Table 1. Thermodynamic parameters of the interactions of CcCBM17 and BspCBM28 with RC in 50 mM potassium phosphate, pH 7.0.
Values are means±S.D. of triplicate experiments. The stoichiometry of the interaction (n) was determined as described in the Materials and methods section. [N]o indicates the concentration of binding sites per g of cellulose, and was determined as described in the Materials and methods section. N/A, not applicable. 1 cal=4.184 J.
| CBM/method | Temp (°C) | No. of sites | 10−4×Ka (M−1) | ΔG (kcal/mol) | ΔH (kcal/mol) | ΔS (cal/mol per K) | n | [N]o (μmol/g) |
|---|---|---|---|---|---|---|---|---|
| CcCBM17 | ||||||||
| ITC | 15 | 1 | 60.7±14.0 | −7.6±0.1 | −21.3±0.6 | −47.5±2.6 | 0.25±0.01 | 6.2±0.2 |
| 2 | 1.2±0.2 | −5.3±0.1 | −8.8±0.3 | −11.8±1.3 | 0.68 | 15.9 | ||
| ITC | 25 | 1 | 54.0±18.0 | −7.8±0.2 | −24.2±0.7 | −55.0±3.1 | 0.23±0.00 | 5.5±0.0 |
| 2 | 1.2±0.4 | −5.5±0.2 | −10.3±1.1 | −15.9±4.5 | 0.68 | 15.9 | ||
| ITC | 35 | 1 | 59.6±0.4 | −8.1±0.0 | −21.5±0.5 | −43.4±1.7 | 0.25±0.01 | 6.2±0.2 |
| 2 | 1.3±0.3 | −5.8±0.2 | −10.5±0.9 | −15.5±3.5 | 0.68 | 15.9 | ||
| Depletion* | 25 | 1 | 113.0±0.1 | −8.4±0.3 | N/A | N/A | N/A | 8.6±1.4 |
| 2 | 1.8±0.5 | −5.9±0.4 | N/A | N/A | N/A | 15.9±1.3 | ||
| ITC – G6† | 25 | − | 5.9±0.1 | −6.6±0.0 | −14.5±0.0 | −27.5±0.7 | 1 | N/A |
| BspCBM28 | ||||||||
| ITC | 15 | 1 | 44.6±2.4 | −7.3±0.3 | −19.3±2.7 | −41.7±10.4 | 0.26±0.02 | 2.7±0.3 |
| 2 | 2.0±0.3 | −5.7±0.1 | −7.3±2.3 | −5.6±7.6 | 0.65 | 6.8 | ||
| Depletion* | 25 | 1 | 99.0±0.2 | −8.3±0.4 | N/A | N/A | N/A | 3.7±0.4 |
| 2 | 2.1±0.1 | −5.9±0.4 | N/A | N/A | N/A | 6.8±0.6 | ||
| ITC – G6‡ | 25 | − | 4.0±0.1 | −6.4±0.0 | −14.9±0.0 | −28.6±0.5 | 1 | N/A |