>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=95.66  E-value=0.019  Score=37.90  Aligned_cols=83  Identities=19%  Similarity=0.386  Sum_probs=61.4

Q ss_pred             HHHHHCCCCCCCCC-CCC-CC-------CCCCCCCCCCCCCEEEEEECHHHHHHHHHHCCEEEEEEEHHHHCCCCCCCCH
Q ss_conf             99985182889997-334-56-------5410035555673699983588999997517401342101210020002681
Q gi|254780762|r   52 NIYNKVCLCSICGN-VDT-TD-------PCAICIDQQRDASVIIVVEDVADLWALERSKAVNALYHVLGGSLSPLDRIGP  122 (201)
Q Consensus        52 ~~~~~i~~C~~C~~-l~~-~~-------~C~iC~d~~Rd~~~lCVVE~~~Di~~IE~t~~y~G~YhVLgG~ispl~g~~p  122 (201)
T Consensus       749 PvY~sIKrC~dcG~QfTd~~~leeli~e~cpkcgs~~~~d~-~-------------------------------------  790 (1843)
T TIGR01054       749 PVYTSIKRCRDCGEQFTDEEDLEELIKELCPKCGSENIEDS-K-------------------------------------  790 (1843)
T ss_pred             EEECCCCEECCCCCCCCCHHHHHHHHHHHHCCCCCCCCCCH-H-------------------------------------
T ss_conf             04411011335887436715589999986025787555652-6-------------------------------------


Q ss_pred             HHCCHHHHHHHHCCCCCCEEEEEECCCCCHHHHHHHHHHHHCCCCCEEEEEECC
Q ss_conf             112889999985157855499994699786899999999820179808874146
Q gi|254780762|r  123 EDIGIQSLIERIEVKKIRELIFAISATIEGQTTAHYIMDKLKGIDVKITRLAYG  176 (201)
Q Consensus       123 ~~l~i~~L~~ri~~~~i~EVIlA~~~t~EGe~Ta~yi~~~lk~~~ikitrla~G  176 (201)
T Consensus       791 --~~ve~lR~-l-A~EvD~v~iaTDPDtEGEKIgwDl~~~~~Py~pnv~R~eFH  840 (1843)
T TIGR01054       791 --SIVEILRE-L-ASEVDEVFIATDPDTEGEKIGWDLALLLRPYNPNVKRAEFH  840 (1843)
T ss_pred             --HHHHHHHH-H-HHHHCEEEECCCCCCCCCCHHHHHHHHHCCCCCCEEEECCC
T ss_conf             --78899987-5-44429888725889875408999999808877752462145