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Aguida B, Babo J, Baouz S, Jourdan N, Procopio M, El-Esawi MA, Engle D, Mills S, Wenkel S, Huck A, Berg-Sørensen K, Kampranis SC, Link J, Ahmad M. 'Seeing' the electromagnetic spectrum: spotlight on the cryptochrome photocycle. FRONTIERS IN PLANT SCIENCE 2024; 15:1340304. [PMID: 38495372 PMCID: PMC10940379 DOI: 10.3389/fpls.2024.1340304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 01/12/2024] [Indexed: 03/19/2024]
Abstract
Cryptochromes are widely dispersed flavoprotein photoreceptors that regulate numerous developmental responses to light in plants, as well as to stress and entrainment of the circadian clock in animals and humans. All cryptochromes are closely related to an ancient family of light-absorbing flavoenzymes known as photolyases, which use light as an energy source for DNA repair but themselves have no light sensing role. Here we review the means by which plant cryptochromes acquired a light sensing function. This transition involved subtle changes within the flavin binding pocket which gave rise to a visual photocycle consisting of light-inducible and dark-reversible flavin redox state transitions. In this photocycle, light first triggers flavin reduction from an initial dark-adapted resting state (FADox). The reduced state is the biologically active or 'lit' state, correlating with biological activity. Subsequently, the photoreduced flavin reoxidises back to the dark adapted or 'resting' state. Because the rate of reoxidation determines the lifetime of the signaling state, it significantly modulates biological activity. As a consequence of this redox photocycle Crys respond to both the wavelength and the intensity of light, but are in addition regulated by factors such as temperature, oxygen concentration, and cellular metabolites that alter rates of flavin reoxidation even independently of light. Mechanistically, flavin reduction is correlated with conformational change in the protein, which is thought to mediate biological activity through interaction with biological signaling partners. In addition, a second, entirely independent signaling mechanism arises from the cryptochrome photocycle in the form of reactive oxygen species (ROS). These are synthesized during flavin reoxidation, are known mediators of biotic and abiotic stress responses, and have been linked to Cry biological activity in plants and animals. Additional special properties arising from the cryptochrome photocycle include responsivity to electromagnetic fields and their applications in optogenetics. Finally, innovations in methodology such as the use of Nitrogen Vacancy (NV) diamond centers to follow cryptochrome magnetic field sensitivity in vivo are discussed, as well as the potential for a whole new technology of 'magneto-genetics' for future applications in synthetic biology and medicine.
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Affiliation(s)
- Blanche Aguida
- Unite Mixed de Recherche (UMR) Centre Nationale de la Recherche Scientifique (CNRS) 8256 (B2A), Institut de Biologie Paris-Seine (IBPS), Sorbonne Université, Paris, France
| | - Jonathan Babo
- Unite Mixed de Recherche (UMR) Centre Nationale de la Recherche Scientifique (CNRS) 8256 (B2A), Institut de Biologie Paris-Seine (IBPS), Sorbonne Université, Paris, France
| | - Soria Baouz
- Unite Mixed de Recherche (UMR) Centre Nationale de la Recherche Scientifique (CNRS) 8256 (B2A), Institut de Biologie Paris-Seine (IBPS), Sorbonne Université, Paris, France
| | - Nathalie Jourdan
- Unite Mixed de Recherche (UMR) Centre Nationale de la Recherche Scientifique (CNRS) 8256 (B2A), Institut de Biologie Paris-Seine (IBPS), Sorbonne Université, Paris, France
| | - Maria Procopio
- Department of Biophysics, Faculty of Arts and Sciences, Johns Hopkins University, Baltimore, MD, United States
| | | | - Dorothy Engle
- Biology Department, Xavier University, Cincinnati, OH, United States
| | - Stephen Mills
- Chemistry Department, Xavier University, Cincinnati, OH, United States
| | - Stephan Wenkel
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Alexander Huck
- DTU Physics, Technical University of Denmark, Kongens Lyngby, Denmark
| | | | - Sotirios C. Kampranis
- Biochemical Engineering Group, Plant Biochemistry Section, Department of Plant and Environment Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Justin Link
- Physics and Engineering Department, Cincinnati, OH, United States
| | - Margaret Ahmad
- Unite Mixed de Recherche (UMR) Centre Nationale de la Recherche Scientifique (CNRS) 8256 (B2A), Institut de Biologie Paris-Seine (IBPS), Sorbonne Université, Paris, France
- Biology Department, Xavier University, Cincinnati, OH, United States
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Pooam M, Dixon N, Hilvert M, Misko P, Waters K, Jourdan N, Drahy S, Mills S, Engle D, Link J, Ahmad M. Effect of temperature on the Arabidopsis cryptochrome photocycle. PHYSIOLOGIA PLANTARUM 2021; 172:1653-1661. [PMID: 33583025 DOI: 10.1111/ppl.13365] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 12/17/2020] [Accepted: 02/05/2021] [Indexed: 05/20/2023]
Abstract
Cryptochromes are blue light-absorbing photoreceptors found in plants and animals with many important signalling functions. These include control of plant growth, development, and the entrainment of the circadian clock. Plant cryptochromes have recently been implicated in adaptations to temperature variation, including temperature compensation of the circadian clock. However, the effect of temperature directly on the photochemical properties of the cryptochrome photoreceptor remains unknown. Here we show that the response to light of purified Arabidopsis Cry1 and Cry2 proteins was significantly altered by temperature. Spectral analysis at 15°C showed a pronounced decrease in flavin reoxidation rates from the biologically active, light-induced (FADH°) signalling state of cryptochrome to the inactive (FADox) resting redox state as compared to ambient (25°C) temperature. This result indicates that at low temperatures, the concentration of the biologically active FADH° redox form of Cry is increased, leading to the counterintuitive prediction that there should be an increased biological activity of Cry at lower temperatures. This was confirmed using Cry1 cryptochrome C-terminal phosphorylation as a direct biological assay for Cry activation in vivo. We conclude that enhanced cryptochrome function in vivo at low temperature is consistent with modulation by temperature of the cryptochrome photocycle.
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Affiliation(s)
- Marootpong Pooam
- Department of Biology, Faculty of Science, Naresuan University, Phitsanulok, Thailand
| | - Nykiera Dixon
- Sorbonne Universités - UPMC Paris 6 - CNRS, UMR8256 - IBPS, Photobiology Research Group, Paris, France
- Institut de Biologie Paris-Seine, Xavier University, Cincinnati, Ohio, USA
| | - Michael Hilvert
- Sorbonne Universités - UPMC Paris 6 - CNRS, UMR8256 - IBPS, Photobiology Research Group, Paris, France
- Institut de Biologie Paris-Seine, Xavier University, Cincinnati, Ohio, USA
| | - Peter Misko
- Sorbonne Universités - UPMC Paris 6 - CNRS, UMR8256 - IBPS, Photobiology Research Group, Paris, France
- Institut de Biologie Paris-Seine, Xavier University, Cincinnati, Ohio, USA
| | - Kristy Waters
- Sorbonne Universités - UPMC Paris 6 - CNRS, UMR8256 - IBPS, Photobiology Research Group, Paris, France
- Institut de Biologie Paris-Seine, Xavier University, Cincinnati, Ohio, USA
| | - Nathalie Jourdan
- Sorbonne Universités - UPMC Paris 6 - CNRS, UMR8256 - IBPS, Photobiology Research Group, Paris, France
| | - Soria Drahy
- Sorbonne Universités - UPMC Paris 6 - CNRS, UMR8256 - IBPS, Photobiology Research Group, Paris, France
| | - Stephen Mills
- Institut de Biologie Paris-Seine, Xavier University, Cincinnati, Ohio, USA
| | - Dorothy Engle
- Institut de Biologie Paris-Seine, Xavier University, Cincinnati, Ohio, USA
| | - Justin Link
- Institut de Biologie Paris-Seine, Xavier University, Cincinnati, Ohio, USA
| | - Margaret Ahmad
- Sorbonne Universités - UPMC Paris 6 - CNRS, UMR8256 - IBPS, Photobiology Research Group, Paris, France
- Institut de Biologie Paris-Seine, Xavier University, Cincinnati, Ohio, USA
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Structural insights into photoactivation of plant Cryptochrome-2. Commun Biol 2021; 4:28. [PMID: 33398020 PMCID: PMC7782693 DOI: 10.1038/s42003-020-01531-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 11/26/2020] [Indexed: 01/07/2023] Open
Abstract
Cryptochromes (CRYs) are evolutionarily conserved photoreceptors that mediate various light-induced responses in bacteria, plants, and animals. Plant cryptochromes govern a variety of critical growth and developmental processes including seed germination, flowering time and entrainment of the circadian clock. CRY's photocycle involves reduction of their flavin adenine dinucleotide (FAD)-bound chromophore, which is completely oxidized in the dark and semi to fully reduced in the light signaling-active state. Despite the progress in characterizing cryptochromes, important aspects of their photochemistry, regulation, and light-induced structural changes remain to be addressed. In this study, we determine the crystal structure of the photosensory domain of Arabidopsis CRY2 in a tetrameric active state. Systematic structure-based analyses of photo-activated and inactive plant CRYs elucidate distinct structural elements and critical residues that dynamically partake in photo-induced oligomerization. Our study offers an updated model of CRYs photoactivation mechanism as well as the mode of its regulation by interacting proteins.
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Song Y, Jia Z, Hou Y, Ma X, Li L, Jin X, An L. Roles of DNA Methylation in Cold Priming in Tartary Buckwheat. FRONTIERS IN PLANT SCIENCE 2020; 11:608540. [PMID: 33365044 PMCID: PMC7750358 DOI: 10.3389/fpls.2020.608540] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 11/23/2020] [Indexed: 05/04/2023]
Abstract
Plants experience a wide array of environmental stimuli, some of which are frequent occurrences of cold weather, which have priming effects on agricultural production and agronomic traits. DNA methylation may act as an epigenetic regulator for the cold response of Tartary buckwheat (Fagopyrum tataricum). Combined with long-term field observation and laboratory experiments, comparative phenome, methylome, and transcriptome analyses were performed to investigate the potential epigenetic contributions for the cold priming of Tartary buckwheat variety Dingku1. Tartary buckwheat cv. Dingku1 exhibited low-temperature resistance. Single-base resolution maps of the DNA methylome were generated, and a global loss of DNA methylation was observed during cold responding in Dingku1. These sites with differential methylation levels were predominant in the intergenic regions. Several hundred genes had different DNA methylation patterns and expressions in different cold treatments (cold memory and cold shock), such as CuAO, RPB1, and DHE1. The application of a DNA methylation inhibitor caused a change of the free lysine content, suggesting that DNA methylation can affect metabolite accumulation for Tartary buckwheat cold responses. The results of the present study suggest important roles of DNA methylation in regulating cold response and forming agronomic traits in Tartary buckwheat.
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Affiliation(s)
- Yuan Song
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Zhifeng Jia
- Qinghai Academy of Animal Science and Veterinary Medicine, Qinghai University, Xining, China
| | - Yukang Hou
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Xiang Ma
- Qinghai Academy of Animal Science and Veterinary Medicine, Qinghai University, Xining, China
| | - Lizhen Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Xing Jin
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Lizhe An
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
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Araguirang GE, Niemann N, Kiontke S, Eckel M, Dionisio-Sese ML, Batschauer A. The Arabidopsis cryptochrome 2 I404F mutant is hypersensitive and shows flavin reduction even in the absence of light. PLANTA 2019; 251:33. [PMID: 31832774 DOI: 10.1007/s00425-019-03323-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 12/03/2019] [Indexed: 06/10/2023]
Abstract
The cryptochrome photoreceptor mutant cry2I404F exhibits hyperactivity in the dark, hypersensitivity in different light conditions, and in contrast to the wild-type protein, its flavin chromophore is reducible even in the absence of light. Plant cryptochromes (cry) are blue-light photoreceptors involved in multiple signaling pathways and various photomorphogenic responses. One biologically hyperactive mutant of a plant cryptochrome that was previously characterized is Arabidopsis cry1L407F (Exner et al. in Plant Physiol 154:1633-1645, 2010). Protein sequence alignments of different cryptochromes revealed that L407 in cry1 corresponds to I404 in cry2. Point mutation of Ile to Phe in cry2 in this position created a novel mutant. The present study provided a baseline data on the elucidation of the properties of cry2I404F. This mutant was still able to bind ATP-triggering conformational changes, as confirmed by partial tryptic digestion and thermo-FAD assays. Surprisingly, the FAD cofactor of cry2I404F was reduced by the addition of reductant even in the absence of light. In vivo, cry2I404F exhibited a cop phenotype in the dark and hypersensitivity to various light conditions compared to cry2 wild type. Overall, these data suggest that the hypersensitivity to red and blue light and hyperactivity of this novel mutant in the dark can be mostly accounted to structural alterations brought forth by the Ile to Phe mutation at position 404 that allows reduction of the flavin chromophore even in the absence of light.
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Affiliation(s)
- Galileo Estopare Araguirang
- Graduate School, University of the Philippines Los Baños, College, 4031, Laguna, Philippines
- Department of Plant Adaptation, Leibniz-Institut für Gemüse- und Zierpflanzenbau (IGZ), Großbeeren, 14979, Germany
| | - Nils Niemann
- Department of Plant Physiology and Photobiology, Faculty of Biology, Philipps-University Marburg, 35032, Marburg, Germany
| | - Stephan Kiontke
- Department of Plant Physiology and Photobiology, Faculty of Biology, Philipps-University Marburg, 35032, Marburg, Germany
| | - Maike Eckel
- Department of Plant Physiology and Photobiology, Faculty of Biology, Philipps-University Marburg, 35032, Marburg, Germany
| | - Maribel L Dionisio-Sese
- Graduate School, University of the Philippines Los Baños, College, 4031, Laguna, Philippines
- Plant Biology Division, Institute of Biological Sciences, College of Arts and Sciences, University of the Philippines Los Baños, College, 4031, Laguna, Philippines
| | - Alfred Batschauer
- Department of Plant Physiology and Photobiology, Faculty of Biology, Philipps-University Marburg, 35032, Marburg, Germany.
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Interaction studies on bacterial stringent response protein RelA with uncharged tRNA provide evidence for its prerequisite complex for ribosome binding. Curr Genet 2019; 65:1173-1184. [PMID: 30968189 DOI: 10.1007/s00294-019-00966-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 04/01/2019] [Accepted: 04/02/2019] [Indexed: 12/11/2022]
Abstract
The bacterial stringent response is regulated by the synthesis of (p)ppGpp which is mediated by RelA in a complex with uncharged tRNA and ribosome. We intended to probe RelA-uncharged tRNA interactions off the ribosome to understand the sequential activation mechanism of RelA. Stringent response is a key regulatory pleiotropic mechanism which allows bacteria to survive in unfavorable conditions. Since the discovery of RelA, it has been believed that it is activated upon binding to ribosomes which already have uncharged tRNA on acceptor site (A-site). However, uncharged tRNA occupied in the A-site of the ribosome prior to RelA binding could not be observed; therefore, recently an alternate model for RelA activation has been proposed in which RelA first binds to uncharged tRNA and then RelA-uncharged tRNA complex is loaded on to the ribosome to synthesize (p)ppGpp. To explore the alternate hypothesis, we report here the in vitro binding of uncharged tRNA to RelA in the absence of ribosome using formaldehyde cross-linking, fluorescence spectroscopy, surface plasmon resonance, size-exclusion chromatography, and hydrogen-deuterium exchange mass spectrometry. Altogether, our results clearly indicate binding between RelA and uncharged tRNA without the involvement of ribosome. Moreover, we have analyzed their binding kinetics and mapping of tRNA-interacting regions of RelA structure. We have also co-purified TGS domain in complex with tRNA to further establish in vivo RelA-tRNA binding. We have observed that TGS domain recognizes all types of uncharged tRNA similar to EF-Tu and tRNA interactions. Altogether, our results demonstrate the complex formation between RelA and uncharged tRNA that may be loaded to the ribosome for (p)ppGpp synthesis.
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