TABLE 2.
Secondary structure of PulS, Sdom, and the PulS-Sdom complex
| Sample | Relative secondary structurea |
Tmb | ΔHb | |||
|---|---|---|---|---|---|---|
| α | β | Turn | Unordered | |||
| °C | kcal/mol | |||||
| PulS | 84 | 0 | 7 | 8 | 77.3 ± 0.1 | 60.8 ± 1.0 |
| Sdom | 17 | 19 | 19 | 46 | NAc | NA |
| PulS + Sdomd | 54 | 5 | 12 | 30 | NA | NA |
| Complex | 63 | 3 | 11 | 24 | 80.6 ± 0.1 | 70.2 ± 1.0 |
a Relative secondary structure was estimated from the far-UV CD spectra using the CDSSTR routine of the DICHROWEB server run on the SP175 reference dataset, see “Experimental Procedures.”
b The thermal denaturation profiles were analyzed by a nonlinear least squares fit assuming a two-state transition and were used to calculate the melting temperature (Tm) and enthalpy of unfolding (ΔH); see under “Experimental Procedures.”
c NA means not applicable.
d Theoretical spectrum of an equimolar mixture of PulS + Sdom was calculated as a mean of each individual spectrum weighted according to their masses and the number of each amino acid in each protein and deconvoluted to give the predicted secondary structure.