Table 3.
Thermodynamics of lectin/sugar binding. Thermodynamics of binding for different monosaccharides interacting with PA-IIL and its mutants, compared to thermodynamic characteristics of mannose-preferring lectin RS-IIL from Ralstonia solanacearum as determined by ITC at 25°C. Standard deviations calculated from three independent measurements for all ligands.
| KA [×104M-1] | KD [μM] | ΔG [kJ/mol] | ΔH [kJ/mol] | -TΔS [kJ/mol] | |
| Me-α-L-Fuc | |||||
| G24N | 524 (± 36.7) | 0.19 (± 0.03) | -38.4 (± 0.2) | -40.1 (± 0.7) | 1.8 (± 0.7) |
| S23A | 418 (± 72.8) | 0.25 (± 0.01) | -37.8 (± 0.4) | -33.9 (± 1.2) | -3.8 (± 0.9) |
| PA-IIL a | 235 (± 8.0) | 0.43 (± 0.01) | -36.4 (± 0.1) | -41.3 (± 1.0) | 4.9 (± 1.0) |
| S22A | 26.4 (± 4.9) | 3.96 (± 0.91) | -30.9 (± 0.5) | -37.1 (± 0.6) | 6.2 (± 0.9) |
| RS-IILb | < 1 | > 100 | |||
| L-Fuc | |||||
| S23A | 23.8 (± 3.4) | 4.3 (± 0.6) | -30.6 (± 0.4) | -26.9 (± 0.2) | -3.7 (± 0.6) |
| G24N | 15.2 (± 2.3) | 6.6 (± 0.9) | -30.0 (± 0.4) | -31.1 (± 0.4) | 1.1 (± 0.7) |
| PA-IIL c | 12.0 (± 1.0) | 8.3 (± 0.7) | -29.0 (± 0.1) | -27.7 (± 0.5) | -1.3 (± 0.5) |
| S22A | 10.3 (± 0.4) | 9.7 (± 0.4) | -28.6 (± 0.1) | -26.8 (± 0.7) | -1.8 (± 0.6) |
| RS-IIL | nd | nd | nd | nd | nd |
| Me-α-L-Gal | |||||
| PA-IIL a | 85.0 (± 5.0) | 1.17 (± 0.07) | -33.8 (± 0.1) | -31.5 (± 0.6) | -2.3 (± 0.7) |
| G24N | 82.2 (± 18.8) | 1.29 (± 0.35) | -33.7 (± 0.6) | -18.7 (± 0.3) | -15.0 (± 0.9) |
| S23A | 81.6 (± 14.4) | 1.23 (± 0.07) | -33.9 (± 0.4) | -26.8 (± 1.7) | 7.1 (± 1.3) |
| S22A | 6.75 (± 0.31) | 15.0 (± 0.66) | -27.6 (± 0.5) | -19.2 (± 0.2) | -8.3 (± 0.3) |
| RS-IIL | nd | nd | nd | nd | nd |
| Me-β-D-Man | |||||
| RS-IIL | 438 (± 2.0) | 0.23 (± 0.01) | -37.9 (± 0.1) | -24.9 (± 0.2) | -13.0 (± 0.2) |
| S22A | 36.0 (± 1.8) | 2.78 (± 0.14) | -31.7 (± 0.1) | -24.3 (± 0.6) | -7.4 (± 0.7) |
| G24N | 2.34 (± 0.17) | 42.9 (± 3.12) | -24.9 (± 0.2) | -27.1 (± 0.8) | 2.1 (± 0.9) |
| S23A | 1.91 (± 0.33) | 54.0 (± 9.32) | -24.4 (± 0.4) | -16.7 (± 2.3) | -7.7 (± 2.7) |
| PA-IIL a | 1.42 (± 0.05) | 71.0 (± 3.00) | -23.7 (± 0.1) | -17.8 (± 1.3) | -5.9 (± 0.3) |
a taken from Sabin, C. et al, 2006 [14]
b value < 104 M-1 [18]
c taken from Perret, S. et al, 2005 [11]