2pr6
From Proteopedia
Structural Basis for Light-dependent Signaling in the Dimeric LOV Photosensor YtvA (Light Structure)
Structural highlights
Function[PHOT_BACSU] Exhibits the same spectroscopical features and blue-light induced photochemistry as plants phototropins, with the reversible formation of a blue-shifted photoproduct, assigned to an FMN-cysteine thiol adduct. Although it is a positive regulator in the activation of the environmental signaling branch of the general stress transcription factor sigma-B, its precise role is undetermined.[1] 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 PubMedThe photosensor YtvA binds flavin mononucleotide and regulates the general stress reaction in Bacillus subtilis in response to blue light illumination. It belongs to the family of light-oxygen-voltage (LOV) proteins that were first described in plant phototropins and form a subgroup of the Per-Arnt-Sim (PAS) superfamily. Here, we report the three-dimensional structure of the LOV domain of YtvA in its dark and light states. The protein assumes the global fold common to all PAS domains and dimerizes via a hydrophobic interface. Directly C-terminal to the core of the LOV domain, an alpha-helix extends into the solvent. Light absorption causes formation of a covalent bond between a conserved cysteine residue and atom C(4a) of the FMN ring, which triggers rearrangements throughout the LOV domain. Concomitantly, in the dark and light structures, the two subunits of the dimeric protein rotate relative to each other by 5 degrees . This small quaternary structural change is presumably a component of the mechanism by which the activity of YtvA is regulated in response to light. In terms of both structure and signaling mechanism, YtvA differs from plant phototropins and more closely resembles prokaryotic heme-binding PAS domains. Structural basis for light-dependent signaling in the dimeric LOV domain of the photosensor YtvA.,Moglich A, Moffat K J Mol Biol. 2007 Oct 12;373(1):112-26. Epub 2007 Aug 2. PMID:17764689[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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