Holliday junction branch migration complex subunit RuvB

UniProtKB accession:  Q9PMT7

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UniProtKB description:  The RuvA-RuvB-RuvC complex processes Holliday junction (HJ) DNA during genetic recombination and DNA repair, while the RuvA-RuvB complex plays an important role in the rescue of blocked DNA replication forks via replication fork reversal (RFR). RuvA specifically binds to HJ cruciform DNA, conferring on it an open structure. The RuvB hexamer acts as an ATP-dependent pump, pulling dsDNA into and through the RuvAB complex. RuvB forms 2 homohexamers on either side of HJ DNA bound by 1 or 2 RuvA tetramers; 4 subunits per hexamer contact DNA at a time. Coordinated motions by a converter formed by DNA-disengaged RuvB subunits stimulates ATP hydrolysis and nucleotide exchange. Immobilization of the converter enables RuvB to convert the ATP-contained energy into a lever motion, pulling 2 nucleotides of DNA out of the RuvA tetramer per ATP hydrolyzed, thus driving DNA branch migration. The RuvB motors rotate together with the DNA substrate, which together with the progressing nucleotide cycle form the mechanistic basis for DNA recombination by continuous HJ branch migration. Branch migration allows RuvC to scan DNA until it finds its consensus sequence, where it cleaves and resolves cruciform DNA.