1
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Khanh NV, Lee YH. LOV1 protein of Pseudomonas cichorii JBC1 modulates its virulence and lifestyles in response to blue light. Sci Rep 2024; 14:15672. [PMID: 38977737 PMCID: PMC11231323 DOI: 10.1038/s41598-024-66422-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 07/01/2024] [Indexed: 07/10/2024] Open
Abstract
Bacteria perceive light signals via photoreceptors and modulate many physiological and genetic processes. The impacts played by light, oxygen, or voltage (LOV) and blue light (BL) photosensory proteins on the virulence-related traits of plant bacterial pathogens are diverse and complex. In this study, we identified LOV protein (Pc-LOV1) from Pseudomonas cichorii JBC1 (PcJBC1) and characterized its function using LOV1-deficient mutant (JBC1Δlov1). In the dark state, the recombinant Pc-LOV1 protein showed an absorption band in UV-A region with a double peak at 340 nm and 365 nm, and within the blue-region, it exhibited a main absorption at 448 nm along with two shoulder peaks at 425 nm and 475 nm, which is a typical feature of oxidized flavin within LOV domain. The adduct-state lifetime (τrec) of Pc-LOV1 was 67.03 ± 4.34 min at 25 °C. BL negatively influenced the virulence of PcJBC1 and the virulence of JBC1Δlov1 increased irrespective of BL, indicating that Pc-LOV1 negatively regulates PcJBC1 virulence. Pc-LOV1 and BL positively regulated traits relevant to colonization on plant surface, such as adhesion to the plant tissue and biofilm formation. In contrast, swarming motility, exopolysaccharide production, and siderophore synthesis were negatively controlled. Gene expression supported the modulation of bacterial features by Pc-LOV1. Overall, our results suggest that the LOV photosensory system plays crucial roles in the adaptive responses and virulence of the bacterial pathogen PcJBC1. The roles of other photoreceptors, sensing of other wavelengths, and signal networking require further investigation.
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Affiliation(s)
- Nguyen Van Khanh
- Division of Biotechnology, Jeonbuk National University, 79 Gobong-ro, Iksan-si, Jeollabuk-do, 54596, Republic of Korea
| | - Yong Hoon Lee
- Division of Biotechnology, Jeonbuk National University, 79 Gobong-ro, Iksan-si, Jeollabuk-do, 54596, Republic of Korea.
- Advanced Institute of Environment and Bioscience, Plant Medical Research Center, and Institute of Bio-industry, Jeonbuk National University, Jeonju-si, Republic of Korea.
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2
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Hemmer S, Siedhoff NE, Werner S, Ölçücü G, Schwaneberg U, Jaeger KE, Davari MD, Krauss U. Machine Learning-Assisted Engineering of Light, Oxygen, Voltage Photoreceptor Adduct Lifetime. JACS AU 2023; 3:3311-3323. [PMID: 38155650 PMCID: PMC10751770 DOI: 10.1021/jacsau.3c00440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 11/07/2023] [Accepted: 11/07/2023] [Indexed: 12/30/2023]
Abstract
Naturally occurring and engineered flavin-binding, blue-light-sensing, light, oxygen, voltage (LOV) photoreceptor domains have been used widely to design fluorescent reporters, optogenetic tools, and photosensitizers for the visualization and control of biological processes. In addition, natural LOV photoreceptors with engineered properties were recently employed for optimizing plant biomass production in the framework of a plant-based bioeconomy. Here, the understanding and fine-tuning of LOV photoreceptor (kinetic) properties is instrumental for application. In response to blue-light illumination, LOV domains undergo a cascade of photophysical and photochemical events that yield a transient covalent FMN-cysteine adduct, allowing for signaling. The rate-limiting step of the LOV photocycle is the dark-recovery process, which involves adduct scission and can take between seconds and days. Rational engineering of LOV domains with fine-tuned dark recovery has been challenging due to the lack of a mechanistic model, the long time scale of the process, which hampers atomistic simulations, and a gigantic protein sequence space covering known mutations (combinatorial challenge). To address these issues, we used machine learning (ML) trained on scarce literature data and iteratively generated and implemented experimental data to design LOV variants with faster and slower dark recovery. Over the three prediction-validation cycles, LOV domain variants were successfully predicted, whose adduct-state lifetimes spanned 7 orders of magnitude, yielding optimized tools for synthetic (opto)biology. In summary, our results demonstrate ML as a viable method to guide the design of proteins even with limited experimental data and when no mechanistic model of the underlying physical principles is available.
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Affiliation(s)
- Stefanie Hemmer
- Institute
of Molecular Enzyme Technology, Heinrich
Heine University Düsseldorf, Wilhelm Johnen Strasse, Jülich 52426, Germany
| | - Niklas Erik Siedhoff
- Institute
of Biotechnology, RWTH Aachen University, Worringer Weg 3, 52074 Aachen, Germany
- DWI-Leibniz
Institute for Interactive Materials, Forckenbeckstraße 50, 52074 Aachen, Germany
| | - Sophia Werner
- Institute
of Molecular Enzyme Technology, Heinrich
Heine University Düsseldorf, Wilhelm Johnen Strasse, Jülich 52426, Germany
| | - Gizem Ölçücü
- Institute
of Molecular Enzyme Technology, Heinrich
Heine University Düsseldorf, Wilhelm Johnen Strasse, Jülich 52426, Germany
| | - Ulrich Schwaneberg
- Institute
of Biotechnology, RWTH Aachen University, Worringer Weg 3, 52074 Aachen, Germany
- DWI-Leibniz
Institute for Interactive Materials, Forckenbeckstraße 50, 52074 Aachen, Germany
| | - Karl-Erich Jaeger
- Institute
of Molecular Enzyme Technology, Heinrich
Heine University Düsseldorf, Wilhelm Johnen Strasse, Jülich 52426, Germany
- Institute
of Bio-and Geosciences IBG 1: Biotechnology, Forschungszentrum Jülich GmbH, Wilhelm Johnen Strasse, Jülich 52426, Germany
| | - Mehdi D. Davari
- Department
of Bioorganic Chemistry, Leibniz Institute
of Plant Biochemistry, Weinberg 3, 06120 Halle, Germany
| | - Ulrich Krauss
- Institute
of Molecular Enzyme Technology, Heinrich
Heine University Düsseldorf, Wilhelm Johnen Strasse, Jülich 52426, Germany
- Institute
of Bio-and Geosciences IBG 1: Biotechnology, Forschungszentrum Jülich GmbH, Wilhelm Johnen Strasse, Jülich 52426, Germany
- Department
of Biochemistry, University of Bayreuth, 95447 Bayreuth, Germany
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3
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Dietler J, Gelfert R, Kaiser J, Borin V, Renzl C, Pilsl S, Ranzani AT, García de Fuentes A, Gleichmann T, Diensthuber RP, Weyand M, Mayer G, Schapiro I, Möglich A. Signal transduction in light-oxygen-voltage receptors lacking the active-site glutamine. Nat Commun 2022; 13:2618. [PMID: 35552382 PMCID: PMC9098866 DOI: 10.1038/s41467-022-30252-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 04/22/2022] [Indexed: 11/12/2022] Open
Abstract
In nature as in biotechnology, light-oxygen-voltage photoreceptors perceive blue light to elicit spatiotemporally defined cellular responses. Photon absorption drives thioadduct formation between a conserved cysteine and the flavin chromophore. An equally conserved, proximal glutamine processes the resultant flavin protonation into downstream hydrogen-bond rearrangements. Here, we report that this glutamine, long deemed essential, is generally dispensable. In its absence, several light-oxygen-voltage receptors invariably retained productive, if often attenuated, signaling responses. Structures of a light-oxygen-voltage paradigm at around 1 Å resolution revealed highly similar light-induced conformational changes, irrespective of whether the glutamine is present. Naturally occurring, glutamine-deficient light-oxygen-voltage receptors likely serve as bona fide photoreceptors, as we showcase for a diguanylate cyclase. We propose that without the glutamine, water molecules transiently approach the chromophore and thus propagate flavin protonation downstream. Signaling without glutamine appears intrinsic to light-oxygen-voltage receptors, which pertains to biotechnological applications and suggests evolutionary descendance from redox-active flavoproteins. Light-oxygen-voltage (LOV) photoreceptors perceive blue light to elicit spatio-temporally defined cellular responses, and their signalling process has been extensively characterized. Here the authors report that the light signal is still transduced in the absence of a conserved Gln residue, thought to be key.
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Affiliation(s)
- Julia Dietler
- Department of Biochemistry, University of Bayreuth, 95447, Bayreuth, Germany
| | - Renate Gelfert
- Department of Biochemistry, University of Bayreuth, 95447, Bayreuth, Germany
| | - Jennifer Kaiser
- Department of Biochemistry, University of Bayreuth, 95447, Bayreuth, Germany
| | - Veniamin Borin
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Christian Renzl
- Life and Medical Sciences (LIMES), University of Bonn, 53121, Bonn, Germany
| | - Sebastian Pilsl
- Life and Medical Sciences (LIMES), University of Bonn, 53121, Bonn, Germany
| | | | | | - Tobias Gleichmann
- Biophysical Chemistry, Humboldt-University Berlin, 10115, Berlin, Germany
| | | | - Michael Weyand
- Department of Biochemistry, University of Bayreuth, 95447, Bayreuth, Germany
| | - Günter Mayer
- Life and Medical Sciences (LIMES), University of Bonn, 53121, Bonn, Germany.,Center of Aptamer Research & Development, University of Bonn, 53121, Bonn, Germany
| | - Igor Schapiro
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Andreas Möglich
- Department of Biochemistry, University of Bayreuth, 95447, Bayreuth, Germany. .,Biophysical Chemistry, Humboldt-University Berlin, 10115, Berlin, Germany. .,Bayreuth Center for Biochemistry & Molecular Biology, Universität Bayreuth, 95447, Bayreuth, Germany. .,North-Bavarian NMR Center, Universität Bayreuth, 95447, Bayreuth, Germany.
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4
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Ding Y, Zhao Z, Matysik J, Gärtner W, Losi A. Mapping the role of aromatic amino acids within a blue-light sensing LOV domain. Phys Chem Chem Phys 2021; 23:16767-16775. [PMID: 34319324 DOI: 10.1039/d1cp02217b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Photosensing LOV (Light, Oxygen, Voltage) domains detect and respond to UVA/Blue (BL) light by forming a covalent adduct between the flavin chromophore and a nearby cysteine, via the decay of the flavin triplet excited state. LOV domains where the reactive cysteine has been mutated are valuable fluorescent tools for microscopy and as genetically encoded photosensitisers for reactive oxygen species. Besides being convenient tools for applications, LOV domains without the reactive cysteine (naturally occurring or engineered) can still be functionally photoactivated via formation of a neutral flavin radical. Tryptophans and tyrosines are held as the main partners as potential electron donors to the flavin excited states. In this work, we explore the relevance of aromatic amino acids in determining the photophysical features of the LOV protein Mr4511 from Methylobacterium radiotolerans by introducing point mutations into the C71S variant that does not form the covalent adduct. By using an array of spectroscopic techniques we measured the fluorescence quantum yields and lifetimes, the triplet yields and lifetimes, and the efficiency of singlet oxygen (SO) formation for eleven Mr4511 variants. Insertion of Trp residues at distances between 0.6 and 1.5 nm from the flavin chromophore results in strong quenching of the flavin excited triplet state and, at the shorter distances even of the singlet excited state. The mutation F130W (ca. 0.6 nm) completely quenches the singlet excited state, preventing triplet formation: in this case, even if the cysteine is present, the photo-adduct is not formed. Tyrosines are also quenchers for the flavin excited states, although not as efficient as Trp residues, as demonstrated with their substitution with the inert phenylalanine. For one of these variants, C71S/Y116F, we found that the quantum yield of formation for singlet oxygen is 0.44 in aqueous aerobic solution, vs 0.17 for C71S. Based on our study with Mr4511 and on literature data for other LOV domains we suggest that Trp and Tyr residues too close to the flavin chromophore (at distances less than 0.9 nm) reduce the yield of photoproduct formation and that introduction of inert Phe residues in key positions can help in developing efficient, LOV-based photosensitisers.
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Affiliation(s)
- Yonghong Ding
- Institute for Analytical Chemistry, University of Leipzig, Linnéstrasse 3, 04103 Leipzig, Germany
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5
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Cheng X, Pu L, Fu S, Xia A, Huang S, Ni L, Xing X, Yang S, Jin F. Engineering Gac/Rsm Signaling Cascade for Optogenetic Induction of the Pathogenicity Switch in Pseudomonas aeruginosa. ACS Synth Biol 2021; 10:1520-1530. [PMID: 34076414 DOI: 10.1021/acssynbio.1c00075] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Bacterial pathogens operate by tightly controlling the pathogenicity to facilitate invasion and survival in host. While small molecule inducers can be designed to modulate pathogenicity to perform studies of pathogen-host interaction, these approaches, due to the diffusion property of chemicals, may have unintended, or pleiotropic effects that can impose limitations on their use. By contrast, light provides superior spatial and temporal resolution. Here, using optogenetics we reengineered GacS of the opportunistic pathogen Pseudomonas aeruginosa, signal transduction protein of the global regulatory Gac/Rsm cascade which is of central importance for the regulation of infection factors. The resultant protein (termed YGS24) displayed significant light-dependent activity of GacS kinases in Pseudomonas aeruginosa. When introduced in the Caenorhabditis elegans host systems, YGS24 stimulated the pathogenicity of the Pseudomonas aeruginosa strain PAO1 in a brain-heart infusion and of another strain, PA14, in slow killing media progressively upon blue-light exposure. This optogenetic system provides an accessible way to spatiotemporally control bacterial pathogenicity in defined hosts, even specific tissues, to develop new pathogenesis systems, which may in turn expedite development of innovative therapeutics.
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Affiliation(s)
- Xinyi Cheng
- Hefei National Laboratory for Physical Sciences at the Microscale; Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Lu Pu
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Shengwei Fu
- Hefei National Laboratory for Physical Sciences at the Microscale; Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Aiguo Xia
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Shuqiang Huang
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Lei Ni
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Xiaochen Xing
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Shuai Yang
- Hefei National Laboratory for Physical Sciences at the Microscale; Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Fan Jin
- Hefei National Laboratory for Physical Sciences at the Microscale; Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
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6
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Choi S, Nakasone Y, Hellingwerf KJ, Terazima M. Photoreaction Dynamics of a Full-Length Protein YtvA and Intermolecular Interaction with RsbRA. Biochemistry 2020; 59:4703-4710. [PMID: 33287544 DOI: 10.1021/acs.biochem.0c00888] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
YtvA from Bacillus subtilis is a sensor protein that responds to blue light stress and regulates the activity of transcription factor σB. It is composed of the N-terminal LOV (light-oxygen-voltage) domain, the C-terminal STAS (sulfate transporter and anti-sigma factor antagonist) domain, and a linker region connecting them. In this study, the photoreaction and kinetics of full-length YtvA and the intermolecular interaction with a downstream protein, RsbRA, were revealed by the transient grating method. Although N-YLOV-linker, which is composed of the LOV domain of YtvA with helices A'α and Jα, exhibits a diffusion change due to the rotational motion of the helices, the YtvA dimer does not show the diffusion change. This result suggests that the STAS domain inhibits the rotational movement of helices A'α and Jα. We found that the YtvA dimer formed a heterotetramer with the RsbRA dimer probably via the interaction between the STAS domains, and we showed the diffusion change upon blue light illumination with a time constant faster than 70 μs. This result suggests a conformational change of the STAS domains; i.e., the interface between the STAS domains of the proteins changes to enhance the friction with water by the rotation structural change of helices A'α and Jα of YtvA.
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Affiliation(s)
- Seokwoo Choi
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Yusuke Nakasone
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Klaas J Hellingwerf
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Masahide Terazima
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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7
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Consiglieri E, Xu QZ, Zhao KH, Gärtner W, Losi A. The first molecular characterisation of blue- and red-light photoreceptors from Methylobacterium radiotolerans. Phys Chem Chem Phys 2020; 22:12434-12446. [PMID: 32458860 DOI: 10.1039/d0cp02014a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Methylobacteria are facultative methylotrophic phytosymbionts of great industrial and agronomical interest, and they are considered as opportunistic pathogens posing a health threat to humans. So far only a few reports mention photoreceptor coding sequences in Methylobacteria genomes, but no investigation at the molecular level has been performed yet. We here present comprehensive in silico research into potential photoreceptors in this bacterial phylum and report the photophysical and photochemical characterisation of two representatives of the most widespread photoreceptor classes, a blue-light sensing LOV (light, oxygen, voltage) protein and a red/far red light sensing BphP (biliverdin-binding bacterial phytochrome) from M. radiotolerans JCM 2831. Overall, both proteins undergo the expected light-triggered reactions, but peculiar features were also identified. The LOV protein Mr4511 has an extremely long photocycle and lacks a tryptophan conserved in ca. 75% of LOV domains. Mutation I37V accelerates the photocycle by one order of magnitude, while the Q112W change underscores the ability of tryptophan in this position to perform efficient energy transfer to the flavin chromophore. Time-resolved photoacoustic experiments showed that Mr4511 has a higher triplet quantum yield than other LOV domains and that the formation of the photoproduct results in a volume expansion, in sharp contrast to other LOV proteins. Mr4511 was found to be astonishingly resistant to denaturation by urea, still showing light-triggered reactions after incubation in urea for more than 20 h. The phytochrome MrBphP1 exhibits the so far most red-shifted absorption maxima for its Pr- and Pfr forms (λmax = 707 nm and 764 nm for the Pr and Pfr forms). The light-driven conversions in both directions occur with relatively high quantum yields of 0.2. Transient ns absorption spectroscopy (μs-ms time range) identifies the decay of the instantaneously formed lumi-intermediate, followed by only one additional intermediate before the formation of the respective final photoproducts for Pr-to-Pfr or Pfr-to-Pr photoconversion, in contrast to other BphPs. The relatively simple photoconversion patterns suggest the absence of the shunt pathways reported for other bacterial phytochromes.
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Affiliation(s)
- Eleonora Consiglieri
- Department of Mathematical, Physical and Computer Sciences, University of Parma, Parco Area delle Scienze 7/A, 43124 Parma, Italy.
| | - Qian-Zhao Xu
- Institute for Analytical Chemistry, University of Leipzig, Linnéstrasse 3, 04103 Leipzig, Germany and State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Kai-Hong Zhao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Wolfgang Gärtner
- Institute for Analytical Chemistry, University of Leipzig, Linnéstrasse 3, 04103 Leipzig, Germany
| | - Aba Losi
- Department of Mathematical, Physical and Computer Sciences, University of Parma, Parco Area delle Scienze 7/A, 43124 Parma, Italy.
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8
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Engineering the orange carotenoid protein for applications in synthetic biology. Curr Opin Struct Biol 2019; 57:110-117. [DOI: 10.1016/j.sbi.2019.01.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 01/13/2019] [Accepted: 01/28/2019] [Indexed: 12/18/2022]
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9
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Kerruth S, Langner P, Raffelberg S, Gärtner W, Heberle J. Characterization of the Blue-Light-Activated Adenylyl Cyclase mPAC by Flash Photolysis and FTIR Spectroscopy. Photochem Photobiol 2018; 93:857-864. [PMID: 28500710 DOI: 10.1111/php.12746] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 01/08/2017] [Indexed: 11/29/2022]
Abstract
The recently discovered photo-activated adenylyl cyclase (mPAC from Microcoleus chthonoplastes) is the first PAC that owes a light-, oxygen- and voltage-sensitive (LOV) domain for blue-light sensing. The photoreaction of the mPAC receptor was studied by time-resolved UV/vis and light-induced Fourier transform infrared (FTIR) absorption difference spectroscopy. The photocycle comprises of the typical triplet state LOV715 and the thio-adduct state LOV390 . While the adduct state decays with a time constant of 8 s, the lifetime of the triplet state is with 656 ns significantly shorter than in all other reported LOV domains. The light-induced FTIR difference spectrum shows the typical bands of the LOV390 and LOV450 intermediates. The negative S-H stretching vibration at 2573 cm-1 is asymmetric suggesting two rotamer configurations of the protonated side chain of C194. A positive band at 3632 cm-1 is observed, which is assigned to an internal water molecule. In contrast to other LOV domains, mPAC exhibits a second positive feature at 3674 cm-1 which is due to the O-H stretch of a second intrinsic water molecule and the side chain of Y476. We conclude that the latter might be involved in the dimerization of the cyclase domain which is crucial for ATP binding.
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Affiliation(s)
- Silke Kerruth
- Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Pit Langner
- Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Sarah Raffelberg
- Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Wolfgang Gärtner
- Max Planck Institute for Chemical Energy Conversion, Mülheim a. d. Ruhr, Germany
| | - Joachim Heberle
- Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
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Abstract
The first stage in biological signaling is based on changes in the functional state of a receptor protein triggered by interaction of the receptor with its ligand(s). The light-triggered nature of photoreceptors allows studies on the mechanism of such changes in receptor proteins using a wide range of biophysical methods and with superb time resolution. Here, we critically evaluate current understanding of proton and electron transfer in photosensory proteins and their involvement both in primary photochemistry and subsequent processes that lead to the formation of the signaling state. An insight emerging from multiple families of photoreceptors is that ultrafast primary photochemistry is followed by slower proton transfer steps that contribute to triggering large protein conformational changes during signaling state formation. We discuss themes and principles for light sensing shared by the six photoreceptor families: rhodopsins, phytochromes, photoactive yellow proteins, light-oxygen-voltage proteins, blue-light sensors using flavin, and cryptochromes.
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Affiliation(s)
- Tilman Kottke
- Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany
| | - Aihua Xie
- Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078, USA
| | - Delmar S. Larsen
- Department of Chemistry, University of California, Davis, California 95616, USA
| | - Wouter D. Hoff
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma 74078, USA
- Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, USA
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11
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Nakagawa S, Weingart O, Marian CM. Dual Photochemical Reaction Pathway in Flavin-Based Photoreceptor LOV Domain: A Combined Quantum-Mechanics/Molecular-Mechanics Investigation. J Phys Chem B 2017; 121:9583-9596. [PMID: 28926259 DOI: 10.1021/acs.jpcb.7b09207] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The primary photochemical reaction of the light, oxygen, and voltage (LOV) domain of the blue-light photosensor YtvA of Bacillus subtilis were investigated using high-level QM(DFT/MRCI)/MM methods. After blue-light excitation, the Sγ atom of the reactive cysteine forms a covalent bond with the C4a of the flavin mononucleotide (FMN) ring. Two conformations for the side chain of reactive cysteine with occupancies of 70% (conf A) and 30% (conf B) are observed in the X-ray crystallographic structures of the YtvA-LOV ( Möglich , A. ; Moffat , K. J. Mol. Biol. 2007 , 373 , 112 - 126 ). In conf A, the thiol group is directed toward the dimethylbenzene moiety of the FMN ring whereas it is placed directly above the N5 atom of the FMN ring in conf B. Starting from both conformations, the singlet and triplet excited pathways were evaluated. The singlet states excited from conf A decay nonradiatively to the triplet states by intersystem crossing (ISC). After the formation of a neutral biradical, the triplet states cross over to the electronic ground state by a second ISC and the adducts are efficiently formed. The singlet states excited from conf B are located near the S1/S0 conical intersection (CIn). A major fraction returns to the initial states through the CIn. The rest may directly reach the adduct state. Thus, the photoexcitation has a dual reaction pathway. In YtvA-LOV, it is inferred that the efficient triplet excitation from conf A was chosen by bypassing the less efficient singlet excitation from conf B.
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Affiliation(s)
- Setsuko Nakagawa
- Department of Human Life and Environment, Kinjo Gakuin University , Omori, Moriyama-ku, Nagoya 463-8521, Japan
| | - Oliver Weingart
- Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf , Universitätsstrasse 1, D-40225 Düsseldorf, Germany
| | - Christel M Marian
- Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf , Universitätsstrasse 1, D-40225 Düsseldorf, Germany
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12
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Lechno-Yossef S, Melnicki MR, Bao H, Montgomery BL, Kerfeld CA. Synthetic OCP heterodimers are photoactive and recapitulate the fusion of two primitive carotenoproteins in the evolution of cyanobacterial photoprotection. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 91:646-656. [PMID: 28503830 DOI: 10.1111/tpj.13593] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 04/25/2017] [Accepted: 05/03/2017] [Indexed: 06/07/2023]
Abstract
The orange carotenoid protein (OCP) governs photoprotection in the majority of cyanobacteria. It is structurally and functionally modular, comprised of a C-terminal regulatory domain (CTD), an N-terminal effector domain (NTD) and a ketocarotenoid; the chromophore spans the two domains in the ground state and translocates fully into the NTD upon illumination. Using both the canonical OCP1 from Fremyella diplosiphon and the presumably more primitive OCP2 paralog from the same organism, we show that an NTD-CTD heterodimer forms when the domains are expressed as separate polypeptides. The carotenoid is required for the heterodimeric association, assembling an orange complex which is stable in the dark. Both OCP1 and OCP2 heterodimers are photoactive, undergoing light-driven heterodimer dissociation, but differ in their ability to reassociate in darkness, setting the stage for bioengineering photoprotection in cyanobacteria as well as for developing new photoswitches for biotechnology. Additionally, we reveal that homodimeric CTD can bind carotenoid in the absence of NTD, and name this truncated variant the C-terminal domain-like carotenoid protein (CCP). This finding supports the hypothesis that the OCP evolved from an ancient fusion event between genes for two different carotenoid-binding proteins ancestral to the NTD and CTD. We suggest that the CCP and its homologs constitute a new family of carotenoproteins within the NTF2-like superfamily found across all kingdoms of life.
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Affiliation(s)
- Sigal Lechno-Yossef
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
| | - Matthew R Melnicki
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Han Bao
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
| | - Beronda L Montgomery
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
| | - Cheryl A Kerfeld
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
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13
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Structure of a LOV protein in apo-state and implications for construction of LOV-based optical tools. Sci Rep 2017; 7:42971. [PMID: 28211532 PMCID: PMC5314338 DOI: 10.1038/srep42971] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 01/17/2017] [Indexed: 12/29/2022] Open
Abstract
Unique features of Light-Oxygen-Voltage (LOV) proteins like relatively small size (~12–19 kDa), inherent modularity, highly-tunable photocycle and oxygen-independent fluorescence have lately been exploited for the generation of optical tools. Structures of LOV domains reported so far contain a flavin chromophore per protein molecule. Here we report two new findings on the short LOV protein W619_1-LOV from Pseudomonas putida. First, the apo-state crystal structure of W619_1-LOV at 2.5 Å resolution reveals conformational rearrangements in the secondary structure elements lining the chromophore pocket including elongation of the Fα helix, shortening of the Eα-Fα loop and partial unfolding of the Eα helix. Second, the apo W619_1-LOV protein binds both natural and structurally modified flavin chromophores. Remarkably different photophysical and photochemical properties of W619_1-LOV bound to 7-methyl-8-chloro-riboflavin (8-Cl-RF) and lumichrome imply application of these variants as novel optical tools as they offer advantages such as no adduct state formation, and a broader choice of wavelengths for in vitro studies.
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14
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Losi A, Gärtner W. Solving Blue Light Riddles: New Lessons from Flavin-binding LOV Photoreceptors. Photochem Photobiol 2017; 93:141-158. [PMID: 27861974 DOI: 10.1111/php.12674] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Accepted: 10/22/2016] [Indexed: 12/15/2022]
Abstract
Detection of blue light (BL) via flavin-binding photoreceptors (Fl-Blues) has evolved throughout all three domains of life. Although the main BL players, that is light, oxygen and voltage (LOV), blue light sensing using flavins (BLUF) and Cry (cryptochrome) proteins, have been characterized in great detail with respect to structure and function, still several unresolved issues at different levels of complexity remain and novel unexpected findings were reported. Here, we review the most prevailing riddles of LOV-based photoreceptors, for example: the relevance of water and/or small metabolites for the dynamics of the photocycle; molecular details of light-to-signal transduction events; the interplay of BL sensing by LOV domains with other environmental stimuli, such as BL plus oxygen-mediating photodamage and its impact on microbial lifestyles; the importance of the cell or chromophore redox state in determining the fate of BL-driven reactions; the evolutionary pathways of LOV-based BL sensing and associated functions through the diverse phyla. We will discuss major novelties emerged during the last few years on these intriguing aspects of LOV proteins by presenting paradigmatic examples from prokaryotic photosensors that exhibit the largest complexity and richness in associated functions.
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Affiliation(s)
- Aba Losi
- Department of Physics and Earth Sciences, University of Parma, Parma, Italy
| | - Wolfgang Gärtner
- Max-Planck-Institute for Chemical Energy Conversion, Mülheim, Germany
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15
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Abstract
The stressosome is a multi-protein signal integration and transduction hub found in a wide range of bacterial species. The role that the stressosome plays in regulating the transcription of genes involved in the general stress response has been studied most extensively in the Gram-positive model organism Bacillus subtilis. The stressosome receives and relays the signal(s) that initiate a complex phosphorylation-dependent partner switching cascade, resulting in the activation of the alternative sigma factor σB. This sigma factor controls transcription of more than 150 genes involved in the general stress response. X-ray crystal structures of individual components of the stressosome and single-particle cryo-EM reconstructions of stressosome complexes, coupled with biochemical and single cell analyses, have permitted a detailed understanding of the dynamic signalling behaviour that arises from this multi-protein complex. Furthermore, bioinformatics analyses indicate that genetic modules encoding key stressosome proteins are found in a wide range of bacterial species, indicating an evolutionary advantage afforded by stressosome complexes. Interestingly, the genetic modules are associated with a variety of signalling modules encoding secondary messenger regulation systems, as well as classical two-component signal transduction systems, suggesting a diversification in function. In this chapter we review the current research into stressosome systems and discuss the functional implications of the unique structure of these signalling complexes.
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16
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Zhu J, Mathes T, Hontani Y, Alexandre MTA, Toh KC, Hegemann P, Kennis JTM. Photoadduct Formation from the FMN Singlet Excited State in the LOV2 Domain of Chlamydomonas reinhardtii Phototropin. J Phys Chem Lett 2016; 7:4380-4384. [PMID: 27766868 DOI: 10.1021/acs.jpclett.6b02075] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The two light, oxygen, and voltage domains of phototropin are blue-light photoreceptor domains that control various functions in plants and green algae. The key step of the light-driven reaction is the formation of a photoadduct between its FMN chromophore and a conserved cysteine, where the canonical reaction proceeds through the FMN triplet state. Here, complete photoreaction mapping of CrLOV2 from Chlamydomonas reinhardtii phototropin and AsLOV2 from Avena sativa phototropin-1 was realized by ultrafast broadband spectroscopy from femtoseconds to microseconds. We demonstrate that in CrLOV2, a direct photoadduct formation channel originates from the initially excited singlet state, in addition to the canonical reaction through the triplet state. This direct photoadduct reaction is coupled by a proton or hydrogen transfer process, as indicated by a significant kinetic isotope effect of 1.4 on the fluorescence lifetime. Kinetic model analyses showed that 38% of the photoadducts are generated from the singlet excited state.
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Affiliation(s)
- Jingyi Zhu
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit , 1081 De Boelelaan, 1081 HV Amsterdam, The Netherlands
| | - Tilo Mathes
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit , 1081 De Boelelaan, 1081 HV Amsterdam, The Netherlands
| | - Yusaku Hontani
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit , 1081 De Boelelaan, 1081 HV Amsterdam, The Netherlands
| | - Maxime T A Alexandre
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit , 1081 De Boelelaan, 1081 HV Amsterdam, The Netherlands
| | - K C Toh
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit , 1081 De Boelelaan, 1081 HV Amsterdam, The Netherlands
| | - Peter Hegemann
- Department of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin , Invalidenstraße 42, 10115 Berlin, Germany
| | - John T M Kennis
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit , 1081 De Boelelaan, 1081 HV Amsterdam, The Netherlands
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17
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Röllen K, Granzin J, Panwalkar V, Arinkin V, Rani R, Hartmann R, Krauss U, Jaeger KE, Willbold D, Batra-Safferling R. Signaling States of a Short Blue-Light Photoreceptor Protein PpSB1-LOV Revealed from Crystal Structures and Solution NMR Spectroscopy. J Mol Biol 2016; 428:3721-36. [DOI: 10.1016/j.jmb.2016.05.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 05/12/2016] [Accepted: 05/14/2016] [Indexed: 11/30/2022]
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18
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Choi S, Nakasone Y, Hellingwerf KJ, Terazima M. Photochemical Reactions of the LOV and LOV-Linker Domains of the Blue Light Sensor Protein YtvA. Biochemistry 2016; 55:3107-15. [PMID: 27203230 DOI: 10.1021/acs.biochem.6b00263] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
YtvA is a blue light sensor protein composed of an N-terminal LOV (light-oxygen-voltage) domain, a linker helix, and the C-terminal sulfate transporter and anti-σ factor antagonist domain. YtvA is believed to act as a positive regulator for light and salt stress responses by regulating the σB transcription factor. Although its biological function has been studied, the reaction dynamics and molecular mechanism underlying the function are not well understood. To improve our understanding of the signaling mechanism, we studied the reaction of the LOV domain (YLOV, amino acids 26-127), the LOV domain with its N-terminal extension (N-YLOV, amino acids 1-127), the LOV domain with its C-terminal linker helix (YLOV-linker, amino acids 26-147), and the YLOV domain with the N-terminal extension and the C-terminal linker helix (N-YLOV-linker, amino acids 1-147) using the transient grating method. The signals of all constructs showed adduct formation, thermal diffusion, and molecular diffusion. YLOV showed no change in the diffusion coefficient (D), while the other three constructs showed a significant decrease in D within ∼70 μs of photoexcitation. This indicates that conformational changes in both the N- and C-terminal helices of the YLOV domain indeed do occur. The time constant in the YtvA derivatives was much faster than the corresponding dynamics of phototropins. Interestingly, an additional reaction was observed as a volume expansion as well as a slight increase in D only when both helices were included. These findings suggest that although the rearrangement of the N- and C-terminal helices occurs independently on the fast time scale, this change induces an additional conformational change only when both helices are present.
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Affiliation(s)
- Seokwoo Choi
- Department of Chemistry, Graduate School of Science, Kyoto University , Kyoto, Japan
| | - Yusuke Nakasone
- Department of Chemistry, Graduate School of Science, Kyoto University , Kyoto, Japan
| | - Klaas J Hellingwerf
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam , 1090 GE Amsterdam, The Netherlands
| | - Masahide Terazima
- Department of Chemistry, Graduate School of Science, Kyoto University , Kyoto, Japan
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19
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Mukhopadhyay S, Gärtner W, Cahen D, Pecht I, Sheves M. Electron transport via a soluble photochromic photoreceptor. Phys Chem Chem Phys 2016; 18:25671-25675. [DOI: 10.1039/c6cp05011e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron transport properties via a photochromic biological photoreceptor have been studied in junctions of monolayer assemblies in solid-state configurations.
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Affiliation(s)
- Sabyasachi Mukhopadhyay
- Department of Materials and Interfaces
- Weizmann Institute of Science
- Israel
- Department of Organic Chemistry
- Weizmann Institute of Science
| | - Wolfgang Gärtner
- Max Planck Institute for Chemical Energy Conversion
- 45470 Mülheim a.d. Ruhr
- Germany
| | - David Cahen
- Department of Materials and Interfaces
- Weizmann Institute of Science
- Israel
| | - Israel Pecht
- Department of Immunology
- Weizmann Institute of Science
- Israel
| | - Mordechai Sheves
- Department of Organic Chemistry
- Weizmann Institute of Science
- Israel
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20
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Lee R, Gam J, Moon J, Lee SG, Suh YG, Lee BJ, Lee J. A critical element of the light-induced quaternary structural changes in YtvA-LOV. Protein Sci 2015; 24:1997-2007. [PMID: 26402155 DOI: 10.1002/pro.2810] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/18/2015] [Accepted: 09/19/2015] [Indexed: 01/27/2023]
Abstract
YtvA, a photosensory LOV (light-oxygen-voltage) protein from Bacillus subtilis, exists as a dimer that previously appeared to undergo surprisingly small structural changes after light illumination compared with other light-sensing proteins. However, we now report that light induces significant structural perturbations in a series of YtvA-LOV domain derivatives in which the Jα helix has been truncated or replaced. Results from native gel analysis showed significant mobility changes in these derivatives after light illumination; YtvA-LOV without the Jα helix dimerized in the dark state but existed as a monomer in the light state. The absence of the Jα helix also affected the dark regeneration kinetics and the stability of the flavin mononucleotide (FMN) binding to its binding site. Our results demonstrate an alternative way of photo-induced signal propagation that leads to a bigger functional response through dimer/monomer conversions of the YtvA-LOV than the local disruption of Jα helix in the As-LOV domain.
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Affiliation(s)
- Rang Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 151-742, Korea
| | - Jongsik Gam
- Department of Medicinal Bioscience, College of Interdisciplinary & Creative Studies, Konyang University, Nonsan-Si, 320-711, Korea
| | - Jayoung Moon
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 151-742, Korea
| | - Seung-Goo Lee
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 305-806, Korea
| | - Young-Ger Suh
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 151-742, Korea
| | - Bong-Jin Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 151-742, Korea
| | - Jeeyeon Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 151-742, Korea
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21
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Kutta RJ, Magerl K, Kensy U, Dick B. A search for radical intermediates in the photocycle of LOV domains. Photochem Photobiol Sci 2015; 14:288-99. [PMID: 25380177 DOI: 10.1039/c4pp00155a] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
LOV domains are the light sensitive parts of phototropins and many other light-activated enzymes that regulate the response to blue light in plants and algae as well as some fungi and bacteria. Unlike all other biological photoreceptors known so far, the photocycle of LOV domains involves the excited triplet state of the chromophore. This chromophore is flavin mononucleotide (FMN) which forms a covalent adduct with a cysteine residue in the signaling state. Since the formation of this adduct from the triplet state involves breaking and forming of two bonds as well as a change from the triplet to the singlet spin state, various intermediates have been proposed, e.g. a protonated triplet state (3)FMNH(+), the radical anion (2)FMN˙(-), or the neutral semiquinone radical (2)FMNH˙. We performed an extensive search for these intermediates by two-dimensional transient absorption (2D-TA) with a streak camera. However, no transient with a rate constant between the decay of fluorescence and the decay of the triplet state could be detected. Analysis of the decay associated difference spectra results in quantum yields for the formation of the adduct from the triplet of ΦA(LOV1) ≈ 0.75 and ΦA(LOV2) ≈ 0.80. This is lower than the values ΦA(LOV1) ≈ 0.95 and ΦA(LOV2) ≈ 0.99 calculated from the rate constants, giving indirect evidence of an intermediate that reacts either to form the adduct or to decay back to the ground state. Since there is no measurable delay between the decay of the triplet and the formation of the adduct, we conclude that this intermediate reacts much faster than it is formed. The LOV1-C57S mutant shows a weak and slowly decaying (τ > 100 μs) transient whose decay associated spectrum has bands at 375 and 500 nm, with a shoulder at 400 nm. This transient is insensitive to the pH change in the range 6.5-10.0 but increases on addition of β-mercaptoethanol as the reducing agent. We assign this intermediate to the radical anion which is protected from protonation by the protein. We propose that the adduct is formed via the same intermediate by combination of the radical ion pair.
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Affiliation(s)
- Roger Jan Kutta
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93053 Regensburg, Germany.
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22
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van der Steen JB, Hellingwerf KJ. Activation of the General Stress Response of Bacillus subtilis by Visible Light. Photochem Photobiol 2015; 91:1032-45. [PMID: 26189730 DOI: 10.1111/php.12499] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Accepted: 06/25/2015] [Indexed: 12/20/2022]
Abstract
A key challenge for microbiology is to understand how evolution has shaped the wiring of regulatory networks. This is amplified by the paucity of information of power-spectra of physicochemical stimuli to which microorganisms are exposed. Future studies of genome evolution, driven by altered stimulus regimes, will therefore require a versatile signal transduction system that allows accurate signal dosing. Here, we review the general stress response of Bacillus subtilis, and its upstream signal transduction network, as a candidate system. It can be activated by red and blue light, and by many additional stimuli. Signal integration therefore is an intricate function of this system. The blue-light response is elicited via the photoreceptor YtvA, which forms an integral part of stressosomes, to activate expression of the stress regulon of B. subtilis. Signal transfer through this network can be assayed with reporter enzymes, while intermediate steps can be studied with live-cell imaging of fluorescently tagged proteins. Different parts of this system have been studied in vitro, such that its computational modeling has made significant progress. One can directly relate the microscopic characteristics of YtvA with activation of the general stress regulon, making this system a very well-suited system for network evolution studies.
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Affiliation(s)
- Jeroen B van der Steen
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Klaas J Hellingwerf
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
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23
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Endres S, Granzin J, Circolone F, Stadler A, Krauss U, Drepper T, Svensson V, Knieps-Grünhagen E, Wirtz A, Cousin A, Tielen P, Willbold D, Jaeger KE, Batra-Safferling R. Structure and function of a short LOV protein from the marine phototrophic bacterium Dinoroseobacter shibae. BMC Microbiol 2015; 15:30. [PMID: 25887755 PMCID: PMC4335406 DOI: 10.1186/s12866-015-0365-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 01/29/2015] [Indexed: 12/29/2022] Open
Abstract
Background Light, oxygen, voltage (LOV) domains are widely distributed in plants, algae, fungi, bacteria, and represent the photo-responsive domains of various blue-light photoreceptor proteins. Their photocycle involves the blue-light triggered adduct formation between the C(4a) atom of a non-covalently bound flavin chromophore and the sulfur atom of a conserved cysteine in the LOV sensor domain. LOV proteins show considerable variation in the structure of N- and C-terminal elements which flank the LOV core domain, as well as in the lifetime of the adduct state. Results Here, we report the photochemical, structural and functional characterization of DsLOV, a LOV protein from the photoheterotrophic marine α-proteobacterium Dinoroseobacter shibae which exhibits an average adduct state lifetime of 9.6 s at 20°C, and thus represents the fastest reverting bacterial LOV protein reported so far. Mutational analysis in D. shibae revealed a unique role of DsLOV in controlling the induction of photopigment synthesis in the absence of blue-light. The dark state crystal structure of DsLOV determined at 1.5 Å resolution reveals a conserved core domain with an extended N-terminal cap. The dimer interface in the crystal structure forms a unique network of hydrogen bonds involving residues of the N-terminus and the β-scaffold of the core domain. The structure of photoexcited DsLOV suggests increased flexibility in the N-cap region and a significant shift in the Cα backbone of β strands in the N- and C-terminal ends of the LOV core domain. Conclusions The results presented here cover the characterization of the unusual short LOV protein DsLOV from Dinoroseobacter shibae including its regulatory function, extremely fast dark recovery and an N-terminus mediated dimer interface. Due to its unique photophysical, structural and regulatory properties, DsLOV might thus serve as an alternative model system for studying light perception by LOV proteins and physiological responses in bacteria. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0365-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Stephan Endres
- Institute of Molecular Enzyme Technology, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich, D-52425, Jülich, Germany.
| | - Joachim Granzin
- Institute of Complex Systems, ICS-6: Structural Biochemistry, Forschungszentrum Jülich, D-52425, Jülich, Germany.
| | - Franco Circolone
- Institute of Molecular Enzyme Technology, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich, D-52425, Jülich, Germany.
| | - Andreas Stadler
- Juelich Centre for Neutron Science JCNS (JCNS-1) & Institute for Complex Systems (ICS-1), Forschungszentrum Jülich, D-52425, Jülich, Germany.
| | - Ulrich Krauss
- Institute of Molecular Enzyme Technology, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich, D-52425, Jülich, Germany.
| | - Thomas Drepper
- Institute of Molecular Enzyme Technology, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich, D-52425, Jülich, Germany.
| | - Vera Svensson
- Institute of Molecular Enzyme Technology, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich, D-52425, Jülich, Germany.
| | - Esther Knieps-Grünhagen
- Institute of Molecular Enzyme Technology, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich, D-52425, Jülich, Germany.
| | - Astrid Wirtz
- Institute of Molecular Enzyme Technology, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich, D-52425, Jülich, Germany.
| | - Anneliese Cousin
- Institute of Complex Systems, ICS-6: Structural Biochemistry, Forschungszentrum Jülich, D-52425, Jülich, Germany.
| | - Petra Tielen
- Institute for Microbiology, Technische Universität Braunschweig, D-38106, Braunschweig, Germany.
| | - Dieter Willbold
- Institute of Complex Systems, ICS-6: Structural Biochemistry, Forschungszentrum Jülich, D-52425, Jülich, Germany. .,Institute of Physical Biology, Heinrich-Heine-Universität Düsseldorf, D-40225, Düsseldorf, Germany.
| | - Karl-Erich Jaeger
- Institute of Molecular Enzyme Technology, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich, D-52425, Jülich, Germany. .,Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, D-52425, Jülich, Germany.
| | - Renu Batra-Safferling
- Institute of Complex Systems, ICS-6: Structural Biochemistry, Forschungszentrum Jülich, D-52425, Jülich, Germany.
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24
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Torra J, Burgos-Caminal A, Endres S, Wingen M, Drepper T, Gensch T, Ruiz-González R, Nonell S. Singlet oxygen photosensitisation by the fluorescent protein Pp2FbFP L30M, a novel derivative of Pseudomonas putida flavin-binding Pp2FbFP. Photochem Photobiol Sci 2015; 14:280-7. [DOI: 10.1039/c4pp00338a] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The flavin-binding protein Pp2FbFP L30M shows a high singlet oxygen quantum yield.
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Affiliation(s)
- Joaquim Torra
- Institut Químic de Sarrià
- Universitat Ramon Llull
- Barcelona
- Spain
| | | | - Stephan Endres
- Institute of Molecular Enzyme Technology
- Heinrich-Heine-University Düsseldorf
- 52425 Jülich
- Germany
| | - Marcus Wingen
- Institute of Molecular Enzyme Technology
- Heinrich-Heine-University Düsseldorf
- 52425 Jülich
- Germany
| | - Thomas Drepper
- Institute of Molecular Enzyme Technology
- Heinrich-Heine-University Düsseldorf
- 52425 Jülich
- Germany
| | - Thomas Gensch
- Institute of Complex Systems 4 (ICS-4
- Cellular Biophysics)
- 52425 Jülich
- Germany
| | | | - Santi Nonell
- Institut Químic de Sarrià
- Universitat Ramon Llull
- Barcelona
- Spain
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25
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Kerruth S, Ataka K, Frey D, Schlichting I, Heberle J. Aureochrome 1 illuminated: structural changes of a transcription factor probed by molecular spectroscopy. PLoS One 2014; 9:e103307. [PMID: 25058114 PMCID: PMC4110000 DOI: 10.1371/journal.pone.0103307] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 06/29/2014] [Indexed: 11/19/2022] Open
Abstract
Aureochrome 1 from Vaucheria frigida is a recently identified blue-light receptor that acts as a transcription factor. The protein comprises a photosensitive light-, oxygen- and voltage-sensitive (LOV) domain and a basic zipper (bZIP) domain that binds DNA rendering aureochrome 1 a prospective optogenetic tool. Here, we studied the photoreaction of full-length aureochrome 1 by molecular spectroscopy. The kinetics of the decay of the red-shifted triplet state and the blue-shifted signaling state were determined by time-resolved UV/Vis spectroscopy. It is shown that the presence of the bZIP domain further prolongs the lifetime of the LOV390 signaling state in comparison to the isolated LOV domain whereas bound DNA does not influence the photocycle kinetics. The light-dark Fourier transform infrared (FTIR) difference spectrum shows the characteristic features of the flavin mononucleotide chromophore except that the S-H stretching vibration of cysteine 254, which is involved in the formation of the thio-adduct state, is significantly shifted to lower frequencies compared to other LOV domains. The presence of the target DNA influences the light-induced FTIR difference spectrum of aureochrome 1. Vibrational bands that can be assigned to arginine and lysine side chains as well to the phosphate backbone, indicate crucial changes in interactions between transcription factor and DNA.
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Affiliation(s)
- Silke Kerruth
- Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Kenichi Ataka
- Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Daniel Frey
- Biomolecular Mechanisms, Max Planck Institut for Medical Research, Heidelberg, Germany
| | - Ilme Schlichting
- Biomolecular Mechanisms, Max Planck Institut for Medical Research, Heidelberg, Germany
| | - Joachim Heberle
- Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
- * E-mail:
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Moon J, Gam J, Lee SG, Suh YG, Lee J. Light-regulated tetracycline binding to the Tet repressor. Chemistry 2014; 20:2508-14. [PMID: 24478132 DOI: 10.1002/chem.201304027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Indexed: 01/21/2023]
Abstract
Elucidation of the signal-transmission pathways between distant sites within proteins is of great importance in medical and bioengineering sciences. The use of optical methods to redesign protein functions is emerging as a general approach for the control of biological systems with high spatiotemporal precision. Here we report the detailed thermodynamic and kinetic characterization of novel chimeric light-regulated Tet repressor (TetR) switches in which light modulates the TetR function. Light absorbed by flavin mononucleotide (FMN) generates a signal that is transmitted to As-LOV and YtvA-LOV fused TetR proteins (LOV=light-oxygen-voltage), in which it alters the binding to tetracycline, the TetR ligand. The engineering of light-sensing protein modules with TetR is a valuable tool that deepens our understanding of the mechanism of signal transmission within proteins. In addition, the light-regulated changes of drug binding that we describe here suggest that engineered light-sensitive proteins may be used for the development of novel therapeutic strategies.
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Affiliation(s)
- Jayoung Moon
- College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742 (Korea), Fax: (+82) 2-884-8334
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27
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Raffelberg S, Gutt A, Gärtner W, Mandalari C, Abbruzzetti S, Viappiani C, Losi A. The amino acids surrounding the flavin 7a-methyl group determine the UVA spectral features of a LOV protein. Biol Chem 2014; 394:1517-28. [PMID: 23828427 DOI: 10.1515/hsz-2013-0163] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 07/01/2013] [Indexed: 11/15/2022]
Abstract
Flavin-binding light, oxygen, and voltage (LOV) domains are UVA/blue-light-sensing protein units that form a reversible flavin mononucleotide-cysteine adduct upon light induction. In their dark-adapted state, LOV domains exhibit the typical spectral features of fully oxidized riboflavin derivatives. A survey on the absorption spectra of various LOV domains revealed that the UVA spectral range is the most variable region (whereas the absorption band at 450 nm is virtually unchanged), showing essentially two distinct patterns found in plant phototropin LOV1 and LOV2 domains, respectively. In this work, we have identified a residue directly interacting with the isoalloxazine methyl group at C(7a) as the major UVA spectral tuner. In YtvA from Bacillus subtilis, this amino acid is threonine 30, and its mutation into apolar residues converts the LOV2-like spectrum of native YtvA into a LOV1-like pattern. Mutation T30A also accelerates the photocycle ca. 4-fold. Together with control mutations at different positions, our results experimentally confirm the previously calculated direction of the transition dipole moment for the UVA ππ* state and identify the mechanisms underlying spectral tuning in the LOV domains.
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28
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Mathes T, van Stokkum IHM, Kennis JTM. Photoactivation mechanisms of flavin-binding photoreceptors revealed through ultrafast spectroscopy and global analysis methods. Methods Mol Biol 2014; 1146:401-442. [PMID: 24764100 DOI: 10.1007/978-1-4939-0452-5_16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Flavin-binding photoreceptor proteins use the isoalloxazine moiety of flavin cofactors to absorb light in the blue/UV-A wavelength region and subsequently translate it into biological information. The underlying photochemical reactions and protein structural dynamics are delicately tuned by the protein environment and represent fundamental reactions in biology and chemistry. Due to their photo-switchable nature, these proteins can be studied efficiently with laser-flash induced transient absorption and emission spectroscopy with temporal precision down to the femtosecond time domain. Here, we describe the application of both visible and mid-IR ultrafast transient absorption and time-resolved fluorescence methods in combination with sophisticated global analysis procedures to elucidate the photochemistry and signal transduction of BLUF (Blue light receptors using FAD) and LOV (Light oxygen voltage) photoreceptor domains.
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Affiliation(s)
- Tilo Mathes
- Department of Physics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, Amsterdam, 1081HV, The Netherlands
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29
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Song SH, Madsen D, van der Steen JB, Pullman R, Freer LH, Hellingwerf KJ, Larsen DS. Primary Photochemistry of the Dark- and Light-Adapted States of the YtvA Protein from Bacillus subtilis. Biochemistry 2013; 52:7951-63. [DOI: 10.1021/bi4012258] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Sang-Hun Song
- Department
of Chemistry, University of California at Davis, One Shields Avenue, Davis, California 95616, United States
| | - Dorte Madsen
- Department
of Chemistry, University of California at Davis, One Shields Avenue, Davis, California 95616, United States
| | - Jeroen B. van der Steen
- Molecular
Microbial Physiology Group, Swammerdam Institute for Life Sciences
(SILS), University of Amsterdam, 1090 GE Amsterdam, The Netherlands
| | - Robert Pullman
- Department
of Chemistry, University of California at Davis, One Shields Avenue, Davis, California 95616, United States
| | - Lucy H. Freer
- Department
of Chemistry, University of California at Davis, One Shields Avenue, Davis, California 95616, United States
| | - Klaas J. Hellingwerf
- Molecular
Microbial Physiology Group, Swammerdam Institute for Life Sciences
(SILS), University of Amsterdam, 1090 GE Amsterdam, The Netherlands
| | - Delmar S. Larsen
- Department
of Chemistry, University of California at Davis, One Shields Avenue, Davis, California 95616, United States
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30
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Silva MR, Mansurova M, Gärtner W, Thiel W. Photophysics of structurally modified flavin derivatives in the blue-light photoreceptor YtvA: a combined experimental and theoretical study. Chembiochem 2013; 14:1648-61. [PMID: 23940057 DOI: 10.1002/cbic.201300217] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Indexed: 11/10/2022]
Abstract
The light-induced processes of two flavin mononucleotide derivatives (1- and 5-deaza flavin mononucleotide, 1DFMN and 5DFMN), incorporated into the LOV domain of YtvA protein from Bacillus subtilis, were studied by a combination of experimental and computational methods. Quantum mechanics/molecular mechanics (QM/MM) calculations were carried out in which the QM part was treated by density functional theory (DFT) using the B3LYP functional for geometry optimizations and the DFT/MRCI method for spectroscopic properties, whereas the MM part was described by the CHARMM force field. 1DFMN is incorporated into the protein binding site, yielding a red-shifted absorption band (λ(max) =530 nm compared to YtvA wild-type λ(max) =445 nm), but does not undergo any LOV-typical photoreactions such as triplet and photoadduct formation. QM/MM computations confirmed the absence of a channel for triplet formation and located a radiation-free channel (through an S₁/S₀ conical intersection) along a hydrogen transfer path that might allow for fast deactivation. By contrast, 5DFMN-YtvA-LOV shows a blue-shifted absorption (λ(max) =410 nm) and undergoes similar photochemical processes to FMN in the wild-type protein, both with regard to the photophysics and the formation of a photoadduct with a flavin-cysteinyl covalent bond. The QM/MM calculations predict a mechanism that involves hydrogen transfer in the T₁ state, followed by intersystem crossing and adduct formation in the S₀ state for the forward reaction. Experimentally, in contrast to wild-type YtvA, dark-state recovery in 5DFMN-YtvA-LOV is not thermally driven but can only be accomplished after absorption of a second photon by the photoadduct, again via the triplet state. The QM/MM calculations suggest a photochemical mechanism for dark-state recovery that is accessible only for the adduct with a C4a--S bond but not for alternative adducts with a C5--S bond.
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Affiliation(s)
- Mario R Silva
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany)
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Characterization of flavin-based fluorescent proteins: an emerging class of fluorescent reporters. PLoS One 2013; 8:e64753. [PMID: 23741385 PMCID: PMC3669411 DOI: 10.1371/journal.pone.0064753] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 04/18/2013] [Indexed: 12/19/2022] Open
Abstract
Fluorescent reporter proteins based on flavin-binding photosensors were recently developed as a new class of genetically encoded probes characterized by small size and oxygen-independent maturation of fluorescence. Flavin-based fluorescent proteins (FbFPs) address two major limitations associated with existing fluorescent reporters derived from the green fluorescent protein (GFP)–namely, the overall large size and oxygen-dependent maturation of fluorescence of GFP. However, FbFPs are at a nascent stage of development and have been utilized in only a handful of biological studies. Importantly, a full understanding of the performance and properties of FbFPs as a practical set of biological probes is lacking. In this work, we extensively characterize three FbFPs isolated from Pseudomonas putida, Bacillus subtilis, and Arabidopsis thaliana, using in vitro studies to assess probe brightness, oligomeric state, maturation time, fraction of fluorescent holoprotein, pH tolerance, redox sensitivity, and thermal stability. Furthermore, we validate FbFPs as stable molecular tags using in vivo studies by constructing a series of FbFP-based transcriptional constructs to probe promoter activity in Escherichia coli. Overall, FbFPs show key advantages as broad-spectrum biological reporters including robust pH tolerance (4–11), thermal stability (up to 60°C), and rapid maturation of fluorescence (<3 min.). In addition, the FbFP derived from Arabidopsis thaliana (iLOV) emerged as a stable and nonperturbative reporter of promoter activity in Escherichia coli. Our results demonstrate that FbFP-based reporters have the potential to address key limitations associated with the use of GFP, such as pH-sensitive fluorescence and slow kinetics of fluorescence maturation (10–40 minutes for half maximal fluorescence recovery). From this view, FbFPs represent a useful new addition to the fluorescent reporter protein palette, and our results constitute an important framework to enable researchers to implement and further engineer improved FbFP-based reporters with enhanced brightness and tighter flavin binding, which will maximize their potential benefits.
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32
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Mansurova M, Simon J, Salzmann S, Marian CM, Gärtner W. Spectroscopic and Theoretical Study on Electronically Modified Chromophores in LOV Domains: 8-Bromo- and 8-Trifluoromethyl-Substituted Flavins. Chembiochem 2013; 14:645-54. [DOI: 10.1002/cbic.201200670] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Indexed: 11/11/2022]
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Tiensuu T, Andersson C, Rydén P, Johansson J. Cycles of light and dark co-ordinate reversible colony differentiation in Listeria monocytogenes. Mol Microbiol 2013; 87:909-24. [PMID: 23331346 PMCID: PMC3610012 DOI: 10.1111/mmi.12140] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2012] [Indexed: 02/03/2023]
Abstract
Recently, several light receptors have been identified in non-phototrophic bacteria, but their physiological roles still remain rather elusive. Here we show that colonies of the saprophytic bacterium Listeria monocytogenes undergo synchronized multicellular behaviour on agar plates, in response to oscillating light/dark conditions, giving rise to alternating ring formation (opaque and translucent rings). On agar plates, bacteria from opaque rings survive increased levels of reactive oxygen species (ROS), as well as repeated cycles of light and dark, better than bacteria from translucent rings. The ring formation is strictly dependent on a blue-light receptor, Lmo0799, acting through the stress-sigma factor, σB. A transposon screening identified 48 mutants unable to form rings at alternating light conditions, with several of them showing a decreased σB activity/level. However, some of the tested mutants displayed a varied σB activity depending on which of the two stress conditions tested (light or H2O2 exposure). Intriguingly, the transcriptional regulator PrfA and the virulence factor ActA were shown to be required for ring formation by a mechanism involving activation of σB. All in all, this suggests a distinct pathway for Lmo0799 that converge into a common signalling pathway for σB activation. Our results show that night and day cycles co-ordinate a reversible differentiation of a L. monocytogenes colony at room temperature, by a process synchronized by a blue-light receptor and σB.
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Affiliation(s)
- Teresa Tiensuu
- Department of Molecular Biology, Umeå University, 90187 Umeå, Sweden
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34
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Conrad KS, Bilwes AM, Crane BR. Light-induced subunit dissociation by a light-oxygen-voltage domain photoreceptor from Rhodobacter sphaeroides. Biochemistry 2013; 52:378-91. [PMID: 23252338 DOI: 10.1021/bi3015373] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Light-oxygen-voltage (LOV) domains bind a flavin chromophore to serve as blue light sensors in a wide range of eukaryotic and prokaryotic proteins. LOV domains are associated with a variable effector domain or a separate protein signaling partner to execute a wide variety of functions that include regulation of kinases, generation of anti-sigma factor antagonists, and regulation of circadian clocks. Here we present the crystal structure, photocycle kinetics, association properties, and spectroscopic features of a full-length LOV domain protein from Rhodobacter sphaeroides (RsLOV). RsLOV exhibits N- and C-terminal helical extensions that form an unusual helical bundle at its dimer interface with some resemblance to the helical transducer of sensory rhodopsin II. The blue light-induced conformational changes of RsLOV revealed from a comparison of light- and dark-state crystal structures support a shared signaling mechanism of LOV domain proteins that originates with the light-induced formation of a flavin-cysteinyl photoadduct. Adduct formation disrupts hydrogen bonding in the active site and propagates structural changes through the LOV domain core to the N- and C-terminal extensions. Single-residue variants in the active site and dimer interface of RsLOV alter photoadduct lifetimes and induce structural changes that perturb the oligomeric state. Size exclusion chromatography, multiangle light scattering, small-angle X-ray scattering, and cross-linking studies indicate that RsLOV dimerizes in the dark but, upon light excitation, dissociates into monomers. This light-induced switch in oligomeric state may prove to be useful for engineering molecular associations in controlled cellular settings.
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Affiliation(s)
- Karen S Conrad
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
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35
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van der Steen JB, Nakasone Y, Hendriks J, Hellingwerf KJ. Modeling the functioning of YtvA in the general stress response in Bacillus subtilis. MOLECULAR BIOSYSTEMS 2013; 9:2331-43. [DOI: 10.1039/c3mb70124g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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36
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Losi A, Gärtner W, Raffelberg S, Cella Zanacchi F, Bianchini P, Diaspro A, Mandalari C, Abbruzzetti S, Viappiani C. A photochromic bacterial photoreceptor with potential for super-resolution microscopy. Photochem Photobiol Sci 2013; 12:231-5. [DOI: 10.1039/c2pp25254f] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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37
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Hisatomi O, Takeuchi K, Zikihara K, Ookubo Y, Nakatani Y, Takahashi F, Tokutomi S, Kataoka H. Blue Light-Induced Conformational Changes in a Light-Regulated Transcription Factor, Aureochrome-1. ACTA ACUST UNITED AC 2012; 54:93-106. [DOI: 10.1093/pcp/pcs160] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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38
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Chan RH, Lewis JW, Bogomolni RA. Photocycle of the LOV-STAS protein from the pathogen Listeria monocytogenes. Photochem Photobiol 2012; 89:361-9. [PMID: 23025752 DOI: 10.1111/php.12004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 09/21/2012] [Indexed: 01/06/2023]
Abstract
Listeria monocytogenes, a food-borne bacterial pathogen causing significant human mortality, propagates by expressing genes in response to environmental signals, such as temperature and pH. Listeria gene (lmo0799) encodes a protein homologous to the Bacillus subtilis YtvA, which has a flavin-light, oxygen or voltage (LOV) domain and a Sulfate Transporters Anti-Sigma factor antagonist (STAS) output domain that regulates transcription-initiation factor Sigma B in the bacterial stress response upon exposure to light. This could be significant for the pathogenesis of listeriosis because Sigma B has been linked to virulence of Listeria, and the Listeria Lmo0799 protein has recently been identified as a virulence factor activated by blue light. We have cloned, expressed heterologously in Escherichia coli and purified the full-length LM-LOV-STAS protein. Although it exhibits photochemical activity similar to that of YtvA, LM-LOV-STAS lacks an almost universally conserved arginine in the flavin-binding site, as well as another positively charged residue, a lysine in YtvA. The absence of these positive charges was found to destabilize retention of the flavin mononucleotide (FMN) chromophore in the LM-LOV-STAS protein, particularly at higher temperatures. The unusual sequence of the LM-LOV-STAS protein alters both spectral features and activation/deactivation kinetics, potentially expanding the sensory capacity of this LOV domain, e.g. to detect light plus cold.
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Affiliation(s)
- Ruby H Chan
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA
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Mukherjee A, Weyant KB, Walker J, Schroeder CM. Directed evolution of bright mutants of an oxygen-independent flavin-binding fluorescent protein from Pseudomonas putida. J Biol Eng 2012; 6:20. [PMID: 23095243 PMCID: PMC3488000 DOI: 10.1186/1754-1611-6-20] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 10/19/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Fluorescent reporter proteins have revolutionized our understanding of cellular bioprocesses by enabling live cell imaging with exquisite spatio-temporal resolution. Existing fluorescent proteins are predominantly based on the green fluorescent protein (GFP) and related analogs. However, GFP-family proteins strictly require molecular oxygen for maturation of fluorescence, which precludes their application for investigating biological processes in low-oxygen environments. A new class of oxygen-independent fluorescent reporter proteins was recently reported based on flavin-binding photosensors from Bacillus subtilis and Pseudomonas putida. However, flavin-binding fluorescent proteins show very limited brightness, which restricts their utility as biological imaging probes. RESULTS In this work, we report the discovery of bright mutants of a flavin-binding fluorescent protein from P. putida using directed evolution by site saturation mutagenesis. We discovered two mutations at a chromophore-proximal amino acid (F37S and F37T) that confer a twofold enhancement in brightness relative to the wild type fluorescent protein through improvements in quantum yield and holoprotein fraction. In addition, we observed that substitution with other aromatic amino acids at this residue (F37Y and F37W) severely diminishes fluorescence emission. Therefore, we identify F37 as a key amino acid residue in determining fluorescence. CONCLUSIONS To increase the scope and utility of flavin-binding fluorescent proteins as practical fluorescent reporters, there is a strong need for improved variants of the wild type protein. Our work reports on the application of site saturation mutagenesis to isolate brighter variants of a flavin-binding fluorescent protein, which is a first-of-its-kind approach. Overall, we anticipate that the improved variants will find pervasive use as fluorescent reporters for biological studies in low-oxygen environments.
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Affiliation(s)
- Arnab Mukherjee
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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40
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Chan RH, Bogomolni RA. Structural water cluster as a possible proton acceptor in the adduct decay reaction of oat phototropin 1 LOV2 domain. J Phys Chem B 2012; 116:10609-16. [PMID: 22845056 DOI: 10.1021/jp304934t] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
LOV domains (Light, Oxygen, Voltage) are the light-sensory modules of phototropins, the blue-light photoreceptor kinases in plants, and of a wide variety of flavoproteins found in all three domains of life. These 12 kDa modules bind a flavin chromophore (FMN or FAD) noncovalently and undergo a photochemical activation in which the sulfur atom of a conserved cysteine forms an adduct to the C(4a) carbon of the flavin. The adduct breaks spontaneously in a base-catalyzed reaction involving a rate-limiting proton-transfer step, regenerating the dark state in seconds. This photocycle involves chromophore and protein structural changes that activate the C-terminal serine/threonine kinase. Previous studies (Biochemistry 2007, 46, 7016-7021) showed that decreased hydration obtained at high glycerol concentrations stabilizes the adduct state in a manner similar to that attained at low temperatures, resulting in much longer adduct decay times. This kinetic effect was attributed to an increased protein rigidity that hindered structural fluctuations necessary for the decay reaction. In this work, we studied the adduct decay kinetics of oat phototropin 1 (phot1) LOV2 at varying hydration using a specially designed chamber that allowed for measurement of UV-visible and FTIR spectra of the same samples. Therefore, we obtained LOV protein concentrations, adduct decay kinetics, and the different populations of bound water by deconvolution of the broad water absorption peak around 3500 cm(-1). A linear dependence of the adduct decay rate constant on the concentration of double and triple hydrogen-bonded waters strongly suggests that the adduct decay is a pseudo-first-order reaction in which both the adduct and the strongly bound waters are reactants. We suggest that a cluster of strongly bound water functions as the proton acceptor in the rate-limiting step of adduct decay.
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Affiliation(s)
- Ruby H Chan
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
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41
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Kraiselburd I, Alet AI, Tondo ML, Petrocelli S, Daurelio LD, Monzón J, Ruiz OA, Losi A, Orellano EG. A LOV protein modulates the physiological attributes of Xanthomonas axonopodis pv. citri relevant for host plant colonization. PLoS One 2012; 7:e38226. [PMID: 22675525 PMCID: PMC3366940 DOI: 10.1371/journal.pone.0038226] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 05/02/2012] [Indexed: 01/04/2023] Open
Abstract
Recent studies have demonstrated that an appropriate light environment is required for the establishment of efficient vegetal resistance responses in several plant-pathogen interactions. The photoreceptors implicated in such responses are mainly those belonging to the phytochrome family. Data obtained from bacterial genome sequences revealed the presence of photosensory proteins of the BLUF (Blue Light sensing Using FAD), LOV (Light, Oxygen, Voltage) and phytochrome families with no known functions. Xanthomonas axonopodis pv. citri is a Gram-negative bacterium responsible for citrus canker. The in silico analysis of the X. axonopodis pv. citri genome sequence revealed the presence of a gene encoding a putative LOV photoreceptor, in addition to two genes encoding BLUF proteins. This suggests that blue light sensing could play a role in X. axonopodis pv. citri physiology. We obtained the recombinant Xac-LOV protein by expression in Escherichia coli and performed a spectroscopic analysis of the purified protein, which demonstrated that it has a canonical LOV photochemistry. We also constructed a mutant strain of X. axonopodis pv. citri lacking the LOV protein and found that the loss of this protein altered bacterial motility, exopolysaccharide production and biofilm formation. Moreover, we observed that the adhesion of the mutant strain to abiotic and biotic surfaces was significantly diminished compared to the wild-type. Finally, inoculation of orange (Citrus sinensis) leaves with the mutant strain of X. axonopodis pv. citri resulted in marked differences in the development of symptoms in plant tissues relative to the wild-type, suggesting a role for the Xac-LOV protein in the pathogenic process. Altogether, these results suggest the novel involvement of a photosensory system in the regulation of physiological attributes of a phytopathogenic bacterium. A functional blue light receptor in Xanthomonas spp. has been described for the first time, showing an important role in virulence during citrus canker disease.
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Affiliation(s)
- Ivana Kraiselburd
- Molecular Biology Division, Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Analía I. Alet
- Molecular Biology Division, Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - María Laura Tondo
- Molecular Biology Division, Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Silvana Petrocelli
- Molecular Biology Division, Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Lucas D. Daurelio
- Molecular Biology Division, Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Jesica Monzón
- Molecular Biology Division, Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Oscar A. Ruiz
- IIB-INTECH, Unidad de Biotecnología, Chascomús, Buenos Aires, Argentina
| | - Aba Losi
- Department of Physics, University of Parma, Parma, Italy
| | - Elena G. Orellano
- Molecular Biology Division, Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
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42
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Rinaldi J, Gallo M, Klinke S, Paris G, Bonomi HR, Bogomolni RA, Cicero DO, Goldbaum FA. The β-scaffold of the LOV domain of the Brucella light-activated histidine kinase is a key element for signal transduction. J Mol Biol 2012; 420:112-27. [PMID: 22504229 DOI: 10.1016/j.jmb.2012.04.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 04/04/2012] [Accepted: 04/05/2012] [Indexed: 01/31/2023]
Abstract
Light-oxygen-voltage (LOV) domains are blue-light-activated signaling modules present in a wide range of sensory proteins. Among them, the histidine kinases are the largest group in prokaryotes (LOV-HK). Light modulates the virulence of the pathogenic bacteria Brucella abortus through LOV-HK. One of the striking characteristic of Brucella LOV-HK is the fact that the protein remains activated upon light sensing, without recovering the basal state in the darkness. In contrast, the light state of the isolated LOV domain slowly returns to the dark state. To gain insight into the light activation mechanism, we have characterized by X-ray crystallography and solution NMR spectroscopy the structure of the LOV domain of LOV-HK in the dark state and explored its light-induced conformational changes. The LOV domain adopts the α/β PAS (PER-ARNT-SIM) domain fold and binds the FMN cofactor within a conserved pocket. The domain dimerizes through the hydrophobic β-scaffold in an antiparallel way. Our results point to the β-scaffold as a key element in the light activation, validating a conserved structural basis for light-to-signal propagation in LOV proteins.
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Affiliation(s)
- Jimena Rinaldi
- Fundación Instituto Leloir, IIBBA-CONICET, Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
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43
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Mitra D, Yang X, Moffat K. Crystal structures of Aureochrome1 LOV suggest new design strategies for optogenetics. Structure 2012; 20:698-706. [PMID: 22483116 PMCID: PMC3322389 DOI: 10.1016/j.str.2012.02.016] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 02/08/2012] [Accepted: 02/09/2012] [Indexed: 11/27/2022]
Abstract
Aureochrome1, a signaling photoreceptor from a eukaryotic photosynthetic stramenopile, confers blue-light-regulated DNA binding on the organism. Its topology, in which a C-terminal LOV sensor domain is linked to an N-terminal DNA-binding bZIP effector domain, contrasts with the reverse sensor-effector topology in most other known LOV-photoreceptors. How, then, is signal transmitted in Aureochrome1? The dark- and light-state crystal structures of Aureochrome1 LOV domain (AuLOV) show that its helical N- and C-terminal flanking regions are packed against the external surface of the core β sheet, opposite to the FMN chromophore on the internal surface. Light-induced conformational changes occur in the quaternary structure of the AuLOV dimer and in Phe298 of the Hβ strand in the core. The properties of AuLOV extend the applicability of LOV domains as versatile design modules that permit fusion to effector domains via either the N- or C-termini to confer blue-light sensitivity.
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Affiliation(s)
- Devrani Mitra
- Department of Biochemistry and Molecular Biology, University of Chicago, 929 E 57 Street, Chicago, IL 60637
| | - Xiaojing Yang
- Department of Biochemistry and Molecular Biology, University of Chicago, 929 E 57 Street, Chicago, IL 60637
| | - Keith Moffat
- Department of Biochemistry and Molecular Biology, University of Chicago, 929 E 57 Street, Chicago, IL 60637
- Institute of Biophysical Dynamics, University of Chicago, 929 E 57 Street, Chicago, IL 60637
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44
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Dorn M, Jurk M, Schmieder P. Blue news update: BODIPY-GTP binds to the blue-light receptor YtvA while GTP does not. PLoS One 2012; 7:e29201. [PMID: 22247770 PMCID: PMC3256143 DOI: 10.1371/journal.pone.0029201] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Accepted: 11/22/2011] [Indexed: 01/23/2023] Open
Abstract
Light is an important environmental factor for almost all organisms. It is mainly used as an energy source but it is also a key factor for the regulation of multiple cellular functions. Light as the extracellular stimulus is thereby converted into an intracellular signal by photoreceptors that act as signal transducers. The blue-light receptor YtvA, a bacterial counterpart of plant phototropins, is involved in the stress response of Bacillus subtilis. The mechanism behind its activation, however, remains unknown. It was suggested based on fluorescence spectroscopic studies that YtvA function involves GTP binding and that this interaction is altered by absorption of light. We have investigated this interaction by several biophysical methods and show here using fluorescence spectroscopy, ITC titrations, and three NMR spectroscopic assays that while YtvA interacts with BODIPY-GTP as a fluorescent GTP analogue originally used for the detection of GTP binding, it does not bind GTP.
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Affiliation(s)
- Matthias Dorn
- Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Berlin, Germany
| | - Marcel Jurk
- Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Berlin, Germany
| | - Peter Schmieder
- Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
- * E-mail:
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45
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Losi A, Gärtner W. The evolution of flavin-binding photoreceptors: an ancient chromophore serving trendy blue-light sensors. ANNUAL REVIEW OF PLANT BIOLOGY 2012; 63:49-72. [PMID: 22136567 DOI: 10.1146/annurev-arplant-042811-105538] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Photoreceptor flavoproteins of the LOV, BLUF, and cryptochrome families are ubiquitous among the three domains of life and are configured as UVA/blue-light systems not only in plants-their original arena-but also in prokaryotes and microscopic algae. Here, we review these proteins' structure and function, their biological roles, and their evolution and impact in the living world, and underline their growing application in biotechnologies. We present novel developments such as the interplay of light and redox stimuli, emerging enzymatic and biological functions, lessons on evolution from picoalgae, metagenomics analysis, and optogenetics applications.
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Affiliation(s)
- Aba Losi
- Department of Physics, University of Parma, Parma, Italy.
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46
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Toyooka T, Hisatomi O, Takahashi F, Kataoka H, Terazima M. Photoreactions of aureochrome-1. Biophys J 2011; 100:2801-9. [PMID: 21641326 DOI: 10.1016/j.bpj.2011.02.043] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Revised: 02/22/2011] [Accepted: 02/24/2011] [Indexed: 10/18/2022] Open
Abstract
Aureochrome is a recently discovered blue light photosensor that controls a light-dependent morphology change. As a photosensor, it has a unique DNA binding domain (bZIP). Although the biological functions of aureochrome have been revealed, the fundamental photochemistry of this protein has not been elucidated. The photochemical reaction dynamics of the LOV (light, oxygen, or voltage) domain of aureochrome-1 (AUREO1-LOV) and the LOV domain with the bZIP domain (AUREO1-ZL) were studied by employing the transient-grating (TG) technique, using size-exclusion chromatography to verify results. For both samples, adduct formation takes place with a time constant of 2.8 μs. Although significant diffusion changes were observed for both AUREO1-LOV and AUREO1-ZL after adduct formation, the origins of these changes were significantly different. The TG signal of AUREO1-LOV was strongly concentration-dependent. From analysis of the signal, it was concluded that AUREO1-LOV exists in equilibrium between the monomer and dimer, and dimerization of the monomer is the main reaction, i.e., irradiation with blue light enhances the strength of the interdomain interaction. On the other hand, the reaction of AUREO1-ZL is independent of concentration, suggesting that an intraprotein conformational change occurs in the bZIP domain with a time constant of 160 ms. These results revealed the different reactions and roles of the two domains; the LOV domain acts as a photosensor, leading to a subsequent conformational change in the bZIP domain, which should change its ability to bind to DNA. A model is proposed that demonstrates how aureochrome uses blue light to control its affinity for DNA.
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Affiliation(s)
- Tsuguyoshi Toyooka
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan
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47
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Jurk M, Dorn M, Schmieder P. Blue Flickers of Hope: Secondary Structure, Dynamics, and Putative Dimerization Interface of the Blue-Light Receptor YtvA from Bacillus subtilis. Biochemistry 2011; 50:8163-71. [DOI: 10.1021/bi200782j] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Marcel Jurk
- Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Str.
10, 13125 Berlin, Germany
- Institute of Chemistry and
Biochemistry, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
| | - Matthias Dorn
- Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Str.
10, 13125 Berlin, Germany
- Institute of Chemistry and
Biochemistry, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
| | - Peter Schmieder
- Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Str.
10, 13125 Berlin, Germany
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48
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Abstract
LOV (light, oxygen or voltage) domains are protein photosensors that are conserved in bacteria, archaea, plants and fungi, and detect blue light via a flavin cofactor. LOV domains are present in both chemotrophic and phototrophic bacterial species, in which they are found amino-terminally of signalling and regulatory domains such as sensor histidine kinases, diguanylate cyclases-phosphodiesterases, DNA-binding domains and regulators of RNA polymerase σ-factors. In this Review, we describe the current state of knowledge about the function of bacterial LOV proteins, the structural basis of LOV domain-mediated signal transduction, and the use of LOV domains as genetically encoded photoswitches in synthetic biology.
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49
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Nakasone Y, Hellingwerf KJ. On the binding of BODIPY-GTP by the photosensory protein YtvA from the common soil bacterium Bacillus subtilis. Photochem Photobiol 2011; 87:542-7. [PMID: 21388385 DOI: 10.1111/j.1751-1097.2011.00919.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The YtvA protein, which is one of the proteins that comprises the network carrying out the signal transfer inducing the general stress response in Bacillus subtilis, is composed of an N-terminal LOV domain (that binds a flavin [FMN]) and a C-terminal STAS domain. This latter domain shows sequence features typical for a nucleotide (NTP) binding protein. It has been proposed (FEBS Lett., 580 [2006], 3818) that BODIPY-GTP can be used as a reporter for nucleotide binding to this site and that activation of the LOV domain by blue light is reflected in an alteration of the BODIPY-GTP fluorescence. Here we confirm that BODIPY-GTP indeed binds to YtvA, but rather nonspecifically, and not limited to the STAS domain. Blue-light modulation of fluorescence emission of YtvA-bound BODIPY-GTP is observed both in the full-length YtvA protein and in a truncated protein composed of the LOV-domain plus the LOV-STAS linker region (YtvA(1-147)) as a light-induced decrease in fluorescence emission. The isolated LOV domain (i.e. without the linker region) does not show such BODIPY-GTP fluorescence changes. Dialysis experiments have confirmed the blue-light-induced release of BODIPY-GTP from YtvA.
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Affiliation(s)
- Yusuke Nakasone
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
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50
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Losi A, Gärtner W. Old Chromophores, New Photoactivation Paradigms, Trendy Applications: Flavins in Blue Light-Sensing Photoreceptors†. Photochem Photobiol 2011; 87:491-510. [DOI: 10.1111/j.1751-1097.2011.00913.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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