Table 3.
Heat capacity changes and solvent-accessible surface area for eRF3 binding to eRF1, GDP and GTPa
| Sample | Ligand |
 (cal mol−1 K−1) |
 (cal mol−1 K−1) |
SAAminb (Å2) | SAAmaxb (Å2) |
|---|---|---|---|---|---|
| eRF3 | GDP | −55 | −39 | 137.5 | 203 |
| eRF3 | eRF1 | −281 | −237 | 702.5 | 1040 |
| eRF3Cp | eRF1 | −270 | −235 | 675 | 1000 |
| eRF1:eRF3 | GDP | −96 | −100 | 240 | 355.5 |
| eRF1:eRF3 | GTP | −1470 | −1480 | 3675 | 5444 |
| eRF1:eRF3Cp | GTP | −850 | −805 | 2125 | 3148 |
aHeat capacity changes were obtained as d(ΔH)/dT and d(ΔS)/d(lnT).
bChanges in SAA were estimated using the following formula: ΔCp = 0.27ΔAaromatic + 0.4ΔAnon-aromatic, where ΔAaromatic and ΔAnon-aromatic are the protected areas due to aromatic and non-aromatic amino acids in Å2, respectively (36). SAAmin and SAAmax are calculated assuming that all the changes are conferred by non-aromatic and aromatic residues, respectively.