Fig. S2.

Silence of reversible photochemistry of ApcEΔ and its variants. Samples were reconstituted in E. coli (Table S5), purified with Ni²⁺ affinity chromatography, and then kept in KPB (20 mM, 0.15 M NaCl, pH 7.5). These absorption (A) spectra were measured under native conditions (solid lines) or darkly denatured conditions (dashed lines), respectively, before irradiation (black lines), after irradiation at 600 nm (blue lines), and after irradiation at 650 nm (red lines) at a light intensity of 30 μmol⋅m⁻²⋅s⁻¹ for 10 min. The difference spectra were inserted. The denaturation was realized with 8 M acidic urea (pH 1.5) for 15 min.