Structural snapshot of a bacterial phytochrome in its functional intermediate state

• DOI: 10.1038/s41467-018-07392-7
• Publication Date: 2018-11-15T15:57:37Z
• Authors: Andrea Schmidt; Luisa Sauthof; Michal Szczepek; Maria Fernandez L...; Francisco Velazqu...; Bilal M. Qureshi; Norbert Michael; David Buhrke; Tammo Stevens; Dennis Kwiatkowski; David von Stetten; Maria Andrea Mrog...; Norbert Krauß; Tilman Lamparter; Peter Hildebrandt; Patrick Scheerer
• Keywords: MODULE; 570; STRUCTURE VALIDATION; Protein Conformation; SPECTRAL PROPERTIES; Science; PROTEIN; Agrobacterium; Article; Molecular conformation; X-ray crystallography; REVEALS; CRYSTAL-STRUCTURE; PHOTOCONVERSION; X-ray crystallography; info:eu-repo/classification/ddc/570; [SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM]; biology; CHROMOPHORE; Q; 540; AGROBACTERIUM-TUMEFACIENS; Molecular conformation; Life sciences; ddc:570; Phytochrome; PFR STATE

AbstractPhytochromes are modular photoreceptors of plants, bacteria and fungi that use light as a source of information to regulate fundamental physiological processes. Interconversion between the active and inactive states is accomplished by a photoinduced reaction sequence which couples the sensor with the output module. However, the underlying molecular mechanism is yet not fully understood due to the lack of structural data of functionally relevant intermediate states. Here we report the crystal structure of a Meta-F intermediate state of an Agp2 variant from Agrobacterium fabrum. This intermediate, the identity of which was verified by resonance Raman spectroscopy, was formed by irradiation of the parent Pfr state and displays significant reorientations of almost all amino acids surrounding the chromophore. Structural comparisons allow identifying structural motifs that might serve as conformational switch for initiating the functional secondary structure change that is linked to the (de-)activation of these photoreceptors.