Modulation of DNA supercoiling activity of Escherichia coli DNA gyrase by F plasmid proteins. Antagonistic actions of LetA (CcdA) and LetD (CcdB) proteins.
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منابع مشابه
Plasmid DNA supercoiling and gyrase activity in Escherichia coli wild-type and rpoS stationary-phase cells.
Stationary-phase cells displayed a distribution of relaxed plasmids and had the ability to recover plasmid supercoiling as soon as nutrients became available. Preexisting gyrase molecules in these cells were responsible for this recovery. Stationary-phase rpoS cells showed a bimodal distribution of plasmids and failed to supercoil plasmids after the addition of nutrients, suggesting that rpoS p...
متن کاملPreferential inhibition of plasmid replication in vivo by altered DNA gyrase activity in Escherichia coli.
The thermosensitive growth phenotype exerted by runaway-mutant plasmids was suppressed by sublethal doses of the DNA gyrase inhibitors novobiocin or nalidixic acid, although the latter drug was less efficient. A novobiocin-resistant gyrB mutant Escherichia coli strain prevented expression of the runaway phenotype at 37 to 42 degrees C in the absence of any drug.
متن کاملStudy of Mutations in the DNA gyrase gyrA Gene of Escherichia coli
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...
متن کاملStudy of Mutations in the DNA gyrase gyrA Gene of Escherichia coli
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...
متن کاملInteractions of CcdB with DNA gyrase. Inactivation of Gyra, poisoning of the gyrase-DNA complex, and the antidote action of CcdA.
The F plasmid-carried bacterial toxin, the CcdB protein, is known to act on DNA gyrase in two different ways. CcdB poisons the gyrase-DNA complex, blocking the passage of polymerases and leading to double-strand breakage of the DNA. Alternatively, in cells that overexpress CcdB, the A subunit of DNA gyrase (GyrA) has been found as an inactive complex with CcdB. We have reconstituted the inactiv...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1992
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(19)49831-1