1N9N: Crystal Structure Of The Phot-lov1 Domain From Chlamydomonas Reinhardtii In Illuminated State. Data Set Of A Single Crystal

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.
PDB ID: 1N9NDownload
MMDB ID: 23435
PDB Deposition Date: 2002/11/25
Updated in MMDB: 2017/11
Experimental Method:
x-ray diffraction
Resolution: 2.3  Å
Source Organism:
Similar Structures:
Biological Unit for 1N9N: monomeric; determined by author
Molecular Components in 1N9N
Label Count Molecule
Protein (1 molecule)
Putative Blue Light Receptor
Molecule annotation
Chemical (1 molecule)
* Click molecule labels to explore molecular sequence information.

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