Site-specific tyrosine recombinase, which acts by catalyzing the cutting and rejoining of the recombining DNA molecules. Binds cooperatively to specific DNA consensus sequences that are separated from XerD binding sites by a short central region, forming the heterotetrameric XerC-XerD complex that recombines DNA substrates. The 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. In the complex XerC specifically exchanges the top DNA strands. FtsK may regulate the catalytic switch between XerC and XerD in the heterotetrameric complex during the two steps of the recombination process. Forms a cyclic heterotetrameric complex composed of two molecules of XerC and two molecules of XerD, in which XerC interacts with XerD via its C-terminal region, XerD interacts with XerC via its C-terminal region and so on. Belongs to the 'phage' integrase family. XerC subfamily.