Part:BBa_K3512001
ccdB Toxin
The CcdB toxin is part of the CcdA-CcdB system. The target of CcdB is the GyrA subunit of DNA gyrase, an essential type II topoisomerase in Escherichia coli. Gyrase alters DNA topology by effecting a transient double-strand break in the DNA backbone, passing the double helix through the gate and resealing the gaps. The CcdB toxin acts by trapping DNA gyrase in a cleaved complex with the gyrase A subunit covalently closed to the cleaved DNA, causing DNA breakage and cell death in a way closely related to quinolones antibiotics.
In absence of the antitoxin CcdA, the CcdB toxin traps DNA-gyrase cleavable complexes, inducing breaks into DNA and cell death.
3D View
Contribution: Bioplus-China 2022
Reference
Mine, N., Guglielmini, J., Wilbaux, M. and Van Melderen, L., 2009. The Decay of the Chromosomally Encoded ccdO157 Toxin–Antitoxin System in the Escherichia coli Species. Genetics, 181(4), pp.1557-1566.
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000INCOMPATIBLE WITH RFC[1000]Illegal BsaI site found at 216
//biosafety/kill_switch
//function/celldeath
dissociation_constant | High affinity = 3.57*10^-3 nM |
protein | Dissociation complex = 1.36*10^-9 nM |