Domain illustration of MGME1 and structural comparison with RecE and RecB nucleases. (A) MGME1 contains characteristic of RecB-type and RecE-type nuclease motifs (Ia, I, II, III, and IV). (B) Overall view of MGME1 (PDB:5ZYW), RecE (PDB: 3H4R), and RecB (1W36) nucleases with their active sites highlighted in (C). Conserved residues at their active sites are highlighted.