>TIGR01059 gyrB DNA gyrase, B subunit; InterPro: IPR011557 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 B subunit (gyrB) as found predominantly in bacteria, but does not include the topoisomerase II enzymes composed of a single polypeptide, as are found in most eukaryotes. GyrB has two functional domains: an N-terminal ATPase and a C-terminal responsible for subunit interactions, the latter differing between subunit B and single polypeptide topoisomerase II . 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, 0005694 chromosome.

Probab=92.31  E-value=0.11  Score=29.98  Aligned_cols=124  Identities=13%  Similarity=0.085  Sum_probs=54.0

Q ss_pred             HHHHHHHHHHHHHHHHHHHHHHHHCCCCCCCCHHHH-HHHHHHHHHHHHHHHHHHH------HH----HHHH--H-HHCC
Q ss_conf             999876752224789999999986034688993899-9999999999999999977------76----7788--8-7419
Q gi|254780903|r  546 FLAKMSHELRTPLNAILGFSEVIKKEIFGELGSVKY-YEYAQDIHYSGQHLLNMIN------NI----LEMS--K-IETE  611 (766)
Q Consensus       546 fla~isHelrtPL~aI~g~~ell~~~~~~~~~~e~~-~~~l~~I~~~~~~l~~lI~------di----Ld~s--r-ieag  611 (766)
T Consensus       609 l~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~y~~~~~E~~~~~~~~~~~~~~~~~~f~~~vvR~G~~~-  687 (818)
T TIGR01059       609 LINRLERKAIRFSEELLIYQDLLEKELLEYESAVKYWLQGALYIYSDKEKEEAKTQLPVHKNAEKELFESSVVRHGLDT-  687 (818)
T ss_pred             HHHHHHHHHCCCHHHHHHHHHHHCHHHHCHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHEEECCCCC-
T ss_conf             7999987404355788875553022220014688889999998875565788887422356778875412114437763-


Q ss_pred             CCCCCEEEECHHHHHHHHHHHHHHHHHHCCCEEEEEECCCCEEEECHHHHHHHHHHHHHHHHH
Q ss_conf             830120331699999999999999998479589998089978998689999999998865653
Q gi|254780903|r  612 KISIDKQNADLIPIINEGIRLIGSSAQSKNIKIEKKIPSELFFNADKRIIKKILFPILSNSIK  674 (766)
Q Consensus       612 ~~~~~~~~~dl~~~i~~~~~~~~~~~~~k~i~l~~~~~~~l~v~~D~~~l~QVl~NLi~NAik  674 (766)
T Consensus       688 ~~~L~~~q~~~~e~~~~~~~~~~~~~~~--~~~~~~~~~~~~~~--~~~~~~~~~~l~~~~~~  746 (818)
T TIGR01059       688 DYILEKEQLELFEYGEIISLELSLQGLF--ETRAKLIRKNKKFE--INSLEEALDKLVELGRK  746 (818)
T ss_pred             CHHHHHHHHHHHHHHHHHHHHCCHHHHH--HHHHHHCCCCCCCC--CCCHHHHHHHHHHCCCC
T ss_conf             2001666643323454344211034554--43432100122310--02589999999840789