title: Streptomycin potency is dependent on MscL channel expression.
abstract: The antibiotic streptomycin is widely used in the treatment of microbial infections. The primary mechanism of action is inhibition of translation by binding to the ribosome, but how it enters the bacterial cell is unclear. Early in the study of this antibiotic, a mysterious streptomycin-induced potassium efflux preceding any decrease in viability was observed; it was speculated that this changed the electrochemical gradient such that streptomycin better accessed the cytoplasm. Here we use a high-throughput screen to search for compounds targeting the mechanosensitive channel of large conductance (MscL) and find dihydrostreptomycin among the 'hits'. Furthermore, we find that MscL is not only necessary for the previously described streptomycin-induced potassium efflux, but also directly increases MscL activity in electrophysiological studies. The data suggest that gating MscL is a novel mode of action of dihydrostreptomycin, and that MscL's large pore may provide a mechanism for cell entry.
authors.affiliation: Department of Physiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9040, USA.
authors.forename: Irene
authors.initials: I
authors.lastname: Iscla
authors.affiliation: Department of Physiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9040, USA.
authors.forename: Robin
authors.initials: R
authors.lastname: Wray
authors.affiliation: Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9038, USA.
authors.forename: Shuguang
authors.initials: S
authors.lastname: Wei
authors.affiliation: Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9038, USA.
authors.forename: Bruce
authors.initials: B
authors.lastname: Posner
authors.affiliation: Department of Physiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9040, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Blount
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004096:Dihydrostreptomycin Sulfate / Q000378:metabolism / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000187:drug effects* / Q000378:metabolism; D057166:High-Throughput Screening Assays; D007473:Ion Channels / Q000187:drug effects* / Q000378:metabolism; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism*; D000198:Spectinomycin / Q000494:pharmacology; D013307:Streptomycin / Q000378:metabolism / Q000494:pharmacology; D014756:Viomycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; D007473:Ion Channels; C086596:MscL protein, E coli; D000198:Spectinomycin; D011188:Potassium; D004096:Dihydrostreptomycin Sulfate; D013307:Streptomycin; D014756:Viomycin