>TIGR01063 gyrA DNA gyrase, A subunit; InterPro: IPR005743 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 II topoisomerases are ATP-dependent enzymes, and can be subdivided according to their structure and reaction mechanisms: type IIA (topoisomerase II or gyrase, and topoisomerase IV) and type IIB (topoisomerase VI). These enzymes are responsible for relaxing supercoiled DNA as well as for introducing both negative and positive supercoils . Topoisomerase II (called gyrase in bacteria) primarily introduces negative supercoils into DNA. In bacteria, topoisomerase II consists of two polypeptide subunits, gyrA and gyrB, which form a heterotetramer: (BA)2. In most eukaryotes, topoisomerase II consists of a single polypeptide, where the N- and C-terminal regions correspond to gyrB and gyrA, respectively. This entry represents the A subunit (gyrA) as found predominantly in bacteria, but does not include the topoisomerase II enzymes composed of a single polypeptide, as are found in most eukaryotes. GyrA has two functional domains: an N-terminal that forms the covalent DNA-protein bridge that is responsible for the breaking- and rejoining function, and a C-terminal that can bind DNA non-specifically . More information about this protein can be found at Protein of the Month: DNA Topoisomerase .; GO: 0003677 DNA binding, 0003918 DNA topoisomerase (ATP-hydrolyzing) activity, 0005524 ATP binding, 0006265 DNA topological change, 0006268 DNA unwinding during replication, 0005694 chromosome.

Probab=99.91 E-value=3.9e-22 Score=217.13 Aligned_cols=192 Identities=19% Similarity=0.337 Sum_probs=98.6 Q ss_pred EEEEEECCCEECCCCCCCCCCCCCCCCCCCCCCCCCCCHHEEEEEECCCCE-EEEEECCCCEEEEECC--CCCCCCCCCC Q ss_conf 189990797052331000002334565211000146410101133237773-9999548939998200--0432244456 Q gi|254780182|r 538 MVVTVSHLGYVKRVPLSVYRAQRRGGKGRSGVVMRDEDFVTDLFIVSTHTS-VLFFSSLGFVYKEKVW--RLPIGSPQAR 614 (910) Q Consensus 538 vvV~lS~~GyIKr~~~~~yr~Q~RggkG~~~~~~ke~D~v~~~~~~~t~d~-LLfFTs~Gkvy~l~v~--~IP~~sr~sk 614 (910) T Consensus 636 yl~~aTk~G~vKk~~L~~F~~~r--s~GiiAi~L~e~D~L~~v~~~~~~~~~v~l~s~~G~~~RF~~~~~~vR~mgR~~~ 713 (864) T TIGR01063 636 YLFLATKNGVVKKTSLTEFSNIR--SNGIIAIKLDEGDELISVRLVDGDDEKVMLGSKNGKAVRFPEEDEEVREMGRATR 713 (864) T ss_pred EEEEECCCCEEEEEECHHHHHHH--HCCEEEEEEECCCEEEEEEEEECCCCEEEEEECCCCEEECCCCCCCHHCCCCCCC T ss_conf 79997267438874001443545--2786999970896899999960788658865148847983688531100245567 Q ss_pred CCCCEEEEECCCC----------------------------CCEEEEEEECCCCCCCCCC-EEEEEECCCCEEEECHHHH Q ss_conf 5541245453655----------------------------6200256630125666871-7999947991898423686 Q gi|254780182|r 615 GKALINILSLNQG----------------------------ERITTIMPFPEDESSWNNL-YVVFATKHGNVRRNKLSDF 665 (910) Q Consensus 615 G~pi~nll~l~~~----------------------------E~I~ail~~~~~~~~~~~~-~Lvl~Tk~G~VKkt~l~ef 665 (910) T Consensus 714 GV~G---i~L~~~~~v~~~~~~~~i~~~~~D~~~~~L~~NlD~vv~~~~~~------e~~~~lL~vt~nGyGKRt~~~~y 784 (864) T TIGR01063 714 GVRG---IKLKNEDSVISMTVLKGINSIKEDRNLEELGVNLDFVVSLEVVS------EESQKLLIVTENGYGKRTSIEEY 784 (864) T ss_pred CEEE---EEECCCCCCCHHHHHHHHHHHHHHHHHHHCCCCEEEEEEEEEEC------CCCCEEEEEEECCCCEECCHHHC T ss_conf 6013---54067774000134432120022224654374243447778624------99837899830684200426257 Q ss_pred HHCCCCC--EEEEEEC-CCCEEEEEEECCCCCEEEEEECCCEEEEEEHHHCCCCCCCCCCCEEEEECCCCCEEEEEEEE Q ss_conf 2047772--2786615-89857888961898269999369859997587623547866553576752899869998973 Q gi|254780182|r 666 IQINRSG--KIAMKLD-SRDEILSVETCTQENDILLTTKLGQCVRFPISAIRVFAGRNSVGVRGISLAKGDQVISMAIV 741 (910) Q Consensus 666 ~~~r~~G--~~aikLk-egD~Li~v~~~~~~~~Iil~T~~G~~lrF~~~evr~~~GR~a~GVkgIkL~~~D~Vv~~~vi 741 (910) T Consensus 785 r~~~RGg~Gv~~~~~~~r~G~vVga~~V~~~d~lm~iT~~G~~iR~~~~~vs~-~GR~t~GVrL~~l~e~d~vv~v~~~ 862 (864) T TIGR01063 785 RLQSRGGKGVKSIKITDRNGQVVGAIAVDDDDELMLITSSGKLIRTSVQDVSI-QGRNTQGVRLIRLDEDDKVVSVSLV 862 (864) T ss_pred CCCCCCCCEEEEEEEECCCCCEEEEEEECCCCHHHHEECCCCEEEEEEEHHCC-CCCCCCCEEEEEECCCCCEEEEEEC T ss_conf 63265662378899864689687898745874000101088379976103211-5653565589851787635642202

HHsearch alignment for GI: 254780182 and conserved domain: TIGR01063