KptA ADP-ribosyltransferase domain observed in kinetoplastid DICER-like (DCL) enzymes. Appears to have lost most residues required for catalyzing phospho-transfer to NAD; however, several positively-charged residues implicated in RNA end recognition remain well-conserved [1].

1: RNA damage in biological conflicts and the diversity of responding RNA repair systems. Burroughs AM, Aravind L; Nucleic Acids Res. 2016;44:8525-8555. PMID:27536007