Residues Clustered in the Light-Sensing Knot of Phytochrome B are Necessary for Conformer-Specific Binding to Signaling Partner PIF3
A–C) Representative zinc blots (zinc) for chromophore attachment and corresponding coomassie-blue (CB) staining controls for protein level of recombinant phyBNT (WT) and missense-mutant phyBNT-derivative proteins synthesized in E. coli. D) Scatter plot of chromophore binding of each phyBNT mutant relative to the corresponding amount of recombinant protein for that mutant. Solid line represents the standard curve for wild-type chromophore binding as determined for a dilution series of wild-type phyBNT protein. Open circles represent chromophore binding for wild-type phyBNT with relative amounts of wild-type protein indicated. Closed circles represent chromophore binding for missense mutants. E) Quantification of chromophore binding relative to undiluted (WT1) wild-type phyBNT recombinant protein.