ccdB基因位于大肠杆菌的 F质粒 上，是被ccd操纵子编码的毒性-抗毒性系统的一部分，确保含F质粒的细胞分裂后F质粒仍存在（分裂后含F质粒的细胞才能存活）。 ccdB编码的毒性蛋白 CcdB，作为DNA促旋酶抑制剂，锁定DNA促旋酶和断裂的双链DNA复合物，使DNA促旋酶不能发挥作用，最终导致细胞死亡。 ccdA是ccd操纵子中的另一个基因，编码抗毒性蛋白 CcdA，保护细胞免受CcdB的毒性作用。 细胞因为丢失F质粒而丢失了ccdA基因，导致细胞屈服于CcdB的毒性。 F …

The CcdA/CcdB Type II Toxin-antitoxin system is one example of the bacterial toxin-antitoxin (TA) systems that encode two proteins, one a potent inhibitor of cell proliferation (toxin) and the other its specific antidote (antitoxin).

2017年12月8日 · The ccdB gene, located on the F sex factor plasmid of E. coli, is part of a toxin-antitoxin system encoded by the ccd operon, which is responsible for plasmid maintenance during cell division. ccdB codes for the toxic protein (CcdB) that acts as a DNA gyrase poison, locking up DNA gyrase with broken double stranded DNA and ultimately causing cel...

In this study, we used the CcdB toxin as a selection marker to improve Cpf1-based plasmids designed for genome-editing in cyanobacteria. Our results demonstrate that this selection increased the rate of success of plasmid construction, and thus of genome editing. Figure 1.

Gateway 的核心之一就是利用 ccdB 的毒性，从而达到negative selection. ccdB是一种DNA gyrase， 其工作原理如下图： 它能让DNA的超螺旋结构变成逆向螺旋，因此对 E.coli 具有毒性。 Gateway如何利用它的毒性呢？

2022年1月2日 · The first commercial application of a toxin–antitoxin system used the ccdB toxic gene to generate a cloning vector that enables positive selection 219,220.

Cell killing by CcdB is accompanied by filamentation, defects in chromosome and plasmid segregation, defects in cell division, formation of anucleate cells, decreased DNA synthesis and plasmid loss. Interferes with the activity of DNA gyrase, inducing it to form a covalent GyrA-DNA complex that cannot be resolved, thus promoting breakage of ...

CcdB, the toxin from the ccd system on the Escherichia coli F plasmid, acts as a gyrase poison [1]. The ccd operon of the F plasmid encodes CcdB, a toxin targeting the essential gyrase of Escherichia coli, and CcdA, the unstable antidote that interacts with CcdB to …

2023年5月4日 · ccdB基因位于大肠杆菌 F性因子质粒 上，是 ccd操纵子 编码的毒素-抗毒素系统的一部分，负责细胞分裂过程中质粒的维持。 ccdB编码毒性蛋白( CcdB )，它作为DNA旋转酶毒剂，与断裂的双链DNA一起锁住DNA旋转酶，最终导致细胞死亡。

The ccd locus of the F plasmid codes for two gene products, CcdA and CcdB, which contribute to the plasmid's high stability by post-segregational killing of plasmid-free bacteria. Like the quinolones, the CcdB protein is a poison of the DNA-topoisomerase II complexes, while CcdA acts as an antidote …