Chimeras Reveal a Single Lipid-Interface Residue that Controls MscL Channel Kinetics as well as Mechanosensitivity

Li Min Yang, Dalian Zhong, Paul Blount

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)520-527
Number of pages8
JournalCell Reports
Volume3
Issue number2
DOIs
StatePublished - Feb 15 2013

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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