Crystal structure of an octameric RuvA-Holliday junction complex.
Holliday junctions occur as intermediates in homologous recombination and DNA repair. In bacteria, resolution of Holliday junctions is accomplished by the RuvABC system, consisting of a junction-specific helicase complex RuvAB, which promotes branch migration, and a junction-specific endonuclease RuvC, which nicks two strands. The crystal structure of a complex between the RuvA protein of M. leprae and a synthetic four-way junction has now been determined. Rather than binding on the open surface of a RuvA tetramer as previously suggested, the DNA is sandwiched between two RuvA tetramers, which form a closed octameric shell, stabilized by a conserved tetramer-tetramer interface. Interactions between the DNA backbone and helix-hairpin-helix motifs from both tetramers suggest a mechanism for strand separation promoted by RuvA.
Department of Biochemistry and Molecular Biology, University College London, United Kingdom.
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D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry; D001665:Binding Sites; D018360:Crystallography, X-Ray / Q000379:methods; D004265:DNA Helicases; D004269:DNA, Bacterial / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000737:chemistry*; D004926:Escherichia coli; D029968:Escherichia coli Proteins; D046911:Macromolecular Substances; D008958:Models, Molecular; D009166:Mycobacterium leprae; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D046911:Macromolecular Substances; C071059:Holliday junction DNA helicase, E coli; D004265:DNA Helicases