Electron microscopic single particle analysis of a tetrameric RuvA/RuvB/Holliday junction DNA complex.
During the late stage of homologous recombination in prokaryotes, RuvA binds to the Holliday junction intermediate and executes branch migration in association with RuvB. The RuvA subunits form two distinct complexes with the Holliday junction: complex I with the single RuvA tetramer on one side of the four way junction DNA, and complex II with two tetramers on both sides. To investigate the functional roles of complexes I and II, we mutated two residues of RuvA (L125D and E126K) to prevent octamer formation. An electron microscopic analysis indicated that the mutant RuvA/RuvB/Holliday junction DNA complex formed the characteristic tripartite structure, with only one RuvA tetramer bound to one side of the Holliday junction, demonstrating the unexpected stability of this complex. The novel bent images of the complex revealed an intriguing morphological similarity to the structure of SV40 large T antigen, which belongs to the same AAA+ family as RuvB.
Mayanagi
Kouta
K
Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga 526-0829, Japan. maya@protein.osaka-u.ac.jp
Fujiwara
Yoshie
Y
Miyata
Tomoko
T
Morikawa
Kosuke
K
D001426:Bacterial Proteins / Q000737:chemistry* / Q000648:ultrastructure*; D001665:Binding Sites; D003198:Computer Simulation; D003461:Crystallography / Q000379:methods; D004265:DNA Helicases / Q000737:chemistry* / Q000648:ultrastructure*; D045566:DNA, Cruciform / Q000737:chemistry* / Q000648:ultrastructure*; D019281:Dimerization; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000648:ultrastructure*; D008854:Microscopy, Electron / Q000379:methods; D008956:Models, Chemical; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D010316:Particle Size; D011485:Protein Binding; D011487:Protein Conformation
D001426:Bacterial Proteins; D045566:DNA, Cruciform; D029968:Escherichia coli Proteins; C061260:RuvB protein, Bacteria; C071059:Holliday junction DNA helicase, E coli; D004265:DNA Helicases