PMID:8227000
| Citation |
Peng, H and Marians, KJ (1993) Escherichia coli topoisomerase IV. Purification, characterization, subunit structure, and subunit interactions. J. Biol. Chem. 268:24481-90 |
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| Abstract |
DNA sequence analysis of Escherichia coli parC and parE, encoding the subunits of topoisomerase IV (Topo IV) (Kato, J.-I., Suzuki, H., and Ikeda, H. (1992) J. Biol. Chem. 267, 25676-25684), showed that ParC was 22 amino acids longer on the N terminus and ParE was 29 amino acids longer on the C terminus than reported previously. E. coli strains bearing bacteriophage T7 RNA polymerase-based expression plasmids carrying both intact and truncated parC and parE were used to overproduce the ParC and ParE proteins. Full-length ParC and ParE were required to reconstitute Topo IV activity, whereas the truncated ParC and ParE were inactive. Topo IV activity was supported only by ATP or dATP. The [ATP]1/2 for DNA relaxation was 0.45 mM, almost 25-fold higher than the [ATP]1/2 for decatenation of kinetoplast DNA. Topo IV activity was inhibited by the quinolone and coumarin antibiotics, although the concentrations required for 50% inhibition of activity were 3-30-fold higher than those required to inhibit DNA gyrase. The norfloxacin-induced DNA cleavage patterns of Topo IV and DNA gyrase were distinct but overlapping. The native forms of ParC and ParE were a dimer and a monomer, respectively; whereas the active form of Topo IV was a heterotetramer, ParC2ParE2. The inactivity of the truncated forms of ParC and ParE could be attributed to their failure to form the heterotetramer. |
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| Keywords |
Amino Acid Sequence; Base Sequence; Chromatography, DEAE-Cellulose; DNA Topoisomerase IV; DNA Topoisomerases, Type I/chemistry; DNA Topoisomerases, Type I/isolation & purification; DNA Topoisomerases, Type I/metabolism; DNA, Bacterial/metabolism; Electrophoresis, Agar Gel; Electrophoresis, Polyacrylamide Gel; Escherichia coli/enzymology; Molecular Sequence Data; Sequence Homology, Nucleic Acid |
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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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