DNA gyrase subunit A; A type II topoisomerase that negatively supercoils closed circular double-stranded (ds) DNA in an ATP-dependent manner to modulate DNA topology and maintain chromosomes in an underwound state. Negative supercoiling favors strand separation, and DNA replication, transcription, recombination and repair, all of which involve strand separation. Also able to catalyze the interconversion of other topological isomers of dsDNA rings, including catenanes and knotted rings. Type II topoisomerases break and join 2 DNA strands simultaneously in an ATP-dependent manner.

DNA topoisomerase I; Releases the supercoiling and torsional tension of DNA, which is introduced during the DNA replication and transcription, by transiently cleaving and rejoining one strand of the DNA duplex. Introduces a single-strand break via transesterification at a target site in duplex DNA. The scissile phosphodiester is attacked by the catalytic tyrosine of the enzyme, resulting in the formation of a DNA- (5'-phosphotyrosyl)-enzyme intermediate and the expulsion of a 3'-OH DNA strand. The free DNA strand then undergoes passage around the unbroken strand, thus removing DNA supe [...]

Hypothetical protein; Antitoxin component of a non-functional type II toxin- antitoxin (TA system). Does not neutralize the effect of any of the RelE or ParE toxins.

Conserved hypothetical protein; Antitoxin component of a type II toxin-antitoxin (TA) system. Neutralizes the effect of cognate toxin ParE1, but no other RelE or ParE toxin. May act as a DNA gyrase inhibitor (By similarity).

Conserved hypothetical protein; Toxic component of a type II toxin-antitoxin (TA) system. Its toxic effect is neutralized by coexpression with cognate antitoxin ParD1 but no other ParD or RelB antitoxin. Low levels of wild-type toxin in the absence of antitoxin decreases the rate of cell growth, and results in death or loss of colony formation abilities and greatly elongated cells. Low levels of a mutant missing the last 4 residues leads to loss of cell division while cell elongation continues.

Conserved hypothetical protein; Toxic component of a type II toxin-antitoxin (TA) system. Its toxic effect is neutralized by coexpression with cognate antitoxin ParD3 but no other ParD or RelB antitoxin.

DNA polymerase III, beta subunit; Confers DNA tethering and processivity to DNA polymerases and other proteins. Acts as a clamp, forming a ring around DNA (a reaction catalyzed by the clamp-loading complex) which diffuses in an ATP- independent manner freely and bidirectionally along dsDNA. Initially characterized for its ability to contact the catalytic subunit of DNA polymerase III (Pol III), a complex, multichain enzyme responsible for most of the replicative synthesis in bacteria; Pol III exhibits 3'-5' exonuclease proofreading activity. The beta chain is required for initiation of [...]

Conserved hypothetical protein; Inhibits all the catalytic activities of DNA gyrase by preventing its interaction with DNA. Acts by binding directly to the C- terminal domain of GyrB, which probably disrupts DNA binding by the gyrase.

Dimethyladenosine transferase; Specifically dimethylates two adjacent adenosines (A1518 and A1519) in the loop of a conserved hairpin near the 3'-end of 16S rRNA in the 30S particle. May play a critical role in biogenesis of 30S subunits.