Plant UVR8 photoreceptor senses UV-B by tryptophan-mediated disruption of cross-dimer salt bridges

Christie, J.M. et al. (2012) Plant UVR8 photoreceptor senses UV-B by tryptophan-mediated disruption of cross-dimer salt bridges. Science, 335(6075), pp. 1492-1496. (doi: 10.1126/science.1218091)

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The recently identified plant photoreceptor UVR8 triggers regulatory changes in gene expression in response to ultraviolet-B (UV-B) light via an unknown mechanism. Here, crystallographic and solution structures of the UVR8 homodimer, together with mutagenesis and far-UV circular dichroism spectroscopy, reveal its mechanisms for UV-B perception and signal transduction. +¦-propeller subunits form a remarkable, tryptophan-dominated, dimer interface stitched together by a complex salt-bridge network. Salt-bridging arginines flank the excitonically coupled cross-dimer tryptophan pyramidresponsible for UV-B sensing. Photoreception reversibly disrupts salt bridges, triggering dimer dissociation and signal initiation. Mutation of a single tryptophan to phenylalanine retunes the photoreceptor to detect UV-C wavelengths. Our analyses establish how UVR8 functions as a photoreceptor without a prosthetic chromophore to promote plant development and survival in sunlight.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Baxter, Dr Katherine and Heilmann, Miss Monika and Kelly, Dr Sharon and Christie, Professor John and Smith, Dr Brian and Jenkins, Professor Gareth
Authors: Christie, J.M., Arvai, A.S., Baxter, K.J., Heilmann, M., Pratt, A.J., O'Hara, A., Kelly, S.M., Hothorn, M., Smith, B.O., Hitomi, K., Jenkins, G.I., and Getzoff, E.D.
College/School:College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
Journal Name:Science
Publisher:American Association for the Advancement of Science
ISSN (Online):1095-9203
Published Online:09 February 2012

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
497051Quest for the Holy Grail of plant photobiology: a UV-B photoreceptorGareth JenkinsLeverhulme Trust (LEVERHULME)F/00179/AZInstitute of Molecular Cell and Systems Biology