Electrostatics at the membrane define MscL channel mechanosensitivity and kinetics

Dalian Zhong, Paul Blount

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The bacterial mechanosensitive channel of large conductance (MscL) serves as a biological emergency release valve, preventing the occurrence of cell lysis caused by acute osmotic stress. Its tractable nature allows it to serve as a paradigm for how a protein can directly sense membrane tension. Although much is known of the importance of the hydrophobicity of specific residues in channel gating, it has remained unclear whether electrostatics at the membrane plays any role. We studied MscL chimeras derived from functionally distinct orthologues: Escherichia coli and Staphylococcus aureus. Dissection of one set led to an observation that changing the charge of a single residue, K101, of E. coli (Ec)-MscL, effects a channel phenotype: when mutated to a negative residue, the channel is less mechanosensitive and has longer open dwell times. Assuming electrostatic interactions, we determined whether they are due to protein - protein or protein - lipid interactions by performing site-directed mutagenesis elsewhere in the protein and reconstituting channels into defined lipids, with and without negative head groups. We found that although both interactions appear to play some role, the primary determinant of the channel phenotype seems to be protein-lipid electrostatics. The data suggest a model for the role of electrostatic interactions in the dynamics of MscL gating.

Original languageEnglish (US)
Pages (from-to)5234-5241
Number of pages8
JournalFASEB Journal
Volume28
Issue number12
DOIs
StatePublished - Dec 1 2014

Fingerprint

Static Electricity
Electrostatics
Membranes
Kinetics
Proteins
Coulomb interactions
Lipids
Escherichia coli
Phenotype
Dissection
Mutagenesis
Osmotic Pressure
Hydrophobicity
Site-Directed Mutagenesis
Hydrophobic and Hydrophilic Interactions
Staphylococcus aureus
Emergencies
Head
Observation

Keywords

  • Liposome reconstitution
  • Mechanosensation
  • Mechanosensory
  • Protein-lipid interactions

ASJC Scopus subject areas

  • Biochemistry
  • Biotechnology
  • Genetics
  • Molecular Biology

Cite this

Electrostatics at the membrane define MscL channel mechanosensitivity and kinetics. / Zhong, Dalian; Blount, Paul.

In: FASEB Journal, Vol. 28, No. 12, 01.12.2014, p. 5234-5241.

Research output: Contribution to journalArticle

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