1n9n
Crystal structure of the Phot-LOV1 domain from Chlamydomonas reinhardtii in illuminated state. Data set of a single crystal.
Structural highlights
FunctionPHOT_CHLRE Protein kinase that acts as a blue light photoreceptor (PubMed:15695460, PubMed:24285544). Required for non-photochemical quenching (NPQ), a mechanism that converts and dissipates the harmful excess absorbed light energy into heat and protect the photosynthetic apparatus from photo-oxidative damage (PubMed:27626383). Controls the energy-dependent chlorophyll fluorescence quenching (qE) activity of chlorophyll excited states by inducing the expression of the qE effector protein LHCSR3 in high light intensities (PubMed:27626383).[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedPhot proteins (phototropins and homologs) are blue-light photoreceptors that control mechanical processes like phototropism, chloroplast relocation, or guard-cell opening in plants. Phot receptors consist of two flavin mononucleotide (FMN)-binding light, oxygen, or voltage (LOV) domains and a C-terminal serine/threonine kinase domain. We determined crystal structures of the LOV1 domain of Phot1 from the green alga Chlamydomonas reinhardtii in the dark and illuminated state to 1.9 A and 2.8 A resolution, respectively. The structure resembles that of LOV2 from Adiantum (Crosson, S. and K. Moffat. 2001. PROC: Natl. Acad. Sci. USA. 98:2995-3000). In the resting dark state of LOV1, the reactive Cys-57 is present in two conformations. Blue-light absorption causes formation of a proposed active signaling state that is characterized by a covalent bond between the flavin C4a and the thiol of Cys-57. There are differences around the FMN chromophore but no large overall conformational changes. Quantum chemical calculations based on the crystal structures revealed the electronic distribution in the active site during the photocycle. The results suggest trajectories for electrons, protons, and the active site cysteine and offer an interpretation of the reaction mechanism. Crystal structures and molecular mechanism of a light-induced signaling switch: The Phot-LOV1 domain from Chlamydomonas reinhardtii.,Fedorov R, Schlichting I, Hartmann E, Domratcheva T, Fuhrmann M, Hegemann P Biophys J. 2003 Apr;84(4):2474-82. PMID:12668455[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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