Putative tyrosine recombinase. Not involved in the cutting and rejoining of the recombining DNA molecules on dif(SL) site. Belongs to the 'phage' integrase family. XerD-like subfamily. Although named XerD by PubMed:11763967, it is not the ortholog of XerD and constitutes a distinct protein family. In contrast to the classic XerD protein, it does not contain the Arg-His-Arg-His (R-H-R-H) sandwich residues that are clustered with the Tyr active site. It also lacks the C-terminal region which is known to mediate the interaction with XerC. It is therefore unknown whether it has tyrosine recombinase activity or act as a regulator.