Assembly of apophytochromes with bilin 8-monoamides. (A) Absorbance spectra are shown for free BV (blue) and BV assembled with DrBphP and then dialyzed to remove unincorporated chromophore (DrBphP:BV, red) Starting amounts of BV were equal. (B) Absorbance spectra are shown for assembly of BV-8MA with DrBphP. Colors and sample handling are as in (A). (C) Adducts formed by assembly of DrBphP with BV (blue), BV-8MA (red), and BV-12MA (green) were analyzed by CD spectroscopy. (D) Absorbance spectra are shown for assembly of Cph1 with PCB. Colors, relative concentrations, and sample handling are as in (A). (E) Absorbance spectra are shown for assembly of Cph1 with PCB-8MA. Colors and sample handling are as in (A). (F) Adducts formed by assembly of Cph1 with PCB (blue), PCB-8MA (red), and PCB-12MA (green) were analyzed by CD spectroscopy.