Total chemical synthesis and electrophysiological characterization of mechanosensitive channels from Escherichia coli and Mycobacterium tuberculosis.
Total chemical protein synthesis was used to generate multimilligram quantities of the mechanosensitive channel of large conductance from Escherichia coli (Ec-MscL) and Mycobacterium tuberculosis (Tb-MscL). Cysteine residues introduced to allow chemical ligation were masked with cysteine-reactive molecules, resulting in side chain functional groups similar to those of the wild-type protein. Synthetic channel proteins were transferred to 2,2,2-trifluoroethanol and reconstituted into vesicle membranes. Fluorescent imaging of vesicles showed that channel proteins were membrane-localized. Single-channel recordings showed that reconstituted synthetic Ec-MscL has conductance, pressure dependence, and substate distribution similar to those of the recombinant channel. Reconstituted synthetic Tb-MscL also displayed conductance and pressure dependence similar to that of the recombinant protein. Possibilities for the incorporation of unnatural amino acids and biophysical probes, and applications of such synthetic ion channel analogs, are discussed.
Clayton
Daniel
D
Gryphon Therapeutics, 600 Gateway Boulevard, South San Francisco, CA 94080, USA.
Shapovalov
George
G
Maurer
Joshua A
JA
Dougherty
Dennis A
DA
Lester
Henry A
HA
Kochendoerfer
Gerd G
GG
D004578:Electron Spin Resonance Spectroscopy; D004926:Escherichia coli / Q000502:physiology*; D007473:Ion Channels / Q000138:chemical synthesis* / Q000502:physiology; D009169:Mycobacterium tuberculosis / Q000502:physiology*
D007473:Ion Channels