Integrase mediates integration of a DNA copy of the viral genomeinto the host chromosome. Integrase is composed of threedomains. The amino-terminal domain is a zinc binding domainPfam:PF02022. This domain is the central catalytic domain. Thecarboxyl terminal domain that is a non-specific DNA bindingdomain Pfam:PF00552. The catalytic domain acts as anendonuclease when two nucleotides are removed from the 3' endsof the blunt-ended viral DNA made by reverse transcription. Thisdomain also catalyses the DNA strand transfer reaction of the 3'ends of the viral DNA to the 5' ends of the integration site[1]. Integrase core domain rve