Fig. 6. Comparison of ion pairs between subunits A and D for the three proteins, PfPCP (a), BaPCP (b), TlPCP (c). There are ten salt bridges at each interface in PfPCP, Asp80-Arg87, Asp87-Lys118, Glu99-Lys118, Asp100-Arg80, and Asp100-Lys118, and its noncrystallographic symmetry-related pairs form salt bridge interactions. The figure was produced using MOLSCRIPT (38).