1n9o
From Proteopedia
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Crystal structure of the Phot-LOV1 domain from Chlamydomonas reinhardtii in illuminated state. Composite data set.
Overview
Phot 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.
About this Structure
1N9O is a Single protein structure of sequence from Chlamydomonas reinhardtii with SO4 and FMN as ligands. Full crystallographic information is available from OCA.
Reference
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
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