Details

Autor(en) / Beteiligte

• Jamroze, Anmbreen
• Perugino, Giuseppe
• Valenti, Anna
• Rashid, Naeem
• Rossi, Mosè
• Akhtar, Muhammad
• Ciaramella, Maria

Titel

The Reverse Gyrase from Pyrobaculum calidifontis, a Novel Extremely Thermophilic DNA Topoisomerase Endowed with DNA Unwinding and Annealing Activities

Ist Teil von

• The Journal of biological chemistry, 2014-02, Vol.289 (6), p.3231-3243

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2014

Quelle

MEDLINE

Beschreibungen/Notizen

• Reverse gyrase is a DNA topoisomerase specific for hyperthermophilic bacteria and archaea. It catalyzes the peculiar ATP-dependent DNA-positive supercoiling reaction and might be involved in the physiological adaptation to high growth temperature. Reverse gyrase comprises an N-terminal ATPase and a C-terminal topoisomerase domain, which cooperate in enzyme activity, but details of its mechanism of action are still not clear. We present here a functional characterization of PcalRG, a novel reverse gyrase from the archaeon Pyrobaculum calidifontis. PcalRG is the most robust and processive reverse gyrase known to date; it is active over a wide range of conditions, including temperature, ionic strength, and ATP concentration. Moreover, it holds a strong ATP-inhibited DNA cleavage activity. Most important, PcalRG is able to induce ATP-dependent unwinding of synthetic Holliday junctions and ATP-stimulated annealing of unconstrained single-stranded oligonucleotides. Combined DNA unwinding and annealing activities are typical of certain helicases, but until now were shown for no other reverse gyrase. Our results suggest for the first time that a reverse gyrase shares not only structural but also functional features with evolutionary conserved helicase-topoisomerase complexes involved in genome stability. Background: The thermophilic DNA topoisomerase reverse gyrase induces DNA-positive supercoiling. Results: The novel reverse gyrase, PcalRG, is presented. Conclusion:PcalRG is the most efficient and robust reverse gyrase known, and the first inducing ATP-dependent unwinding of Holliday junctions and annealing of single-stranded oligonucleotides. Significance:PcalRG shares structural and functional features with evolutionary conserved helicase-topoisomerase complexes involved in genome stability.