Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia.
Channels (Austin). 2012 Jul-Aug;6(4):262-71. doi: 10.4161/chan.20833. Epub 2012 Jul 1.
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.
使用“飞片”膜片钳技术研究了大肠杆菌细菌机械敏感小电导通道 MscS/MscK 在高压（HHP）下的活性。通道由负管电压门控，并在 0.1 至 80 MPa 的 HHP 下测量其开放概率。通道开放概率随 HHP 的增加而降低。当渗透压调节剂甲胺 N-氧化物（TMAO）施加到大肠杆菌巨大原生质体的外翻膜片的细胞质侧时，TMAO 在高达 40 MPa 的压力下抑制了 HHP 对通道活性的抑制作用。在 40 MPa 及以上，通道开放概率的降低方式与是否存在 TMAO 相似。我们的研究表明，TMAO 通过“屏蔽”通道的细胞质结构域，有助于在高达 40 MPa 的 HHP 下对抗 MscS/MscK 开放状态的影响。
