DNA gyrase and DNA unwinding

Fluoroquinolone Binding to DNA Gyrase

DNA gyrase and topoisomerase IV control bacterial DNA topology by breaking DNA, passing duplex DNA through the break, and then resealing the break. This process is subject to reversible corruption by fluoroquinolones, antibacterials that form drug-enzyme-DNA complexes in which the DNA is broken. The complexes, called cleaved complexes due to the presence of DNA breaks, have been crystallized an...

DNA unwinding via minichromosome maintenance

Minichromosome maintenance (MCM) proteins play an essential role in DNA unwinding and are completely conserved throughout eukaryotic and archaeal cells, underscoring their fundamental importance in DNA replication. Biochemists have characterized some of the protein motifs that affect the unwinding of DNA by MCM proteins. Elizabeth Jenkinson and James Chong studied how changes in the MCM protein...

Interaction between DNA gyrase and its cleavage site on DNA.

DNA gyrase negatively supercoils DNA. When the requisite breaking and resealing of the DNA are uncoupled by gyrase inhibitors, the DNA becomes cleaved at specific sites. ATP, the cofactor for supercoiling, changes the sites of DNA cleavage. The mechanism of this effect was studied at sites in ColEl and @X174 DNA at which ATP strikingly enhanced cleavage. The following results showed that this i...

Novobiocin and coumermycin inhibit DNA supercoiling catalyzed by DNA gyrase.

Novobiocin and coumermycin are known to inhibit the replication of DNA iing of DNA catalyzed by E. coli DNA gyrase, a recently discovered enzyme that introduces negative superhelical turns into covalently circular DNA. The activity of DNA gyrase purified from a coumermycin-resistant mutant strain is resistant to both drugs. The inhibition by novobiocin of colicin E1 plasmid DNA replication in a...

On the Unwinding of Dna.