title: Mutational analysis of Escherichia coli topoisomerase IV. I. Selection of dominant-negative parE alleles.
abstract: In order to define regions of ParE, one of the two subunits of topoisomerase IV, that are involved in catalysis during topoisomerization, we developed a selection procedure to isolate dominant-negative parE alleles. Both wild-type parC and mutagenized parE were expressed from a tightly-regulated lac promoter on a moderate-copy plasmid. Mutated parE alleles were rescued from those plasmids that caused IPTG-dependent cell death. The mutant ParE proteins could be divided into two groups when reconstituted with ParC to form topoisomerase IV, those that elicited hyper-DNA cleavage and those that affected covalent complex formation.
authors.affiliation: Molecular Biology Graduate Program, Cornell University Graduate School of Medical Sciences, New York, New York 10021, USA.
authors.forename: E
authors.initials: E
authors.lastname: Mossessova
authors.forename: C
authors.initials: C
authors.lastname: Levine
authors.forename: H
authors.initials: H
authors.lastname: Peng
authors.forename: P
authors.initials: P
authors.lastname: Nurse
authors.forename: S
authors.initials: S
authors.lastname: Bahng
authors.forename: K J
authors.initials: KJ
authors.lastname: Marians
mesh_terms: D000483:Alleles; D001426:Bacterial Proteins / Q000235:genetics*; D027101:DNA Topoisomerase IV; D004250:DNA Topoisomerases, Type II / Q000235:genetics*; D004278:DNA, Superhelical / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology*; D007544:Isopropyl Thiogalactoside / Q000378:metabolism; D008856:Microscopy, Fluorescence; D009154:Mutation; D010641:Phenotype
chemical_list: D001426:Bacterial Proteins; D004278:DNA, Superhelical; D004268:DNA-Binding Proteins; D007544:Isopropyl Thiogalactoside; D027101:DNA Topoisomerase IV; D004250:DNA Topoisomerases, Type II