>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=97.67  E-value=0.00011  Score=53.16  Aligned_cols=90  Identities=18%  Similarity=0.198  Sum_probs=70.2

Q ss_pred             EEECCCCCCCCHHHHHHHHHHHHHHC-CCCE-EEEECCCCCHHHHHHHHHHHHHHCCCCC---CCCCCCCCHHHHHHHHH
Q ss_conf             23113544444247899999998522-6742-6774345124568899999753035321---22358661245422899
Q gi|254780709|r  113 VILVVGVNGVGKTTVIGKLSKKMSDA-GLKV-MLAAGDTFRSAAIDQLKIWADRTSADFV---CSEIGSDAAALAYEAFK  187 (321)
Q Consensus       113 vil~vG~nG~GKTTT~aKLA~~~~~~-g~kV-~lva~DtfR~aA~eQL~~~a~~~~v~~~---~~~~~~dp~~v~~~a~~  187 (321)
T Consensus       101 SFai~APTGVGKttFG~~mslflA~kKGkR~y~ilPT~lLv~Qv~~kl~~~~~k~g~~~~~l~~~yhS~L~~~~kke~~E  180 (1843)
T TIGR01054       101 SFAIVAPTGVGKTTFGLVMSLFLAKKKGKRSYIILPTTLLVKQVAEKLSSLAEKEGVGIVRLLGAYHSKLSTKEKKEVKE  180 (1843)
T ss_pred             CEEEECCCCCCHHHHHHHHHHHHHHHCCCEEEEEECHHHHHHHHHHHHHHHCCCCCCCCEEEEEEEECCCCHHHHHHHHH
T ss_conf             64898058876779999999998654298789994707889999999875200257500002221011265456788999


Q ss_pred             HHHHHCCCEEEEECCC
Q ss_conf             9965148759986543
Q gi|254780709|r  188 QAQAKKVDVLIIDTAG  203 (321)
Q Consensus       188 ~a~~~~~DvvliDTAG  203 (321)
T Consensus       181 ri~~GDfdi-litT~~  195 (1843)
T TIGR01054       181 RIENGDFDI-LITTSM  195 (1843)
T ss_pred             HHHCCCEEE-EHHHHH
T ss_conf             873189178-612246