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PDBsum entry 2v0u
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References listed in PDB file
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Key reference
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Title
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N- And c-Terminal flanking regions modulate light-Induced signal transduction in the lov2 domain of the blue light sensor phototropin 1 from avena sativa.
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Authors
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A.S.Halavaty,
K.Moffat.
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Ref.
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Biochemistry, 2007,
46,
14001-14009.
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PubMed id
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Abstract
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Light sensing by photoreceptors controls phototropism, chloroplast movement,
stomatal opening, and leaf expansion in plants. Understanding the molecular
mechanism by which these processes are regulated requires a quantitative
description of photoreceptor dynamics. We focus on a light-driven signal
transduction mechanism in the LOV2 domain (LOV, light, oxygen, voltage) of the
blue light photoreceptor phototropin 1 from Avena sativa (oat). High-resolution
crystal structures of the dark and light states of an oat LOV2 construct
including residues Leu404 through Leu546 (LOV2 (404-546)) have been determined
at 105 and 293 K. In all four structures, LOV2 (404-546) exhibits the typical
Per-ARNT-Sim (PAS) fold, flanked by an additional conserved N-terminal
turn-helix-turn motif and a C-terminal flanking region containing an amphipathic
Jalpha helix. These regions dock on the LOV2 core domain and bury several
hydrophobic residues of the central beta-sheet of the core domain that would
otherwise be exposed to solvent. Light structures of LOV2 (404-546) reveal that
formation of the covalent bond between Cys450 and the C4a atom of the flavin
mononucleotide (FMN) results in local rearrangement of the hydrogen-bonding
network in the FMN binding pocket. These rearrangements are associated with
disruption of the Asn414-Asp515 hydrogen bond on the surface of the protein and
displacement of the N- and C-terminal flanking regions of LOV2 (404-546), both
of which constitute a structural signal.
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