The F plasmid CcdB protein induces efficient ATP-dependent DNA cleavage by gyrase.
DNA topoisomerases perform essential roles in DNA replication, gene transcription, and chromosome segregation. Recently, we identified a new type of topoisomerase II poison: the CcdB protein of plasmid F. When its action is not prevented by CcdA protein, the CcdB protein is a potent cytotoxin. In this paper, using purified CcdB, CcdA and gyrase, we show that CcdB protein efficiently traps gyrase in a cleavable complex. The CcdA protein not only prevents the gyrase poisoning activity of CcdB but also reverses its effect on gyrase. The mechanism by which the CcdB protein induces DNA strand breakage is closely related to the action of quinolone antibiotics. However, the ATP dependence of the CcdB cleavage process differentiates the CcdB mechanism from quinolone-dependent reactions because the quinolone antibiotics stimulate efficient DNA breakage, whether or not ATP is present. We previously showed that bacteria resistant to quinolone antibiotics are sensitive to CcdB and vice versa. Elucidation of the mechanism of action of CcdB protein may permit the design of drugs targeting gyrase so as to take advantage of this new poisoning mechanism.
Bernard
P
P
Département de Biologie Moléculaire, Université Libre de Bruxelles, Rhode Saint Genèse, Belgium.
Kézdy
K E
KE
Van Melderen
L
L
Steyaert
J
J
Wyns
L
L
Pato
M L
ML
Higgins
P N
PN
Couturier
M
M
D000255:Adenosine Triphosphate / Q000378:metabolism; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism*; D001427:Bacterial Toxins / Q000302:isolation & purification / Q000378:metabolism*; D001483:Base Sequence; D003603:Cytotoxins / Q000378:metabolism*; D017931:DNA Primers; D004250:DNA Topoisomerases, Type II / Q000302:isolation & purification / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005144:F Factor; D005798:Genes, Bacterial; D007700:Kinetics; D008969:Molecular Sequence Data; D010957:Plasmids; D016133:Polymerase Chain Reaction; D015183:Restriction Mapping; D059005:Topoisomerase II Inhibitors
D001426:Bacterial Proteins; D001427:Bacterial Toxins; C068355:CcdA protein, Bacteria; C068356:CcdB protein, Plasmid F; D003603:Cytotoxins; D017931:DNA Primers; D059005:Topoisomerase II Inhibitors; D000255:Adenosine Triphosphate; D004250:DNA Topoisomerases, Type II