This superfamily represents domain IV (residues 128-272), from intein homing endonuclease. Inteins are segments of protein which excise themselves from a precursor protein and mediate the rejoining of the remainder of the precursor (the extein). Most inteins consist of a splicing domain which is split into two segments by a homing endonuclease domain.

According to DALI server, proteins with the closest structural homologies in domain IV are putative DNA binding proteins such as the predicted transcription regulator (PDB 1XMA), Esa1 histone acetyltransferase fragment (PDB 1FY7), and the cell division control protein 6 (Cdc6, PDB 1FNN). Because the corresponding domain of Cdc6 has been reported to be highly conserved, and to possibly be a DNA binding element, domain IV of PI-TkoII might have the potential to bind to DNA. Many positive-charged residues are located on the surface of domain IV.

DOI:10.1002/prot.20858,PFAM:PF14890