TY - JOUR
T1 - Chimeras Reveal a Single Lipid-Interface Residue that Controls MscL Channel Kinetics as well as Mechanosensitivity
AU - Yang, Li Min
AU - Zhong, Dalian
AU - Blount, Paul
N1 - Funding Information:
The authors would like to acknowledge all of the scientists and rotating students that, in the near and distant past, initiated aspects of chimera projects within our laboratory. We would also like to thank Drs. Irene Iscla and Hannah Malcolm for helpful discussions and critical reading of the manuscript. This work was supported by grant I-1420 from the Welch Foundation, grant NNH08ZTT003N NRA from NASA, grant RP100146 from the Cancer Prevention & Research Institute of Texas, and grants AI080807 and GM061028 from the National Institutes of Health. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. L.Y. and D.Z. contributed equally to this work. D.Z. made the vast majority of the chimera constructs. L.Y. produced, analyzed, and interpreted the majority of the patch clamp traces; L.Y. also served as a mentor and teacher for D.Z. mastering electrophysiology, and both ultimately contributed to this aspect of the project. P.B. conceived of and supervised the project. All authors contributed to the writing of the paper.
PY - 2013
Y1 - 2013
N2 - MscL, the highly conserved bacterial mechanosensitive channel of large conductance, serves as an osmotic " emergency release valve," is among the best-studied mechanosensors, and is a paradigm of how a channel senses and responds to membrane tension. Although all homologs tested thus far encode channel activity, many show functional differences. We tested Escherichia coli and Staphylococcus aureus chimeras and found that the periplasmic region of the protein, particularly E. coli I49 and the equivalent S. aureus F47 at the periplasmic lipid-aqueous interface of the first transmembrane domain, drastically influences both the open dwell time and the threshold of channel opening. One mutant shows a severe hysteresis, confirming the importance of this residue in determining the energy barriers for channel gating. We propose that this site acts similarly to a spring for a clasp knife, adjusting the resistance for obtaining and stabilizing an open or closed channel structure.
AB - MscL, the highly conserved bacterial mechanosensitive channel of large conductance, serves as an osmotic " emergency release valve," is among the best-studied mechanosensors, and is a paradigm of how a channel senses and responds to membrane tension. Although all homologs tested thus far encode channel activity, many show functional differences. We tested Escherichia coli and Staphylococcus aureus chimeras and found that the periplasmic region of the protein, particularly E. coli I49 and the equivalent S. aureus F47 at the periplasmic lipid-aqueous interface of the first transmembrane domain, drastically influences both the open dwell time and the threshold of channel opening. One mutant shows a severe hysteresis, confirming the importance of this residue in determining the energy barriers for channel gating. We propose that this site acts similarly to a spring for a clasp knife, adjusting the resistance for obtaining and stabilizing an open or closed channel structure.
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U2 - 10.1016/j.celrep.2013.01.018
DO - 10.1016/j.celrep.2013.01.018
M3 - Article
C2 - 23416054
AN - SCOPUS:84874238162
SN - 2211-1247
VL - 3
SP - 520
EP - 527
JO - Cell Reports
JF - Cell Reports
IS - 2
ER -