Cold-active DnaK of an Antarctic psychrotroph Shewanella sp. Ac10 supporting the growth of dnaK-null mutant of Escherichia coli at cold temperatures
Cold-active DnaK of an Antarctic psychrotroph Shewanella sp. Ac10 supporting the growth of dnaK-null mutant of Escherichia coli at cold temperatures
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DOI：
10.1007/s00792-004-0429-9
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发表时间：
2005-04
期刊：
影响因子：
2.9
通讯作者：
K. Yoshimune;A. Galkin;Ljudmila Kulakova;T. Yoshimura;N. Esaki
中科院分区：
文献类型：
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作者：
K. Yoshimune;A. Galkin;Ljudmila Kulakova;T. Yoshimura;N. Esaki
希瓦内拉斯普。Ac10是一种从南极洲分离出来的嗜冷细菌，在0°C这样的低温下活跃生长。免疫印迹分析表明，热休克蛋白DnaK是由细菌在24°C诱导形成的，这比引起嗜温菌（如大肠杆菌）热休克的温度低得多。结果表明，在低温下，ShewanellaDnaK（SheDnaK）的ATP酶活性明显高于E.大肠杆菌（EcoDnaK）：冷活性酶的特征。重组SheDnaK基因既不支持adnaK缺失突变株的生长，也不支持AdnaK缺失突变株的生长。在43°C的大肠杆菌中也没有λ噬菌体在甚至更低的温度（30°C）下繁殖。然而，重组SheDnaK基因使E.在15°C下生长。这是第一个DnaK支持adnaK无效突变体在低温下生长的报告。
Shewanellasp. Ac10 is a psychrotrophic bacterium isolated from the Antarctica that actively grows at such low temperatures as 0°C. Immunoblot analyses showed that a heat-shock protein DnaK is inducibly formed by the bacterium at 24°C, which is much lower than the temperatures causing heat shock in mesophiles such asEscherichia coli. We found that theShewanellaDnaK (SheDnaK) shows much higher ATPase activity at low temperatures than the DnaK ofE. coli(EcoDnaK): a characteristic of a cold-active enzyme. The recombinant SheDnaK gene supported neither the growth of adnaK-null mutant ofE. coliat 43°C nor λ phage propagation at an even lower temperature, 30°C. However, the recombinant SheDnaK gene enabled theE. colimutant to grow at 15°C. This is the first report of a DnaK supporting the growth of adnaK-null mutant at low temperatures.