title: Structure and mechanism of the RuvB Holliday junction branch migration motor.
abstract: The RuvB hexamer is the chemomechanical motor of the RuvAB complex that migrates Holliday junction branch-points in DNA recombination and the rescue of stalled DNA replication forks. The 1.6 A crystal structure of Thermotoga maritima RuvB together with five mutant structures reveal that RuvB is an ATPase-associated with diverse cellular activities (AAA+-class ATPase) with a winged-helix DNA-binding domain. The RuvB-ADP complex structure and mutagenesis suggest how AAA+-class ATPases couple nucleotide binding and hydrolysis to interdomain conformational changes and asymmetry within the RuvB hexamer implied by the crystallographic packing and small-angle X-ray scattering in solution. ATP-driven domain motion is positioned to move double-stranded DNA through the hexamer and drive conformational changes between subunits by altering the complementary hydrophilic protein- protein interfaces. Structural and biochemical analysis of five motifs in the protein suggest that ATP binding is a strained conformation recognized both by sensors and the Walker motifs and that intersubunit activation occurs by an arginine finger motif reminiscent of the GTPase-activating proteins. Taken together, these results provide insights into how RuvB functions as a motor for branch migration of Holliday junctions.
authors.affiliation: Department of Molecular Biology, Skaggs Institute for Chemical Biology, The Scripps Research Institute, MB 4, 10550 North Torrey Pines Rd, La Jolla, CA 92037, USA.
authors.forename: C D
authors.initials: CD
authors.lastname: Putnam
authors.forename: S B
authors.initials: SB
authors.lastname: Clancy
authors.forename: H
authors.initials: H
authors.lastname: Tsuruta
authors.forename: S
authors.initials: S
authors.lastname: Gonzalez
authors.forename: J G
authors.initials: JG
authors.lastname: Wetmur
authors.forename: J A
authors.initials: JA
authors.lastname: Tainer
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001120:Arginine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009690:Nucleic Acid Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D011995:Recombination, Genetic / Q000235:genetics; D016415:Sequence Alignment; D013379:Substrate Specificity; D020124:Thermotoga maritima / Q000201:enzymology* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D020409:Molecular Motor Proteins; D009097:Multienzyme Complexes; D021122:Protein Subunits; C061260:RuvB protein, Bacteria; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D004247:DNA; D001120:Arginine; D000251:Adenosine Triphosphatases