Practice question

Branch migration by RuvAB creates mobile junction but final separation into two duplexes demands nuclease action. RuvC is endonuclease that recognizes Holliday junction structure specifically, introducing paired nicks on opposing strands at preferred sequence 5'-(A/TTTG/C)-3' near crossover. Dimeric enzyme coordinates two active sites containing conserved aspartates binding magnesium, executing concerted cleavage producing ligatable products. Orientation of cuts determines outcome: north-south cutting yields non-crossover patches, east-west cutting yields crossover splices. RuvC action terminates recombination, resolving linkages that would otherwise block chromosome segregation during replication fork rescue and double-strand break repair.