CHANNELS, RECEPTORS, AND ELECTRICAL SIGNALING |
Confirming the Revised C-terminal Domain of the MscL Crystal Structure
Joshua A. Maurer 1*, Donald E. Elmore 2, Daniel Clayton 3, Li Xiong 2, Henry A. Lester 4 and Dennis A. Dougherty 4
1 Washington Univeristy
2 Wellesley College
3 California Institute of Technology
4 California Institution of Technology
* To whom correspondence should be addressed. E-mail: maurer{at}wustl.edu.
Submitted on December 6, 2007
Revised on January 22, 2008
Accepted on 23 January 2008
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Abstract |
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The structure of the C-terminal domain of the mechanosensitive channel of large conductance (MscL) has generated significant controversy. As a result, several structures have been proposed for this region: the original crystal structure (1MSL) of the M. tuberculosis homologue (Tb), a model of the E. coli homologue (Ec), and most recently a revised crystal structure of Tb-MscL (2OAR). In order to understand which of these structures represents a physiological conformation, we measured the impact of mutations to the C-terminal domain on the thermal stability of Tb-MscL using circular dichroism and performed molecular dynamics simulations of the original and the revised crystal structures of Tb-MscL. Our results imply that this region is helical and adopts an 
-helical bundle conformation similar to that observed in the Ec-MscL model and the revised Tb-MscL crystal structure.
Key Words:
Circular Dichroism, Ion Channels, Mechanosensation, Molecular Dynamics, MscL, Structural Verification
