>TIGR01054 rgy reverse gyrase; InterPro: IPR005736 DNA topoisomerases regulate the number of topological links between two DNA strands (i.e. change the number of superhelical turns) by catalysing transient single- or double-strand breaks, crossing the strands through one another, then resealing the breaks. These enzymes have several functions: to remove DNA supercoils during transcription and DNA replication; for strand breakage during recombination; for chromosome condensation; and to disentangle intertwined DNA during mitosis , . DNA topoisomerases are divided into two classes: type I enzymes (5.99.1.2 from EC; topoisomerases I, III and V) break single-strand DNA, and type II enzymes (5.99.1.3 from EC; topoisomerases II, IV and VI) break double-strand DNA . Type I topoisomerases are ATP-independent enzymes (except for reverse gyrase), and can be subdivided according to their structure and reaction mechanisms: type IA (bacterial and archaeal topoisomerase I, topoisomerase III and reverse gyrase) and type IB (eukaryotic topoisomerase I and topoisomerase V). These enzymes are primarily responsible for relaxing positively and/or negatively supercoiled DNA, except for reverse gyrase, which can introduce positive supercoils into DNA. Reverse gyrase is a type IA topoisomerase that is unique among these enzymes in its requirement for ATP. Reverse gyrase is a hyperthermophile-specific enzyme that acts as a renaturase by positively supercoiling DNA, and by annealing complementary single-strand circles . Hyperthermophilic organisms must protect themselves against heat-induced degradation, and reverse gyrase acts to reduce the rate of double-strand DNA breakage, a function that does not require ATP hydrolysis and which is independent of its positive supercoiling abilities. Reverse gyrase achieves this by recognising nicked DNA and recruiting a protein coat to the site of damage . More information about this protein can be found at Protein of the Month: DNA Topoisomerase .; GO: 0003677 DNA binding, 0003916 DNA topoisomerase activity, 0006265 DNA topological change, 0006268 DNA unwinding during replication, 0005694 chromosome.

Probab=99.34  E-value=2.7e-10  Score=80.60  Aligned_cols=123  Identities=19%  Similarity=0.207  Sum_probs=92.9

Q ss_pred             HHHHHHHHHHCCCEEEEECCCCCHHHHHHHHHHHHHHCCCCCEEEEECCHHHHHHHHHHHHHHCCCCCCEE----EEEEC
Q ss_conf             99999999967980999588998689999999999975999499991604656999999998558888159----99858
Q gi|255764515|r    7 QTKIVDWILDHKRCAIWASMGSGKTVSVLTALSYIHLWGEKSVLVIAPLRVAQSVWTSEVQRWSNFSHMNI----SVITG   82 (458)
Q Consensus         7 Q~~~v~~~~~~~~~ll~~~~G~GKT~~al~~~~~l~~~~~~~~LIv~P~~l~~~~W~~Ei~kf~~~~~~~~----~~~~g   82 (458)
T Consensus        89 Qk~WAKRv~~~~SFai~APTGVGKttFG~~mslflA~kKGkR~y~ilPT~lLv~Qv~~kl~~~~~k~g~~~~~l~~~yhS  168 (1843)
T TIGR01054        89 QKSWAKRVLKGDSFAIVAPTGVGKTTFGLVMSLFLAKKKGKRSYIILPTTLLVKQVAEKLSSLAEKEGVGIVRLLGAYHS  168 (1843)
T ss_pred             HHHHHHHHHCCCCEEEECCCCCCHHHHHHHHHHHHHHHCCCEEEEEECHHHHHHHHHHHHHHHCCCCCCCCEEEEEEEEC
T ss_conf             79999996417964898058876779999999998654298789994707889999999875200257500002221011


Q ss_pred             --CHHHH----HHHHCCCCCEEEECCCCHHHHHHHCCCCCCCCEEECCCCCCC
Q ss_conf             --97898----887307798699806420233442000113220440453100
Q gi|255764515|r   83 --TVKQR----TKVLKTPAVLYVINFENLGWLVQELKGTWPFATIVVDESTKL  129 (458)
Q Consensus        83 --~~~~r----~~~~~~~~~i~i~s~e~~~~~~~~~~~~~~~~~iIiDEaH~l  129 (458)
T Consensus       169 ~L~~~~kke~~Eri~~GDfdilitT~~FL~K~~~~L~~~y~F~liFVDDVDa~  221 (1843)
T TIGR01054       169 KLSTKEKKEVKERIENGDFDILITTSMFLSKNFDKLKNQYKFDLIFVDDVDAL  221 (1843)
T ss_pred             CCCHHHHHHHHHHHHCCCEEEEHHHHHHHHHHHHHCCCCCEEEEEEEECHHHH
T ss_conf             26545678899987318917861224688876651789851448997153676