HPLC chromatograms for c-di-GMP PDE activities of E169A Fe-TM0186: (A) as-isolated, (B) as-isolated and preincubated with 10 mM manganous chloride (+Mn2+), (C) reduced, (D), reduced and preincubated with 80 μM ferrous ammonium sulfate (+Fe2+), or (E) reduced and preincubated with 10 mM manganous chloride (+Mn2+), and sampled at the indicated times following addition of c-di-GMP.