Fig. 2.

Overview of the crystal structures of bacterial phytochromes from A. fabrum. Structures (ribbon representation) of the monomers are shown for the dark adapted Pfr state of a wild-type Agp2-PCM (PDB entry 6G1Y) and b Agp2-PAiRFP2 (PDB entry 6G1Z), c a Meta-F sub-state (Mol A) of the Agp2-PAiRFP2 (PDB entry 6G20) and d the Pr state of the Agp1-PCM (Agp1-PCM_SER13 of A. fabrum, PDB entry 5HSQ³⁰). Close-up view of the chromophore-binding pockets (a–d) including BV and amino acid residues within the hydrogen bond network of BV (stick representation) as well as selected water molecules (red spheres). PAS domains are displayed in grey, PHY domains in black and GAF domains are depicted in different colours