5dcf
C-terminal domain of XerD recombinase in complex with gamma domain of FtsK
Structural highlights
FunctionXERC_ECOLI Site-specific tyrosine recombinase, which acts by catalyzing the cutting and rejoining of the recombining DNA molecules. Binds cooperatively to specific DNA consensus sequences that are separated from XerD binding sites by a short central region, forming the heterotetrameric XerC-XerD complex that recombines DNA substrates. The complex is essential to convert dimers of the bacterial chromosome into monomers to permit their segregation at cell division. It also contributes to the segregational stability of plasmids at ColE1 xer (or cer) and pSC101 (or psi) sites. In the complex XerC specifically exchanges the top DNA strands (By similarity).[1] [2] [3] Publication Abstract from PubMedBacterial chromosomes are most often circular DNA molecules. This can produce a topological problem; a genetic crossover from homologous recombination results in dimerization of the chromosome. A chromosome dimer is lethal unless resolved. A site-specific recombination system catalyses this dimer-resolution reaction at the chromosomal site dif. In Escherichia coli, two tyrosine-family recombinases, XerC and XerD, bind to dif and carry out two pairs of sequential strand exchange reactions. However, what makes the reaction unique among site-specific recombination reactions is that the first step, XerD-mediated strand exchange, relies on interaction with the very C-terminus of the FtsK DNA translocase. FtsK is a powerful molecular motor that functions in cell division, co-ordinating division with clearing chromosomal DNA from the site of septation and also acts to position the dif sites for recombination. This is a model system for unlinking, separating and segregating large DNA molecules. Here we describe the molecular detail of the interaction between XerD and FtsK that leads to activation of recombination as deduced from a co-crystal structure, biochemical and in vivo experiments. FtsKgamma interacts with the C-terminal domain of XerD, above a cleft where XerC is thought to bind. We present a model for activation of recombination based on structural data. Activation of Xer-recombination at dif: structural basis of the FtsKgamma-XerD interaction.,Keller AN, Xin Y, Boer S, Reinhardt J, Baker R, Arciszewska LK, Lewis PJ, Sherratt DJ, Lowe J, Grainge I Sci Rep. 2016 Oct 6;6:33357. doi: 10.1038/srep33357. PMID:27708355[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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