Property of cold inducible DEAD-box RNA helicase in hyperthermophilic archaea.
Property of cold inducible DEAD-box RNA helicase in hyperthermophilic archaea.
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DOI：
10.1016/j.bbrc.2009.09.038
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发表时间：
2009-11
影响因子：
3.1
通讯作者：
Y. Shimada;Wakao Fukuda;Yohei Akada;Mayumi Ishida;J. Nakayama;T. Imanaka;S. Fujiwara
中科院分区：
文献类型：
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作者：
Y. Shimada;Wakao Fukuda;Yohei Akada;Mayumi Ishida;J. Nakayama;T. Imanaka;S. Fujiwara
Kodakaraensis的TK0306(TK-Dead)基因被注释为DEAD-box解旋酶基因；然而，它的同源基因在通常生长温度高于T.kodakarasis的近缘属中尚未被鉴定，这表明TK-Dead的冷诱导RNA解旋酶在冷胁迫条件下发挥作用。定量RT-PCR结果显示，TK-DEAD在对数和稳定期均以60℃转录为主，85℃和93℃转录较差。免疫印迹分析表明，TK-DEAD仅在60℃培养的对数生长期细胞中检测到，而在85℃和93℃培养的对数生长期细胞中几乎检测不到TK-Dead。因此，TK-DEAD的表达是转录后调控的，并在60℃的旺盛生长条件下出现。纯化到均一的重组TK-DEAD在20℃开始展开，在70℃完全展开，并在50℃显示出最大的ATPase活性和单链对RNA的解离活性，低于kodakaraensis的生长极限。
TK0306 (Tk-DeaD) of hyperthermophilic archaeon Thermococcus kodakaraensis is annotated as the DEAD-box helicase gene; nevertheless, its ortholog has not been identified in closely related genera, Pyrococcus spp., which generally grow at higher temperature than T. kodakaraensis, suggesting that the cold-inducible RNA helicase of Tk-DeaD functions under cold stress conditions. Quantitative RT-PCR revealed that Tk-deaD was more dominantly transcribed at 60°C than at 85°C and 93°C in both logarithmic and stationary phases. Immunoblot analyses revealed that Tk-DeaD was detected only in logarithmic-phase cells cultivated at 60°C but hardly detected at 85°C and 93°C in both phases. Tk-DeaD expression is, hence, post-transcriptionally regulated and appears under vigorous growth conditions at 60°C. Recombinant Tk-DeaD purified to homogeneity started to unfold at 20°C, fully unfolded at 70°C, and exhibited maximal ATPase activity and unwinding activity specific for single-strand paired RNA at 50°C, which is lower than the growth limit of T. kodakaraensis.