title: Structural snapshots of Xer recombination reveal activation by synaptic complex remodeling and DNA bending.
abstract: Bacterial Xer site-specific recombinases play an essential genome maintenance role by unlinking chromosome multimers, but their mechanism of action has remained structurally uncharacterized. Here, we present two high-resolution structures ofHelicobacter pyloriXerH with its recombination site DNAdifH, representing pre-cleavage and post-cleavage synaptic intermediates in the recombination pathway. The structures reveal that activation of DNA strand cleavage and rejoining involves large conformational changes and DNA bending, suggesting how interaction with the cell division protein FtsK may license recombination at the septum. Together with biochemical and in vivo analysis, our structures also reveal how a small sequence asymmetry indifHdefines protein conformation in the synaptic complex and orchestrates the order of DNA strand exchanges. Our results provide insights into the catalytic mechanism of Xer recombination and a model for regulation of recombination activity during cell division.
authors.affiliation: Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Bebel
authors.affiliation: Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
authors.forename: Ezgi
authors.initials: E
authors.lastname: Karaca
authors.affiliation: Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
authors.forename: Banushree
authors.initials: B
authors.lastname: Kumar
authors.affiliation: Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, United Kingdom.
authors.forename: W Marshall
authors.initials: WM
authors.lastname: Stark
authors.affiliation: Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
authors.forename: Orsolya
authors.identifier: 0000-0002-2873-5872
authors.initials: O
authors.lastname: Barabas
mesh_terms: D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D016480:Helicobacter pylori / Q000201:enzymology*; D006868:Hydrolysis; D008954:Models, Biological; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D011487:Protein Conformation; D045522:Recombinases / Q000737:chemistry* / Q000378:metabolism*; D011995:Recombination, Genetic; D014961:X-Ray Diffraction
chemical_list: D045522:Recombinases; D004247:DNA
keywords: E. coli; Helicobacter pylori; X-ray crystallography; biophysics; chromosome segregation; chromosomes; genes; genome maintenance; microbiology; site-specific DNA recombination; structural biology