Table 2. Thermal stability of single-residue variants determined by DSF and predicted fold-stability of each substitution by STRUM analysis.
| Protein | Tm (°C)1 | ΔTm (°C)2 | ΔΔGcalc (kcal/mol)3 |
|---|---|---|---|
| I153A | 57.3 ± 0.1 | −5 | −1.98 |
| Y178A | 58.4 ± 0.1 | −4.1 | −1.79 |
| A31L | 58.4 ± 0.1 | −4.1 | −0.47 |
| G35T | 59.4 ± 0.1 | −3.1 | −0.45 |
| D23A | 59.8 ± 0.1 | −2.7 | +0.16 |
| K36A | 63.1 ± 0.1 | +0.6 | +0.83 |
| K36E | 66.1 ± 0.1 | +3.6 | +0.65 |
| WT | 62.5 ± 0.1 | N/A | N/A |
1
The Tm values were determined from the thermal melt curves for each C3larvinA protein using Thermal Shift Software v1 (Applied Biosystems).
2
The ΔTm values were calculated from the difference between the WT Tm (62.5°C) and each variant (Δ Tm = Tm variant − Tm wild-type).
3
The ΔΔG values (kcal/mol) for folded stability change for each substitution variant were calculated using the STRUM algorithm where ΔΔG = ΔG wild-type − ΔG variant. A ΔΔG value above zero indicates the substitution is stabilizing, while a value under zero indicates the substitution is destabilizing.