1
|
Conserved histidine and tyrosine determine spectral responses through the water network in Deinococcus radiodurans phytochrome. PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES : OFFICIAL JOURNAL OF THE EUROPEAN PHOTOCHEMISTRY ASSOCIATION AND THE EUROPEAN SOCIETY FOR PHOTOBIOLOGY 2022; 21:1975-1989. [PMID: 35906527 DOI: 10.1007/s43630-022-00272-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 07/12/2022] [Indexed: 10/16/2022]
Abstract
Phytochromes are red light-sensing photoreceptor proteins that bind a bilin chromophore. Here, we investigate the role of a conserved histidine (H260) and tyrosine (Y263) in the chromophore-binding domain (CBD) of Deinococcus radiodurans phytochrome (DrBphP). Using crystallography, we show that in the H260A variant, the missing imidazole side chain leads to increased water content in the binding pocket. On the other hand, Y263F mutation reduces the water occupancy around the chromophore. Together, these changes in water coordination alter the protonation and spectroscopic properties of the biliverdin. These results pinpoint the importance of this conserved histidine and tyrosine, and the related water network, for the function and applications of phytochromes.
Collapse
|
2
|
Kamo T, Eki T, Hirose Y. Pressurized Liquid Extraction of a Phycocyanobilin Chromophore and Its Reconstitution with a Cyanobacteriochrome Photosensor for Efficient Isotopic Labeling. PLANT & CELL PHYSIOLOGY 2021; 62:334-347. [PMID: 33386854 PMCID: PMC8112840 DOI: 10.1093/pcp/pcaa164] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 12/09/2020] [Indexed: 06/12/2023]
Abstract
Linear tetrapyrrole compounds (bilins) are chromophores of the phytochrome and cyanobacteriochrome classes of photosensors and light-harvesting phycobiliproteins. Various spectroscopic techniques, such as resonance Raman, Fourier transform-infrared and nuclear magnetic resonance, have been used to elucidate the structures underlying their remarkable spectral diversity, in which the signals are experimentally assigned to specific structures using isotopically labeled bilin. However, current methods for isotopic labeling of bilins require specialized expertise, time-consuming procedures and/or expensive reagents. To address these shortcomings, we established a method for pressurized liquid extraction of phycocyanobilin (PCB) from the phycobiliprotein powder Lina Blue and also the cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis). PCB was efficiently cleaved in ethanol with three extractions (5 min each) under nitrogen at 125�C and 100 bars. A prewash at 75�C was effective for removing cellular pigments of Synechocystis without PCB cleavage. Liquid chromatography and mass spectrometry suggested that PCB was cleaved in the C3-E (majority) and C3-Z (partial) configurations. 15N- and 13C/15N-labeled PCBs were prepared from Synechocystis cells grown with NaH13CO3 and/or Na15NO3, the concentrations of which were optimized based on cell growth and pigmentation. Extracted PCB was reconstituted with a recombinant apoprotein of the cyanobacteriochrome-class photosensor RcaE. Yield of the photoactive holoprotein was improved by optimization of the expression conditions and cell disruption in the presence of Tween 20. Our method can be applied for the isotopic labeling of other PCB-binding proteins and for the commercial production of non-labeled PCB for food, cosmetic and medical applications.
Collapse
Affiliation(s)
- Takanari Kamo
- Department of Applied Chemistry and Life Science, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku, Toyohashi, Aichi, 441-8580 Japan
| | - Toshihiko Eki
- Department of Applied Chemistry and Life Science, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku, Toyohashi, Aichi, 441-8580 Japan
| | - Yuu Hirose
- Department of Applied Chemistry and Life Science, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku, Toyohashi, Aichi, 441-8580 Japan
| |
Collapse
|
3
|
Song JY, Lee HY, Yang HW, Song JJ, Lagarias JC, Park YI. Spectral and photochemical diversity of tandem cysteine cyanobacterial phytochromes. J Biol Chem 2020; 295:6754-6766. [PMID: 32184354 DOI: 10.1074/jbc.ra120.012950] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/13/2020] [Indexed: 11/06/2022] Open
Abstract
The atypical trichromatic cyanobacterial phytochrome NpTP1 from Nostoc punctiforme ATCC 29133 is a linear tetrapyrrole (bilin)-binding photoreceptor protein that possesses tandem-cysteine residues responsible for shifting its light-sensing maximum to the violet spectral region. Using bioinformatics and phylogenetic analyses, here we established that tandem-cysteine cyanobacterial phytochromes (TCCPs) compose a well-supported monophyletic phytochrome lineage distinct from prototypical red/far-red cyanobacterial phytochromes. To investigate the light-sensing diversity of this family, we compared the spectroscopic properties of NpTP1 (here renamed NpTCCP) with those of three phylogenetically diverged TCCPs identified in the draft genomes of Tolypothrix sp. PCC7910, Scytonema sp. PCC10023, and Gloeocapsa sp. PCC7513. Recombinant photosensory core modules of ToTCCP, ScTCCP, and GlTCCP exhibited violet-blue-absorbing dark-states consistent with dual thioether-linked phycocyanobilin (PCB) chromophores. Photoexcitation generated singly-linked photoproduct mixtures with variable ratios of yellow-orange and red-absorbing species. The photoproduct ratio was strongly influenced by pH and by mutagenesis of TCCP- and phytochrome-specific signature residues. Our experiments support the conclusion that both photoproduct species possess protonated 15E bilin chromophores, but differ in the ionization state of the noncanonical "second" cysteine sulfhydryl group. We found that the ionization state of this and other residues influences subsequent conformational change and downstream signal transmission. We also show that tandem-cysteine phytochromes present in eukaryotes possess similar amino acid substitutions within their chromophore-binding pocket, which tune their spectral properties in an analogous fashion. Taken together, our findings provide a roadmap for tailoring the wavelength specificity of plant phytochromes to optimize plant performance in diverse natural and artificial light environments.
Collapse
Affiliation(s)
- Ji-Young Song
- Department of Biological Sciences, Chungnam National University, Daejeon 34134, Korea
| | - Ha Yong Lee
- Department of Biological Sciences, Chungnam National University, Daejeon 34134, Korea
| | - Hee Wook Yang
- Department of Biological Sciences, Chungnam National University, Daejeon 34134, Korea
| | - Ji-Joon Song
- Department of Biological Science and KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - J Clark Lagarias
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California 95616
| | - Youn-Il Park
- Department of Biological Sciences, Chungnam National University, Daejeon 34134, Korea
| |
Collapse
|
4
|
Fernandez Lopez M, Nguyen AD, Velazquez Escobar F, González R, Michael N, Nogacz Ż, Piwowarski P, Bartl F, Siebert F, Heise I, Scheerer P, Gärtner W, Mroginski MA, Hildebrandt P. Role of the Propionic Side Chains for the Photoconversion of Bacterial Phytochromes. Biochemistry 2019; 58:3504-3519. [DOI: 10.1021/acs.biochem.9b00526] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Maria Fernandez Lopez
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Anh Duc Nguyen
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Francisco Velazquez Escobar
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Ronald González
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Norbert Michael
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Żaneta Nogacz
- Humboldt Universität zu Berlin, Institut für Biologie, Biophysikalische Chemie, Invalidenstraße 42, D-10115 Berlin, Germany
| | - Patrick Piwowarski
- Humboldt Universität zu Berlin, Institut für Biologie, Biophysikalische Chemie, Invalidenstraße 42, D-10115 Berlin, Germany
| | - Franz Bartl
- Humboldt Universität zu Berlin, Institut für Biologie, Biophysikalische Chemie, Invalidenstraße 42, D-10115 Berlin, Germany
| | - Friedrich Siebert
- Albert-Ludwigs-Universität Freiburg, Institut für Molekulare Medizin und Zellforschung, Sektion Biophysik, Hermann-Herderstraße 9, D-79104 Freiburg, Germany
| | - Inge Heise
- Max Planck Institut für Chemische Energiekonversion, Stiftstraße 34-36, D-45470 Mülheim, Germany
| | - Patrick Scheerer
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, D-10117 Berlin, Germany
| | - Wolfgang Gärtner
- Max Planck Institut für Chemische Energiekonversion, Stiftstraße 34-36, D-45470 Mülheim, Germany
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany
| | - Maria Andrea Mroginski
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Peter Hildebrandt
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| |
Collapse
|
5
|
The conformation of biliverdin in dimethyl sulfoxide: implications for the coordination with copper. Struct Chem 2019. [DOI: 10.1007/s11224-019-01354-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
6
|
Sugishima M, Wada K, Unno M, Fukuyama K. Bilin-metabolizing enzymes: site-specific reductions catalyzed by two different type of enzymes. Curr Opin Struct Biol 2019; 59:73-80. [PMID: 30954759 DOI: 10.1016/j.sbi.2019.03.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 01/09/2019] [Accepted: 03/04/2019] [Indexed: 02/05/2023]
Abstract
In mammals, the green heme metabolite biliverdin is converted to a yellow anti-oxidant by NAD(P)H-dependent biliverdin reductase (BVR), whereas in O2-dependent photosynthetic organisms it is converted to photosynthetic or light-sensing pigments by ferredoxin-dependent bilin reductases (FDBRs). In NADP+-bound and biliverdin-bound BVR-A, two biliverdins are stacked at the binding cleft; one is positioned to accept hydride from NADPH, and the other appears to donate a proton to the first biliverdin through a neighboring arginine residue. During the FDBR-catalyzed reaction, electrons and protons are supplied to bilins from ferredoxin and from FDBRs and waters bound within FDBRs, respectively. Thus, the protonation sites of bilin and catalytic residues are important for the analysis of site-specific reduction. The neutron structure of FDBR sheds light on this issue.
Collapse
Affiliation(s)
- Masakazu Sugishima
- Department of Medical Biochemistry, Kurume University School of Medicine, Fukuoka 830-0011, Japan.
| | - Kei Wada
- Department of Medical Sciences, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Masaki Unno
- Graduate School of Science and Engineering, Ibaraki University, Ibaraki 316-8511, Japan
| | - Keiichi Fukuyama
- Department of Biological Sciences, Graduate School of Science, Osaka University, Osaka 560-0043, Japan
| |
Collapse
|
7
|
Rumfeldt JA, Takala H, Liukkonen A, Ihalainen JA. UV‐Vis Spectroscopy Reveals a Correlation Between Y263 and BV Protonation States in Bacteriophytochromes. Photochem Photobiol 2019; 95:969-979. [DOI: 10.1111/php.13095] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 02/26/2019] [Indexed: 11/29/2022]
Affiliation(s)
- Jessica A. Rumfeldt
- Department of Biological and Environmental Science Nanoscience Center University of Jyväskylä Jyväskylä Finland
| | - Heikki Takala
- Department of Biological and Environmental Science Nanoscience Center University of Jyväskylä Jyväskylä Finland
- Anatomy Faculty of Medicine University of Helsinki Helsinki Finland
| | - Alli Liukkonen
- Department of Biological and Environmental Science Nanoscience Center University of Jyväskylä Jyväskylä Finland
| | - Janne A. Ihalainen
- Department of Biological and Environmental Science Nanoscience Center University of Jyväskylä Jyväskylä Finland
| |
Collapse
|
8
|
Sheehan MM, Magaraci MS, Kuznetsov IA, Mancini JA, Kodali G, Moser CC, Dutton PL, Chow BY. Rational Construction of Compact de Novo-Designed Biliverdin-Binding Proteins. Biochemistry 2018; 57:6752-6756. [PMID: 30468389 PMCID: PMC6293442 DOI: 10.1021/acs.biochem.8b01076] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report the rational construction of de novo-designed biliverdin-binding proteins by first principles of protein design, informed by energy minimization modeling in Rosetta. The self-assembling tetrahelical bundles bind biliverdin IXa (BV) cofactor autocatalytically in vitro, like photosensory proteins that bind BV (and related bilins or linear tetrapyrroles) despite lacking sequence and structural homology to the natural counterparts. Upon identification of a suitable site for ligation of the cofactor to the protein scaffold, stepwise placement of residues stabilized BV within the hydrophobic core. Rosetta modeling was used in the absence of a high-resolution structure to inform the structure-function relationships of the cofactor binding pocket. Holoprotein formation stabilized BV, resulting in increased far-red BV fluorescence. Via removal of segments extraneous to cofactor stabilization or bundle stability, the initial 15 kDa de novo-designed fluorescence-activating protein was truncated without any change to its optical properties, down to a miniature 10 kDa "mini", in which the protein scaffold extends only a half-heptad repeat beyond the hypothetical position of the bilin D-ring. This work demonstrates how highly compact holoprotein fluorochromes can be rationally constructed using de novo protein design technology and natural cofactors.
Collapse
|
9
|
Rockwell NC, Martin SS, Lagarias JC. There and Back Again: Loss and Reacquisition of Two‐Cys Photocycles in Cyanobacteriochromes. Photochem Photobiol 2017; 93:741-754. [DOI: 10.1111/php.12708] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 11/01/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Nathan C. Rockwell
- Department of Molecular and Cellular Biology University of California Davis CA
| | - Shelley S. Martin
- Department of Molecular and Cellular Biology University of California Davis CA
| | - John Clark Lagarias
- Department of Molecular and Cellular Biology University of California Davis CA
| |
Collapse
|
10
|
Rockwell NC, Martin SS, Li FW, Mathews S, Lagarias JC. The phycocyanobilin chromophore of streptophyte algal phytochromes is synthesized by HY2. THE NEW PHYTOLOGIST 2017; 214:1145-1157. [PMID: 28106912 PMCID: PMC5388591 DOI: 10.1111/nph.14422] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 12/04/2016] [Indexed: 05/11/2023]
Abstract
Land plant phytochromes perceive red and far-red light to control growth and development, using the linear tetrapyrrole (bilin) chromophore phytochromobilin (PΦB). Phytochromes from streptophyte algae, sister species to land plants, instead use phycocyanobilin (PCB). PCB and PΦB are synthesized by different ferredoxin-dependent bilin reductases (FDBRs): PΦB is synthesized by HY2, whereas PCB is synthesized by PcyA. The pathway for PCB biosynthesis in streptophyte algae is unknown. We used phylogenetic analysis and heterologous reconstitution of bilin biosynthesis to investigate bilin biosynthesis in streptophyte algae. Phylogenetic results suggest that PcyA is present in chlorophytes and prasinophytes but absent in streptophytes. A system reconstituting bilin biosynthesis in Escherichia coli was modified to utilize HY2 from the streptophyte alga Klebsormidium flaccidum (KflaHY2). The resulting bilin was incorporated into model cyanobacterial photoreceptors and into phytochrome from the early-diverging streptophyte alga Mesostigma viride (MvirPHY1). All photoreceptors tested incorporate PCB rather than PΦB, indicating that KflaHY2 is sufficient for PCB synthesis without any other algal protein. MvirPHY1 exhibits a red-far-red photocycle similar to those seen in other streptophyte algal phytochromes. These results demonstrate that streptophyte algae use HY2 to synthesize PCB, consistent with the hypothesis that PΦB synthesis arose late in HY2 evolution.
Collapse
Affiliation(s)
- Nathan C. Rockwell
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Shelley S. Martin
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Fay-Wei Li
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Sarah Mathews
- CSIRO National Research Collections Australia, Australian National Herbarium, Canberra, ACT, 2601, Australia
| | - J. Clark Lagarias
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| |
Collapse
|
11
|
Takao H, Hirabayashi K, Nishigaya Y, Kouriki H, Nakaniwa T, Hagiwara Y, Harada J, Sato H, Yamazaki T, Sakakibara Y, Suiko M, Asada Y, Takahashi Y, Yamamoto K, Fukuyama K, Sugishima M, Wada K. A substrate-bound structure of cyanobacterial biliverdin reductase identifies stacked substrates as critical for activity. Nat Commun 2017; 8:14397. [PMID: 28169272 PMCID: PMC5309722 DOI: 10.1038/ncomms14397] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 12/23/2016] [Indexed: 01/20/2023] Open
Abstract
Biliverdin reductase catalyses the last step in haem degradation and produces the major lipophilic antioxidant bilirubin via reduction of biliverdin, using NAD(P)H as a cofactor. Despite the importance of biliverdin reductase in maintaining the redox balance, the molecular details of the reaction it catalyses remain unknown. Here we present the crystal structure of biliverdin reductase in complex with biliverdin and NADP+. Unexpectedly, two biliverdin molecules, which we designated the proximal and distal biliverdins, bind with stacked geometry in the active site. The nicotinamide ring of the NADP+ is located close to the reaction site on the proximal biliverdin, supporting that the hydride directly attacks this position of the proximal biliverdin. The results of mutagenesis studies suggest that a conserved Arg185 is essential for the catalysis. The distal biliverdin probably acts as a conduit to deliver the proton from Arg185 to the proximal biliverdin, thus yielding bilirubin.
Collapse
Affiliation(s)
- Haruna Takao
- Organization for Promotion of Tenure Track, University of Miyazaki, Miyazaki 889-1692, Japan
- Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Kei Hirabayashi
- Organization for Promotion of Tenure Track, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Yuki Nishigaya
- Advanced Analysis Center, National Agriculture and Food Research Organization, Ibaraki 305-8602, Japan
| | - Haruna Kouriki
- Organization for Promotion of Tenure Track, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Tetsuko Nakaniwa
- Department of Biological Sciences, Graduate School of Science, Osaka University, Osaka 560-0043, Japan
| | - Yoshinori Hagiwara
- Department of Biochemistry and Applied Chemistry, National Institute of Technology, Kurume College, Fukuoka 830-8555, Japan
| | - Jiro Harada
- Department of Medical Biochemistry, Kurume University School of Medicine, Fukuoka 830-0011, Japan
| | - Hideaki Sato
- Department of Medical Biochemistry, Kurume University School of Medicine, Fukuoka 830-0011, Japan
| | - Toshimasa Yamazaki
- Advanced Analysis Center, National Agriculture and Food Research Organization, Ibaraki 305-8602, Japan
| | - Yoichi Sakakibara
- Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Masahito Suiko
- Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Yujiro Asada
- Department of Pathology, Faculty of Medicine, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Yasuhiro Takahashi
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Ken Yamamoto
- Department of Medical Biochemistry, Kurume University School of Medicine, Fukuoka 830-0011, Japan
| | - Keiichi Fukuyama
- Department of Biological Sciences, Graduate School of Science, Osaka University, Osaka 560-0043, Japan
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan
| | - Masakazu Sugishima
- Department of Medical Biochemistry, Kurume University School of Medicine, Fukuoka 830-0011, Japan
| | - Kei Wada
- Organization for Promotion of Tenure Track, University of Miyazaki, Miyazaki 889-1692, Japan
| |
Collapse
|
12
|
Rockwell NC, Martin SS, Lagarias JC. Identification of Cyanobacteriochromes Detecting Far-Red Light. Biochemistry 2016; 55:3907-19. [DOI: 10.1021/acs.biochem.6b00299] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nathan C. Rockwell
- Department of Molecular and
Cellular Biology, University of California, Davis, California 95616, United States
| | - Shelley S. Martin
- Department of Molecular and
Cellular Biology, University of California, Davis, California 95616, United States
| | - J. Clark Lagarias
- Department of Molecular and
Cellular Biology, University of California, Davis, California 95616, United States
| |
Collapse
|
13
|
Rockwell NC, Martin SS, Lim S, Lagarias JC, Ames JB. Characterization of Red/Green Cyanobacteriochrome NpR6012g4 by Solution Nuclear Magnetic Resonance Spectroscopy: A Hydrophobic Pocket for the C15-E,anti Chromophore in the Photoproduct. Biochemistry 2015; 54:3772-83. [DOI: 10.1021/acs.biochem.5b00438] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Nathan C. Rockwell
- Department of Molecular
and Cellular Biology and ‡Department of Chemistry, University of California, Davis, California 95616, United States
| | - Shelley S. Martin
- Department of Molecular
and Cellular Biology and ‡Department of Chemistry, University of California, Davis, California 95616, United States
| | - Sunghyuk Lim
- Department of Molecular
and Cellular Biology and ‡Department of Chemistry, University of California, Davis, California 95616, United States
| | - J. Clark Lagarias
- Department of Molecular
and Cellular Biology and ‡Department of Chemistry, University of California, Davis, California 95616, United States
| | - James B. Ames
- Department of Molecular
and Cellular Biology and ‡Department of Chemistry, University of California, Davis, California 95616, United States
| |
Collapse
|
14
|
Rockwell NC, Martin SS, Lim S, Lagarias JC, Ames JB. Characterization of Red/Green Cyanobacteriochrome NpR6012g4 by Solution Nuclear Magnetic Resonance Spectroscopy: A Protonated Bilin Ring System in Both Photostates. Biochemistry 2015; 54:2581-600. [DOI: 10.1021/bi501548t] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Nathan C. Rockwell
- Department of Molecular
and Cellular Biology and ‡Department of Chemistry, University of California, Davis, California 95616, United States
| | - Shelley S. Martin
- Department of Molecular
and Cellular Biology and ‡Department of Chemistry, University of California, Davis, California 95616, United States
| | - Sunghyuk Lim
- Department of Molecular
and Cellular Biology and ‡Department of Chemistry, University of California, Davis, California 95616, United States
| | - J. Clark Lagarias
- Department of Molecular
and Cellular Biology and ‡Department of Chemistry, University of California, Davis, California 95616, United States
| | - James B. Ames
- Department of Molecular
and Cellular Biology and ‡Department of Chemistry, University of California, Davis, California 95616, United States
| |
Collapse
|
15
|
Rockwell NC, Martin SS, Gan F, Bryant DA, Lagarias JC. NpR3784 is the prototype for a distinctive group of red/green cyanobacteriochromes using alternative Phe residues for photoproduct tuning. Photochem Photobiol Sci 2015; 14:258-69. [DOI: 10.1039/c4pp00336e] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We report chromophore–protein interactions used by cyanobacteriochrome NpR3784 and related proteins for spectral tuning of the green-absorbing photoproduct state. These interactions are distinct from those used by canonical red/green cyanobacteriochromes.
Collapse
Affiliation(s)
- Nathan C. Rockwell
- Department of Molecular and Cell Biology
- University of California at Davis
- Davis
- USA
| | - Shelley S. Martin
- Department of Molecular and Cell Biology
- University of California at Davis
- Davis
- USA
| | - Fei Gan
- Department of Biochemistry and Molecular Biology
- The Pennsylvania State University
- University Park
- USA
| | - Donald A. Bryant
- Department of Biochemistry and Molecular Biology
- The Pennsylvania State University
- University Park
- USA
- Department of Chemistry and Biochemistry
| | - J. Clark Lagarias
- Department of Molecular and Cell Biology
- University of California at Davis
- Davis
- USA
| |
Collapse
|
16
|
Rockwell NC, Martin SS, Lagarias JC. Identification of DXCF cyanobacteriochrome lineages with predictable photocycles. Photochem Photobiol Sci 2015; 14:929-41. [DOI: 10.1039/c4pp00486h] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Two specialized subgroups of cyanobacteriochromes with predictable green/blue and blue/orange photocycles are defined by these studies.
Collapse
Affiliation(s)
- Nathan C. Rockwell
- Department of Molecular and Cellular Biology
- University of California at Davis
- Davis
- USA
| | - Shelley S. Martin
- Department of Molecular and Cellular Biology
- University of California at Davis
- Davis
- USA
| | - J. Clark Lagarias
- Department of Molecular and Cellular Biology
- University of California at Davis
- Davis
- USA
| |
Collapse
|
17
|
Rockwell NC, Martin SS, Gulevich AG, Lagarias JC. Conserved Phenylalanine Residues Are Required for Blue-Shifting of Cyanobacteriochrome Photoproducts. Biochemistry 2014; 53:3118-30. [DOI: 10.1021/bi500037a] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nathan C. Rockwell
- Department of Molecular and
Cellular Biology, University of California, Davis, California 95616, United States
| | - Shelley S. Martin
- Department of Molecular and
Cellular Biology, University of California, Davis, California 95616, United States
| | - Alexander G. Gulevich
- Department of Molecular and
Cellular Biology, University of California, Davis, California 95616, United States
| | - J. Clark Lagarias
- Department of Molecular and
Cellular Biology, University of California, Davis, California 95616, United States
| |
Collapse
|
18
|
Nieder JB, Stojković EA, Moffat K, Forest KT, Lamparter T, Bittl R, Kennis JTM. Pigment–Protein Interactions in Phytochromes Probed by Fluorescence Line Narrowing Spectroscopy. J Phys Chem B 2013; 117:14940-50. [DOI: 10.1021/jp409110q] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Jana B. Nieder
- Fachbereich
Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Emina A. Stojković
- Department of Biochemistry and Molecular Biology, Center for Advanced
Radiation Sources, and Institute for Biophysical Dynamics, University of Chicago, 920 East 58th Street, Chicago, Illinois 60637, United States
| | - Keith Moffat
- Department of Biochemistry and Molecular Biology, Center for Advanced
Radiation Sources, and Institute for Biophysical Dynamics, University of Chicago, 920 East 58th Street, Chicago, Illinois 60637, United States
| | - Katrina T. Forest
- Department of Bacteriology, University of Wisconsin—Madison, 1550 Linden Drive, Madison, Wisconsin 53706, United States
| | - Tilman Lamparter
- Botany
1, KIT - Karlsruhe Institute of Technology, Kaiserstrasse 2, D 76131 Karlsruhe, Germany
| | - Robert Bittl
- Fachbereich
Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - John T. M. Kennis
- Department of Physics and Astronomy, Biophysics Section, VU University Amsterdam, De Boelelaan 1081, NL-1081 HV Amsterdam, The Netherlands
| |
Collapse
|
19
|
Liu Z, Müller J, Li T, Alvey RM, Vogl K, Frigaard NU, Rockwell NC, Boyd ES, Tomsho LP, Schuster SC, Henke P, Rohde M, Overmann J, Bryant DA. Genomic analysis reveals key aspects of prokaryotic symbiosis in the phototrophic consortium "Chlorochromatium aggregatum". Genome Biol 2013; 14:R127. [PMID: 24267588 PMCID: PMC4053972 DOI: 10.1186/gb-2013-14-11-r127] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 11/22/2013] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND 'Chlorochromatium aggregatum' is a phototrophic consortium, a symbiosis that may represent the highest degree of mutual interdependence between two unrelated bacteria not associated with a eukaryotic host. 'Chlorochromatium aggregatum' is a motile, barrel-shaped aggregate formed from a single cell of 'Candidatus Symbiobacter mobilis", a polarly flagellated, non-pigmented, heterotrophic bacterium, which is surrounded by approximately 15 epibiont cells of Chlorobium chlorochromatii, a non-motile photolithoautotrophic green sulfur bacterium. RESULTS We analyzed the complete genome sequences of both organisms to understand the basis for this symbiosis. Chl. chlorochromatii has acquired relatively few symbiosis-specific genes; most acquired genes are predicted to modify the cell wall or function in cell-cell adhesion. In striking contrast, 'Ca. S. mobilis' appears to have undergone massive gene loss, is probably no longer capable of independent growth, and thus may only reproduce when consortia divide. A detailed model for the energetic and metabolic bases of the dependency of 'Ca. S. mobilis' on Chl. chlorochromatii is described. CONCLUSIONS Genomic analyses suggest that three types of interactions lead to a highly sophisticated relationship between these two organisms. Firstly, extensive metabolic exchange, involving carbon, nitrogen, and sulfur sources as well as vitamins, occurs from the epibiont to the central bacterium. Secondly, 'Ca. S. mobilis' can sense and move towards light and sulfide, resources that only directly benefit the epibiont. Thirdly, electron cycling mechanisms, particularly those mediated by quinones and potentially involving shared protonmotive force, could provide an important basis for energy exchange in this and other symbiotic relationships.
Collapse
Affiliation(s)
- Zhenfeng Liu
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
- Current address: Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Johannes Müller
- Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Tao Li
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
- Current address: Algal Genomics Research Group, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Richard M Alvey
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
- Current address: Department of Biology, Chaminade University, Honolulu, HI 96816, USA
| | - Kajetan Vogl
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Niels-Ulrik Frigaard
- Section for Marine Biology, Department of Biology, University of Copenhagen, Strandpromenaden 5 3000, Helsingør, Denmark
| | - Nathan C Rockwell
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Eric S Boyd
- Department of Microbiology, Montana State University, Bozeman, MT 59717, USA
| | - Lynn P Tomsho
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Stephan C Schuster
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Petra Henke
- Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Manfred Rohde
- Helmholtz-Zentrum für Infektionsforschung, 38124 Braunschweig, Germany
| | - Jörg Overmann
- Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Microbiology, Montana State University, Bozeman, MT 59717, USA
| |
Collapse
|
20
|
Anders K, Daminelli-Widany G, Mroginski MA, von Stetten D, Essen LO. Structure of the cyanobacterial phytochrome 2 photosensor implies a tryptophan switch for phytochrome signaling. J Biol Chem 2013; 288:35714-25. [PMID: 24174528 DOI: 10.1074/jbc.m113.510461] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phytochromes are highly versatile photoreceptors, which occur ubiquitously in plants as well as in many light-responsive microorganisms. Here, photosynthetic cyanobacteria utilize up to three different phytochrome architectures, where only the plant-like and the single-domain cyanobacteriochromes are structurally characterized so far. Cph2 represents a third group in Synechocystis species and affects their capability of phototaxis by controlling c-di-GMP synthesis and degradation. The 2.6-Å crystal structure of its red/far-red responsive photosensory module in the Pr state reveals a tandem-GAF bidomain that lacks the figure-of-eight knot of the plant/cph1 subfamily. Its covalently attached phycocyanobilin chromophore adopts a highly tilted ZZZssa conformation with a novel set of interactions between its propionates and the GAF1 domain. The tongue-like protrusion from the GAF2 domain interacts with the GAF1-bound chromophore via its conserved PRXSF, WXE, and W(G/A)G motifs. Mutagenesis showed that the integrity of the tongue is indispensable for Pr → Pfr photoconversion and involves a swap of the motifs' tryptophans within the tongue-GAF1 interface. This "Trp switch" is supposed to be a crucial element for the photochromicity of all multidomain phytochromes.
Collapse
Affiliation(s)
- Katrin Anders
- From the Department of Chemistry, Biomedical Research Centre, Philipps-Universität, D-35032 Marburg, Germany
| | | | | | | | | |
Collapse
|
21
|
Green/red cyanobacteriochromes regulate complementary chromatic acclimation via a protochromic photocycle. Proc Natl Acad Sci U S A 2013; 110:4974-9. [PMID: 23479641 DOI: 10.1073/pnas.1302909110] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cyanobacteriochromes (CBCRs) are cyanobacterial members of the phytochrome superfamily of photosensors. Like phytochromes, CBCRs convert between two photostates by photoisomerization of a covalently bound linear tetrapyrrole (bilin) chromophore. Although phytochromes are red/far-red sensors, CBCRs exhibit diverse photocycles spanning the visible spectrum and the near-UV (330-680 nm). Two CBCR subfamilies detect near-UV to blue light (330-450 nm) via a "two-Cys photocycle" that couples bilin 15Z/15E photoisomerization with formation or elimination of a second bilin-cysteine adduct. On the other hand, mechanisms for tuning the absorption between the green and red regions of the spectrum have not been elucidated as of yet. CcaS and RcaE are members of a CBCR subfamily that regulates complementary chromatic acclimation, in which cyanobacteria optimize light-harvesting antennae in response to green or red ambient light. CcaS has been shown to undergo a green/red photocycle: reversible photoconversion between a green-absorbing 15Z state ((15Z)P(g)) and a red-absorbing 15E state ((15E)P(r)). We demonstrate that RcaE from Fremyella diplosiphon undergoes the same photocycle and exhibits light-regulated kinase activity. In both RcaE and CcaS, the bilin chromophore is deprotonated as (15Z)P(g) but protonated as (15E)P(r). This change of bilin protonation state is modulated by three key residues that are conserved in green/red CBCRs. We therefore designate the photocycle of green/red CBCRs a "protochromic photocycle," in which the dramatic change from green to red absorption is not induced by initial bilin photoisomerization but by a subsequent change in bilin protonation state.
Collapse
|
22
|
Rockwell NC, Martin SS, Lagarias JC. Red/green cyanobacteriochromes: sensors of color and power. Biochemistry 2012; 51:9667-77. [PMID: 23151047 DOI: 10.1021/bi3013565] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Phytochromes are red/far-red photoreceptors using cysteine-linked linear tetrapyrrole (bilin) chromophores to regulate biological responses to light. Light absorption triggers photoisomerization of the bilin between the 15Z and 15E photostates. The related cyanobacteriochromes (CBCRs) extend the photosensory range of the phytochrome superfamily to shorter wavelengths of visible light. Several subfamilies of CBCRs have been described. Representatives of one such subfamily, including AnPixJ and NpR6012g4, exhibit red/green photocycles in which the 15Z photostate is red-absorbing like that of phytochrome but the 15E photoproduct is instead green-absorbing. Using recombinant expression of individual CBCR domains in Escherichia coli, we fully survey the red/green subfamily from the cyanobacterium Nostoc punctiforme. In addition to 14 new photoswitching CBCRs, one apparently photochemically inactive protein exhibiting intense red fluorescence was observed. We describe a novel orange/green photocycle in one of these CBCRs, NpF2164g7. Dark reversion varied in this panel of CBCRs; some examples were stable as the 15E photoproduct for days, while others reverted to the 15Z dark state in minutes or even seconds. In the case of NpF2164g7, dark reversion was so rapid that reverse photoconversion of the green-absorbing photoproduct was not significant in restoring the dark state, resulting in a broadband response to light. Our results demonstrate that red/green CBCRs can thus act as sensors for the color or intensity of the ambient light environment.
Collapse
Affiliation(s)
- Nathan C Rockwell
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | | | | |
Collapse
|
23
|
Rockwell NC, Martin SS, Lagarias JC. Mechanistic Insight into the Photosensory Versatility of DXCF Cyanobacteriochromes. Biochemistry 2012; 51:3576-85. [DOI: 10.1021/bi300171s] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nathan C. Rockwell
- Department of Molecular and Cellular Biology, University of California, Davis, California 95616,
United States
| | - Shelley S. Martin
- Department of Molecular and Cellular Biology, University of California, Davis, California 95616,
United States
| | - J. Clark Lagarias
- Department of Molecular and Cellular Biology, University of California, Davis, California 95616,
United States
| |
Collapse
|
24
|
Rockwell NC, Martin SS, Gulevich AG, Lagarias JC. Phycoviolobilin formation and spectral tuning in the DXCF cyanobacteriochrome subfamily. Biochemistry 2012; 51:1449-63. [PMID: 22279972 DOI: 10.1021/bi201783j] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phytochromes are red/far-red photosensory proteins that regulate adaptive responses to light via photoswitching of cysteine-linked linear tetrapyrrole (bilin) chromophores. The related cyanobacteriochromes (CBCRs) extend the photosensory range of the phytochrome superfamily to shorter wavelengths of visible light. CBCRs and phytochromes share a conserved Cys residue required for bilin attachment. In one CBCR subfamily, often associated with a blue/green photocycle, a second Cys lies within a conserved Asp-Xaa-Cys-Phe (DXCF) motif and is essential for the blue/green photocycle. Such DXCF CBCRs use isomerization of the phycocyanobilin (PCB) chromophore into the related phycoviolobilin (PVB) to shorten the conjugated system for sensing green light. We here use recombinant expression of individual CBCR domains in Escherichia coli to survey the DXCF subfamily from the cyanobacterium Nostoc punctiforme. We describe ten new photoreceptors with well-resolved photocycles and three additional photoproteins with overlapping dark-adapted and photoproduct states. We show that the ability of this subfamily to form PVB or retain PCB provides a powerful mechanism for tuning the photoproduct absorbance, with blue-absorbing dark states leading to a broad range of photoproducts absorbing teal, green, yellow, or orange light. Moreover, we use a novel green/teal CBCR that lacks the blue-absorbing dark state to demonstrate that PVB formation requires the DXCF Cys residue. Our results demonstrate that this subfamily exhibits much more spectral diversity than had been previously appreciated.
Collapse
Affiliation(s)
- Nathan C Rockwell
- Department of Molecular and Cellular Biology, University of California, Davis, California 95616, United States
| | | | | | | |
Collapse
|
25
|
Kim PW, Freer LH, Rockwell NC, Martin SS, Lagarias JC, Larsen DS. Femtosecond Photodynamics of the Red/Green Cyanobacteriochrome NpR6012g4 from Nostoc punctiforme. 1. Forward Dynamics. Biochemistry 2012; 51:608-18. [DOI: 10.1021/bi201507k] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Peter W. Kim
- Department
of Chemistry and ‡Department of Molecular and Cell Biology, University of California, One Shields Avenue, Davis,
California
95616, United States
| | - Lucy H. Freer
- Department
of Chemistry and ‡Department of Molecular and Cell Biology, University of California, One Shields Avenue, Davis,
California
95616, United States
| | - Nathan C. Rockwell
- Department
of Chemistry and ‡Department of Molecular and Cell Biology, University of California, One Shields Avenue, Davis,
California
95616, United States
| | - Shelley S. Martin
- Department
of Chemistry and ‡Department of Molecular and Cell Biology, University of California, One Shields Avenue, Davis,
California
95616, United States
| | - J. Clark Lagarias
- Department
of Chemistry and ‡Department of Molecular and Cell Biology, University of California, One Shields Avenue, Davis,
California
95616, United States
| | - Delmar S. Larsen
- Department
of Chemistry and ‡Department of Molecular and Cell Biology, University of California, One Shields Avenue, Davis,
California
95616, United States
| |
Collapse
|
26
|
Diverse two-cysteine photocycles in phytochromes and cyanobacteriochromes. Proc Natl Acad Sci U S A 2011; 108:11854-9. [PMID: 21712441 DOI: 10.1073/pnas.1107844108] [Citation(s) in RCA: 159] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phytochromes are well-known as photoactive red- and near IR-absorbing chromoproteins with cysteine-linked linear tetrapyrrole (bilin) prosthetic groups. Phytochrome photoswitching regulates adaptive responses to light in both photosynthetic and nonphotosynthetic organisms. Exclusively found in cyanobacteria, the related cyanobacteriochrome (CBCR) sensors extend the photosensory range of the phytochrome superfamily to shorter wavelengths of visible light. Blue/green light sensing by a well-studied subfamily of CBCRs proceeds via a photolabile thioether linkage to a second cysteine fully conserved in this subfamily. In the present study, we show that dual-cysteine photosensors have repeatedly evolved in cyanobacteria via insertion of a second cysteine at different positions within the bilin-binding GAF domain (cGMP-specific phosphodiesterases, cyanobacterial adenylate cyclases, and formate hydrogen lyase transcription activator FhlA) shared by CBCRs and phytochromes. Such sensors exhibit a diverse range of photocycles, yet all share ground-state absorbance of near-UV to blue light and a common mechanism of light perception: reversible photoisomerization of the bilin 15,16 double bond. Using site-directed mutagenesis, chemical modification and spectroscopy to characterize novel dual-cysteine photosensors from the cyanobacterium Nostoc punctiforme ATCC 29133, we establish that this spectral diversity can be tuned by varying the light-dependent stability of the second thioether linkage. We also show that such behavior can be engineered into the conventional phytochrome Cph1 from Synechocystis sp. PCC6803. Dual-cysteine photosensors thus allow the phytochrome superfamily in cyanobacteria to sense the full solar spectrum at the earth surface from near infrared to near ultraviolet.
Collapse
|