Table 1.

Analysis of equilibrium unfolding of wild type and fluorine-labelled variants of BsCspB using fluorescence spectroscopy (Fig. 2) to determine the overall thermodynamic stability, ΔG⁰. The cooperativity of protein unfolding has been used as global parameter in Eq. (3) taking all seven folded-to-unfolding transitions into account and has been determined to m = −2.9 ± 0.1 kJ/(mol M).

Protein	ΔG0/kJ/mol	CM/M
wt BsCspB	11.1 ± 0.5	3.8 ± 0.2
2-19F-Phe-BsCspB	10.0 ± 0.7	3.5 ± 0.2
3-19F-Phe-BsCspB	10.5 ± 0.6	3.6 ± 0.2
4-19F-Phe-BsCspB	9.6 ± 0.6	3.3 ± 0.2
4-19F-Trp-BsCspB	12.7 ± 1.1	4.4 ± 0.4
5-19F-Trp-BsCspB	9.0 ± 0.5	3.1 ± 0.2
6-19F-Trp-BsCspB	11.0 ± 0.7	3.8 ± 0.2

The midpoint of folded-to-unfolding transition, C_M, has been calculated using C_M = ΔG⁰/m.