>TIGR01055 parE_Gneg DNA topoisomerase IV, B subunit; InterPro: IPR005737 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 . This entry represents subunit B (parE) of topoisomerase IV from Gram negative bacteria. Topoisomerase IV primarily decatenates DNA and relaxes positive supercoils, which is important in bacteria, where the circular chromosome becomes catenated, or linked, during replication . Topoisomerase IV consists of two polypeptide subunits, parC (subunit A), which is homologous to gyrA of topoisomerase II, and parE (subunit B), which is homologous to gyrB of 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=92.30  E-value=0.1  Score=30.35  Aligned_cols=60  Identities=15%  Similarity=0.291  Sum_probs=33.7

Q ss_pred             EEEEEEEEC-CCCCEEEEEEEEEEEEECCCEEEEEEEEECCCHHHHHHHHHHHHHHHHHHHHHHHHHHEEE
Q ss_conf             899999886-9898899889999998379606999998446179999999999999999999854455158
Q gi|254780903|r  328 LDQIFHMRH-ASGADIWIQVRAQMMRTISGGMNIIGIAMDLTEKYHLEKRYAEADQRLSKAIECTSEALVL  397 (766)
Q Consensus       328 ~~~e~Ri~~-~DG~~~Wi~~r~~~i~d~~G~~~~iGi~~DITErK~ae~~l~ese~rlr~~ie~~~~~i~~  397 (766)
T Consensus       258 ~~~~WAl~W~~~~~~~~~~SY~N~iPT~QGGTH~~G----------L~~~lL~a~~~f~E~~~~~P~~~~L  318 (647)
T TIGR01055       258 EAVEWALLWLPEGGELLMESYVNLIPTIQGGTHVNG----------LRQGLLDALREFCEMRNLLPRGVKL  318 (647)
T ss_pred             HHCCEEEEECCCCCHHHHHCCCCCCCCCCCCCHHHH----------HHHHHHHHHHHHHHHHCCCCCEEEC
T ss_conf             100244663278840032041101578988710457----------8999999999988875188640221