DNA gyrase inhibitors, cyclothialidines B, C, D and E were isolated from four Streptomycete strains (NR 0659, NR 0660, NR 0661 and NR 0662). Their structures have been elucidated based on the amino acid analysis of the hydrolysates, NMR and HRFAB-MS experiments and shown to be cyclothialidine analogs. The absolute stereochemistry has been determined by the chiral HPLC analysis of the hydrolysat...

Staphylococcus aureus gyrA and gyrB genes, which encode the DNA gyrase A and B proteins, have been isolated and found to map contiguously. DNA sequence analysis revealed close homology between the S. aureus gyrase subunits and their counterparts in Bacillus subtilis and Escherichia coli, including several conserved amino acid residues whose substitution in E. coli confers resistance to 4-quinol...

DNA gyrase is a target of quinolone antibacterial agents, but the molecular details of the quinolone-gyrase interaction are not clear. Quinolone resistance mutations frequently occur at residues Ser(83) and Asp(87) of the gyrase A subunit, suggesting that these residues are involved in drug binding. Single and double alanine substitutions were created at these positions (Ala(83), Ala(87), and A...

Topoisomerases are essential ubiquitous enzymes, falling into two distinct classes. A number of eubacteria including Escherichia coli, typically contain four topoisomerases, two type I topoisomerases and two type II topoisomerases viz. DNA gyrase and topoisomerase IV. In contrast several other bacterial genomes including mycobacteria, encode for one type I topoisomerase and a DNA gyrase. Here w...

Mycobacterium tuberculosis DNA gyrase, an indispensable nanomachine involved in the regulation of DNA topology, is the only type II topoisomerase present in this organism and is hence the sole target for quinolone action, a crucial drug active against multidrug-resistant tuberculosis. To understand at an atomic level the quinolone resistance mechanism, which emerges in extensively drug resistan...

DNA gyrase is the only enzyme known to negatively supercoil DNA. The enzyme is a heterotetramer of A(2)B(2) subunit composition. Alignment of the primary sequence of gyrase B (GyrB) from various species shows that they can be grouped into two classes. The GyrB of Gram-negative eubacteria has a stretch of about 165 amino acids in the C-terminal half, which is lacking in other GyrB subunits and t...

DNA gyrase is the only topoisomerase capable of introducing (-) supercoils into relaxed DNA. The C-terminal domain of the gyrase A subunit (GyrA-CTD) and the presence of a gyrase-specific 'GyrA-box' motif within this domain are essential for this unique (-) supercoiling activity by allowing gyrase to wrap DNA around itself. Here we report the crystal structure of Xanthomonas campestris GyrA-CTD...

Mechanisms of Staphylococcus aureus resistance to fluoroquinolones were characterized. Subunit A and B proteins of DNA gyrase were partially purified from fluoroquinolone-susceptible strain SA113 and resistant isolate MS16405, which was 250- to 1,000-fold less susceptible to fluoroquinolones such as ciprofloxacin, norfloxacin, ofloxacin, temafloxacin, and sparfloxacin than SA113 was. The superc...

In this study, in vitro activity of flouroquinolone group antibiotics againts Listeria strains was investigated. For that reason ofloxacine, ciprofloxacine, pefloxacine, norfloxacine against 111 investigated.
 Flouroquinolone inhibited DNA gyrase enzyme microorganisms.
 found respectively enoxacine 73. 9 % , ciprofloxacine 63. ofloxacine 63.1 and pefloxacine 46.8 %.

DNA gyrase is the only type II topoisomerase in Mycobacterium tuberculosis and needs to catalyse DNA supercoiling, relaxation and decatenation reactions in order to fulfil the functions normally carried out by gyrase and DNA topoisomerase IV in other bacteria. We have obtained evidence for the existence of a Ca(2+)-binding site in the GyrA subunit of M. tuberculosis gyrase. Ca(2+) cannot suppor...