On the mechanism of photoinduced dimer dissociation in the plant UVR8 photoreceptor

UV-B absorption by the photoreceptor UV resistance locus 8 (UVR8) consisting of two identical protein units triggers a signal chain used by plants in connection with protection and repair of UV-B induced damage. X-ray structural analysis of the purified protein [Christie JM, et al. (2012) Science 33...

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Main Authors: Voityuk, Alexander A., Marcus, Rudolph A., Michel-Beyerle, Maria-Elisabeth
Other Authors: School of Physical and Mathematical Sciences
Format: Journal Article
Language:English
Published: 2014
Subjects:
Online Access:https://hdl.handle.net/10356/104113
http://hdl.handle.net/10220/19525
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author Voityuk, Alexander A.
Marcus, Rudolph A.
Michel-Beyerle, Maria-Elisabeth
author2 School of Physical and Mathematical Sciences
author_facet School of Physical and Mathematical Sciences
Voityuk, Alexander A.
Marcus, Rudolph A.
Michel-Beyerle, Maria-Elisabeth
author_sort Voityuk, Alexander A.
collection NTU
description UV-B absorption by the photoreceptor UV resistance locus 8 (UVR8) consisting of two identical protein units triggers a signal chain used by plants in connection with protection and repair of UV-B induced damage. X-ray structural analysis of the purified protein [Christie JM, et al. (2012) Science 335(6075):1492–1496] [Wu D, et al. (2012) Nature 484(7393): 214–220] has revealed that the dimer is held together by arginine–aspartate salt bridges. In this paper we address the initial processes in the signal chain. On the basis of high-level quantum-chemical calculations, we propose a mechanism for the photodissociation of UVR8 that consists of three steps: (i) In each monomer, multiple tryptophans form an extended light-harvesting system in which the La excited state of Trp233 experiences strong electrostatic stabilization by the protein environment. The strong stabilization singles out this tryptophan to be an efficient exciton acceptor that accumulates the excitation energy from the entire protein subunit. (ii) A fast decay of the locally excited state by charge separation generates the radical ion pair Trp285(+)-Trp233(−) with a dipole moment of ∼18 D. (iii) Key to the proposed mechanism is that this large dipole moment drives the breaking of the salt bridges between the two monomer subunits. The suggested mechanism for the UV-B–driven dissociation of the dimer that rests on the prominent players Trp233 and Trp285 explains the experimental results obtained from mutagenesis of UVR8.
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spelling ntu-10356/1041132023-02-28T19:44:33Z On the mechanism of photoinduced dimer dissociation in the plant UVR8 photoreceptor Voityuk, Alexander A. Marcus, Rudolph A. Michel-Beyerle, Maria-Elisabeth School of Physical and Mathematical Sciences DRNTU::Science::Physics::Optics and light UV-B absorption by the photoreceptor UV resistance locus 8 (UVR8) consisting of two identical protein units triggers a signal chain used by plants in connection with protection and repair of UV-B induced damage. X-ray structural analysis of the purified protein [Christie JM, et al. (2012) Science 335(6075):1492–1496] [Wu D, et al. (2012) Nature 484(7393): 214–220] has revealed that the dimer is held together by arginine–aspartate salt bridges. In this paper we address the initial processes in the signal chain. On the basis of high-level quantum-chemical calculations, we propose a mechanism for the photodissociation of UVR8 that consists of three steps: (i) In each monomer, multiple tryptophans form an extended light-harvesting system in which the La excited state of Trp233 experiences strong electrostatic stabilization by the protein environment. The strong stabilization singles out this tryptophan to be an efficient exciton acceptor that accumulates the excitation energy from the entire protein subunit. (ii) A fast decay of the locally excited state by charge separation generates the radical ion pair Trp285(+)-Trp233(−) with a dipole moment of ∼18 D. (iii) Key to the proposed mechanism is that this large dipole moment drives the breaking of the salt bridges between the two monomer subunits. The suggested mechanism for the UV-B–driven dissociation of the dimer that rests on the prominent players Trp233 and Trp285 explains the experimental results obtained from mutagenesis of UVR8. Published version 2014-06-03T04:09:27Z 2019-12-06T21:26:42Z 2014-06-03T04:09:27Z 2019-12-06T21:26:42Z 2014 2014 Journal Article Voityuk, A. A., Marcus, R. A., & Michel-Beyerle, M.-E. (2014). On the mechanism of photoinduced dimer dissociation in the plant UVR8 photoreceptor. Proceedings of the National Academy of Sciences, 111(14), 5219-5224. 1091-6490 https://hdl.handle.net/10356/104113 http://hdl.handle.net/10220/19525 10.1073/pnas.1402025111 24639509 en Proceedings of the national academy of sciences of the United States of America © 2014 The Author(s). This paper was published in Proceedings of the National Academy of Sciences of the United States of America and is made available as an electronic reprint (preprint) with permission of the Author(s). The paper can be found at the following official DOI: http://dx.doi.org/10.1073/pnas.1402025111.  One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law. application/pdf
spellingShingle DRNTU::Science::Physics::Optics and light
Voityuk, Alexander A.
Marcus, Rudolph A.
Michel-Beyerle, Maria-Elisabeth
On the mechanism of photoinduced dimer dissociation in the plant UVR8 photoreceptor
title On the mechanism of photoinduced dimer dissociation in the plant UVR8 photoreceptor
title_full On the mechanism of photoinduced dimer dissociation in the plant UVR8 photoreceptor
title_fullStr On the mechanism of photoinduced dimer dissociation in the plant UVR8 photoreceptor
title_full_unstemmed On the mechanism of photoinduced dimer dissociation in the plant UVR8 photoreceptor
title_short On the mechanism of photoinduced dimer dissociation in the plant UVR8 photoreceptor
title_sort on the mechanism of photoinduced dimer dissociation in the plant uvr8 photoreceptor
topic DRNTU::Science::Physics::Optics and light
url https://hdl.handle.net/10356/104113
http://hdl.handle.net/10220/19525
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