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叶绿体H^+-ATP酶在平板脂双层上重组及其质子传导的研究

PROTON-CONDUCTIVITY OF CF_0-CF_1 RECONSTRUCTED INTO PLANAR LIPID BILAYER
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摘要 从菠菜(Spinacia oleracea Mill.)叶中分离获得H^+-ATP酶(CF_0-CF_1)复合体。将CF_0-CF_1重组于平板脂双层上,在电压钳位下,研究CF_0~CF_1的质子传导性能,观察到:(1)当CF_0-CF_1重组于平板脂双层上后,平板膜电阻由10~20GΩ立即下降到1GΩ左右。(2)溶液中蛋白质(CF_0-CF_1)浓度在2mg/L下可记录到单通道电流的涨落,单位电导约在5~10pS。(3)通道电流随膜两侧ΔpH变化而改变,在ΔpH为2~4时,膜电流随ΔpH增加而增大,在ΔpH为4.5时膜电流呈现回落。(4)质子传导抑制剂Dicyclohexyl-carbodiimide(DCCD)显示出迅速地且不可逆地阻断通道电流。(5)无金属离子的溶液中,跨膜(BLM)的ΔpH为3时,在0~+150mV钳位下,镁离子比钙离子所引起的CF_0-CF_1的通道电流要大得多。以上结果不仅表明CF_0-CF_1已成功地组装于人工膜上,而且也显示出镁离子直接参与了质子传导过程。 The proton conductable ATP synthase (CF0-CF1)is the key enzyme of energy conversion in the membrane of bacteria, mitochondria and chloroplast. In spite of a large body of studies, the structure and molecular mechanism of ATP synthases are still elusive. In order to learn the mechanism of ATP synthases, the authors used voltage-olamp technique to study the effect of different conditions on the proton conductance of F0-F1 into planar lipid bilayer membrane. The results obtained were as follows: (1) When CF0-CF1 was reconstructed into planar lipid bilayer membrane, the resistance decreased by 10 times. (2) Channel-like current was recorded at the low concentration of CF0-CF1 (protein 2 mg/L) in the solution. (3) In metal ion-free solution, the channel currents changed with the trans-membrane proton gradient (ApH). Under holding potential from 0 to + 150 mV, the stimulation of ApH on channel current increased with a rise in the ApH from 2 to 4, the stimulation of 4.5 ApH on channel current was weaker than that of ApH 4.0. (4) The proton conductance inhibitor, dicyclohexylcarbodiimide (DCCD), showed a rapid and irreversible inhibition effect on the channel current. (5) In metal ion-free solution (10 mmol/L Tris-HCl), when the ApH across the black lipid membrane (BLM) maintained at 3.0, the addition of Mg2+ caused a arger channel current of CF0-CF1 than the addition of Ca2+ , with holding potential from 0 to + 150 mV. The results indicated that reconstruction of CF0-CF1 was successful and Mg2+ was directly involved in the proton conductance pathways.
出处 《Acta Botanica Sinica》 CSCD 1997年第4期322-328,共7页 Acta Botanica Sinica(植物学报:英文版)
关键词 叶绿体 腺苷三磷酸 质子传导 平板脂双层 H+-ATPase complex, Proton conduction, Voltage-olamp, Planar lipid bilayer
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参考文献6

  • 1黄有国,第五届全国生物膜学术讨论会论文摘要集,1993年
  • 2施玉梁,生理学报,1991年,43卷,128页
  • 3吴少龙,植物生理学报,1989年,15卷,125页
  • 4杜子云,生物化学与生物物理学报,1988年,20卷,510页
  • 5程秋琛,植物生理学报,1986年,12卷,9页
  • 6卫瑾,植物生理学报,1984年,10卷,249页
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