Table 2. Zinc-binding properties of ZiPD, FlRd-lactamase domain and its E81H mutant as determined by ITC.
Isothermal titrations of zinc to ZiPD, FlRd-lactamase domain and its E81H mutant were performed as described in the Experimental section and as depicted in Figure 3. Isothermal titration curves were analysed applying the sequential binding sites model with two binding sites. Temperature was 22 °C. 1 cal=4.184 J.
| ZiPD | FlRd-lactamase domain | FlRd-lactamase domain, E81H | |
|---|---|---|---|
| Kd1 (μM) | 2.2±0.2 | 0.7±0.1 | 30±4 |
| ΔH1 (cal/mol) | −6511±90 | −7607±71 | −15990±1126 |
| ΔS1 [cal/(mol·deg)] | 3.9 | 2.5 | −33.5 |
| ΔG1 (cal/mol) | −7661 | −8345 | −6107 |
| Kd2 (μM) | 23.0±0.6 | 26.0±0.1 | 23±2 |
| ΔH2 (cal/mol) | −12090±158 | −12000±142 | −4008±1297 |
| ΔS2 [cal/(mol·deg)] | −19.8 | −19.7 | 7.6 |
| ΔG2 (cal/mol) | −6249 | −6189 | −6250 |