>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=97.38  E-value=0.00031  Score=51.35  Aligned_cols=111  Identities=14%  Similarity=0.130  Sum_probs=69.9

Q ss_pred             EEECCCCCCHHHHHHHH-HHHC-CCCEEEEECCHHHHHHHHHHHHHHCCCCEEEECCCCCCCCHHCCCCCHHHHHHHHHH
Q ss_conf             89803765227999999-9862-998999929989999999999985799809985722467010048998999999999
Q gi|254780947|r   18 ITLSPVIDGTEGFILAE-IARL-GLSLVYICSDERILINLKKILTLVVPDIRVIIFPAWDCLPYDRVSPSPYVVTRRLSC   95 (1187)
Q Consensus        18 i~l~Gl~gs~~allla~-l~~~-~rpilvI~~d~~~A~~l~~dL~~f~~~~~V~~FP~~E~LPYd~~sp~~di~~eRl~~   95 (1187)
T Consensus       105 ~APTGVGKttFG~~mslflA~kKGkR~y~ilPT~lLv~Qv~~kl~~~~~k~g~~~~~l~-~~yhS~L-----~~~~kke~  178 (1843)
T TIGR01054       105 VAPTGVGKTTFGLVMSLFLAKKKGKRSYIILPTTLLVKQVAEKLSSLAEKEGVGIVRLL-GAYHSKL-----STKEKKEV  178 (1843)
T ss_pred             ECCCCCCHHHHHHHHHHHHHHHCCCEEEEEECHHHHHHHHHHHHHHHCCCCCCCCEEEE-EEEECCC-----CHHHHHHH
T ss_conf             80588767799999999986542987899947078899999998752002575000022-2101126-----54567889


Q ss_pred             HHHHHHCCCCCCCEEEEECHHHHHCCCCCHHHHH-CCEEEEECCCCC
Q ss_conf             9998412446887699956678523699866885-154899409741
Q gi|254780947|r   96 ISNLVSFNSSKETIIVLTTVSAVMCRSVNIMSIK-DYKLSIQSKDQI  141 (1187)
Q Consensus        96 L~~L~~~~~~~~~~IIVtt~~ALlqklpp~~~l~-~~~l~L~vGd~i  141 (1187)
T Consensus       179 ~Eri~----~GDfdilitT~~FL~K~~---~~L~~~y~F~liFVDDV  218 (1843)
T TIGR01054       179 KERIE----NGDFDILITTSMFLSKNF---DKLKNQYKFDLIFVDDV  218 (1843)
T ss_pred             HHHHH----CCCEEEEHHHHHHHHHHH---HHCCCCCEEEEEEEECH
T ss_conf             99873----189178612246888766---51789851448997153