1ab4 | pdb_00001ab4
59KDA FRAGMENT OF GYRASE A FROM E. COLI
Structural highlights
Function[GYRA_ECOLI] DNA gyrase negatively supercoils closed circular double-stranded DNA in an ATP-dependent manner and also catalyzes the interconversion of other topological isomers of double-stranded DNA rings, including catenanes and knotted rings.[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedDNA gyrase is a type II DNA topoisomerase from bacteria that introduces supercoils into DNA. It catalyses the breakage of a DNA duplex (the G segment), the passage of another segment (the T segment) through the break, and then the reunification of the break. This activity involves the opening and dosing of a series of molecular 'gates' which is coupled to ATP hydrolysis. Here we present the crystal structure of the 'breakage-reunion' domain of the gyrase at 2.8 A resolution. Comparison of the structure of this 59K (relative molecular mass, 59,000) domain with that of a 92K fragment of yeast topoisomerase II reveals a very different quaternary organization, and we propose that the two structures represent two principal conformations that participate in the enzymatic pathway. The gyrase structure reveals a new dimer contact with a grooved concave surface for binding the G segment and a cluster of conserved charged residues surrounding the active-site tyrosines. It also shows how breakage of the G segment can occur and, together with the topoisomerase II structure, suggests a pathway by which the T segment can be released through the second gate of the enzyme. Mutations that confer resistance to the quinolone antibacterial agents cluster at the new dimer interface, indicating how these drugs might interact with the gyrase-DNA complex. Crystal structure of the breakage-reunion domain of DNA gyrase.,Morais Cabral JH, Jackson AP, Smith CV, Shikotra N, Maxwell A, Liddington RC Nature. 1997 Aug 28;388(6645):903-6. PMID:9278055[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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