UniProt functional annotation for O29238

UniProt code: O29238.

Organism: Archaeoglobus fulgidus (strain ATCC 49558 / VC-16 / DSM 4304 / JCM 9628 / NBRC 100126).
Taxonomy: Archaea; Euryarchaeota; Archaeoglobi; Archaeoglobales; Archaeoglobaceae; Archaeoglobus.
Function: Modifies the topological state of DNA by introducing positive supercoils in an ATP-dependent process. It cleaves transiently a single DNA strand and remains covalently bound to the 5' DNA end through a tyrosine residue. May be involved in rewinding the DNA strands in the regions of the chromosome that have opened up to allow transcription or replication.
Catalytic activity: ATP + H(2)O = ADP + phosphate.
Catalytic activity: ATP-dependent breakage, passage and rejoining of double-stranded DNA.
Cofactor: Magnesium. Binds two Mg(2+) per subunit (By similarity).
Subunit: Monomer.
Domain: Both the DNA unwinding and positive supercoiling activities require the cooperation of both domains. The cooperative action between the helicase-like and the topoisomerase domains is specific. The helicase-like domain probably does not directly unwind DNA but acts more likely by driving ATP-dependent conformational changes within the whole enzyme, functioning more like a protein motor. The "latch" region of the N-terminal domain plays a regulatory role in the enzyme, repressing topoisomerase activity in the absence of ATP and therefore preventing the enzyme from acting as an ATP-independent relaxing enzyme; it also helps to coordinate nucleotide hydrolysis by the ATPase domain with the supercoiling activity of the topoisomerase domain.
Miscellaneous: This enzyme is the only unique feature of hyperthermophilic bacteria/archaea discovered so far. It appears to be essential for adaptation to life at high temperatures.
Similarity: In the N-terminal section; belongs to the DEAD box helicase family. DDVD subfamily.
Similarity: In the C-terminal section; belongs to the prokaryotic type I/III topoisomerase family.
Similarity: Contains 1 helicase ATP-binding domain.
Similarity: Contains 1 Toprim domain.

Annotations taken from UniProtKB at the EBI.