Data for: Circular dichroism spectroscopy reveals multiple phytochrome photoproducts in equilibrium

This work involves characterization of the model cyanobacterial
phytochrome photoreceptor Cph1 from Synechocystis sp. PCC6803, using
characterization of different truncations and variant proteins constructed
using site-directed mutagenesis. Wild-type Cph1 photoconverts between two
photostates: a red-absorbing, dark-adapted Pr state in which the
phycocyanobilin (PCB) chromophore is in the 15Z configuration, and a
far-red-absorbing Pfr photoproduct in which PCB is instead in the 15E
configuration. Proteins were characterized using absorption and circular
dichroism spectroscopy. Absorption spectra were taken under native and
denaturing conditions. Absorption and circular dichroism (CD) spectra were
also taken at different pH values. All variants were examined after
recombinant co-expression with enzymes for the synthesis of PCB in E.
coli. One additional variant was also examined after expression and
purification without chromophore biosynthesis, followed by in vitro
assembly with PCB.