Native mass spectrometry reveals the conformational diversity of the UVR8 photoreceptor

Camacho, I. S., Theisen, A., Johannissen, L. O., Díaz-Ramos, L. A., Christie, J. M. , Jenkins, G. I. , Bellina, B., Barran, P. and Jones, A. R. (2019) Native mass spectrometry reveals the conformational diversity of the UVR8 photoreceptor. Proceedings of the National Academy of Sciences of the United States of America, 116(4), pp. 1116-1125. (doi: 10.1073/pnas.1813254116) (PMID:30610174) (PMCID:PMC6347689)

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Abstract

UVR8 is a plant photoreceptor protein that regulates photomorphogenic and protective responses to UV light. The inactive, homodimeric state absorbs UV-B light, resulting in dissociation into monomers, which are considered to be the active state and comprise a β-propeller core domain and intrinsically disordered N- and C-terminal tails. The C terminus is required for functional binding to signaling partner COP1. To date, however, structural studies have only been conducted with the core domain where the terminal tails have been truncated. Here, we report structural investigations of full-length UVR8 using native ion mobility mass spectrometry adapted for photoactivation. We show that, while truncated UVR8 photoconverts from a single conformation of dimers to a single monomer conformation, the full-length protein exists in numerous conformational families. The full-length dimer adopts both a compact state and an extended state where the C terminus is primed for activation. In the monomer the extended C terminus destabilizes the core domain to produce highly extended yet stable conformations, which we propose are the fully active states that bind COP1. Our results reveal the conformational diversity of full-length UVR8. We also demonstrate the potential power of native mass spectrometry to probe functionally important structural dynamics of photoreceptor proteins throughout nature.

Item Type:Articles
Additional Information:I.S.C. was supported by a PhD studentship from the Engineering and Physical Sciences Research Council. A.T. is supported by Biotechnology and Biological Sciences Research Council Grants BB/L002655/1 and BB/L016486/1, which is a studentship award with additional financial support from Waters Corp. L.A.D.-R. is supported by a PhD studentship from Consejo Nacional de Ciencia y Tecnología.
Keywords:UVR8, intrinsically disordered proteins, ion mobility, native mass spectrometry, plant photoreception.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Diaz Ramos, Lourdes and Christie, Professor John and Jenkins, Professor Gareth
Authors: Camacho, I. S., Theisen, A., Johannissen, L. O., Díaz-Ramos, L. A., Christie, J. M., Jenkins, G. I., Bellina, B., Barran, P., and Jones, A. R.
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:Proceedings of the National Academy of Sciences of the United States of America
Publisher:National Academy of Sciences
ISSN:0027-8424
ISSN (Online):1091-6490
Published Online:04 January 2019
Copyright Holders:Copyright © 2019 The Authors
First Published:First published in Proceedings of the National Academy of Sciences of the United States of America 116(4): 1116-1125
Publisher Policy:Reproduced under a Creative Commons License

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