Residues Clustered in the Light-Sensing Knot of Phytochrome B are Necessary for Conformer-Specific Binding to Signaling Partner PIF3
A) Phytochrome difference spectra of recombinant phyBNT (WT) and missense-mutant phyBNT-derivative proteins synthesized in E. coli. B) Western-blot (WB) staining of wild-type phyBNT and missense mutants showing relative protein amount. C) Scatter plot showing ΔΔAbsorbance of each missense mutant and wild-type phyBNT normalized to relative protein amount determined from WB staining as in panel B. Solid line represents the wild-type standard curve determined from a dilution series, as in Figure 4D. Open circles represent values for wild-type protein and closed circles represent values for mutant variants. D) Quantification of difference spectra for each mutant relative to wild-type phyB protein. E) Pr and Pfr absorbance spectra for wild-type and Class II phyBNT mutant proteins showing normal spectral properties.