1
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Salvadori G, Mennucci B. Analogies and Differences in the Photoactivation Mechanism of Bathy and Canonical Bacteriophytochromes Revealed by Multiscale Modeling. J Phys Chem Lett 2024:8078-8084. [PMID: 39087732 DOI: 10.1021/acs.jpclett.4c01823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2024]
Abstract
Bacteriophytochromes are light-sensing biological machines that switch between two photoreversible states, Pr and Pfr. Their relative stability is opposite in canonical and bathy bacteriophytochromes, but in both cases the switch between them is triggered by the photoisomerization of an embedded bilin chromophore. We applied an integrated multiscale strategy of excited-state QM/MM nonadiabatic dynamics and (QM/)MM molecular dynamics simulations with enhanced sampling techniques to the Agrobacterium fabrum bathy phytochrome and compared the results with those obtained for the canonical phytochrome Deinococcus radiodurans. Contrary to what recently suggested, we found that photoactivation in both phytochromes is triggered by the same hula-twist motion of the bilin chromophore. However, only in the bathy phytochrome, the bilin reaches the final rotated structure already in the first intermediate. This allows a reorientation of the binding pocket in a microsecond time scale, which can propagate through the entire protein causing the spine to tilt.
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Affiliation(s)
- Giacomo Salvadori
- Institute for Computational Biomedicine (INM-9/IAS-5), Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Benedetta Mennucci
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, 56124 Pisa, Italy
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2
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Sadeghi M, Balke J, Rafaluk-Mohr T, Alexiev U. Long-Distance Protonation-Conformation Coupling in Phytochrome Species. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238395. [PMID: 36500486 PMCID: PMC9737838 DOI: 10.3390/molecules27238395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/25/2022] [Accepted: 11/27/2022] [Indexed: 12/04/2022]
Abstract
Phytochromes are biological red/far-red light sensors found in many organisms. The connection between photoconversion and the cellular output signal involves light-mediated global structural changes in the interaction between the photosensory module (PAS-GAF-PHY, PGP) and the C-terminal transmitter (output) module. We recently showed a direct correlation of chromophore deprotonation with pH-dependent conformational changes in the various domains of the prototypical phytochrome Cph1 PGP. These results suggested that the transient phycocyanobilin (PCB) chromophore deprotonation is closely associated with a higher protein mobility both in proximal and distal protein sites, implying a causal relationship that might be important for the global large-scale protein rearrangements. Here, we investigate the prototypical biliverdin (BV)-binding phytochrome Agp1. The structural changes at various positions in Agp1 PGP were investigated as a function of pH using picosecond time-resolved fluorescence anisotropy and site-directed fluorescence labeling of cysteine variants of Agp1 PGP. We show that the direct correlation of chromophore deprotonation with pH-dependent conformational changes does not occur in Agp1. Together with the absence of long-range effects between the PHY domain and chromophore pKa, in contrast to the findings in Cph1, our results imply phytochrome species-specific correlations between transient chromophore deprotonation and intramolecular signal transduction.
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3
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De Luca G, Fochesato S, Lavergne J, Forest KT, Barakat M, Ortet P, Achouak W, Heulin T, Verméglio A. Light on the cell cycle of the non-photosynthetic bacterium Ramlibacter tataouinensis. Sci Rep 2019; 9:16505. [PMID: 31712689 PMCID: PMC6848086 DOI: 10.1038/s41598-019-52927-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 10/22/2019] [Indexed: 12/27/2022] Open
Abstract
Ramlibacter tataouinensis TTB310, a non-photosynthetic betaproteobacterium isolated from a semi-arid region of southern Tunisia, forms both rods and cysts. Cysts are resistant to desiccation and divide when water and nutrients are available. Rods are motile and capable of dissemination. Due to the strong correlation between sunlight and desiccation, light is probably an important external signal for anticipating desiccating conditions. Six genes encoding potential light sensors were identified in strain TTB310. Two genes encode for bacteriophytochromes, while the four remaining genes encode for putative blue light receptors. We determined the spectral and photochemical properties of the two recombinant bacteriophytochromes RtBphP1 and RtBphP2. In both cases, they act as sensitive red light detectors. Cyst divisions and a complete cyst-rod-cyst cycle are the main processes in darkness, whereas rod divisions predominate in red or far-red light. Mutant phenotypes caused by the inactivation of genes encoding bacteriophytochromes or heme oxygenase clearly show that both bacteriophytochromes are involved in regulating the rod-rod division. This process could favor rapid rod divisions at sunrise, after dew formation but before the progressive onset of desiccation. Our study provides the first evidence of a light-based strategy evolved in a non-photosynthetic bacterium to exploit scarse water in a desert environment.
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Affiliation(s)
- Gilles De Luca
- Aix Marseille Univ, CEA, CNRS, BIAM, LEMiRE, Saint Paul-Lez-Durance, F-13108, France
| | - Sylvain Fochesato
- Aix Marseille Univ, CEA, CNRS, BIAM, LEMiRE, Saint Paul-Lez-Durance, F-13108, France
| | - Jérôme Lavergne
- Aix Marseille Univ, CEA, CNRS, BIAM, LEMiRE, Saint Paul-Lez-Durance, F-13108, France
| | - Katrina T Forest
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Mohamed Barakat
- Aix Marseille Univ, CEA, CNRS, BIAM, LEMiRE, Saint Paul-Lez-Durance, F-13108, France
| | - Philippe Ortet
- Aix Marseille Univ, CEA, CNRS, BIAM, LEMiRE, Saint Paul-Lez-Durance, F-13108, France
| | - Wafa Achouak
- Aix Marseille Univ, CEA, CNRS, BIAM, LEMiRE, Saint Paul-Lez-Durance, F-13108, France
| | - Thierry Heulin
- Aix Marseille Univ, CEA, CNRS, BIAM, LEMiRE, Saint Paul-Lez-Durance, F-13108, France.
| | - André Verméglio
- Aix Marseille Univ, CEA, CNRS, BIAM, LEMiRE, Saint Paul-Lez-Durance, F-13108, France
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4
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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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5
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Xue P, El Kurdi A, Kohler A, Ma H, Kaeser G, Ali A, Fischer R, Krauß N, Lamparter T. Evidence for weak interaction between phytochromes Agp1 and Agp2 from Agrobacterium fabrum. FEBS Lett 2019; 593:926-941. [PMID: 30941759 DOI: 10.1002/1873-3468.13376] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 03/25/2019] [Accepted: 03/28/2019] [Indexed: 11/09/2022]
Abstract
During bacterial conjugation, plasmid DNA is transferred from cell to cell. In Agrobacterium fabrum, conjugation is regulated by the phytochrome photoreceptors Agp1 and Agp2. Both contribute equally to this regulation. Agp1 and Agp2 are histidine kinases, but, for Agp2, we found no autophosphorylation activity. A clear autophosphorylation signal, however, was obtained with mutants in which the phosphoaccepting Asp of the C-terminal response regulator domain is replaced. Thus, the Agp2 histidine kinase differs from the classical transphosphorylation pattern. We performed size exclusion, photoconversion, dark reversion, autophosphorylation, chromophore assembly kinetics and fluorescence resonance energy transfer measurements on mixed Agp1/Agp2 samples. These assays pointed to an interaction between both proteins. This could partially explain the coaction of both phytochromes in the cell.
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Affiliation(s)
- Peng Xue
- Botanical Institute, Karlsruhe Institute of Technology, Germany
| | - Afaf El Kurdi
- Botanical Institute, Karlsruhe Institute of Technology, Germany
| | - Anja Kohler
- Botanical Institute, Karlsruhe Institute of Technology, Germany
| | - Hongju Ma
- Botanical Institute, Karlsruhe Institute of Technology, Germany
| | - Gero Kaeser
- Botanical Institute, Karlsruhe Institute of Technology, Germany
| | - Arin Ali
- Institute for Applied Biosciences, Karlsruhe Institute of Technology, Germany
| | - Reinhard Fischer
- Institute for Applied Biosciences, Karlsruhe Institute of Technology, Germany
| | - Norbert Krauß
- Botanical Institute, Karlsruhe Institute of Technology, Germany
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6
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Schmidt A, Sauthof L, Szczepek M, Lopez MF, Escobar FV, Qureshi BM, Michael N, Buhrke D, Stevens T, Kwiatkowski D, von Stetten D, Mroginski MA, Krauß N, Lamparter T, Hildebrandt P, Scheerer P. Structural snapshot of a bacterial phytochrome in its functional intermediate state. Nat Commun 2018; 9:4912. [PMID: 30464203 PMCID: PMC6249285 DOI: 10.1038/s41467-018-07392-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 10/31/2018] [Indexed: 11/09/2022] Open
Abstract
Phytochromes are modular photoreceptors of plants, bacteria and fungi that use light as a source of information to regulate fundamental physiological processes. Interconversion between the active and inactive states is accomplished by a photoinduced reaction sequence which couples the sensor with the output module. However, the underlying molecular mechanism is yet not fully understood due to the lack of structural data of functionally relevant intermediate states. Here we report the crystal structure of a Meta-F intermediate state of an Agp2 variant from Agrobacterium fabrum. This intermediate, the identity of which was verified by resonance Raman spectroscopy, was formed by irradiation of the parent Pfr state and displays significant reorientations of almost all amino acids surrounding the chromophore. Structural comparisons allow identifying structural motifs that might serve as conformational switch for initiating the functional secondary structure change that is linked to the (de-)activation of these photoreceptors.
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Affiliation(s)
- Andrea Schmidt
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute for Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Charitéplatz 1, Berlin, D-10117, Germany
| | - Luisa Sauthof
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute for Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Charitéplatz 1, Berlin, D-10117, Germany
| | - Michal Szczepek
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute for Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Charitéplatz 1, Berlin, D-10117, Germany
| | - Maria Fernandez Lopez
- Technische Universität Berlin, Institut für Chemie, Sekr. PC 14, Straße des 17. Juni 135, Berlin, D-10623, Germany
| | - Francisco Velazquez Escobar
- Technische Universität Berlin, Institut für Chemie, Sekr. PC 14, Straße des 17. Juni 135, Berlin, D-10623, Germany
| | - Bilal M Qureshi
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute for Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Charitéplatz 1, Berlin, D-10117, Germany
- Division of Biological & Environmental Sciences & Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Norbert Michael
- Technische Universität Berlin, Institut für Chemie, Sekr. PC 14, Straße des 17. Juni 135, Berlin, D-10623, Germany
| | - David Buhrke
- Technische Universität Berlin, Institut für Chemie, Sekr. PC 14, Straße des 17. Juni 135, Berlin, D-10623, Germany
| | - Tammo Stevens
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute for Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Charitéplatz 1, Berlin, D-10117, Germany
| | - Dennis Kwiatkowski
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute for Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Charitéplatz 1, Berlin, D-10117, Germany
| | - David von Stetten
- Structural Biology Group, European Synchrotron Radiation Facility, CS 40220 F-38043, Grenoble Cedex 9, France
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation c/o DESY, Notkestrasse 85, Hamburg, D-22607, Germany
| | - Maria Andrea Mroginski
- Technische Universität Berlin, Institut für Chemie, Sekr. PC 14, Straße des 17. Juni 135, Berlin, D-10623, Germany
| | - Norbert Krauß
- Karlsruhe Institute of Technology (KIT), Botanical Institute, Fritz-Haber-Weg 4, Karlsruhe, D-76131, Germany
| | - Tilman Lamparter
- Karlsruhe Institute of Technology (KIT), Botanical Institute, Fritz-Haber-Weg 4, Karlsruhe, D-76131, Germany
| | - Peter Hildebrandt
- Technische Universität Berlin, Institut für Chemie, Sekr. PC 14, Straße des 17. Juni 135, Berlin, D-10623, Germany.
| | - Patrick Scheerer
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute for Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Charitéplatz 1, Berlin, D-10117, Germany.
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7
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Bai Y, Rottwinkel G, Feng J, Liu Y, Lamparter T. Bacteriophytochromes control conjugation in Agrobacterium fabrum. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2016; 161:192-9. [PMID: 27261700 DOI: 10.1016/j.jphotobiol.2016.05.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 05/11/2016] [Indexed: 10/21/2022]
Abstract
Bacterial conjugation, the transfer of single stranded plasmid DNA from donor to recipient cell, is mediated through the type IV secretion system. We performed conjugation assays using a transmissible artificial plasmid as reporter. With this assay, conjugation in Agrobacterium fabrum was modulated by the phytochromes Agp1 and Agp2, photoreceptors that are most sensitive in the red region of visible light. In conjugation studies with wild-type donor cells carrying a pBIN-GUSINT plasmid as reporter that lacked the Ti (tumor inducing) plasmid, no conjugation was observed. When either agp1(-) or agp2(-) knockout donor strains were used, plasmid DNA was delivered to the recipient, indicating that both phytochromes suppress conjugation in the wild type donor. In the recipient strains, the loss of Agp1 or Agp2 led to diminished conjugation. When wild type cells with Ti plasmid and pBIN-GUS reporter plasmid were used as donor, a high rate of conjugation was observed. The DNA transfer was down regulated by red or far-red light by a factor of 3.5. With agp1(-) or agp2(-) knockout donor cells, conjugation in the dark was about 10 times lower than with the wild type donor, and with the double knockout donor no conjugation was observed. These results imply that the phytochrome system has evolved to inhibit conjugation in the light. The decrease of conjugation under different temperature correlated with the decrease of phytochrome autophosphorylation.
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Affiliation(s)
- Yingnan Bai
- Karlsruhe Institute of Technology (KIT), Botanical Institute, Kaiserstr. 2, D-76131 Karlsruhe, Germany; University of Electronic Science and Technology of China (UESTC), School of Science and Technology, No. 4, Sections 2, North Jianshe Road, Chengdu 610054, China
| | - Gregor Rottwinkel
- Karlsruhe Institute of Technology (KIT), Botanical Institute, Kaiserstr. 2, D-76131 Karlsruhe, Germany
| | - Juan Feng
- University of Electronic Science and Technology of China (UESTC), School of Science and Technology, No. 4, Sections 2, North Jianshe Road, Chengdu 610054, China
| | - Yiyao Liu
- University of Electronic Science and Technology of China (UESTC), School of Science and Technology, No. 4, Sections 2, North Jianshe Road, Chengdu 610054, China
| | - Tilman Lamparter
- Karlsruhe Institute of Technology (KIT), Botanical Institute, Kaiserstr. 2, D-76131 Karlsruhe, Germany.
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8
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Singer P, Wörner S, Lamparter T, Diller R. Spectroscopic Investigation on the Primary Photoreaction of Bathy Phytochrome Agp2-Pr ofAgrobacterium fabrum: Isomerization in a pH-dependent H-bond Network. Chemphyschem 2016; 17:1288-97. [DOI: 10.1002/cphc.201600199] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Patrick Singer
- Department of Physics; University of Kaiserslautern; Erwin-Schrödinger-Strasse, Geb. 46 67663 Kaiserslautern Germany), Fax: +49-631-205-3902
| | - Sybille Wörner
- Botanical Institute; Karlsruhe Institute of Technology; Kaiserstraße 2 76131 Karlsruhe Germany
| | - Tilman Lamparter
- Botanical Institute; Karlsruhe Institute of Technology; Kaiserstraße 2 76131 Karlsruhe Germany
| | - Rolf Diller
- Department of Physics; University of Kaiserslautern; Erwin-Schrödinger-Strasse, Geb. 46 67663 Kaiserslautern Germany), Fax: +49-631-205-3902
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9
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Takala H, Björling A, Linna M, Westenhoff S, Ihalainen JA. Light-induced Changes in the Dimerization Interface of Bacteriophytochromes. J Biol Chem 2015; 290:16383-92. [PMID: 25971964 DOI: 10.1074/jbc.m115.650127] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Indexed: 11/06/2022] Open
Abstract
Phytochromes are dimeric photoreceptor proteins that sense red light levels in plants, fungi, and bacteria. The proteins are structurally divided into a light-sensing photosensory module consisting of PAS, GAF, and PHY domains and a signaling output module, which in bacteriophytochromes typically is a histidine kinase (HK) domain. Existing structural data suggest that two dimerization interfaces exist between the GAF and HK domains, but their functional roles remain unclear. Using mutational, biochemical, and computational analyses of the Deinococcus radiodurans phytochrome, we demonstrate that two dimerization interfaces between sister GAF and HK domains stabilize the dimer with approximately equal contributions. The existence of both dimerization interfaces is critical for thermal reversion back to the resting state. We also find that a mutant in which the interactions between the GAF domains were removed monomerizes under red light. This implies that the interactions between the HK domains are significantly altered by photoconversion. The results suggest functional importance of the dimerization interfaces in bacteriophytochromes.
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Affiliation(s)
- Heikki Takala
- From the University of Gothenburg, Department of Chemistry and Molecular Biology, Gothenburg, SE-40530 Sweden and University of Jyvaskyla, Nanoscience Center, Department of Biological and Environmental Sciences, Jyväskylä, FI-40014 Finland
| | - Alexander Björling
- From the University of Gothenburg, Department of Chemistry and Molecular Biology, Gothenburg, SE-40530 Sweden and
| | - Marko Linna
- University of Jyvaskyla, Nanoscience Center, Department of Biological and Environmental Sciences, Jyväskylä, FI-40014 Finland
| | - Sebastian Westenhoff
- From the University of Gothenburg, Department of Chemistry and Molecular Biology, Gothenburg, SE-40530 Sweden and
| | - Janne A Ihalainen
- University of Jyvaskyla, Nanoscience Center, Department of Biological and Environmental Sciences, Jyväskylä, FI-40014 Finland
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10
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Piatkevich KD, Subach FV, Verkhusha VV. Far-red light photoactivatable near-infrared fluorescent proteins engineered from a bacterial phytochrome. Nat Commun 2014; 4:2153. [PMID: 23842578 PMCID: PMC3749836 DOI: 10.1038/ncomms3153] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2013] [Accepted: 06/15/2013] [Indexed: 01/11/2023] Open
Abstract
Ability to modulate fluorescence of optical probes can be used to enhance signal-to-noise ratio for imaging within highly autofluorescent environments, such as intact tissues and living organisms. Here we report two phytochrome-based photoactivatable near-infrared fluorescent proteins, named PAiRFP1 and PAiRFP2. PAiRFPs utilize heme-derived biliverdin, ubiquitous in mammalian tissues, as the chromophore. Initially weakly fluorescent PAiRFPs undergo photoconversion into a highly fluorescent state with excitation/emission at 690 nm/717 nm following a brief irradiation with far-red light. After photoactivation, PAiRFPs slowly revert back to initial state, enabling multiple photoactivation-relaxation cycles. Low-temperature optical spectroscopy reveals several intermediates involved in PAiRFP photocycles, which all differ from that of the bacteriophytochrome precursor. PAiRFPs can be photoactivated in a spatially selective manner in mouse tissues, and optical modulation of their fluorescence allows for substantial contrast enhancement, making PAiRFPs advantageous over permanently fluorescent probes for in vivo imaging conditions of high autofluorescence and low signal levels.
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Affiliation(s)
- Kiryl D Piatkevich
- Department of Anatomy and Structural Biology, Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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11
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Zienicke B, Molina I, Glenz R, Singer P, Ehmer D, Escobar FV, Hildebrandt P, Diller R, Lamparter T. Unusual spectral properties of bacteriophytochrome Agp2 result from a deprotonation of the chromophore in the red-absorbing form Pr. J Biol Chem 2013; 288:31738-51. [PMID: 24036118 DOI: 10.1074/jbc.m113.479535] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phytochromes are widely distributed photoreceptors with a bilin chromophore that undergo a typical reversible photoconversion between the two spectrally different forms, Pr and Pfr. The phytochrome Agp2 from Agrobacterium tumefaciens belongs to the group of bathy phytochromes that have a Pfr ground state as a result of the Pr to Pfr dark conversion. Agp2 has untypical spectral properties in the Pr form reminiscent of a deprotonated chromophore as confirmed by resonance Raman spectroscopy. UV/visible absorption spectroscopy showed that the pKa is >11 in the Pfr form and ∼7.6 in the Pr form. Unlike other phytochromes, photoconversion thus results in a pKa shift of more than 3 units. The Pr/Pfr ratio after saturating irradiation with monochromatic light is strongly pH-dependent. This is partially due to a back-reaction of the deprotonated Pr chromophore at pH 9 after photoexcitation as found by flash photolysis. The chromophore protonation and dark conversion were affected by domain swapping and site-directed mutagenesis. A replacement of the PAS or GAF domain by the respective domain of the prototypical phytochrome Agp1 resulted in a protonated Pr chromophore; the GAF domain replacement afforded an inversion of the dark conversion. A reversion was also obtained with the triple mutant N12S/Q190L/H248Q, whereas each single point mutant is characterized by decelerated Pr to Pfr dark conversion.
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Affiliation(s)
- Benjamin Zienicke
- From the Botanical Institute, Karlsruhe Institute of Technology, Kaiserstrasse 2, D-76131 Karlsruhe, Germany
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Zienicke B, Chen LY, Khawn H, Hammam MAS, Kinoshita H, Reichert J, Ulrich AS, Inomata K, Lamparter T. Fluorescence of phytochrome adducts with synthetic locked chromophores. J Biol Chem 2010; 286:1103-13. [PMID: 21071442 DOI: 10.1074/jbc.m110.155143] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We performed steady state fluorescence measurements with phytochromes Agp1 and Agp2 of Agrobacterium tumefaciens and three mutants in which photoconversion is inhibited. These proteins were assembled with the natural chromophore biliverdin (BV), with phycoerythrobilin (PEB), which lacks a double bond in the ring C-D-connecting methine bridge, and with synthetic bilin derivatives in which the ring C-D-connecting methine bridge is locked. All PEB and locked chromophore adducts are photoinactive. According to fluorescence quantum yields, the adducts may be divided into four different groups: wild type BV adducts exhibiting a weak fluorescence, mutant BV adducts with about 10-fold enhanced fluorescence, adducts with locked chromophores in which the fluorescence quantum yields are around 0.02, and PEB adducts with a high quantum yield of around 0.5. Thus, the strong fluorescence of the PEB adducts is not reached by the locked chromophore adducts, although the photoconversion energy dissipation pathway is blocked. We therefore suggest that ring D of the bilin chromophore, which contributes to the extended π-electron system of the locked chromophores, provides an energy dissipation pathway that is independent on photoconversion.
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Affiliation(s)
- Benjamin Zienicke
- Botanical Institute, Karlsruhe Institute of Technology, Campus South, Kaiserstrasse 2, D-76131 Karlsruhe, Germany
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Abstract
Phytochromes are biliprotein photoreceptors that are found in plants, bacteria, and fungi. Prototypical phytochromes have a Pr ground state that absorbs in the red spectral range and is converted by light into the Pfr form, which absorbs longer-wavelength, far-red light. Recently, some bacterial phytochromes have been described that undergo dark conversion of Pr to Pfr and thus have a Pfr ground state. We show here that such so-called bathy phytochromes are widely distributed among bacteria that belong to the order Rhizobiales. We measured in vivo spectral properties and the direction of dark conversion for species which have either one or two phytochrome genes. Agrobacterium tumefaciens C58 contains one bathy phytochrome and a second phytochrome which undergoes dark conversion of Pfr to Pr in vivo. The related species Agrobacterium vitis S4 contains also one bathy phytochrome and another phytochrome with novel spectral properties. Rhizobium leguminosarum 3841, Rhizobium etli CIAT652, and Azorhizobium caulinodans ORS571 contain a single phytochrome of the bathy type, whereas Xanthobacter autotrophicus Py2 contains a single phytochrome with dark conversion of Pfr to Pr. We propose that bathy phytochromes are adaptations to the light regime in the soil. Most bacterial phytochromes are light-regulated histidine kinases, some of which have a C-terminal response regulator subunit on the same protein. According to our phylogenetic studies, the group of phytochromes with this domain arrangement has evolved from a bathy phytochrome progenitor.
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Inomata K, Khawn H, Chen LY, Kinoshita H, Zienicke B, Molina I, Lamparter T. Assembly of Agrobacterium Phytochromes Agp1 and Agp2 with Doubly Locked Bilin Chromophores. Biochemistry 2009; 48:2817-27. [DOI: 10.1021/bi802334u] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Katsuhiko Inomata
- Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan, and Universität Karlsruhe, Botanik I, Kaiserstrasse 2, D-76131 Karlsruhe, Germany
| | - Htoi Khawn
- Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan, and Universität Karlsruhe, Botanik I, Kaiserstrasse 2, D-76131 Karlsruhe, Germany
| | - Li-Yi Chen
- Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan, and Universität Karlsruhe, Botanik I, Kaiserstrasse 2, D-76131 Karlsruhe, Germany
| | - Hideki Kinoshita
- Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan, and Universität Karlsruhe, Botanik I, Kaiserstrasse 2, D-76131 Karlsruhe, Germany
| | - Benjamin Zienicke
- Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan, and Universität Karlsruhe, Botanik I, Kaiserstrasse 2, D-76131 Karlsruhe, Germany
| | - Isabel Molina
- Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan, and Universität Karlsruhe, Botanik I, Kaiserstrasse 2, D-76131 Karlsruhe, Germany
| | - Tilman Lamparter
- Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan, and Universität Karlsruhe, Botanik I, Kaiserstrasse 2, D-76131 Karlsruhe, Germany
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