FIGURE 3.

A and B, comparison of CPV resolvase (A) and E. coli RuvC (B) structures. The α1 and α2 helices are longer in RuvC, and RuvC has a short α3 helix not present in resolvase. The α4 helix is longer in CPV resolvase. In A, residues whose alanine mutations disrupt activity in FPV resolvase are colored red (Asp⁸, Glu⁵⁹, Lys¹⁰¹, Asp¹³¹, and Asp¹³⁴), and those that retain some activity are black (Glu³², Asp⁵⁴, and Asp¹³⁰). In B, the conserved active site residues are indicated (yellow/red). C, superposition of resolvase and RuvC subunits. The RuvC structure shown is PDB code 1HJR.