title: On the collective nature of phytochrome photoactivation.
abstract: The red/far-red-sensing biological photoreceptor phytochrome is a paradigmatic two-state signaling system. The two thermally stable states are interconverted via a photoreaction of the covalently bound tetrapyrrole chromophore. Applying recently developed solid-state nuclear magnetic resonance, we study both the chromophore and its protein pocket in the Pr (red-absorbing) and Pfr (far-red-absorbing) states. The observations show that the phototransformation combines local chemical reactions with a mesoscopic transition of order. Both the chromophore and its binding pocket are quasi-liquid and disordered in Pr, yet quasi-solid and ordered in Pfr. Possible biochemical implications are discussed.
authors: Leids Instituut voor Chemisch Onderzoek, Universiteit Leiden, 2300 RA Leiden, The Netherlands.
authors: Chen
authors: C
authors: Song
authors: Georgios
authors: G
authors: Psakis
authors: Christina
authors: C
authors: Lang
authors: Jo
authors: J
authors: Mailliet
authors: Jan
authors: J
authors: Zaanen
authors: Wolfgang
authors: W
authors: Gärtner
authors: Jon
authors: J
authors: Hughes
authors: Jörg
authors: J
authors: Matysik
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry; D001665:Binding Sites; D055162:Biocatalysis; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008968:Molecular Conformation; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D010446:Peptide Fragments / Q000737:chemistry; D055668:Photochemical Processes; D020283:Photoreceptors, Microbial; D055519:Photoreceptors, Plant / Q000737:chemistry*; D052980:Phycobilins / Q000737:chemistry; D010798:Phycocyanin / Q000737:chemistry; D010834:Phytochrome / Q000737:chemistry*; D051942:Phytochrome A / Q000737:chemistry; D051939:Phytochrome B / Q000737:chemistry; D011494:Protein Kinases / Q000737:chemistry; D015398:Signal Transduction; D045725:Tetrapyrroles / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D010446:Peptide Fragments; D020283:Photoreceptors, Microbial; D055519:Photoreceptors, Plant; D052980:Phycobilins; D051942:Phytochrome A; D045725:Tetrapyrroles; D010798:Phycocyanin; D010834:Phytochrome; D051939:Phytochrome B; C011069:phycocyanobilin; D011494:Protein Kinases; C413623:Cph1 phytochrome protein, bacteria