Abstract
The crystal structure of an open form of the Escherichia coli MscS mechanosensitive channel was recently solved. However, the conformation of the closed state and the gating transition remain uncharacterized. The pore-lining transmembrane helix contains a conserved glycine- and alanine-rich motif that forms a helix-helix interface. We show that introducing 'knobs' on the smooth glycine face by replacing glycine with alanine, and substituting conserved alanines with larger residues, increases the pressure required for gating. Creation of a glycine-glycine interface lowers activation pressure. The importance of residues Gly104, Ala106 and Gly108, which flank the hydrophobic seal, is demonstrated. A new structural model is proposed for the closed-to-open transition that involves rotation and tilt of the pore-lining helices. Introduction of glycine at Ala106 validated this model by acting as a powerful suppressor of defects seen with mutations at Gly104 and Gly108.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 113-119 |
| Number of pages | 7 |
| Journal | Nature Structural and Molecular Biology |
| Volume | 12 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 20 2005 |
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ASJC Scopus subject areas
- Structural Biology
- Molecular Biology
Cite this
Pivotal role of the glycine-rich TM3 helix in gating the MscS mechanosensitive channel. / Edwards, Michelle D.; Li, Yuezhou; Kim, Sanguk; Miller, Samantha; Bartlett, Wendy; Black, Susan; Dennison, Sally; Iscla, Irene; Blount, Paul; Bowie, James U.; Booth, Ian R.
In: Nature Structural and Molecular Biology, Vol. 12, No. 2, 20.02.2005, p. 113-119.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Pivotal role of the glycine-rich TM3 helix in gating the MscS mechanosensitive channel
AU - Edwards, Michelle D.
AU - Li, Yuezhou
AU - Kim, Sanguk
AU - Miller, Samantha
AU - Bartlett, Wendy
AU - Black, Susan
AU - Dennison, Sally
AU - Iscla, Irene
AU - Blount, Paul
AU - Bowie, James U.
AU - Booth, Ian R.
PY - 2005/2/20
Y1 - 2005/2/20
N2 - The crystal structure of an open form of the Escherichia coli MscS mechanosensitive channel was recently solved. However, the conformation of the closed state and the gating transition remain uncharacterized. The pore-lining transmembrane helix contains a conserved glycine- and alanine-rich motif that forms a helix-helix interface. We show that introducing 'knobs' on the smooth glycine face by replacing glycine with alanine, and substituting conserved alanines with larger residues, increases the pressure required for gating. Creation of a glycine-glycine interface lowers activation pressure. The importance of residues Gly104, Ala106 and Gly108, which flank the hydrophobic seal, is demonstrated. A new structural model is proposed for the closed-to-open transition that involves rotation and tilt of the pore-lining helices. Introduction of glycine at Ala106 validated this model by acting as a powerful suppressor of defects seen with mutations at Gly104 and Gly108.
AB - The crystal structure of an open form of the Escherichia coli MscS mechanosensitive channel was recently solved. However, the conformation of the closed state and the gating transition remain uncharacterized. The pore-lining transmembrane helix contains a conserved glycine- and alanine-rich motif that forms a helix-helix interface. We show that introducing 'knobs' on the smooth glycine face by replacing glycine with alanine, and substituting conserved alanines with larger residues, increases the pressure required for gating. Creation of a glycine-glycine interface lowers activation pressure. The importance of residues Gly104, Ala106 and Gly108, which flank the hydrophobic seal, is demonstrated. A new structural model is proposed for the closed-to-open transition that involves rotation and tilt of the pore-lining helices. Introduction of glycine at Ala106 validated this model by acting as a powerful suppressor of defects seen with mutations at Gly104 and Gly108.
UR - http://www.scopus.com/inward/record.url?scp=20144372892&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=20144372892&partnerID=8YFLogxK
U2 - 10.1038/nsmb895
DO - 10.1038/nsmb895
M3 - Article
C2 - 15665866
AN - SCOPUS:20144372892
VL - 12
SP - 113
EP - 119
JO - Nature Structural and Molecular Biology
JF - Nature Structural and Molecular Biology
SN - 1545-9993
IS - 2
ER -