TY - JOUR
T1 - Single molecule FRET reveals pore size and opening mechanism of a mechano-sensitive ion channel
AU - Wang, Yong
AU - Liu, Yanxin
AU - DeBerg, Hannah A.
AU - Nomura, Takeshi
AU - Hoffman, Melinda Tonks
AU - Rohde, Paul R.
AU - Schulten, Klaus
AU - Martinac, Boris
AU - Selvin, Paul R.
PY - 2014/2/18
Y1 - 2014/2/18
N2 - The mechanosensitive channel of large conductance, which serves as a model system for mechanosensitive channels, has previously been crystallized in the closed form, but not in the open form. Ensemble measurements and electrophysiological sieving experiments show that the open-diameter of the channel pore is >25 Å, but the exact size and whether the conformational change follows a helix-tilt or barrel-stave model are unclear. Here we report measurements of the distance changes on liposome-reconstituted MscL transmembrane α-helices, using a 'virtual sorting' single-molecule fluorescence energy transfer. We observed directly that the channel opens via the helix-tilt model and the open pore reaches 2.8 nm in diameter. In addition, based on the measurements, we developed a molecular dynamics model of the channel structure in the open state which confirms our direct observations.
AB - The mechanosensitive channel of large conductance, which serves as a model system for mechanosensitive channels, has previously been crystallized in the closed form, but not in the open form. Ensemble measurements and electrophysiological sieving experiments show that the open-diameter of the channel pore is >25 Å, but the exact size and whether the conformational change follows a helix-tilt or barrel-stave model are unclear. Here we report measurements of the distance changes on liposome-reconstituted MscL transmembrane α-helices, using a 'virtual sorting' single-molecule fluorescence energy transfer. We observed directly that the channel opens via the helix-tilt model and the open pore reaches 2.8 nm in diameter. In addition, based on the measurements, we developed a molecular dynamics model of the channel structure in the open state which confirms our direct observations.
UR - http://www.scopus.com/inward/record.url?scp=84898741942&partnerID=8YFLogxK
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U2 - 10.7554/eLife.01834.001
DO - 10.7554/eLife.01834.001
M3 - Article
C2 - 24550255
AN - SCOPUS:84898741942
SN - 2050-084X
VL - 2014
JO - eLife
JF - eLife
IS - 3
M1 - e01834
ER -