Sequences A-D were recovered from a BLAST search of the environmental subdivision database using the I-TevI linker as query sequence (amino acids 93-167). Residue numbering of I-TevI is below the sequence. Sequence alignments are shown as blocks that correspond to the I-TevI catalytic domain, the linker, the DNA-binding domain, and residues C-terminal to the DNA binding domain. Black shading represents residues that are absolutely conserved among the five sequences and gray shading represents conserved residues with conservative changes. Residues that correspond to the GIY-YIG signature sequences are boxed. GenBank IDs to the hypothetical proteins (Marine Metagenome ID) are: A, 140852551 (Gos_3956749); B, 136178932 (Gos_8413892); C, 136165525 (Gos_8427889); D, 140538853 (Gos_4034147).