The protective effect of osmoprotectant TMAO on bacterial mechanosensitive channels of small conductance MscS/MscK under high hydrostatic pressure.
Activity of the bacterial mechanosensitive channels of small conductance MscS/MscK of E. coli was investigated under high hydrostatic pressure (HHP) using the "flying-patch" patch-clamp technique. The channels were gated by negative pipette voltage and their open probability was measured at HHP of 0.1 to 80 MPa. The channel open probability decreased with increasing HHP. When the osmolyte methylamine N-oxide (TMAO) was applied to the cytoplasmic side of the inside-out excised membrane patches of E. coli giant spheroplasts the inhibitory effect of HHP on the channel activity was suppressed at pressures of up to 40 MPa. At 40 MPa and above the channel open probability decreased in a similar fashion with or without TMAO. Our study suggests that TMAO helps to counteract the effect of HHP up to 40 MPa on the MscS/MscK open state by "shielding" the cytoplasmic domain of the channels.
Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia. petrov67@gmail.com
Evgeny
E
Petrov
Paul R
PR
Rohde
Bruce
B
Cornell
Boris
B
Martinac
D002462:Cell Membrane / Q000378:metabolism; D055724:Electrophysiological Phenomena; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006874:Hydrostatic Pressure; D007473:Ion Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008744:Methylamines / Q000494:pharmacology*; D008958:Models, Molecular; D016877:Oxidants / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D013104:Spheroplasts / Q000187:drug effects*
D029968:Escherichia coli Proteins; D007473:Ion Channels; D008744:Methylamines; C469542:MscS protein, E coli; D016877:Oxidants; C005855:trimethyloxamine