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Guo R, Xu YL, Zhu JX, Scheer H, Zhao KH. Assembly of CpcL-phycobilisomes. Plant J 2024; 118:1207-1217. [PMID: 38319793 DOI: 10.1111/tpj.16666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/01/2023] [Accepted: 01/19/2024] [Indexed: 02/08/2024]
Abstract
CpcL-phycobilisomes (CpcL-PBSs) are a reduced type of phycobilisome (PBS) found in several cyanobacteria. They lack the traditional PBS terminal energy emitters, but still show the characteristic red-shifted fluorescence at ~670 nm. We established a method of assembling in vitro a rod-membrane linker protein, CpcL, with phycocyanin, generating complexes with the red-shifted spectral features of CpcL-PBSs. The red-shift arises from the interaction of a conserved key glutamine, Q57 of CpcL in Synechocystis sp. PCC 6803, with a single phycocyanobilin chromophore of trimeric phycocyanin at one of the three β82-sites. This chromophore is the terminal energy acceptor of CpcL-PBSs and donor to the photosystem(s). This mechanism also operates in PBSs from Acaryochloris marina MBIC11017. We then generated multichromic complexes harvesting light over nearly the complete visible range via the replacement of phycocyanobilin chromophores at sites α84 and β153 of phycocyanins by phycoerythrobilin and/or phycourobilin. The results demonstrate the rational design of biliprotein-based light-harvesting elements by engineering CpcL and phycocyanins, which broadens the light-harvesting range and accordingly improves the light-harvesting capacity and may be potentially applied in solar energy harvesting.
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Affiliation(s)
- Rui Guo
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, P.R. China
| | - Ya-Li Xu
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, P.R. China
| | - Jun-Xun Zhu
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, P.R. China
| | - Hugo Scheer
- Department Biologie I, Universität München, Menzinger Str. 67, D-80638, München, Germany
| | - Kai-Hong Zhao
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, P.R. China
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Beck WF. Intramolecular charge transfer and the function of vibronic excitons in photosynthetic light harvesting. Photosynth Res 2024:10.1007/s11120-024-01095-5. [PMID: 38656684 DOI: 10.1007/s11120-024-01095-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Accepted: 03/15/2024] [Indexed: 04/26/2024]
Abstract
A widely discussed explanation for the prevalence of pairs or clusters of closely spaced electronic chromophores in photosynthetic light-harvesting proteins is the presence of ultrafast and highly directional excitation energy transfer pathways mediated by vibronic excitons, the delocalized optical excitations derived from mixing of the electronic and vibrational states of the chromophores. We discuss herein the hypothesis that internal conversion processes between exciton states on the <100 fs timescale are possible when the excitonic potential energy surfaces are controlled by the vibrational modes that induce charge transfer character in a strongly coupled system of chromophores. We discuss two examples, the peridinin-chlorophyll protein from marine dinoflagellates and the intact phycobilisome from cyanobacteria, in which the intramolecular charge-transfer (ICT) character arising from out-of-plane distortion of the conjugation of carotenoid or bilin chromophores also results in localization of the initially delocalized optical excitation on the vibrational timescale. Tuning of the ground state conformations of the chromophores to manipulate their ICT character provides a natural photoregulatory mechanism, which would control the overall quantum yield of excitation energy transfer by turning on and off the delocalized character of the optical excitations.
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Affiliation(s)
- Warren F Beck
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA.
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Theiß M, Grupe M, Lamparter T, Mroginski MA, Diller R. Ultrafast proton release reaction and primary photochemistry of phycocyano bilin in solution observed with fs-time-resolved mid-IR and UV/Vis spectroscopy. Photochem Photobiol Sci 2021; 20:715-32. [PMID: 34002345 DOI: 10.1007/s43630-021-00045-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/16/2021] [Indexed: 12/27/2022]
Abstract
Deactivation processes of photoexcited (λex = 580 nm) phycocyanobilin (PCB) in methanol were investigated by means of UV/Vis and mid-IR femtosecond (fs) transient absorption (TA) as well as static fluorescence spectroscopy, supported by density-functional-theory calculations of three relevant ground state conformers, PCBA, PCBB and PCBC, their relative electronic state energies and normal mode vibrational analysis. UV/Vis fs-TA reveals time constants of 2.0, 18 and 67 ps, describing decay of PCBB*, of PCBA* and thermal re-equilibration of PCBA, PCBB and PCBC, respectively, in line with the model by Dietzek et al. (Chem Phys Lett 515:163, 2011) and predecessors. Significant substantiation and extension of this model is achieved first via mid-IR fs-TA, i.e. identification of molecular structures and their dynamics, with time constants of 2.6, 21 and 40 ps, respectively. Second, transient IR continuum absorption (CA) is observed in the region above 1755 cm-1 (CA1) and between 1550 and 1450 cm-1 (CA2), indicative for the IR absorption of highly polarizable protons in hydrogen bonding networks (X-H…Y). This allows to characterize chromophore protonation/deprotonation processes, associated with the electronic and structural dynamics, on a molecular level. The PCB photocycle is suggested to be closed via a long living (> 1 ns), PCBC-like (i.e. deprotonated), fluorescent species.
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Kamo T, Eki T, Hirose Y. Pressurized Liquid Extraction of a Phycocyano bilin Chromophore and Its Reconstitution with a Cyanobacteriochrome Photosensor for Efficient Isotopic Labeling. Plant Cell Physiol 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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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
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Fushimi K, Narikawa R. Phytochromes and Cyanobacteriochromes: Photoreceptor Molecules Incorporating a Linear Tetrapyrrole Chromophore. Adv Exp Med Biol 2021; 1293:167-87. [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] [What about the content of this article? (0)] [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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Overkamp KE, Gasper R, Kock K, Herrmann C, Hofmann E, Frankenberg-Dinkel N. Insights into the biosynthesis and assembly of cryptophycean phycobiliproteins. J Biol Chem 2014; 289:26691-26707. [PMID: 25096577 DOI: 10.1074/jbc.m114.591131] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Phycobiliproteins are employed by cyanobacteria, red algae, glaucophytes, and cryptophytes for light-harvesting and consist of apoproteins covalently associated with open-chain tetrapyrrole chromophores. Although the majority of organisms assemble the individual phycobiliproteins into larger aggregates called phycobilisomes, members of the cryptophytes use a single type of phycobiliprotein that is localized in the thylakoid lumen. The cryptophyte Guillardia theta (Gt) uses phycoerythrin PE545 utilizing the uncommon chromophore 15,16-dihydrobiliverdin (DHBV) in addition to phycoerythrobilin (PEB). Both the biosynthesis and the attachment of chromophores to the apophycobiliprotein have not yet been investigated for cryptophytes. In this study, we identified and characterized enzymes involved in PEB biosynthesis. In addition, we present the first in-depth biochemical characterization of a eukaryotic phycobiliprotein lyase (GtCPES). Plastid-encoded HO (GtHo) was shown to convert heme into biliverdin IXα providing the substrate with a putative nucleus-encoded DHBV:ferredoxin oxidoreductase (GtPEBA). A PEB:ferredoxin oxidoreductase (GtPEBB) was found to convert DHBV to PEB, which is the substrate for the phycobiliprotein lyase GtCPES. The x-ray structure of GtCPES was solved at 2.0 Å revealing a 10-stranded β-barrel with a modified lipocalin fold. GtCPES is an S-type lyase specific for binding of phycobilins with reduced C15=C16 double bonds (DHBV and PEB). Site-directed mutagenesis identified residues Glu-136 and Arg-146 involved in phycobilin binding. Based on the crystal structure, a model for the interaction of GtCPES with the apophycobiliprotein CpeB is proposed and discussed.
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Affiliation(s)
- Kristina E Overkamp
- Physiology of Microorganisms, Faculty for Biology and Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - Raphael Gasper
- Protein Crystallography, Faculty for Biology and Biotechnology, and Ruhr University Bochum, 44780 Bochum, Germany
| | - Klaus Kock
- Physical Chemistry I, Protein Interactions, Faculty for Chemistry and Biochemistry, Ruhr University Bochum, 44780 Bochum, Germany
| | - Christian Herrmann
- Physical Chemistry I, Protein Interactions, Faculty for Chemistry and Biochemistry, Ruhr University Bochum, 44780 Bochum, Germany
| | - Eckhard Hofmann
- Protein Crystallography, Faculty for Biology and Biotechnology, and Ruhr University Bochum, 44780 Bochum, Germany
| | - Nicole Frankenberg-Dinkel
- Physiology of Microorganisms, Faculty for Biology and Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany.
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Burgie ES, Wang T, Bussell AN, Walker JM, Li H, Vierstra RD. Crystallographic and electron microscopic analyses of a bacterial phytochrome reveal local and global rearrangements during photoconversion. J Biol Chem 2014; 289:24573-87. [PMID: 25006244 DOI: 10.1074/jbc.m114.571661] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phytochromes are multidomain photoswitches that drive light perception in plants and microorganisms by coupling photoreversible isomerization of their bilin chromophore to various signaling cascades. How changes in bilin conformation affect output by these photoreceptors remains poorly resolved and might include several species-specific routes. Here, we present detailed three-dimensional models of the photosensing module and a picture of an entire dimeric photoreceptor through structural analysis of the Deinococcus radiodurans phytochrome BphP assembled with biliverdin (BV). A 1.16-Å resolution crystal structure of the bilin-binding pocket in the dark-adapted red light-absorbing state illuminated the intricate network of bilin/protein/water interactions and confirmed the protonation and ZZZssa conformation of BV. Structural and spectroscopic comparisons with the photochemically compromised D207A mutant revealed that substitutions of Asp-207 allow inclusion of cyclic porphyrins in addition to BV. A crystal structure of the entire photosensing module showed a head-to-head, twisted dimeric arrangement with bowed helical spines and a hairpin protrusion connecting the cGMP phosphodiesterase/adenylyl cyclase/FhlA (GAF) and phytochrome-specific (PHY) domains. A key conserved hairpin feature is its anti-parallel, two β-strand stem, which we show by mutagenesis to be critical for BphP photochemistry. Comparisons of single particle electron microscopic images of the full-length BphP dimer in the red light-absorbing state and the photoactivated far-red light-absorbing state revealed a large scale reorientation of the PHY domain relative to the GAF domain, which alters the position of the downstream histidine kinase output module. Together, our data support a toggle model whereby bilin photoisomerization alters GAF/PHY domain interactions through conformational modification of the hairpin, which regulates signaling by impacting the relationship between sister output modules.
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Affiliation(s)
- E Sethe Burgie
- From the Department of Genetics, University of Wisconsin, Madison, Wisconsin 53706
| | - Tong Wang
- the Biology Department, Brookhaven National Laboratory, Upton, New York 11973, and
| | - Adam N Bussell
- From the Department of Genetics, University of Wisconsin, Madison, Wisconsin 53706
| | - Joseph M Walker
- From the Department of Genetics, University of Wisconsin, Madison, Wisconsin 53706
| | - Huilin Li
- the Biology Department, Brookhaven National Laboratory, Upton, New York 11973, and the Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794
| | - Richard D Vierstra
- From the Department of Genetics, University of Wisconsin, Madison, Wisconsin 53706,
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Cornilescu CC, Cornilescu G, Burgie ES, Markley JL, Ulijasz AT, Vierstra RD. Dynamic structural changes underpin photoconversion of a blue/green cyanobacteriochrome between its dark and photoactivated states. J Biol Chem 2013; 289:3055-65. [PMID: 24337572 DOI: 10.1074/jbc.m113.531053] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The phytochrome superfamily of photoreceptors exploits reversible light-driven changes in the bilin chromophore to initiate a variety of signaling cascades. The nature of these alterations and how they impact the protein moiety remain poorly resolved and might include several species-specific routes. Here, we provide a detailed picture of photoconversion for the photosensing cGMP phosphodiesterase/adenylyl cyclase/FhlA (GAF) domain from Thermosynechococcus elongatus (Te) PixJ, a member of the cyanobacteriochrome clade. Solution NMR structures of the blue light-absorbing dark state Pb and green light-absorbing photoactivated state Pg, combined with paired crystallographic models, revealed that the bilin and GAF domain dynamically transition via breakage of the C10/Cys-494 thioether bond, opposite rotations of the A and D pyrrole rings, sliding of the bilin in the GAF pocket, and the appearance of an extended region of disorder that includes Cys-494. Changes in GAF domain backbone dynamics were also observed that are likely important for inter-domain signal propagation. Taken together, photoconversion of T. elongatus PixJ from Pb to Pg involves complex structural changes within the GAF domain pocket that transduce light into a mechanical signal, many aspects of which should be relevant to others within the extended phytochrome superfamily.
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Affiliation(s)
- Claudia C Cornilescu
- From the National Magnetic Resonance Facility at Madison, Department of Biochemistry and
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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