ParC subunit of DNA topoisomerase IV of Streptococcus pneumoniae is a primary target of fluoroquinolones and cooperates with DNA gyrase A subunit in forming resistance phenotype.
The genes encoding the ParC and ParE subunits of topoisomerase IV of Streptococcus pneumoniae, together with the region encoding amino acids 46 to 172 (residue numbers are as in Escherichia coli) of the pneumococcal GyrA subunit, were partially characterized. The gyrA gene maps to a physical location distant from the gyrB and parC loci on the chromosome, whereas parC is closely linked to parE. Ciprofloxacin-resistant (Cpr) clinical isolates of S. pneumoniae had mutations affecting amino acid residues of the quinolone resistance-determining region of ParC (low-level Cpr) or in both quinolone resistance-determining regions of ParC and GyrA (high-level Cpr). Mutations were found in residue positions equivalent to the serine at position 83 and the aspartic acid at position 87 of the E. coli GyrA subunit. Transformation experiments suggest that ParC is the primary target of ciprofloxacin. Mutation in parC appears to be a prerequisite before mutations in gyrA can influence resistance levels.
Muñoz
R
R
(Consejo Superior de Investigaciones Cientificas), Centro Nacional de Biologia Celular y Retrovirus, Instituto de Salud Carlos III, Madrid, Spain.
De La Campa
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AG
D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001483:Base Sequence; D002876:Chromosomes, Bacterial / Q000502:physiology; D027101:DNA Topoisomerase IV; D004250:DNA Topoisomerases, Type II / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000032:analysis / Q000302:isolation & purification; D004352:Drug Resistance, Microbial / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D024841:Fluoroquinolones; D008969:Molecular Sequence Data; D010641:Phenotype; D016133:Polymerase Chain Reaction; D013296:Streptococcus pneumoniae / Q000201:enzymology* / Q000235:genetics; D059005:Topoisomerase II Inhibitors; D014169:Transformation, Bacterial
D000890:Anti-Infective Agents; D004269:DNA, Bacterial; D024841:Fluoroquinolones; D059005:Topoisomerase II Inhibitors; D027101:DNA Topoisomerase IV; D004250:DNA Topoisomerases, Type II