Ip Stephen C Y, Bregu Migena, Barre François-Xavier, Sherratt David J
University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
EMBO J. 2003 Dec 1;22(23):6399-407. doi: 10.1093/emboj/cdg589.
DNA replication results in interlinked (catenated) sister duplex molecules as a consequence of the intertwined helices that comprise duplex DNA. DNA topoisomerases play key roles in decatenation. We demonstrate a novel, efficient and directional decatenation process in vitro, which uses the combination of the Escherichia coli XerCD site-specific recombination system and a protein, FtsK, which facilitates simple synapsis of dif recombination sites during its translocation along DNA. We propose that the FtsK-XerCD recombination machinery, which converts chromosomal dimers to monomers, may also function in vivo in removing the final catenation links remaining upon completion of DNA replication.
由于构成双链DNA的螺旋相互缠绕,DNA复制会产生相互连接(连环)的姐妹双链分子。DNA拓扑异构酶在解连环过程中起关键作用。我们在体外证明了一种新的、高效且定向的解连环过程,该过程利用了大肠杆菌XerCD位点特异性重组系统和一种蛋白质FtsK的组合,FtsK在沿DNA易位过程中促进dif重组位点的简单联会。我们提出,将染色体二聚体转化为单体的FtsK-XerCD重组机制在体内也可能发挥作用,以去除DNA复制完成后留下的最终连环连接。