Fig. 2.
Comparison of BfiI with EDTA-resistant nonspecific Nuc nuclease from S. typhimurium. (a) Structural superposition of the N-terminal domain dimer of BfiI (light and dark blue) and Nuc nuclease (green). The active-site region of Nuc nuclease is boxed in red. (b) Close-up view of the active-site residues of Nuc nuclease (green) and their structural equivalents in BfiI (light and dark blue) shown in the same orientation as in a. The tungstate molecule coordinated at the putative scissile DNA phosphate-binding site in Nuc is shown in stick representation colored by atom type. Amino acid residues from both subunits of Nuc and BfiI contribute to a single active site located in the intersubunit cleft.