>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=97.52 E-value=0.0011 Score=47.54 Aligned_cols=154 Identities=18% Similarity=0.268 Sum_probs=93.4 Q ss_pred CCCCCHHHHHHHHHHHHHHHHHHCCCCCC-CCCCCHHHHHHH-HHHCCCCEEEEECCCHHHHHHHHHHHHHHHHHHCCCC Q ss_conf 65430134336778999998741123664-432101377655-6416772677621310027699999999998510111 Q gi|254780332|r 173 GGFHTFSDAMTVAIDMAGQAFNRDGRLAG-VSTGIQTLDKQM-GGLQRSDLIIIAGRPGMGKTSLATNIAYNVADAYKAE 250 (504) Q Consensus 173 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~G-i~TG~~~LD~~~-gGl~~G~l~Viaarpg~GKTalalniA~~~A~~~~~~ 250 (504) T Consensus 61 K~~~~~~~~~k~f~~FF~~~-------~G~~pws---~Qk~WAKRv~~~~SFai~APTGVGKttFG~~mslflA~k---- 126 (1843) T TIGR01054 61 KEYCSLDEELKEFEEFFKKA-------VGSEPWS---IQKSWAKRVLKGDSFAIVAPTGVGKTTFGLVMSLFLAKK---- 126 (1843) T ss_pred HHHHHHHHHHHHHHHHHHHH-------HCCCCHH---HHHHHHHHHHCCCCEEEECCCCCCHHHHHHHHHHHHHHH---- T ss_conf 55433789999999999997-------1888435---679999996417964898058876779999999998654---- Q ss_pred CCCCCCCCCCCCCEE-EEEECCCCHHHHHHHHHHHHH--HHCCCC---CCCCCCCHHHHHHHHHHHHHHHHC--CEEEEC Q ss_conf 233333212479758-999585217999878999987--410110---001213768899899999998627--807825 Q gi|254780332|r 251 LQTDGSYKTINGGIV-GFYSLEMSSEQLATRIISEQT--EVPSSK---IRRGELTRPDYEKIVACSQVMQKL--PLYIDQ 322 (504) Q Consensus 251 ~~~~~~~~~~~g~~V-l~fSlEMs~~el~~R~is~~s--~I~~~~---i~~g~l~~~e~~~i~~a~~~l~~~--~l~I~d 322 (504) T Consensus 127 ----------KGkR~y~ilPT~lLv~Qv~~kl~~~~~k~g~~~~~l~~~yhS~L~~~~kke~---~Eri~~GDfdili-- 191 (1843) T TIGR01054 127 ----------KGKRSYIILPTTLLVKQVAEKLSSLAEKEGVGIVRLLGAYHSKLSTKEKKEV---KERIENGDFDILI-- 191 (1843) T ss_pred ----------CCCEEEEEECHHHHHHHHHHHHHHHCCCCCCCCEEEEEEEECCCCHHHHHHH---HHHHHCCCEEEEH-- T ss_conf ----------2987899947078899999998752002575000022210112654567889---9987318917861-- Q ss_pred CCCCCHHHHHHHHHHHCCCCCCCEEEECCHH-HCCCC Q ss_conf 8998899999988640224447467767135-32566 Q gi|254780332|r 323 TGGISMSQLATRARRLKRQRGLDLLIVDYIQ-LMTTS 358 (504) Q Consensus 323 ~~~~ti~~I~~~~r~~~~~~gi~~vvIDYLq-li~~~ 358 (504) T Consensus 192 t---T~~FL~K~~~~L~~~y~F~liFVDDVDa~Lk~s 225 (1843) T TIGR01054 192 T---TSMFLSKNFDKLKNQYKFDLIFVDDVDALLKAS 225 (1843) T ss_pred H---HHHHHHHHHHHCCCCCEEEEEEEECHHHHHHCC T ss_conf 2---246888766517898514489971536763165

HHsearch alignment for GI: 254780332 and conserved domain: TIGR01054