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Updated: Jun 20, 2026

A G-quadruplex DNA-affinity Approach for Purification of Enzymatically Active G4 Resolvase1
Published on: March 18, 2017
Property of cold inducible DEAD-box RNA helicase in hyperthermophilic archaea
Yoko Shimada1, Wakao Fukuda, Yohei Akada
1Department of Bioscience, Graduate School of Science and Technology, Kwansei-Gakuin University, 2-1 Gakuen, Sanda, Hyogo, Japan.
Abstract:
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 degrees C than at 85 degrees C and 93 degrees C in both logarithmic and stationary phases. Immunoblot analyses revealed that Tk-DeaD was detected only in logarithmic-phase cells cultivated at 60 degrees C but hardly detected at 85 degrees C and 93 degrees C in both phases. Tk-DeaD expression is, hence, post-transcriptionally regulated and appears under vigorous growth conditions at 60 degrees C. Recombinant Tk-DeaD purified to homogeneity started to unfold at 20 degrees C, fully unfolded at 70 degrees C, and exhibited maximal ATPase activity and unwinding activity specific for single-strand paired RNA at 50 degrees C, which is lower than the growth limit of T. kodakaraensis.
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