• ciprofloxacin
  • It has also been shown that the newer more potent quinolone drugs such as ciprofloxacin and ofloxacin have an additional effect on the bacterial cells in that the chromosome is broken down into fragments of DNA, some of which are estimated to be as small as 4kb in length. (bl.uk)
  • We find that gyrase can cleave duplexes down to ∼20 bp in size in the presence of the quinolone drugs ciprofloxacin and oxolinic acid. (le.ac.uk)
  • binds
  • DNA gyrase binds to the family of prokaryotic repetitive extragenic palindromic sequences. (nih.gov)
  • Regulation of the ccd operon by the CCdA/CCdB complex is dependent upon the ratio of the two molecules to each other in the complex: a (CcdA)2-(CcdB)2 complex binds the DNA of the operon thus repressing transcription, but when CcdB is in excess of CcdA de-repression occurs, whereas repression will occur when CcdA levels are greater than or equal to that of CcdB. (wikipedia.org)
  • fragment
  • DNase I footprinting shows that gyrase protects 205 base pairs on a REP-containing DNA fragment enclosing the REP sequences. (nih.gov)
  • enzymes
  • Gyrase is present in prokaryotes and some eukaryotes, but the enzymes are not entirely similar in structure or sequence, and have different affinities for different molecules. (wikipedia.org)
  • It kills bacteria by interfering with the enzymes that cause DNA to unwind and duplicate. (wikipedia.org)
  • interactions
  • We suggest that cleavage site specificity with short DNA duplexes is determined by drug-DNA interactions whereas with longer fragments the positioning effect of the DNA wrap around gyrase prescribes the site of cleavage. (le.ac.uk)
  • Interactions of CcdB with DNA gyrase. (wikipedia.org)
  • cleavage
  • In agreement with the above results, a comparison of the REP consensus sequence with the sequence of previously identified pBR322 "strong" gyrase cleavage sites reveals a high degree of homology. (nih.gov)
  • We have analysed the DNA cleavage reaction of DNA gyrase using oligonucleotides annealed to a singlestranded M13 derivative containing a preferred gyrase cleavage site. (le.ac.uk)
  • With either drug, cleavage will not occur within 6 bases from the end of a DNA duplex or a nick. (le.ac.uk)
  • vitro
  • Following on from the finding that the complex of quinolone and gyrase on DNA results in truncated mRNAs in vitro, the results presented in this thesis show that in vivo, the addition of quinolone drugs results in the production of truncated mRNAs which are presumably translated into truncated proteins. (bl.uk)
  • reaction
  • Therefore, it can be suggested that two ATP molecules are hydrolyzed per cycle of reaction by gyrase, leading to the introduction of a linking difference of -2. (wikipedia.org)
  • affinity
  • Gyrase has at least a 10-fold higher affinity for DNA containing REP sequences than for DNA not containing REP sequences. (nih.gov)
  • mutations
  • In conclusion, the presence of mutations at amino acids 50 and 119 suggests that in addition to QRDR section and Tyr-122, these sites are also essential for DNA gyrase activity. (ac.ir)
  • chromosomal
  • This process appears similar to the degradation of chromosomal DNA that occurs during apoptosis of some eukaryotic cells. (bl.uk)
  • superhelical
  • The number of superhelical turns introduced into an initially relaxed circular DNA has been calculated to be approximately equal to the number of ATP molecules hydrolyzed by gyrase. (wikipedia.org)
  • interaction
  • Because REP sequences are numerous and found throughout the genome, we suggest they have physiological functions mediated through their interaction with gyrase, such as being sites of action for the maintenance of DNA supercoiling. (nih.gov)
  • cell division
  • The University of Illinois at Chicago explains that DNA must replicate itself so that during cell division, both daughter cells receive the same genetic in. (reference.com)