PMID:1334483

Citation	Kato, J , Suzuki, H and Ikeda, H (1992) Purification and characterization of DNA topoisomerase IV in Escherichia coli. J. Biol. Chem. 267:25676-84
Abstract	The subunits of topoisomerase IV (topo IV), the ParC and ParE proteins in Escherichia coli, were purified to near homogeneity from the respective overproducers. They revealed type II topoisomerase activity only when they were combined with each other. In the presence of Mg2+ and ATP, topo IV was capable of relaxing a negatively or positively supercoiled plasmid DNA or converting the knotted P4 phage DNA, whether nicked or ligated, to a simple ring. However, supercoiling activity was not detected. The topoisomerase activity was not detectable when the purified ParC and ParE proteins were combined with the purified GyrB and GyrA proteins, respectively. This is consistent with the result that neither a parC nor a parE mutation was compensated by transformation with a plasmid carrying either the gyrA or the gyrB gene. Simultaneous introduction of both the gyrA and gyrB plasmids corrected the phenotypic defect of parC and parE mutants. The results suggest that DNA gyrase can substitute for topo IV at least in some part of the function for chromosome partitioning. Antisera were prepared against the purified ParC, ParE, GyrA, and GyrB proteins and used to investigate cellular localization of these gene products. ParC protein was found to be specifically associated with inner membranes only in the presence of DNA. This result suggests that one of the functions of topo IV might be to anchor chromosomes on membranes as previously proposed for eukaryotic topoisomerase II.
Links	PubMed
Keywords	Bacterial Proteins/genetics; Bacterial Proteins/isolation & purification; Bacterial Proteins/metabolism; Cell Membrane/enzymology; Chromatography; Chromatography, Gel; DNA Gyrase; DNA Topoisomerase IV; DNA Topoisomerases, Type I/genetics; DNA Topoisomerases, Type I/isolation & purification; DNA Topoisomerases, Type I/metabolism; DNA Topoisomerases, Type II/genetics; DNA Topoisomerases, Type II/isolation & purification; DNA Topoisomerases, Type II/metabolism; DNA, Bacterial/genetics; DNA, Bacterial/isolation & purification; Durapatite; Escherichia coli/enzymology; Escherichia coli/genetics; Genes, Bacterial; Hydroxyapatites; Kinetics; Macromolecular Substances; Magnesium/pharmacology; Plasmids
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Materials and Methods Used

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• Topoisomerase IV is purified and its topoisomerase activity characterized in vitro

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Phenotype of	Taxon Information	Genotype Information (if known)	Condition Information	OMP ID	OMP Term Name	ECO ID	ECO Term Name	Notes	Status
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