UniProt functional annotation for O51934



	UniProt functional annotation for O51934

UniProt code: O51934.

Organism: Thermotoga maritima (strain ATCC 43589 / DSM 3109 / JCM 10099 / NBRC 100826 / MSB8).

Taxonomy: Bacteria; Thermotogae; Thermotogales; Thermotogaceae; Thermotoga.

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: Reaction=ATP + H2O = ADP + H(+) + phosphate; Xref=Rhea:RHEA:13065, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:30616, ChEBI:CHEBI:43474, ChEBI:CHEBI:456216; EC=3.6.4.12; Evidence={ECO:0000255|HAMAP-Rule:MF_01125};

Catalytic activity: Reaction=ATP-dependent breakage, passage and rejoining of double- stranded DNA.; EC=5.6.2.2; Evidence={ECO:0000255|HAMAP- Rule:MF_01125};

Cofactor: Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000255|HAMAP-Rule:MF_01125}; Note=Binds two Mg(2+) per subunit. {ECO:0000255|HAMAP-Rule:MF_01125};

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. {ECO:0000255|HAMAP-Rule:MF_01125}.

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. {ECO:0000255|HAMAP-Rule:MF_01125}.

Similarity: In the C-terminal section; belongs to the prokaryotic type I/III topoisomerase family. {ECO:0000255|HAMAP-Rule:MF_01125}.

Annotations taken from UniProtKB at the EBI.


Organism:		Thermotoga maritima (strain ATCC 43589 / DSM 3109 / JCM 10099 / NBRC 100826 / MSB8).
Taxonomy:		Bacteria; Thermotogae; Thermotogales; Thermotogaceae; Thermotoga.



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:		Reaction=ATP + H2O = ADP + H(+) + phosphate; Xref=Rhea:RHEA:13065, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:30616, ChEBI:CHEBI:43474, ChEBI:CHEBI:456216; EC=3.6.4.12; Evidence={ECO:0000255\|HAMAP-Rule:MF_01125};
Catalytic activity:		Reaction=ATP-dependent breakage, passage and rejoining of double- stranded DNA.; EC=5.6.2.2; Evidence={ECO:0000255\|HAMAP- Rule:MF_01125};
Cofactor:		Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000255\|HAMAP-Rule:MF_01125}; Note=Binds two Mg(2+) per subunit. {ECO:0000255\|HAMAP-Rule:MF_01125};
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. {ECO:0000255\|HAMAP-Rule:MF_01125}.
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. {ECO:0000255\|HAMAP-Rule:MF_01125}.
Similarity:		In the C-terminal section; belongs to the prokaryotic type I/III topoisomerase family. {ECO:0000255\|HAMAP-Rule:MF_01125}.