Site-specific tyrosine recombinase, which acts by catalyzing the cutting and rejoining of the recombining DNA molecules. The XerC-XerD complex is essential to convert dimers of the bacterial chromosome into monomers to permit their segregation at cell division. It also contributes to the segregational stability of plasmids. Forms a cyclic heterotetrameric complex composed of two molecules of XerC and two molecules of XerD. Belongs to the 'phage' integrase family. XerD subfamily.