The N-terminal domain of the resolvase family (this family) contains the active site and the dimer interface. The extended arm at the C-terminus of this domain connects to the C-terminal helix-turn-helix domain of resolvase - see Pfam:PF02796.
This domain is usually found associated with Pfam:PF00239 in putative integrases/recombinases of mobile genetic elements of diverse bacteria and phages.