Modulation of bacterial chromosomal supercoiling is a function of DNA gyrase-catalyzed strand breakage and rejoining. This reaction is exploited by both antibiotic and proteic gyrase inhibitors, which trap the gyrase molecule at the DNA cleavage stage. Owing to this interaction, double-stranded DNA breaks are introduced and replication machinery is arrested at blocked replication forks. This im...

DNA gyrase is an essential enzyme in DNA replication in Escherichia coli. It mediates the introduction of negative supercoils near oriC, removal of positive supercoils ahead of the growing DNA fork, and separation of the two daughter duplexes. In the course of purifying DNA gyrase from E. coli KL16, we found an 18-kDa protein that inhibited the supercoiling activity of DNA gyrase, and we coined...

quinolones are a large and widely consumed class of synthetic drugs. expanded-spectrum quinolones, like ciprofloxacin are highly effective against gram-negative bacteria, especially escherichia coli. in e. coli the major target for quinolones is dna gyrase. this enzyme is composed of two subunits, gyra and gyrb encoding by gyra and gyrb, respectively. mutations in either of these genes cause qu...

OBJECTIVES Garenoxacin, a des-fluoro(6)-quinolone, exhibits potent activity against Mycoplasma pneumoniae, including macrolide-resistant strains. There has been no report on the inhibitory activity of garenoxacin against the target enzyme of M. pneumoniae. METHODS Subunits of DNA gyrase (GyrA and GyrB) proteins of M. pneumoniae FH were separately expressed as His-tagged proteins in Escherichi...

DNA gyrase is an essential type II topoisomerase found in bacteria. We have previously characterized DNA gyrase from Mycobacterium tuberculosis and Mycobacterium smegmatis. In this study, several monoclonal antibodies were generated against the gyrase A subunit (GyrA) of M. smegmatis. Three, MsGyrA:C3, MsGyrA:H11 and MsGyrA:E9, were further analyzed for their interaction with the enzyme. The mo...

DNA gyrase is the only topoisomerase able to introduce negative supercoils into DNA. Absent in humans, gyrase is a successful target for antibacterial drugs. However, increasing drug resistance is a serious problem and new agents are urgently needed. The naturally-produced Escherichia coli toxin CcdB has been shown to target gyrase by what is predicted to be a novel mechanism. CcdB has been pre...

The sugarcane pathogen Xanthomonas albilineans produces a family of antibiotics and phytotoxins termed albicidins, which inhibit plant and bacterial DNA gyrase supercoiling activity, with a 50% inhibitory concentration (50 nM) comparable to those of coumarins and quinolones. Here we show that X. albilineans has an unusual, antibiotic-resistant DNA gyrase. The X. albilineans gyrA and gyrB genes ...

A total of 19 novel (3a-3s) N'-benzoyl-3-(4-bromophenyl)-1H-pyrazole-5-carbohydrazide analogs were designed, synthesized, and evaluated for biological activities as potential DNA gyrase inhibitors. The results showed that compound 3k can strongly inhibit Staphylococcus aureus DNA gyrase and Bacillus subtilis DNA gyrase (with IC50 of 0.15 µg/mL and 0.25 µg/mL, respectively). Structure-activity r...

The DNA gyrase negative supercoiling mechanism involves the assembly of a large gyrase/DNA complex and conformational rearrangements coupled to ATP hydrolysis. To establish the complex arrangement that directs the reaction towards negative supercoiling, bacterial gyrase complexes bound to 137- or 217-bp DNA fragments representing the starting conformational state of the catalytic cycle were cha...

The main mechanism of fluoroquinolone (FQ) resistance in Mycobacterium tuberculosis is mutation in DNA gyrase (GyrA(2)GyrB(2)), especially in gyrA. However, the discovery of unknown mutations in gyrB whose implication in FQ resistance is unclear has become more frequent. We investigated the impact on FQ susceptibility of eight gyrB mutations in M. tuberculosis clinical strains, three of which w...