An Optomechanical Transducer in the Blue Light Receptor Phototropin from Avena sativa

The PHOT1 (NPH1) gene from Avena sativa specifies the blue light receptor for phototropism, phototropin, which comprises two FMN-binding LOV domains and a serine/threonine protein kinase domain. Light exposure is conducive to autophosphorylation of the protein kinase domain. We have reconstituted a...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2001-10, Vol.98 (22), p.12357-12361
Main Authors: Salomon, Michael, Eisenreich, Wolfgang, Dürr, Harald, Schleicher, Erik, Knieb, Elke, Massey, Vincent, Rüdiger, Wolfhart, Müller, Franz, Bacher, Adelbert, Richter, Gerald
Format: Article
Language:English
Subjects:
Adducts
Atoms
Avena sativa
Biochemistry
Biological Sciences
Carbon
Chemical equilibrium
Chromophores
Flowers & plants
NPH1 gene
Phosphates
PHOT1 gene
Receptors
Scientific imaging
Spectroscopy
Spectrum analysis
Visible spectrum
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Summary:The PHOT1 (NPH1) gene from Avena sativa specifies the blue light receptor for phototropism, phototropin, which comprises two FMN-binding LOV domains and a serine/threonine protein kinase domain. Light exposure is conducive to autophosphorylation of the protein kinase domain. We have reconstituted a recombinant LOV2 domain of A. sativa phototropin with various13C/15N-labeled isotopomers of the cofactor, FMN. The reconstituted protein samples were analyzed by NMR spectroscopy under dark and light conditions. Blue light irradiation is shown to result in the addition of a thiol group (cysteine 450) to the 4a position of the FMN chromophore. The adduct reverts spontaneously in the dark by elimination. The light-driven flavin adduct formation results in conformational modification, which was diagnosed by1Hand31P NMR spectroscopy. This conformational change is proposed to initiate the transmission of the light signal via conformational modulation of the protein kinase domain conducive to autophosphorylation of NPH1.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.221455298