Table 3.
Interplay of IIAGlc and Nb with LacY:melibiose binary complexa
| Titrant (Syringe) | Titrand (Sample Cell) | Kd (nM) | ΔG[ΔΔG]b | ΔH [ΔΔH] | −TΔS [−TΔΔS] | N |
|---|---|---|---|---|---|---|
| (kJ/mol) | ||||||
| IIAGlc | WT LacY:Nb-9036 | ND | ND | ND | ND | |
| IIAGlc | WT LacY:Nb-9065 | ND | ND | ND | ND | |
| Nb-9036 | WT LacY | 39.3 (8.2) | −42.3 (0.5) | −38.1 (0.6) | −4.2 (0.7) | 1.0 (0.1) |
| WT LacY: IIAGlc | 80.5 (1.7) | −40.5 (0.1) | −40.9 (0.5) | 0.4 (0.6) | 1.0 (0.1) | |
| [1.8±] | [−2.8±] | [3.8*] | ||||
| Nb-9065 | WT LacY | 138.6 (23.1) | −39.2 (0.5) | −31.4 (0.8) | −7.9 (1.3) | 1.2 (0.1) |
| WT LacY: IIAGlc | 1,915.2 (255.2) | −32.7 (0.3) | −19.0 (0.2) | −13.7 (0.2) | 0.9 (0.0) | |
| [6.5**] | [12.3**] | [−5.9*] | ||||
a
ITC were measured at 25 °C in the presence of 10 mM melibiose and data were presented in Fig. 4;
b
Difference in the absence and presence of IIAGlc;
c
s.e.m., number of tests = 2-3. N, stoichiometry;
±
not quite statistically significant;
*
statistically significant;
**
very statistically significant.