This is the N-terminal restriction endonuclease-like domain found in several archaeal TATA-binding protein (TBP)-interacting proteins [1].

1: Crystal structure of TBP-interacting protein (Tk-TIP26) and implications for its inhibition mechanism of the interaction between TBP and TATA-DNA. Yamamoto T, Matsuda T, Inoue T, Matsumura H, Morikawa M, Kanaya S, Kai Y; Protein Sci. 2006;15:152-161. PMID:16322571

2: Sequence, structure and functional diversity of PD-(D/E)XK phosphodiesterase superfamily. Steczkiewicz K, Muszewska A, Knizewski L, Rychlewski L, Ginalski K; Nucleic Acids Res. 2012;40:7016-7045. PMID:22638584