagine) substitution of the other residues in the lipid-protein interface did not impair the channel's mechanosensitivity. These observations suggest that the disturbance of the hydrophobic interaction between the membrane lipid and the periplasmic rim of the channel's funnel impairs the function of MscL.",
author = "Kenjiro Yoshimura and Takeshi Nomura and Masahiro Sokabe",
year = "2004",
month = "4",
language = "English",
volume = "86",
pages = "2113--2120",
journal = "Biophysical Journal",
issn = "0006-3495",
publisher = "Biophysical Society",
number = "4",

}

TY - JOUR

T1 - Loss-of-Function Mutations at the Rim of the Funnel of Mechanosensitive Channel MscL

AU - Yoshimura, Kenjiro

AU - Nomura, Takeshi

AU - Sokabe, Masahiro

PY - 2004/4

Y1 - 2004/4

N2 - MscL is a bacterial mechanosensitive channel that is activated directly by membrane stretch. Although the gene has been cloned and the crystal structure of the closed channel has been defined, how membrane tension causes conformational changes in MscL remains largely unknown. To identify the site where MscL senses membrane tension, we examined the function of the mutants generated by random and scanning mutagenesis. In vitro (patch-clamp) and in vivo (hypoosmotic-shock) experiments showed that when a hydrophilic amino acid replaces one of the hydrophobic residues that are thought to make contact with the membrane lipid near the periplasmic end of the M1 or M2 transmembrane domain, MscL loses the ability to open in response to membrane tension. Hydrophilic (asparagine) substitution of the other residues in the lipid-protein interface did not impair the channel's mechanosensitivity. These observations suggest that the disturbance of the hydrophobic interaction between the membrane lipid and the periplasmic rim of the channel's funnel impairs the function of MscL.

AB - MscL is a bacterial mechanosensitive channel that is activated directly by membrane stretch. Although the gene has been cloned and the crystal structure of the closed channel has been defined, how membrane tension causes conformational changes in MscL remains largely unknown. To identify the site where MscL senses membrane tension, we examined the function of the mutants generated by random and scanning mutagenesis. In vitro (patch-clamp) and in vivo (hypoosmotic-shock) experiments showed that when a hydrophilic amino acid replaces one of the hydrophobic residues that are thought to make contact with the membrane lipid near the periplasmic end of the M1 or M2 transmembrane domain, MscL loses the ability to open in response to membrane tension. Hydrophilic (asparagine) substitution of the other residues in the lipid-protein interface did not impair the channel's mechanosensitivity. These observations suggest that the disturbance of the hydrophobic interaction between the membrane lipid and the periplasmic rim of the channel's funnel impairs the function of MscL.

UR - http://www.scopus.com/inward/record.url?scp=1942423623&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=1942423623&partnerID=8YFLogxK

M3 - Article

C2 - 15041651

AN - SCOPUS:1942423623

VL - 86

SP - 2113

EP - 2120

JO - Biophysical Journal

JF - Biophysical Journal

SN - 0006-3495

IS - 4

ER -