Figure 3.
Zinc-binding affinity of AdcAs and PAR competition for zinc ions. A, the five protein constructs used to determine the biophysical properties. The constructs were overexpressed in E. coli BL21 (DE3) strain and purified. B, UV-visible spectra of PAR, which competes for zinc, for Zn-C-AdcA, Zn-N-AdcA, and Zn2-AdcA in the presence or absence of guanidine hydrochloride (Gdn.HCl). C–G, isothermal titration calorimetry binding curves of WT AdcA (C), C-AdcA (D), N-AdcA (E), the N-lobe (F), and the C-lobe (G) at 25 °C. The parameters N, KD, ΔH, and ΔS are shown in the diagrams.