| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Biophys J, July 2002, p. 290-298, Vol. 83, No. 1
Department of Biology, University of Maryland, College Park, Maryland 20742 USA
The small mechanosensitive channel, MscS, is a part of
the turgor-driven solute efflux system that protects bacteria from lysis in the event of osmotic downshift. It has been identified in
Escherichia coli as a product of the orphan
yggB gene, now called mscS (Levina et
al., 1999, EMBO J. 18:1730). Here I show that that the
isolated 31-kDa MscS protein is sufficient to form a functional
mechanosensitive channel gated directly by tension in the lipid
bilayer. MscS-6His complexes purified in the presence of octylglucoside
and lipids migrate in a high-resolution gel-filtration column as
particles of ~200 kDa. Consistent with that, the protein cross-linking patterns predict a hexamer. The channel reconstituted in
soybean asolectin liposomes was activated by pressures of 20-60 mm Hg
and displayed the same asymmetric I-V curve and slight anionic preference as in situ. At the same time, the single-channel conductance is proportional to the buffer conductivity in a wide range of salt
concentrations. The rate of channel activation in response to
increasing pressure gradient across the patch was slower than the rate
of closure in response to decreasing steps of pressure gradient.
Therefore, the open probability curves were recorded with descending
series of pressures. Determination of the curvature of patches by video
imaging permitted measurements of the channel activity as a function of
membrane tension (
). Po() curves had the midpoint
at 5.5 ± 0.1 dyne/cm and gave estimates for the energy of opening
G = 11.4 ± 0.5 kT, and the
transition-related area change A = 8.4 ± 0.4 nm2 when fitted with a two-state Boltzmann model. The
correspondence between channel properties in the native and
reconstituted systems is discussed.
Biophys J, July 2002, p. 290-298, Vol. 83, No. 1
© 2002 by the Biophysical Society 0006-3495/02/07/290/09 $2.00
This article has been cited by other articles:
 |
|
 |
|
  W. Wang, S. S. Black, M. D. Edwards, S. Miller, E. L. Morrison, W. Bartlett, C. Dong, J. H. Naismith, and I. R. Booth The Structure of an Open Form of an E. coli Mechanosensitive Channel at 3.45 A Resolution Science, August 29, 2008; 321(5893): 1179 - 1183. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Anishkin, K. Kamaraju, and S. Sukharev Mechanosensitive Channel MscS in the Open State: Modeling of the Transition, Explicit Simulations, and Experimental Measurements of Conductance J. Gen. Physiol., July 1, 2008; 132(1): 67 - 83. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. D. Edwards, W. Bartlett, and I. R. Booth Pore Mutations of the Escherichia coli MscS Channel Affect Desensitization but Not Ionic Preference Biophys. J., April 15, 2008; 94(8): 3003 - 3013. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Nomura, M. Sokabe, and K. Yoshimura Interaction between the Cytoplasmic and Transmembrane Domains of the Mechanosensitive Channel MscS Biophys. J., March 1, 2008; 94(5): 1638 - 1645. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Anishkin, B. Akitake, and S. Sukharev Characterization of the Resting MscS: Modeling and Analysis of the Closed Bacterial Mechanosensitive Channel of Small Conductance Biophys. J., February 15, 2008; 94(4): 1252 - 1266. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Akitake, R. E. J. Spelbrink, A. Anishkin, J. A. Killian, B. de Kruijff, and S. Sukharev 2,2,2-Trifluoroethanol Changes the Transition Kinetics and Subunit Interactions in the Small Bacterial Mechanosensitive Channel MscS Biophys. J., April 15, 2007; 92(8): 2771 - 2784. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Sotomayor, V. Vasquez, E. Perozo, and K. Schulten Ion Conduction through MscS as Determined by Electrophysiology and Simulation Biophys. J., February 1, 2007; 92(3): 886 - 902. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Nomura, M. Sokabe, and K. Yoshimura Lipid-Protein Interaction of the MscS Mechanosensitive Channel Examined by Scanning Mutagenesis Biophys. J., October 15, 2006; 91(8): 2874 - 2881. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. A. Spronk, D. E. Elmore, and D. A. Dougherty Voltage-Dependent Hydration and Conduction Properties of the Hydrophobic Pore of the Mechanosensitive Channel of Small Conductance Biophys. J., May 15, 2006; 90(10): 3555 - 3569. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Sotomayor, T. A. van der Straaten, U. Ravaioli, and K. Schulten Electrostatic Properties of the Mechanosensitive Channel of Small Conductance MscS Biophys. J., May 15, 2006; 90(10): 3496 - 3510. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Akitake, A. Anishkin, and S. Sukharev The "Dashpot" Mechanism of Stretch-dependent Gating in MscS J. Gen. Physiol., January 31, 2005; 125(2): 143 - 154. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Anishkin, C.-S. Chiang, and S. Sukharev Gain-of-function Mutations Reveal Expanded Intermediate States and a Sequential Action of Two Gates in MscL J. Gen. Physiol., January 31, 2005; 125(2): 155 - 170. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Sotomayor and K. Schulten Molecular Dynamics Study of Gating in the Mechanosensitive Channel of Small Conductance MscS Biophys. J., November 1, 2004; 87(5): 3050 - 3065. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Yu. Noskov, W. Im, and B. Roux Ion Permeation through the {alpha}-Hemolysin Channel: Theoretical Studies Based on Brownian Dynamics and Poisson-Nernst-Plank Electrodiffusion Theory Biophys. J., October 1, 2004; 87(4): 2299 - 2309. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Shapovalov and H. A. Lester Gating Transitions in Bacterial Ion Channels Measured at 3 {micro}s Resolution J. Gen. Physiol., July 26, 2004; 124(2): 151 - 161. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. Martinac Mechanosensitive ion channels: molecules of mechanotransduction J. Cell Sci., May 15, 2004; 117(12): 2449 - 2460. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Anishkin and S. Sukharev Water Dynamics and Dewetting Transitions in the Small Mechanosensitive Channel MscS Biophys. J., May 1, 2004; 86(5): 2883 - 2895. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Miller, M. D. Edwards, C. Ozdemir, and I. R. Booth The Closed Structure of the MscS Mechanosensitive Channel: CROSS-LINKING OF SINGLE CYSTEINE MUTANTS J. Biol. Chem., August 22, 2003; 278(34): 32246 - 32250. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Shapovalov, R. Bass, D. C. Rees, and H. A. Lester Open-State Disulfide Crosslinking between Mycobacterium tuberculosis Mechanosensitive Channel Subunits Biophys. J., April 1, 2003; 84(4): 2357 - 2365. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Koprowski and A. Kubalski C Termini of the Escherichia coli Mechanosensitive Ion Channel (MscS) Move Apart upon the Channel Opening J. Biol. Chem., March 21, 2003; 278(13): 11237 - 11245. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Anishkin, V. Gendel, N. A. Sharifi, C.-S. Chiang, L. Shirinian, H. R. Guy, and S. Sukharev On the Conformation of the COOH-terminal Domain of the Large Mechanosensitive Channel MscL J. Gen. Physiol., February 24, 2003; 121(3): 227 - 244. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. B. Bass, P. Strop, M. Barclay, and D. C. Rees Crystal Structure of Escherichia coli MscS, a Voltage-Modulated and Mechanosensitive Channel Science, November 22, 2002; 298(5598): 1582 - 1587. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
