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Malla TN, Hernandez C, Muniyappan S, Menendez D, Bizhga D, Mendez JH, Schwander P, Stojković EA, Schmidt M. Photoreception and signaling in bacterial phytochrome revealed by single-particle cryo-EM. SCIENCE ADVANCES 2024; 10:eadq0653. [PMID: 39121216 PMCID: PMC11313861 DOI: 10.1126/sciadv.adq0653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Accepted: 07/08/2024] [Indexed: 08/11/2024]
Abstract
Phytochromes are red-light photoreceptors discovered in plants with homologs in bacteria and fungi that regulate a variety of physiological responses. They display a reversible photocycle between two distinct states: a red-light-absorbing Pr state and a far-red light-absorbing Pfr state. The photoconversion regulates the activity of an enzymatic domain, usually a histidine kinase (HK). The molecular mechanism that explains how light controls the HK activity is not understood because structures of unmodified bacterial phytochromes with HK activity are missing. Here, we report three cryo-electron microscopy structures of a wild-type bacterial phytochrome with HK activity determined as Pr and Pfr homodimers and as a Pr/Pfr heterodimer with individual subunits in distinct states. We propose that the Pr/Pfr heterodimer is a physiologically relevant signal transduction intermediate. Our results offer insight into the molecular mechanism that controls the enzymatic activity of the HK as part of a bacterial two-component system that perceives and transduces light signals.
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Affiliation(s)
- Tek Narsingh Malla
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
| | | | | | - David Menendez
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA
| | - Dorina Bizhga
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA
| | - Joshua H. Mendez
- New York Structural Biology Center (NYSBC), New York, NY 10027, USA
| | - Peter Schwander
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
| | - Emina A. Stojković
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA
| | - Marius Schmidt
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
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Malla TN, Hernandez C, Menendez D, Bizhga D, Mendez JH, Muniyappan S, Schwander P, Stojković EA, Schmidt M. Signal Transduction in an Enzymatic Photoreceptor Revealed by Cryo-Electron Microscopy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.08.566274. [PMID: 37986774 PMCID: PMC10659365 DOI: 10.1101/2023.11.08.566274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Phytochromes are essential photoreceptor proteins in plants with homologs in bacteria and fungi that regulate a variety of important environmental responses. They display a reversible photocycle between two distinct states, the red-light absorbing Pr and the far-red light absorbing Pfr, each with its own structure. The reversible Pr to Pfr photoconversion requires covalently bound bilin chromophore and regulates the activity of a C-terminal enzymatic domain, which is usually a histidine kinase (HK). In plants, phytochromes translocate to nucleus where the C-terminal effector domain interacts with protein interaction factors (PIFs) to induce gene expression. In bacteria, the HK phosphorylates a response-regulator (RR) protein triggering downstream gene expression through a two-component signaling pathway. Although plant and bacterial phytochromes share similar structural composition, they have contrasting activity in the presence of light with most BphPs being active in the dark. The molecular mechanism that explains bacterial and plant phytochrome signaling has not been well understood due to limited structures of full-length phytochromes with enzymatic domain resolved at or near atomic resolution in both Pr and Pfr states. Here, we report the first Cryo-EM structures of a wild-type bacterial phytochrome with a HK enzymatic domain, determined in both Pr and Pfr states, between 3.75 and 4.13 Å resolution, respectively. Furthermore, we capture a distinct Pr/Pfr heterodimer of the same protein as potential signal transduction intermediate at 3.75 Å resolution. Our three Cryo-EM structures of the distinct signaling states of BphPs are further reinforced by Cryo-EM structures of the truncated PCM of the same protein determined for the Pr/Pfr heterodimer as well as Pfr state. These structures provide insight into the different light-signaling mechanisms that could explain how bacteria and plants see the light.
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Sun C, Yu Q, Zhao Z, Zhang Y. Extracellular electron uptake for CO 2 fixation by Rhodopseudomonas palustris during electro-cultivation in darkness. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 849:157864. [PMID: 35934039 DOI: 10.1016/j.scitotenv.2022.157864] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/20/2022] [Accepted: 08/02/2022] [Indexed: 06/15/2023]
Abstract
As a vital part of the global carbon cycle, photosynthesis helps in fixing CO2 to produce diverse biomass. However, over-reliance on optical density results in inadequate photosynthesis under limited light sources. The coupling of extracellular respiration and photosynthetic chain via the quinone pool provides a possibility for electrically driven photosynthesis in darkness, which is not well understood. In this study, CO2 fixation of photosynthetic bacteria Rhodopseudomonas palustris was enhanced in the dark via extracellular electron uptake from the electrode at -0.4 V. The copy number of R. palustris increased by 35 folds during 28 days of operation, accompanied by the increase of ATP content, NADH/NAD+, and NADPH/NADP+ of cells. Especially, the activity of Rubisco, the key enzyme of the Calvin cycle, increased by 28 % during electro-cultivation. Accordingly, the electrochemical activity of R. palustris was found to increase, which might be attributed to the structural modification of protein-like substances due to the enhanced proton-coupled electron transfer (PCET) process in electro-cultivation, which was further confirmed by in situ Fourier transform infrared spectroscopy and kinetic isotope effect tests. This study indicated that extracellular respiration could be electrostimulated via PCET to maintain photosynthesis in R. palustris in the dark.
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Affiliation(s)
- Cheng Sun
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Qilin Yu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Zhiqiang Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Yaobin Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
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Phytochromes and Cyanobacteriochromes: Photoreceptor Molecules Incorporating a Linear Tetrapyrrole Chromophore. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1293:167-187. [PMID: 33398813 DOI: 10.1007/978-981-15-8763-4_10] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this chapter, we summarize the molecular mechanisms of the linear tetrapyrrole-binding photoreceptors, phytochromes, and cyanobacteriochromes. We especially focus on the color-tuning mechanisms and conformational changes during the photoconversion process. Furthermore, we introduce current status of development of the optogenetic tools based on these molecules. Huge repertoire of these photoreceptors with diverse spectral properties would contribute to development of multiplex optogenetic regulation. Among them, the photoreceptors incorporating the biliverdin IXα chromophore is advantageous for in vivo optogenetics because this is intrinsic in the mammalian cells, and absorbs far-red light penetrating into deep mammalian tissues.
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Huang Z, Li Z, Zhang X, Kang S, Dong R, Sun L, Fu X, Vaisar D, Watanabe K, Gu L. Creating Red Light-Switchable Protein Dimerization Systems as Genetically Encoded Actuators with High Specificity. ACS Synth Biol 2020; 9:3322-3333. [PMID: 33179507 DOI: 10.1021/acssynbio.0c00397] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Protein dimerization systems controlled by red light with increased tissue penetration depth are a highly needed tool for clinical applications such as cell and gene therapies. However, mammalian applications of existing red light-induced dimerization systems are hampered by limitations of their two components: a photosensory protein (or photoreceptor) which often requires a mammalian exogenous chromophore and a naturally occurring photoreceptor binding protein typically having a complex structure and nonideal binding properties. Here, we introduce an efficient, generalizable method (COMBINES-LID) for creating highly specific, reversible light-induced heterodimerization systems independent of any existing binders to a photoreceptor. It involves a two-step binder screen (phage display and yeast two-hybrid) of a combinatorial nanobody library to obtain binders that selectively engage a light-activated form of a photoswitchable protein or domain not the dark form. Proof-of-principle was provided by engineering nanobody-based, red light-induced dimerization (nanoReD) systems comprising a truncated bacterial phytochrome sensory module using a mammalian endogenous chromophore, biliverdin, and light-form specific nanobodies. Selected nanoReD systems were biochemically characterized, exhibiting low dark activity and high induction specificity, and further demonstrated for the reversible control of protein translocation and activation of gene expression in mice. Overall, COMBINES-LID opens new opportunities for creating genetically encoded actuators for the optical manipulation of biological processes.
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Affiliation(s)
- Zhimin Huang
- Department of Biochemistry and Institute for Protein Design, University of Washington, Seattle, Washington 98195, United States
| | - Zengpeng Li
- Department of Biochemistry and Institute for Protein Design, University of Washington, Seattle, Washington 98195, United States
- Key Laboratory of Marine Genetic Resources, State Key Laboratory Breeding Base of Marine Genetic Resources, Fujian Key Laboratory of Marine Genetic Resources, Fujian Collaborative Innovation Centre for Exploitation and Utilization of Marine Biological Resources, Third Institute of Oceanography Ministry of Natural Resources, Xiamen 361005, PR China
| | - Xiao Zhang
- Department of Biochemistry and Institute for Protein Design, University of Washington, Seattle, Washington 98195, United States
| | - Shoukai Kang
- Department of Biochemistry and Institute for Protein Design, University of Washington, Seattle, Washington 98195, United States
| | - Runze Dong
- Department of Biochemistry and Institute for Protein Design, University of Washington, Seattle, Washington 98195, United States
| | - Li Sun
- Department of Biochemistry and Institute for Protein Design, University of Washington, Seattle, Washington 98195, United States
| | - Xiaonan Fu
- Department of Biochemistry and Institute for Protein Design, University of Washington, Seattle, Washington 98195, United States
| | - David Vaisar
- Department of Biochemistry and Institute for Protein Design, University of Washington, Seattle, Washington 98195, United States
| | - Kurumi Watanabe
- Department of Biochemistry and Institute for Protein Design, University of Washington, Seattle, Washington 98195, United States
| | - Liangcai Gu
- Department of Biochemistry and Institute for Protein Design, University of Washington, Seattle, Washington 98195, United States
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Figueroa D, Rojas V, Romero A, Larrondo LF, Salinas F. The rise and shine of yeast optogenetics. Yeast 2020; 38:131-146. [PMID: 33119964 DOI: 10.1002/yea.3529] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/20/2020] [Accepted: 10/22/2020] [Indexed: 12/11/2022] Open
Abstract
Optogenetics refers to the control of biological processes with light. The activation of cellular phenomena by defined wavelengths has several advantages compared with traditional chemically inducible systems, such as spatiotemporal resolution, dose-response regulation, low cost, and moderate toxic effects. Optogenetics has been successfully implemented in yeast, a remarkable biological platform that is not only a model organism for cellular and molecular biology studies, but also a microorganism with diverse biotechnological applications. In this review, we summarize the main optogenetic systems implemented in the budding yeast Saccharomyces cerevisiae, which allow orthogonal control (by light) of gene expression, protein subcellular localization, reconstitution of protein activity, and protein sequestration by oligomerization. Furthermore, we review the application of optogenetic systems in the control of metabolic pathways, heterologous protein production and flocculation. We then revise an example of a previously described yeast optogenetic switch, named FUN-LOV, which allows precise and strong activation of the target gene. Finally, we describe optogenetic systems that have not yet been implemented in yeast, which could therefore be used to expand the panel of available tools in this biological chassis. In conclusion, a wide repertoire of optogenetic systems can be used to address fundamental biological questions and broaden the biotechnological toolkit in yeast.
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Affiliation(s)
- David Figueroa
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.,ANID - Millennium Science Initiative - Millennium Institute for Integrative Biology (iBIO), Santiago, Chile
| | - Vicente Rojas
- ANID - Millennium Science Initiative - Millennium Institute for Integrative Biology (iBIO), Santiago, Chile.,Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Andres Romero
- ANID - Millennium Science Initiative - Millennium Institute for Integrative Biology (iBIO), Santiago, Chile.,Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Luis F Larrondo
- ANID - Millennium Science Initiative - Millennium Institute for Integrative Biology (iBIO), Santiago, Chile.,Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Francisco Salinas
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.,ANID - Millennium Science Initiative - Millennium Institute for Integrative Biology (iBIO), Santiago, Chile
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Sanchez JC, Carrillo M, Pandey S, Noda M, Aldama L, Feliz D, Claesson E, Wahlgren WY, Tracy G, Duong P, Nugent AC, Field A, Šrajer V, Kupitz C, Iwata S, Nango E, Tanaka R, Tanaka T, Fangjia L, Tono K, Owada S, Westenhoff S, Schmidt M, Stojković EA. High-resolution crystal structures of a myxobacterial phytochrome at cryo and room temperatures. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2019; 6:054701. [PMID: 31559319 PMCID: PMC6748860 DOI: 10.1063/1.5120527] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 08/27/2019] [Indexed: 05/04/2023]
Abstract
Phytochromes (PHYs) are photoreceptor proteins first discovered in plants, where they control a variety of photomorphogenesis events. PHYs as photochromic proteins can reversibly switch between two distinct states: a red light (Pr) and a far-red light (Pfr) absorbing form. The discovery of Bacteriophytochromes (BphPs) in nonphotosynthetic bacteria has opened new frontiers in our understanding of the mechanisms by which these natural photoswitches can control single cell development, although the role of BphPs in vivo remains largely unknown. BphPs are dimeric proteins that consist of a photosensory core module (PCM) and an enzymatic domain, often a histidine kinase. The PCM is composed of three domains (PAS, GAF, and PHY). It holds a covalently bound open-chain tetrapyrrole (biliverdin, BV) chromophore. Upon absorption of light, the double bond between BV rings C and D isomerizes and reversibly switches the protein between Pr and Pfr states. We report crystal structures of the wild-type and mutant (His275Thr) forms of the canonical BphP from the nonphotosynthetic myxobacterium Stigmatella aurantiaca (SaBphP2) in the Pr state. Structures were determined at 1.65 Å and 2.2 Å (respectively), the highest resolution of any PCM construct to date. We also report the room temperature wild-type structure of the same protein determined at 2.1 Å at the SPring-8 Angstrom Compact free electron LAser (SACLA), Japan. Our results not only highlight and confirm important amino acids near the chromophore that play a role in Pr-Pfr photoconversion but also describe the signal transduction into the PHY domain which moves across tens of angstroms after the light stimulus.
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Affiliation(s)
- Juan C. Sanchez
- Department of Biology, Northeastern Illinois University, 5500 N. St. Louis Ave., Chicago, Illinois 60625, USA
| | - Melissa Carrillo
- Department of Biology, Northeastern Illinois University, 5500 N. St. Louis Ave., Chicago, Illinois 60625, USA
| | - Suraj Pandey
- Physics Department, University of Wisconsin-Milwaukee, 3135 N. Maryland Ave., Milwaukee, Wisconsin 53211, USA
| | - Moraima Noda
- Department of Biology, Northeastern Illinois University, 5500 N. St. Louis Ave., Chicago, Illinois 60625, USA
| | - Luis Aldama
- Department of Biology, Northeastern Illinois University, 5500 N. St. Louis Ave., Chicago, Illinois 60625, USA
| | - Denisse Feliz
- Department of Biology, Northeastern Illinois University, 5500 N. St. Louis Ave., Chicago, Illinois 60625, USA
| | - Elin Claesson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 40530 Gothenburg, Sweden
| | - Weixiao Yuan Wahlgren
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 40530 Gothenburg, Sweden
| | - Gregory Tracy
- Department of Biology, Northeastern Illinois University, 5500 N. St. Louis Ave., Chicago, Illinois 60625, USA
| | - Phu Duong
- Department of Biology, Northeastern Illinois University, 5500 N. St. Louis Ave., Chicago, Illinois 60625, USA
| | - Angela C. Nugent
- Department of Biology, Northeastern Illinois University, 5500 N. St. Louis Ave., Chicago, Illinois 60625, USA
| | - Andrew Field
- Department of Biology, Northeastern Illinois University, 5500 N. St. Louis Ave., Chicago, Illinois 60625, USA
| | - Vukica Šrajer
- The University of Chicago, Center for Advanced Radiation Sources, 9700 South Cass Ave., Bldg 434B, Argonne, Illinois 60439, USA
| | - Christopher Kupitz
- Physics Department, University of Wisconsin-Milwaukee, 3135 N. Maryland Ave., Milwaukee, Wisconsin 53211, USA
| | | | | | | | | | | | | | | | - Sebastian Westenhoff
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 40530 Gothenburg, Sweden
| | - Marius Schmidt
- Physics Department, University of Wisconsin-Milwaukee, 3135 N. Maryland Ave., Milwaukee, Wisconsin 53211, USA
| | - Emina A. Stojković
- Department of Biology, Northeastern Illinois University, 5500 N. St. Louis Ave., Chicago, Illinois 60625, USA
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8
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Serdyuk OP, Smolygina LD, Khristin MS. Membrane-Bound Bacteriophytochrome-Like Complex of Phototrophic Purple Non-Sulfur Bacterium Rhodopseudomonas palustris. DOKL BIOCHEM BIOPHYS 2018; 482:284-287. [PMID: 30397894 DOI: 10.1134/s1607672918050149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Indexed: 11/23/2022]
Abstract
A pigment-protein complex of yellow color with absorption maxima at 682 and 776 nm, characteristic for bacteriophytochromes, was isolated from the photosynthetic membranes of the purple bacterium Rhodopseudomonas palustris. Zinc-induced fluorescence of the complex indicated the presence of the biliverdin chromophore covalently bound to the protein. The parameters of low-temperature fluorescence (λ excitation at 680 nm, λ emission at 695 nm) indicated the ability of the complex to undergo photoconversion. These data, as well as the kinetics of accumulation of the red (Pr)-form on far red light, allowed the complex to be classified as a bacteriophytochrome-like complex with its localization in the photosynthetic membranes of Rps. palustris.
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Affiliation(s)
- O P Serdyuk
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow oblast, 142290, Russia.
| | - L D Smolygina
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow oblast, 142290, Russia
| | - M S Khristin
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow oblast, 142290, Russia
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Synthesis of Carotenoids of Industrial Interest in the Photosynthetic Bacterium Rhodopseudomonas palustris : Bioengineering and Growth Conditions. Methods Mol Biol 2018; 1852:211-220. [PMID: 30109633 DOI: 10.1007/978-1-4939-8742-9_12] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Rhodopseudomonas palustris is a purple photosynthetic bacterium that accumulates in the inner membrane the photosynthetic pigment spirilloxanthin, formed from lycopene. Here, we describe the procedures used to successfully engineer Rps. palustris strains to reroute the production of lycopene toward the synthesis of ß-carotene or canthaxanthin. The crtCD genes specifically involved in spirilloxanthin were replaced by crtY and crtW genes from Bradyrhizobium ORS278 to synthesize ß-carotene and (or) canthaxanthin, two pigments of industrial interest. Since the synthesis of canthaxanthin depends on the presence of oxygen, the procedure to optimize their production is also proposed. By modulating the light and oxygen during the growth process, a single species of photosynthetic bacteria, with an efficient growth rate, produces various carotenoids of economical interest.
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A bacterial phytochrome-based optogenetic system controllable with near-infrared light. Nat Methods 2016; 13:591-7. [PMID: 27159085 PMCID: PMC4927390 DOI: 10.1038/nmeth.3864] [Citation(s) in RCA: 164] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 04/10/2016] [Indexed: 12/23/2022]
Abstract
Light-mediated control of protein-protein interactions to regulate metabolic pathways is an important approach of optogenetics. Here, we report the first optogenetic system based on a reversible light-induced binding between a bacterial phytochrome BphP1 and its natural partner PpsR2 from Rhodopseudomonas palustris bacteria. We extensively characterized the BphP1–PpsR2 interaction both in vitro and in mammalian cells, and then used it to translocate target proteins to specific cellular compartments, such as plasma membrane and nucleus. Applying this approach we achieved a light-control of cell morphology resulting in the substantial increase of cell area. We next demonstrated the light-induced gene expression with the 40-fold contrast in cultured cells, 32-fold subcutaneously and 5.7-fold in deep tissues in mice. The unique characteristics of the BphP1–PpsR2 optogenetic system are its sensitivity to 740–780 nm near-infrared light, ability to utilize an endogenous biliverdin chromophore in eukaryotes including mammals, and spectral compatibility with blue-light optogenetic systems.
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Light regulation of swarming motility in Pseudomonas syringae integrates signaling pathways mediated by a bacteriophytochrome and a LOV protein. mBio 2013; 4:e00334-13. [PMID: 23760465 PMCID: PMC3684834 DOI: 10.1128/mbio.00334-13] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The biological and regulatory roles of photosensory proteins are poorly understood for nonphotosynthetic bacteria. The foliar bacterial pathogen Pseudomonas syringae has three photosensory protein-encoding genes that are predicted to encode the blue-light-sensing LOV (light, oxygen, or voltage) histidine kinase (LOV-HK) and two red/far-red-light-sensing bacteriophytochromes, BphP1 and BphP2. We provide evidence that LOV-HK and BphP1 form an integrated network that regulates swarming motility in response to multiple light wavelengths. The swarming motility of P. syringae B728a deletion mutants indicated that LOV-HK positively regulates swarming motility in response to blue light and BphP1 negatively regulates swarming motility in response to red and far-red light. BphP2 does not detectably regulate swarming motility. The histidine kinase activity of each LOV-HK and BphP1 is required for this regulation based on the loss of complementation upon mutation of residues key to their kinase activity. Surprisingly, mutants lacking both lov and bphP1 were similar in motility to a bphP1 single mutant in blue light, indicating that the loss of bphP1 is epistatic to the loss of lov and also that BphP1 unexpectedly responds to blue light. Moreover, whereas expression of bphP1 did not alter motility under blue light in a bphP1 mutant, it reduced motility in a mutant lacking lov and bphP1, demonstrating that LOV-HK positively regulates motility by suppressing negative regulation by BphP1. These results are the first to show cross talk between the LOV protein and phytochrome signaling pathways in bacteria, and the similarity of this regulatory network to that of photoreceptors in plants suggests a possible common ancestry. IMPORTANCE Photosensory proteins enable organisms to perceive and respond to light. The biological and ecological roles of these proteins in nonphotosynthetic bacteria are largely unknown. This study discovered that a blue-light-sensing LOV (light, oxygen, or voltage) protein and a red/far-red-light-sensing bacteriophytochrome both regulate swarming motility in the foliar pathogen Pseudomonas syringae. These proteins form an integrated signaling network in which the bacteriophytochrome represses swarming motility in response to red, far-red, and blue light, and LOV positively regulates swarming motility by suppressing bacteriophytochrome-mediated blue-light signaling. This is the first example of cross talk between LOV and phytochrome signaling pathways in bacteria, which shows unexpected similarity to photoreceptor signaling in plants.
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12
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Abstract
Phytochromes are environmental sensors, historically thought of as red/far-red photoreceptors in plants. Their photoperception occurs through a covalently linked tetrapyrrole chromophore, which undergoes a light-dependent conformational change propagated through the protein to a variable output domain. The phytochrome composition is modular, typically consisting of a PAS-GAF-PHY architecture for the N-terminal photosensory core. A collection of three-dimensional structures has uncovered key features, including an unusual figure-of-eight knot, an extension reaching from the PHY domain to the chromophore-binding GAF domain, and a centrally located, long α-helix hypothesized to be crucial for intramolecular signaling. Continuing identification of phytochromes in microbial systems has expanded the assigned sensory abilities of this family out of the red and into the yellow, green, blue, and violet portions of the spectrum. Furthermore, phytochromes acting not as photoreceptors but as redox sensors have been recognized. In addition, architectures other than PAS-GAF-PHY are known, thus revealing phytochromes to be a varied group of sensory receptors evolved to utilize their modular design to perceive a signal and respond accordingly. This review focuses on the structures of bacterial phytochromes and implications for signal transmission. We also discuss the small but growing set of bacterial phytochromes for which a physiological function has been ascertained.
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Affiliation(s)
- Michele E Auldridge
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
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13
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Giraud E, Lavergne J, Verméglio A. Characterization of Bacteriophytochromes from Photosynthetic Bacteria. Methods Enzymol 2010; 471:135-59. [DOI: 10.1016/s0076-6879(10)71009-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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14
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Giraud E, Verméglio A. Bacteriophytochromes in anoxygenic photosynthetic bacteria. PHOTOSYNTHESIS RESEARCH 2008; 97:141-153. [PMID: 18612842 DOI: 10.1007/s11120-008-9323-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 06/16/2008] [Indexed: 05/26/2023]
Abstract
Since the first discovery of a bacteriophytochrome in Rhodospirillum centenum, numerous bacteriophytochromes have been identified and characterized in other anoxygenic photosynthetic bacteria. This review is focused on the biochemical and biophysical properties of bacteriophytochromes with a special emphasis on their roles in the synthesis of the photosynthetic apparatus.
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Affiliation(s)
- Eric Giraud
- Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, CIRAD, AGRO-M, INRA, UM2, TA A-82/J, Campus de Baillarguet, 34398, Montpellier Cedex 5, France
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