RuvABC (Recombination UV) is a complex of three proteins that mediate branch migration and resolve the Holliday junction created during homologous recombination in bacteria. As such, RuvABC is critical to bacterial DNA repair. RuvA and RuvB bind to the four strand DNA structure formed in the Holliday junction intermediate, and migrate the strands through each other, using a putative spooling mechanism. The RuvAB complex can carry out DNA helicase activity, which helps unwind the duplex DNA. The binding of the RuvC protein to the RuvAB complex is thought to cleave the DNA strands, thereby resolving the Holliday junction. RuvB is an ATPase that is only active in the presence of DNA and compared to RuvA, RuvB has a low affinity for DNA. The RuvB proteins are thought to form hexameric rings on the exit points of the newly formed DNA duplexes, and it is proposed that they 'spool' the emerging DNA through the RuvA tetramer. Here you can see a recent cryoEM structure of RuvB protein hexamer in complex with a synthetic DNA and isolated from the thermophilic bacterium Thermus thermophilus (PDB code: 8EFV)

#molecularart ... #immolecular ... #helicase ... #DNArepair ... #holliday ... #junction ... #ruvb ... #atpase ... #cryoem

Structure rendered with @proteinimaging and depicted with @corelphotopaint