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Lone MS, Merino-Chavez OD, Ricks NJ, Hammond MC, Noriega R. Electron Transfer Drives the Photosensitized Polymerization of Contrast Agents by Flavoprotein Tags for Correlative Microscopy. J Am Chem Soc 2024; 146:23797-23805. [PMID: 39150381 DOI: 10.1021/jacs.4c05397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Singlet oxygen generation has long been considered the key feature that allows genetically encoded fluorescent tags to produce polymeric contrast agents for electron microscopy. Optimization of the singlet oxygen sensitization quantum yield has not included the effects of electron-rich monomers on the sensitizer's photocycle. We report that at monomer concentrations employed for staining, quenching by electron transfer is the primary deactivation pathway for photoexcitations. A simple photochemical model including contributions from both processes reproduces the observed reaction rates and indicates that most of the product is driven by pathways that involve electron transfer with monomers─not by the sensitization of singlet oxygen. Realizing the importance of these competing reaction pathways offers a new paradigm to guide the development of genetically encodable tags and suggests opportunities to expand the materials scope and growth conditions for polymeric contrast agents (e.g., biocompatible monomers, O2 poor environments).
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Affiliation(s)
- Mohd Sajid Lone
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Olga D Merino-Chavez
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
- Henry Eyring Center for Cell and Genome Science, University of Utah, Salt Lake City, Utah 84112, United States
| | - Nathan J Ricks
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
- Henry Eyring Center for Cell and Genome Science, University of Utah, Salt Lake City, Utah 84112, United States
| | - Ming C Hammond
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
- Henry Eyring Center for Cell and Genome Science, University of Utah, Salt Lake City, Utah 84112, United States
| | - Rodrigo Noriega
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
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2
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Bregnhøj M, Thorning F, Ogilby PR. Singlet Oxygen Photophysics: From Liquid Solvents to Mammalian Cells. Chem Rev 2024. [PMID: 39106038 DOI: 10.1021/acs.chemrev.4c00105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/07/2024]
Abstract
Molecular oxygen, O2, has long provided a cornerstone for studies in chemistry, physics, and biology. Although the triplet ground state, O2(X3Σg-), has garnered much attention, the lowest excited electronic state, O2(a1Δg), commonly called singlet oxygen, has attracted appreciable interest, principally because of its unique chemical reactivity in systems ranging from the Earth's atmosphere to biological cells. Because O2(a1Δg) can be produced and deactivated in processes that involve light, the photophysics of O2(a1Δg) are equally important. Moreover, pathways for O2(a1Δg) deactivation that regenerate O2(X3Σg-), which address fundamental principles unto themselves, kinetically compete with the chemical reactions of O2(a1Δg) and, thus, have practical significance. Due to technological advances (e.g., lasers, optical detectors, microscopes), data acquired in the past ∼20 years have increased our understanding of O2(a1Δg) photophysics appreciably and facilitated both spatial and temporal control over the behavior of O2(a1Δg). One goal of this Review is to summarize recent developments that have broad ramifications, focusing on systems in which oxygen forms a contact complex with an organic molecule M (e.g., a liquid solvent). An important concept is the role played by the M+•O2-• charge-transfer state in both the formation and deactivation of O2(a1Δg).
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Affiliation(s)
- Mikkel Bregnhøj
- Department of Chemistry, Aarhus University, 140 Langelandsgade, Aarhus 8000, Denmark
| | - Frederik Thorning
- Department of Chemistry, Aarhus University, 140 Langelandsgade, Aarhus 8000, Denmark
| | - Peter R Ogilby
- Department of Chemistry, Aarhus University, 140 Langelandsgade, Aarhus 8000, Denmark
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3
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Felčíková K, Hovan A, Polák M, Loginov DS, Holotová V, Díaz C, Kožár T, Lee O, Varhač R, Novák P, Bánó G, Sedlák E. Design of AsLOV2 domain as a carrier of light-induced dissociable FMN photosensitizer. Protein Sci 2024; 33:e4921. [PMID: 38501448 PMCID: PMC10949324 DOI: 10.1002/pro.4921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 01/09/2024] [Accepted: 01/25/2024] [Indexed: 03/20/2024]
Abstract
Flavin mononucleotide (FMN) is a highly efficient photosensitizer (PS) yielding singlet oxygen (1 O2 ). However, its 1 O2 production efficiency significantly decreases upon isoalloxazine ring encapsulation into the protein matrix in genetically encoded photosensitizers (GEPS). Reducing isoalloxazine ring interactions with surrounding amino acids by protein engineering may increase 1 O2 production efficiency GEPS, but at the same time weakened native FMN-protein interactions may cause undesirable FMN dissociation. Here, in contrast, we intentionally induce the FMN release by light-triggered sulfur oxidation of strategically placed cysteines (oxidation-prone amino acids) in the isoalloxazine-binding site due to significantly increased volume of the cysteinyl side residue(s). As a proof of concept, in three variants of the LOV2 domain of Avena sativa (AsLOV2), namely V416C, T418C, and V416C/T418C, the effective 1 O2 production strongly correlated with the efficiency of irradiation-induced FMN dissociation (wild type (WT) < V416C < T418C < V416C/T418C). This alternative approach enables us: (i) to overcome the low 1 O2 production efficiency of flavin-based GEPSs without affecting native isoalloxazine ring-protein interactions and (ii) to utilize AsLOV2, due to its inherent binding propensity to FMN, as a PS vehicle, which is released at a target by light irradiation.
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Affiliation(s)
- Kristína Felčíková
- Department of Biophysics, Faculty of ScienceP.J. Šafárik UniversityKošiceSlovakia
| | - Andrej Hovan
- Department of Biophysics, Faculty of ScienceP.J. Šafárik UniversityKošiceSlovakia
| | - Marek Polák
- Institute of Microbiology ‐ BioCeV, Academy of Sciences of the Czech RepublicPragueCzech Republic
- Department of Biochemistry, Faculty of ScienceCharles UniversityPragueCzech Republic
| | - Dmitry S. Loginov
- Institute of Microbiology ‐ BioCeV, Academy of Sciences of the Czech RepublicPragueCzech Republic
| | - Veronika Holotová
- Center for Interdisciplinary Biosciences, Technology and Innovation ParkP.J. Šafárik UniversityKošiceSlovakia
| | - Carlos Díaz
- Center for Interdisciplinary Biosciences, Technology and Innovation ParkP.J. Šafárik UniversityKošiceSlovakia
| | - Tibor Kožár
- Center for Interdisciplinary Biosciences, Technology and Innovation ParkP.J. Šafárik UniversityKošiceSlovakia
| | - One‐Sun Lee
- Center for Interdisciplinary Biosciences, Technology and Innovation ParkP.J. Šafárik UniversityKošiceSlovakia
| | - Rastislav Varhač
- Department of Biochemistry, Faculty of ScienceP.J. Šafárik UniversityKošiceSlovakia
| | - Petr Novák
- Institute of Microbiology ‐ BioCeV, Academy of Sciences of the Czech RepublicPragueCzech Republic
| | - Gregor Bánó
- Department of Biophysics, Faculty of ScienceP.J. Šafárik UniversityKošiceSlovakia
| | - Erik Sedlák
- Center for Interdisciplinary Biosciences, Technology and Innovation ParkP.J. Šafárik UniversityKošiceSlovakia
- Department of Biochemistry, Faculty of ScienceP.J. Šafárik UniversityKošiceSlovakia
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4
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Henke P, Rindom C, Kanta Aryal U, Frydenlund Jespersen M, Broløs L, Mansø M, Turkovic V, Madsen M, Mikkelsen KV, Ogilby PR, Brøndsted Nielsen M. Imparting Stability to Organic Photovoltaic Components through Molecular Engineering: Mitigating Reactions with Singlet Oxygen. CHEMSUSCHEM 2023:e202202320. [PMID: 36897647 DOI: 10.1002/cssc.202202320] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/08/2023] [Indexed: 06/18/2023]
Abstract
One key challenge in the development of viable organic photovoltaic devices is to design component molecules that do not degrade during combined exposure to oxygen and light. Such molecules should thus remain comparatively unreactive towards singlet molecular oxygen and not act as photosensitizers for the generation of this undesirable species. Here, novel redox-active chromophores that combine these two properties are presented. By functionalizing indenofluorene-extended tetrathiafulvalenes (IF-TTFs) with cyano groups at the indenofluorene core using Pd-catalyzed cyanation reactions, we find that the reactivity of the exocyclic fulvene carbon-carbon double bonds towards singlet oxygen is considerably reduced. The new cyano-functionalized IF-TTFs were tested in non-fullerene acceptor based organic photovoltaic proof-of-principle devices, revealing enhanced device stability.
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Affiliation(s)
- Petr Henke
- Department of Chemistry, University of Aarhus, Langelandsgade 140, DK-8000, Aarhus C, Denmark
| | - Cecilie Rindom
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100, Copenhagen Ø, Denmark
| | - Um Kanta Aryal
- Centre for Advanced Photovoltaics and Thin Film Energy Devices (SDU CAPE), Mads Clausen Institute, University of Southern Denmark, Alsion 2, DK-6400, Sønderborg, Denmark
| | | | - Line Broløs
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100, Copenhagen Ø, Denmark
| | - Mads Mansø
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100, Copenhagen Ø, Denmark
| | - Vida Turkovic
- Centre for Advanced Photovoltaics and Thin Film Energy Devices (SDU CAPE), Mads Clausen Institute, University of Southern Denmark, Alsion 2, DK-6400, Sønderborg, Denmark
| | - Morten Madsen
- Centre for Advanced Photovoltaics and Thin Film Energy Devices (SDU CAPE), Mads Clausen Institute, University of Southern Denmark, Alsion 2, DK-6400, Sønderborg, Denmark
| | - Kurt V Mikkelsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100, Copenhagen Ø, Denmark
| | - Peter R Ogilby
- Department of Chemistry, University of Aarhus, Langelandsgade 140, DK-8000, Aarhus C, Denmark
| | - Mogens Brøndsted Nielsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100, Copenhagen Ø, Denmark
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Blue Light Sensing BlsA-Mediated Modulation of Meropenem Resistance and Biofilm Formation in Acinetobacter baumannii. mSystems 2023; 8:e0089722. [PMID: 36622157 PMCID: PMC9948694 DOI: 10.1128/msystems.00897-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The presence or absence of BlsA, a protein with a blue light-sensing flavin domain in the genomes of Acinetobacter species has aroused curiosity about its roles in the regulation of bacterial lifestyle under light. Genomic and transcriptomic analyses revealed the loss of BlsA in several multidrug-resistant (MDR) A. baumannii strains as well as the light-mediated induction of blsA, along with a possible BlsA-interacting partner BipA. Their direct in vivo interactions were verified using a bacterial two-hybrid system. The results demonstrated that the C-terminal region of BipA could bind to the C-terminal residues of BlsA under blue light at 23°C but not at 37°C. Genetic manipulations of blsA and bipA revealed that the coexistence of BlsA and BipA was required to induce the light-dependent expression of ompA in A. baumannii ATCC 17978 at 23°C. The same phenomenon occurred in the BlsA-deficient MDR strain in our functional complementation assay; however, the underlying molecular mechanism remains poorly understood. BlsA-modulated amounts of OmpA, the most abundant porin, in the outer membrane affected the membrane integrity and permeability of small molecules. Dark conditions or the deletion of ompA made the membrane more permeable to lipophilic ethidium bromide (EtBr) but not to meropenem. Interestingly, light illumination and low temperature conditions made the cells more sensitive to meropenem; however, this bactericidal effect was not noted in the blsA mutant or in the BlsA-deficient MDR strains. Light-mediated cell death and the reduction of biofilm formation at 23°C were abolished in the blsA mutant strain, suggesting multifaceted roles of BlsA in A. baumannii strains. IMPORTANCE Little is known about the functional roles of BlsA and its interacting partners in Acinetobacter species. Intriguingly, no BlsA homolog was found in several clinical isolates, suggesting that BlsA was not required inside the host because of the lack of blue light and the warm temperature conditions. As many chromophore-harboring proteins interact with various partners to control light-dependent cellular behaviors, the maintenance of blsA in the genomes of many Acinetobacter species during their evolution may be beneficial when fluctuations occur in two important environmental factors: light and temperature. Our study is the first to report the novel protein partner of BlsA, namely, BipA, and its contribution to multiple phenotypic changes, including meropenem resistance and biofilm formation. Rapid physiological acclimation to changing light or temperature conditions may be possible in the presence of the light-sensing BlsA protein, which may have more interacting partners than expected.
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Ribes J, Cossard P, Al Yaman K, Bestel I, Badarau E. Investigating the photosensitization activities of flavins irradiated by blue LEDs. RSC Adv 2023; 13:2355-2364. [PMID: 36741136 PMCID: PMC9841770 DOI: 10.1039/d2ra07379j] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 01/05/2023] [Indexed: 01/19/2023] Open
Abstract
Due to their ability to easily absorb light and to generate highly reactive species, photosensitizers emerged as promising tools in a wide variety of physico-chemical and biological processes. Natural photosensitizers have the benefit of a life-compatible toxicological profile. Porphyrins and flavins are such examples that already proved their efficiency as photo-dynamic therapeutics. The present article describes a reliable, easy-to-implement, readily available and reproducible method that can be used to characterize the photosensitizing activity of flavins. Several key factors were investigated during this study, the optimum parameters were: (i) a blue LED light source (λ em = 455 nm) at 6.69 mW; (ii) a pH of 6 mimicking the tumoral environment; (iii) an air-saturated atmosphere reaction medium, (iv) a tetrazolium dye (MTT) was used to monitor the photosensitization efficacy via the generation of the colored MTT-formazan product. This method can be used to rank a series of flavins based on their photosensitizing activities. Such structure-photosensitization activity relationships are essential for the discovery of future potent photosensitizers for photodynamic therapy.
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Affiliation(s)
- Jonathan Ribes
- University of Bordeaux, CNRS, CBMN, UMR 5248, Institute of Chemistry and Biology of Membranes & Nano-objects (CBMN)Allée Geoffroy Saint Hilaire, Bât B1433600 PessacFrance
| | - Pauline Cossard
- University of Bordeaux, CNRS, CBMN, UMR 5248, Institute of Chemistry and Biology of Membranes & Nano-objects (CBMN)Allée Geoffroy Saint Hilaire, Bât B1433600 PessacFrance
| | - Khaled Al Yaman
- University of Bordeaux, CNRS, CBMN, UMR 5248, Institute of Chemistry and Biology of Membranes & Nano-objects (CBMN)Allée Geoffroy Saint Hilaire, Bât B1433600 PessacFrance
| | - Isabelle Bestel
- University of Bordeaux, CNRS, CBMN, UMR 5248, Institute of Chemistry and Biology of Membranes & Nano-objects (CBMN)Allée Geoffroy Saint Hilaire, Bât B1433600 PessacFrance
| | - Eduard Badarau
- University of Bordeaux, CNRS, CBMN, UMR 5248, Institute of Chemistry and Biology of Membranes & Nano-objects (CBMN)Allée Geoffroy Saint Hilaire, Bât B1433600 PessacFrance
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7
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Hovan A, Sedláková D, Berta M, Bánó G, Sedlák E. Singlet oxygen quenching as a probe for cytochrome c molten globule state formation. Phys Chem Chem Phys 2022; 24:13317-13324. [PMID: 35608043 DOI: 10.1039/d2cp01281b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Singlet oxygen refers to the nonradical metastable excited state of molecular oxygen that readily oxidizes various cellular components. Its behavior in different biological systems has been studied for many years. Recently, we analyzed the effect of singlet oxygen quenching by heme cofactor in cytochrome c (cyt c). Here, we have exploited this effect in the investigation of conformational differences in the molten globule states of cyt c induced by different sodium anions, namely sulfate, chloride and perchlorate. The high efficiency of heme toward quenching singlet oxygen enabled us to use this property for the analysis of the otherwise experimentally difficult-to-determine parameter of heme upon exposure to solvents as highly similar conformational states of cyt c in the molten globule states are induced by different salts at acidic pH. Our results from singlet oxygen quenching experiments correlate well with other spectroscopic methods, such as circular dichroism and fluorescence measurements, and suggest increasing availability of heme in the order: perchlorate < chloride < sulfate. Based on our findings we propose that singlet oxygen phosphorescence measurements are useful in determining the differences in the protein conformation of their heme regions, particularly regarding the relative heme exposure to the solvent.
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Affiliation(s)
- Andrej Hovan
- Department of Biophysics, Faculty of Science, P. J. Šafárik University in Košice, Jesenná 5, 041 54 Košice, Slovakia
| | - Dagmar Sedláková
- Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Košice, Slovakia
| | - Martin Berta
- Department of Biophysics, Faculty of Science, P. J. Šafárik University in Košice, Jesenná 5, 041 54 Košice, Slovakia
| | - Gregor Bánó
- Department of Biophysics, Faculty of Science, P. J. Šafárik University in Košice, Jesenná 5, 041 54 Košice, Slovakia
| | - Erik Sedlák
- Center for Interdisciplinary Biosciences, Technology and Innovation Park, P. J. Šafárik University in Košice, Jesenná 5, 041 54 Košice, Slovakia
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Zerlotti R, Losi A, Polverini E. Oxygen diffusion pathways in mutated forms of a LOV photoreceptor from Methylobacterium radiotolerans: A molecular dynamics study. Biomol Concepts 2022; 13:164-174. [DOI: 10.1515/bmc-2022-0013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 03/08/2022] [Indexed: 11/15/2022] Open
Abstract
Abstract
Mr4511 from Methylobacterium radiotolerans is a photoreceptor of the light, oxygen voltage (LOV) family, binding flavin mononucleotide (FMN) as a chromophore. It exhibits the prototypical LOV photocycle, with the reversible formation of an FMN-Cys71 adduct via fast decay of the FMN triplet state. Mr4511 has high potential as a photosensitiser for singlet oxygen (SO) upon mutation of C71. Mr4511-C71S shows a triplet lifetime (τ
T) of several hundreds of microseconds, ensuring efficient energy transfer to dioxygen to form SO. In this work, we have explored the potential diffusion pathways for dioxygen within Mr4511 using molecular dynamics (MD) simulations. The structural model of wild-type (wt) Mr4511 showed a dimeric structure stabilised by a strong leucine zipper at the two C-terminal helical ends. We then introduced in silico the C71S mutation and analysed transient and persistent oxygen channels. MD simulations indicate that the chromophore binding site is highly accessible to dioxygen. Mutations that might favour SO generation were designed based on their position with respect to FMN and the oxygen channels. In particular, the C71S-Y61T and C71S-Y61S variants showed an increased diffusion and persistence of oxygen molecules inside the binding cavity.
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Affiliation(s)
- Rocco Zerlotti
- NeuroTrans ETN Network c/o Nanion Technologies GmbH, Ganghoferstraße 70/a , 80339 München , Bayern , Germany
- Department of Mathematical, Physical and Computer Sciences, University of Parma, Parco Area delle Scienze 7/A , 43124 Parma , Italy
| | - Aba Losi
- Department of Mathematical, Physical and Computer Sciences, University of Parma, Parco Area delle Scienze 7/A , 43124 Parma , Italy
| | - Eugenia Polverini
- Department of Mathematical, Physical and Computer Sciences, University of Parma, Parco Area delle Scienze 7/A , 43124 Parma , Italy
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9
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Mogensen DJ, Etzerodt M, Ogilby PR. Photoinduced Bleaching in an Efficient Singlet Oxygen Photosensitizing Protein: Identifying a Culprit in the Flavin-Binding LOV-Based Protein SOPP3. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2022.113894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Lafaye C, Aumonier S, Torra J, Signor L, von Stetten D, Noirclerc-Savoye M, Shu X, Ruiz-González R, Gotthard G, Royant A, Nonell S. Riboflavin-binding proteins for singlet oxygen production. Photochem Photobiol Sci 2022; 21:1545-1555. [PMID: 35041199 DOI: 10.1007/s43630-021-00156-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 12/07/2021] [Indexed: 12/27/2022]
Abstract
miniSOG, developed as the first fully genetically encoded singlet oxygen photosensitiser, has found various applications in cell imaging and functional studies. Yet, miniSOG has suboptimal properties, including a low yield of singlet oxygen generation, which can nevertheless be improved tenfold upon blue light irradiation. In a previous study, we showed that this improvement was due to the photolysis of the miniSOG chromophore, flavin mononucleotide (FMN), into lumichrome, with concomitant removal of the phosphoribityl tail, thereby improving oxygen access to the alloxazine ring. We thus reasoned that a chromophore with a shorter tail would readily improve the photosensitizing properties of miniSOG. In this work, we show that the replacement of FMN by riboflavin (RF), which lacks the bulky phosphate group, significantly improves the singlet oxygen quantum yield (ΦΔ). We then proceeded to mutagenize the residues stabilizing the phosphate group of FMN to alter the chromophore specificity. We identified miniSOG-R57Q as a flavoprotein that selectively binds RF in cellulo, with a modestly improved ΦΔ. Our results show that it is possible to modify the flavin specificity of a given flavoprotein, thus providing a new option to tune its photophysical properties, including those leading to photosensitization. We also determined the structure of miniSOG-Q103L, a mutant with a much increased ΦΔ, which allowed us to postulate the existence of another access channel to FMN for molecular oxygen.
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Affiliation(s)
- Céline Lafaye
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), 71 Avenue des Martyrs, 38044, Grenoble Cedex 9, France
| | - Sylvain Aumonier
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38043, Grenoble Cedex 9, France
| | - Joaquim Torra
- Institut Químic de Sarrià, Universitat Ramon Llull, Via Augusta 390, 08017, Barcelona, Spain
| | - Luca Signor
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), 71 Avenue des Martyrs, 38044, Grenoble Cedex 9, France
| | - David von Stetten
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38043, Grenoble Cedex 9, France
| | - Marjolaine Noirclerc-Savoye
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), 71 Avenue des Martyrs, 38044, Grenoble Cedex 9, France
| | - Xiaokun Shu
- Department of Pharmaceutical Chemistry, University of California-San Francisco, San Francisco, CA, 94158-9001, USA.,Cardiovascular Research Institute, University of California-San Francisco, San Francisco, CA, 94158-9001, USA
| | - Rubén Ruiz-González
- Institut Químic de Sarrià, Universitat Ramon Llull, Via Augusta 390, 08017, Barcelona, Spain
| | - Guillaume Gotthard
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38043, Grenoble Cedex 9, France
| | - Antoine Royant
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), 71 Avenue des Martyrs, 38044, Grenoble Cedex 9, France. .,European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38043, Grenoble Cedex 9, France.
| | - Santi Nonell
- Institut Químic de Sarrià, Universitat Ramon Llull, Via Augusta 390, 08017, Barcelona, Spain.
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Ding Y, Zhao Z, Matysik J, Gärtner W, Losi A. Mapping the role of aromatic amino acids within a blue-light sensing LOV domain. Phys Chem Chem Phys 2021; 23:16767-16775. [PMID: 34319324 DOI: 10.1039/d1cp02217b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Photosensing LOV (Light, Oxygen, Voltage) domains detect and respond to UVA/Blue (BL) light by forming a covalent adduct between the flavin chromophore and a nearby cysteine, via the decay of the flavin triplet excited state. LOV domains where the reactive cysteine has been mutated are valuable fluorescent tools for microscopy and as genetically encoded photosensitisers for reactive oxygen species. Besides being convenient tools for applications, LOV domains without the reactive cysteine (naturally occurring or engineered) can still be functionally photoactivated via formation of a neutral flavin radical. Tryptophans and tyrosines are held as the main partners as potential electron donors to the flavin excited states. In this work, we explore the relevance of aromatic amino acids in determining the photophysical features of the LOV protein Mr4511 from Methylobacterium radiotolerans by introducing point mutations into the C71S variant that does not form the covalent adduct. By using an array of spectroscopic techniques we measured the fluorescence quantum yields and lifetimes, the triplet yields and lifetimes, and the efficiency of singlet oxygen (SO) formation for eleven Mr4511 variants. Insertion of Trp residues at distances between 0.6 and 1.5 nm from the flavin chromophore results in strong quenching of the flavin excited triplet state and, at the shorter distances even of the singlet excited state. The mutation F130W (ca. 0.6 nm) completely quenches the singlet excited state, preventing triplet formation: in this case, even if the cysteine is present, the photo-adduct is not formed. Tyrosines are also quenchers for the flavin excited states, although not as efficient as Trp residues, as demonstrated with their substitution with the inert phenylalanine. For one of these variants, C71S/Y116F, we found that the quantum yield of formation for singlet oxygen is 0.44 in aqueous aerobic solution, vs 0.17 for C71S. Based on our study with Mr4511 and on literature data for other LOV domains we suggest that Trp and Tyr residues too close to the flavin chromophore (at distances less than 0.9 nm) reduce the yield of photoproduct formation and that introduction of inert Phe residues in key positions can help in developing efficient, LOV-based photosensitisers.
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Affiliation(s)
- Yonghong Ding
- Institute for Analytical Chemistry, University of Leipzig, Linnéstrasse 3, 04103 Leipzig, Germany
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12
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Lang Y, Wu S, Yang Q, Luo Y, Jiang X, Wu P. Analysis of the Isotopic Purity of D 2O with the Characteristic NIR-II Phosphorescence of Singlet Oxygen from a Photostable Polythiophene Photosensitizer. Anal Chem 2021; 93:9737-9743. [PMID: 34235917 DOI: 10.1021/acs.analchem.1c01160] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
D2O plays important roles in a variety of fields (such as the nuclear industry and bioorganic analysis), and thus its isotopic purity (H2O contents) is highly concerned. Due to its highly similar physical properties to H2O and large excess amounts of H2O over D2O, it is challenging to distinguish D2O from H2O. On the basis of the characteristic NIR-II phosphorescence of singlet oxygen (1O2), and the fact that H2O is a more efficient quencher for 1O2 than D2O, here, we proposed to simply use the 1275 nm emission of 1O2 for the analysis of the isotopic purity of D2O. In normal cases (a xenon lamp for excitation), such steady-state emission is extremely weak for valid analytical applications, we thus employed laser excitation for intensification. To this goal, a series of photosensitizers were screened, and eventually polythiophene PT10 was selected with high singlet oxygen quantum yield (ΦΔ = 0.51), high H2O/D2O contrast, and excellent photostability. Upon excitation with a 445 nm laser, a limit of detection (LOD, 3σ) of 0.1% for H2O in D2O was achieved. The accuracy of the proposed method was verified by the analysis of the isotopic purity of several D2O samples (with randomly added H2O). More interestingly, the hygroscopicity of D2O was sensitively monitored with the proposed probe in a real-time manner; the results of which are important for strengthening the care of D2O storage and the importance of humidity control during related investigations. Besides D2O isotopic purity evaluation, this work also indicated the potential usefulness of the NIR-II emission of singlet oxygen in future analytical detection.
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Gurruchaga-Pereda J, Martínez-Martínez V, Formoso E, Azpitarte O, Rezabal E, Lopez X, Cortajarena AL, Salassa L. Enhancing the Photocatalytic Conversion of Pt(IV) Substrates by Flavoprotein Engineering. J Phys Chem Lett 2021; 12:4504-4508. [PMID: 33960797 DOI: 10.1021/acs.jpclett.1c00802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Our recent work demonstrates that certain flavoproteins can catalyze the redox activation of Pt(IV) prodrug complexes under light irradiation. Herein, we used site-directed mutagenesis on the mini singlet oxygen generator (mSOG) to modulate the photocatalytic activity of this flavoprotein toward two model Pt(IV) substrates. Among the prepared mutants, Q103V mSOG displayed enhanced catalytic efficiency as a result of its longer triplet excited-state lifetime. This study shows, for the first time, that protein engineering can improve the catalytic capacity of a protein toward metal-containing substrates.
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Affiliation(s)
- Juan Gurruchaga-Pereda
- Donostia International Physics Center, Paseo Manuel de Lardizabal 4, Donostia 20018, Spain
- Center for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA), Paseo de Miramón 194, Donostia, San Sebastián 20014, Spain
| | | | - Elena Formoso
- Donostia International Physics Center, Paseo Manuel de Lardizabal 4, Donostia 20018, Spain
- Kimika Fisikoa, Farmazia Fakultatea, Euskal Herriko Unibertsitatea UPV/EHU, Paseo de la Universidad 7, Vitoria-Gasteiz 01006, Spain
| | - Oksana Azpitarte
- Donostia International Physics Center, Paseo Manuel de Lardizabal 4, Donostia 20018, Spain
- Polimero eta Material Aurreratuak: Fisika, Kimika eta Teknologia, Kimika Fakultatea, Euskal Herriko Unibertsitatea UPV/EHU, Paseo Manuel de Lardizabal 3, Donostia 20018, Spain
| | - Elixabete Rezabal
- Donostia International Physics Center, Paseo Manuel de Lardizabal 4, Donostia 20018, Spain
- Polimero eta Material Aurreratuak: Fisika, Kimika eta Teknologia, Kimika Fakultatea, Euskal Herriko Unibertsitatea UPV/EHU, Paseo Manuel de Lardizabal 3, Donostia 20018, Spain
| | - Xabier Lopez
- Donostia International Physics Center, Paseo Manuel de Lardizabal 4, Donostia 20018, Spain
- Polimero eta Material Aurreratuak: Fisika, Kimika eta Teknologia, Kimika Fakultatea, Euskal Herriko Unibertsitatea UPV/EHU, Paseo Manuel de Lardizabal 3, Donostia 20018, Spain
| | - Aitziber L Cortajarena
- Center for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA), Paseo de Miramón 194, Donostia, San Sebastián 20014, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao 48011, Spain
| | - Luca Salassa
- Donostia International Physics Center, Paseo Manuel de Lardizabal 4, Donostia 20018, Spain
- Polimero eta Material Aurreratuak: Fisika, Kimika eta Teknologia, Kimika Fakultatea, Euskal Herriko Unibertsitatea UPV/EHU, Paseo Manuel de Lardizabal 3, Donostia 20018, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao 48011, Spain
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Mogensen DJ, Westberg M, Breitenbach T, Etzerodt M, Ogilby PR. Stable Transfection of the Singlet Oxygen Photosensitizing Protein SOPP3: Examining Aspects of Intracellular Behavior †. Photochem Photobiol 2021; 97:1417-1430. [PMID: 33934354 DOI: 10.1111/php.13440] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 04/26/2021] [Indexed: 01/28/2023]
Abstract
Protein-encased chromophores that photosensitize the production of reactive oxygen species, ROS, have been the center of recent activity in studies of oxidative stress. One potential attribute of such systems is that the local environment surrounding the chromophore, and that determines the chromophore's photophysics, ideally remains constant and independent of the global environment into which the system is placed. Therefore, a protein-encased sensitizer localized in the mitochondria would arguably have the same photophysics as that protein-encased sensitizer at the plasma membrane, for example. One thus obtains a useful tool to study processes modulated by spatially localized ROS. One ROS of interest is singlet oxygen, O2 (a1 Δg ). We recently developed a singlet oxygen photosensitizing protein, SOPP, in which flavin mononucleotide, FMN, is encased in a re-engineered light-oxygen-voltage protein. One goal was to ascertain how a version of this system, SOPP3, which selectively makes O2 (a1 Δg ), in vitro, behaves in a cell. We now demonstrate that SOPP3 undergoes exacerbated irradiation-mediated bleaching when expressed at either the plasma membrane or mitochondria in stable cell lines. We find that the environment around the SOPP3 system affects the bleaching rate, which argues against one of the key suppositions in support of a protein-encased chromophore.
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Affiliation(s)
| | | | | | - Michael Etzerodt
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Peter R Ogilby
- Department of Chemistry, Aarhus University, Aarhus, Denmark
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15
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Dichmann L, Bregnhøj M, Liu H, Westberg M, Poulsen TB, Etzerodt M, Ogilby PR. Photophysics of a protein-bound derivative of malachite green that sensitizes the production of singlet oxygen. Photochem Photobiol Sci 2021; 20:435-449. [DOI: 10.1007/s43630-021-00032-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 02/23/2021] [Indexed: 12/25/2022]
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16
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Diaz D, Vidal X, Sunna A, Care A. Bioengineering a Light-Responsive Encapsulin Nanoreactor: A Potential Tool for In Vitro Photodynamic Therapy. ACS APPLIED MATERIALS & INTERFACES 2021; 13:7977-7986. [PMID: 33586952 DOI: 10.1021/acsami.0c21141] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Encapsulins, a prokaryotic class of self-assembling protein nanocompartments, are being re-engineered to serve as "nanoreactors" for the augmentation or creation of key biochemical reactions. However, approaches that allow encapsulin nanoreactors to be functionally activated with spatial and temporal precision are lacking. We report the construction of a light-responsive encapsulin nanoreactor for "on demand" production of reactive oxygen species (ROS). Herein, encapsulins were loaded with the fluorescent flavoprotein mini-singlet oxygen generator (miniSOG), a biological photosensitizer that is activated by blue light to generate ROS, primarily singlet oxygen (1O2). We established that the nanocompartments stably encased miniSOG and in response to blue light were able to mediate the photoconversion of molecular oxygen into ROS. Using an in vitro model of lung cancer, we showed that ROS generated by the nanoreactor triggered photosensitized oxidation reactions which exerted a toxic effect on tumor cells, suggesting utility in photodynamic therapy. This encapsulin nanoreactor thus represents a platform for the light-controlled initiation and/or modulation of ROS-driven processes in biomedicine and biotechnology.
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Affiliation(s)
- Dennis Diaz
- Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Xavier Vidal
- Fraunhofer Institut für Angewandte Festkörperphysik (IAF), Tullastrasse 72, 79108 Freiburg, Germany
| | - Anwar Sunna
- Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
- ARC Centre of Excellence for Nanoscale BioPhotonics, Macquarie University, Sydney, NSW 2109, Australia
| | - Andrew Care
- ARC Centre of Excellence for Nanoscale BioPhotonics, Macquarie University, Sydney, NSW 2109, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW 2109, Australia
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW 2007, Australia
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17
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Oxygen- and pH-Dependent Photophysics of Fluorinated Fluorescein Derivatives: Non-Symmetrical vs. Symmetrical Fluorination. SENSORS 2020; 20:s20185172. [PMID: 32927830 PMCID: PMC7570907 DOI: 10.3390/s20185172] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/02/2020] [Accepted: 09/07/2020] [Indexed: 11/23/2022]
Abstract
Fluorescein, and derivatives of fluorescein, are often used as fluorescent probes and sensors. In systems where pH is a variable, protonation/deprotonation of the molecule can influence the pertinent photophysics. Fluorination of the xanthene moiety can alter the molecule’s pKa such as to render a probe whose photophysics remains invariant over a wide pH range. Di-fluorination is often sufficient to accomplish this goal, as has been demonstrated with compounds such as Oregon Green in which the xanthene moiety is symmetrically difluorinated. In this work, we synthesized a non-symmetrical difluorinated analog of Oregon Green which we call Athens Green. We ascertained that the photophysics and photochemistry of Athens Green, including the oxygen-dependent photophysics that results in the sensitized production of singlet oxygen, O2(a1Δg), can differ appreciably from the photophysics of Oregon Green. Our data indicate that Athens Green will be a more benign fluorescent probe in systems that involve the production and removal of O2(a1Δg). These results expand the available options in the toolbox of fluorescein-based fluorophores.
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18
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Carroll L, Gardiner K, Ignasiak M, Holmehave J, Shimodaira S, Breitenbach T, Iwaoka M, Ogilby PR, Pattison DI, Davies MJ. Interaction kinetics of selenium-containing compounds with oxidants. Free Radic Biol Med 2020; 155:58-68. [PMID: 32439383 DOI: 10.1016/j.freeradbiomed.2020.05.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 05/07/2020] [Accepted: 05/10/2020] [Indexed: 02/03/2023]
Abstract
Selenium compounds have been identified as potential oxidant scavengers for biological applications due to the nucleophilicity of Se, and the ease of oxidation of the selenium centre. Previous studies have reported apparent second order rate constants for a number of oxidants (e.g. HOCl, ONOOH) with some selenium species, but these data are limited. Here we provide apparent second order rate constants for reaction of selenols (RSeH), selenides (RSeR') and diselenides (RSeSeR') with biologically-relevant oxidants (HOCl, H2O2, other peroxides) as well as overall consumption data for the excited state species singlet oxygen (1O2). Selenols show very high reactivity with HOCl and 1O2, with rate constants > 108 M-1 s-1, whilst selenides and diselenides typically react with rate constants one- (selenides) or two- (diselenides) orders of magnitude slower. Rate constants for reaction of diselenides with H2O2 and other hydroperoxides are much slower, with k for H2O2 being <1 M-1 s-1, and for amino acid and peptide hydroperoxides ~102 M-1 s-1. The rate constants determined for HOCl and 1O2 with these selenium species are greater than, or similar to, rate constants for amino acid side chains on proteins, including the corresponding sulfur-centered species (Cys and Met), suggesting that selenium containing compounds may be effective oxidant scavengers. Some of these reactions may be catalytic in nature due to ready recycling of the oxidized selenium species. These data may aid the development of highly efficacious, and catalytic, oxidant scavengers.
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Affiliation(s)
- Luke Carroll
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - Kelly Gardiner
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark; The Heart Research Institute, Sydney, Australia; Sydney Medical School, University of Sydney, Australia
| | - Marta Ignasiak
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark; Department of Chemistry, Adam Mickiewicz University, Poznan, Poland
| | | | - Shingo Shimodaira
- Brain Korea (BK21), Dept. of Chemistry, KAIST 373-1, Daejeon, South Korea
| | | | - Michio Iwaoka
- Department of Chemistry, Tokai University, Hiratsuka, Japan
| | - Peter R Ogilby
- Department of Chemistry, Aarhus University, Aarhus, Denmark
| | - David I Pattison
- The Heart Research Institute, Sydney, Australia; Sydney Medical School, University of Sydney, Australia; Department of Plant and Environmental Sciences, University of Copenhagen, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark; The Heart Research Institute, Sydney, Australia; Sydney Medical School, University of Sydney, Australia.
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19
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Photoinduced damage of AsLOV2 domain is accompanied by increased singlet oxygen production due to flavin dissociation. Sci Rep 2020; 10:4119. [PMID: 32139757 PMCID: PMC7058016 DOI: 10.1038/s41598-020-60861-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 02/13/2020] [Indexed: 01/05/2023] Open
Abstract
Flavin mononucleotide (FMN) belongs to the group of very efficient endogenous photosensitizers producing singlet oxygen, 1O2, but with limited ability to be targeted. On the other hand, in genetically-encoded photosensitizers, which can be targeted by means of various tags, the efficiency of FMN to produce 1O2 is significantly diminished due to its interactions with surrounding amino acid residues. Recently, an increase of 1O2 production yield by FMN buried in a protein matrix was achieved by a decrease of quenching of the cofactor excited states by weakening of the protein-FMN interactions while still forming a complex. Here, we suggest an alternative approach which relies on the blue light irradiation-induced dissociation of FMN to solvent. This dissociation unlocks the full capacity of FMN as 1O2 producer. Our suggestion is based on the study of an irradiation effect on two variants of the LOV2 domain from Avena sativa; wild type, AsLOV2 wt, and the variant with a replaced cysteine residue, AsLOV2 C450A. We detected irradiation-induced conformational changes as well as oxidation of several amino acids in both AsLOV2 variants. Detailed analysis of these observations indicates that irradiation-induced increase in 1O2 production is caused by a release of FMN from the protein. Moreover, an increased FMN dissociation from AsLOV2 wt in comparison with AsLOV2 C450A points to a role of C450 oxidation in repelling the cofactor from the protein.
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20
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Petrenčáková M, Varhač R, Kožár T, Nemergut M, Jancura D, Schwer MS, Sedlák E. Conformational properties of LOV2 domain and its C450A variant within broad pH region. Biophys Chem 2020; 259:106337. [PMID: 32126442 DOI: 10.1016/j.bpc.2020.106337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 02/03/2020] [Accepted: 02/24/2020] [Indexed: 11/28/2022]
Abstract
LOV2 (Light-Oxygen-Voltage) domain from Avena sativa phototropin 1 (AsLOV2) belongs to the superfamily of PAS (Per-Arnt-Sim) domains, members of which function as signaling sensors. AsLOV2 undergoes a conformational change upon blue-light absorption by its FMN cofactor. AsLOV2 wild type (wt) is intensively studied as a photo-switchable element in conjugation with various proteins. On the other hand, its variant AsLOV2 with replaced cysteinyl residue C450, which is critical for the forming a covalent adduct with FMN upon irradiation, forms a precursor for some recently developed genetically encoded photosensitizers. In the presented work, we investigated conformational properties of AsLOV2 wt and its variant C450A by circular dichroism, tryptophan and FMN fluorescence, and differential scanning calorimetry in dependence on pH and temperature. We show that both variants are similarly sensitive towards pH of solvent. On the other hand, the mutation C450A leads to a more stable AsLOV2 variant in comparison with the wild type. Thermal transitions of the AsLOV2 proteins monitored by circular dichroism indicate the presence of significant residual structure in thermally-denatured states of both proteins in the pH range from 4 to 9. Both pH- and thermal- transitions of AsLOV2 are accompanied by FMN leaching to solvent. Higher stability, reversibility of thermal transitions, and efficiency of FMN rebinding in the case of C450A variant suggest that the cofactor release may be modulated by suitable mutations in combination with a suitable physicochemical perturbation. These findings can have implications for a design of genetically encoded photosensitizers.
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Affiliation(s)
- Martina Petrenčáková
- Department of Biophysics, Faculty of Science, P.J. Šafárik University, Jesenná 5, 041 54 Košice, Slovakia
| | - Rastislav Varhač
- Department of Biochemistry, Faculty of Science, P.J. Šafárik University, Moyzesova 11, 041 54 Košice, Slovakia
| | - Tibor Kožár
- Center for Interdisciplinary Biosciences, Technology and Innovation Park, P.J. Šafárik University, Jesenná 5, 041 54 Košice, Slovakia
| | - Michal Nemergut
- Center for Interdisciplinary Biosciences, Technology and Innovation Park, P.J. Šafárik University, Jesenná 5, 041 54 Košice, Slovakia
| | - Daniel Jancura
- Department of Biophysics, Faculty of Science, P.J. Šafárik University, Jesenná 5, 041 54 Košice, Slovakia; Center for Interdisciplinary Biosciences, Technology and Innovation Park, P.J. Šafárik University, Jesenná 5, 041 54 Košice, Slovakia
| | - Marc-Simon Schwer
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Erik Sedlák
- Department of Biochemistry, Faculty of Science, P.J. Šafárik University, Moyzesova 11, 041 54 Košice, Slovakia; Center for Interdisciplinary Biosciences, Technology and Innovation Park, P.J. Šafárik University, Jesenná 5, 041 54 Košice, Slovakia.
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21
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Khalitova LR, Grabovskii SA, Kabal’nova NN. Formation of Singlet Oxygen during Thermal Degradation of Hydrotrioxides of Triorganosilanes. HIGH ENERGY CHEMISTRY 2020. [DOI: 10.1134/s0018143919060109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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22
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Bregnhøj M, Prete M, Turkovic V, Petersen AU, Nielsen MB, Madsen M, Ogilby PR. Oxygen-dependent photophysics and photochemistry of prototypical compounds for organic photovoltaics: inhibiting degradation initiated by singlet oxygen at a molecular level. Methods Appl Fluoresc 2019; 8:014001. [DOI: 10.1088/2050-6120/ab4edc] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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23
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Consiglieri E, Xu Q, Bregnhøj M, Westberg M, Ogilby PR, Losi A. Single mutation in a novel bacterial LOV protein yields a singlet oxygen generator. Photochem Photobiol Sci 2019; 18:2657-2660. [PMID: 31624823 DOI: 10.1039/c9pp00328b] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Mr4511 from Methylobacterium radiotolerans is a 164 amino acid protein built of a flavin mononucleotide (FMN) binding, blue-light responsive LOV (Light, Oxygen, Voltage) core domain plus flanking regions. In contrast to the majority of LOV domains, Mr4511 lacks a tryptophan residue that was previously identified as a major quencher for the FMN triplet state in photosensitizers for singlet oxygen (SO) engineered from these photoreceptors. Here we show that for Mr4511 it is sufficient to only mutate the reactive cysteine responsible for the photocycle (Cys71) in the native protein to generate an efficient SO photosensitizer: both C71S and C71G variants exhibit SO quantum yields of formation, ΦΔ, around 0.2 in air-saturated solutions. Under oxygen saturated conditions, ΦΔ reaches ∼0.5 in deuterated buffer. The introduction of Trp112 in the canonical position for LOV domains dramatically lowers ΦΔ to values comparable to miniSOG, one of the early FMN binding proteins touted as a SO sensitizer. Besides its SO properties, Mr4511 is also exceedingly robust against denaturation with urea and is more photostable than free FMN.
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Affiliation(s)
- Eleonora Consiglieri
- Department of Mathematical, Physical and Computer Sciences, University of Parma, Parco Area delle Scienze 7/A, 43124 Parma, Italy.
| | - Qianzhao Xu
- Institute for Analytical Chemistry, University of Leipzig, Linnéstrasse 3, 04103 Leipzig, Germany and State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Mikkel Bregnhøj
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
| | - Michael Westberg
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
| | - Peter R Ogilby
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
| | - Aba Losi
- Department of Mathematical, Physical and Computer Sciences, University of Parma, Parco Area delle Scienze 7/A, 43124 Parma, Italy.
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Bregnhøj M, Ogilby PR. Two-Photon Excitation of Neat Aerated Solvents with Visible Light Produces Singlet Oxygen. J Phys Chem A 2019; 123:7567-7575. [DOI: 10.1021/acs.jpca.9b05517] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Mikkel Bregnhøj
- Chemistry Department, Aarhus University, DK-8000 Aarhus, Denmark
| | - Peter R. Ogilby
- Chemistry Department, Aarhus University, DK-8000 Aarhus, Denmark
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25
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Westberg M, Etzerodt M, Ogilby PR. Rational design of genetically encoded singlet oxygen photosensitizing proteins. Curr Opin Struct Biol 2019; 57:56-62. [DOI: 10.1016/j.sbi.2019.01.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 01/14/2019] [Accepted: 01/29/2019] [Indexed: 01/29/2023]
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26
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Torra J, Lafaye C, Signor L, Aumonier S, Flors C, Shu X, Nonell S, Gotthard G, Royant A. Tailing miniSOG: structural bases of the complex photophysics of a flavin-binding singlet oxygen photosensitizing protein. Sci Rep 2019; 9:2428. [PMID: 30787421 PMCID: PMC6382843 DOI: 10.1038/s41598-019-38955-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 01/11/2019] [Indexed: 11/15/2022] Open
Abstract
miniSOG is the first flavin-binding protein that has been developed with the specific aim of serving as a genetically-encodable light-induced source of singlet oxygen (1O2). We have determined its 1.17 Å resolution structure, which has allowed us to investigate its mechanism of photosensitization using an integrated approach combining spectroscopic and structural methods. Our results provide a structural framework to explain the ability of miniSOG to produce 1O2 as a competition between oxygen- and protein quenching of its triplet state. In addition, a third excited-state decay pathway has been identified that is pivotal for the performance of miniSOG as 1O2 photosensitizer, namely the photo-induced transformation of flavin mononucleotide (FMN) into lumichrome, which increases the accessibility of oxygen to the flavin FMN chromophore and makes protein quenching less favourable. The combination of the two effects explains the increase in the 1O2 quantum yield by one order of magnitude upon exposure to blue light. Besides, we have identified several surface electron-rich residues that are progressively photo-oxidized, further contributing to facilitate the production of 1O2. Our results help reconcile the apparent poor level of 1O2 generation by miniSOG and its excellent performance in correlative light and electron microscopy experiments.
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Affiliation(s)
- Joaquim Torra
- Institut Químic de Sarrià, Universitat Ramon Llull, Via Augusta 390, Barcelona, 08017, Spain
| | - Céline Lafaye
- Univ. Grenoble Alpes, CNRS, CEA, IBS (Institut de Biologie Structurale), F-38000, Grenoble, France
| | - Luca Signor
- Univ. Grenoble Alpes, CNRS, CEA, IBS (Institut de Biologie Structurale), F-38000, Grenoble, France
| | - Sylvain Aumonier
- European Synchrotron Radiation Facility, F-38043, Grenoble, France
| | - Cristina Flors
- Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanoscience), Ciudad Universitaria de Cantoblanco, C/Faraday 9, 28049, Madrid, Spain.,Nanobiotechnology Unit Associated to the National Center for Biotechnology (CNB-CSIC-IMDEA), Ciudad Universitaria de Cantoblanco, 28049, Madrid, Spain
| | - Xiaokun Shu
- Department of Pharmaceutical Chemistry, University of California-San Francisco, San Francisco, California, 94158-9001, United States.,Cardiovascular Research Institute, University of California-San Francisco, San Francisco, California, 94158-9001, United States
| | - Santi Nonell
- Institut Químic de Sarrià, Universitat Ramon Llull, Via Augusta 390, Barcelona, 08017, Spain.
| | | | - Antoine Royant
- Univ. Grenoble Alpes, CNRS, CEA, IBS (Institut de Biologie Structurale), F-38000, Grenoble, France. .,European Synchrotron Radiation Facility, F-38043, Grenoble, France.
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Bregnhøj M, Strunge K, Sørensen RJ, Ströbele M, Hummel T, Meyer HJ, Jensen F, Ogilby PR. Tungsten Iodide Clusters as Singlet Oxygen Photosensitizers: Exploring the Domain of Resonant Energy Transfer at 1 eV. J Phys Chem A 2019; 123:1730-1739. [DOI: 10.1021/acs.jpca.9b00541] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mikkel Bregnhøj
- Department of Chemistry, Aarhus University, 8000 Aarhus, Denmark
| | - Kris Strunge
- Department of Chemistry, Aarhus University, 8000 Aarhus, Denmark
| | | | - Markus Ströbele
- Department of Inorganic Chemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Thorsten Hummel
- Department of Inorganic Chemistry, University of Tübingen, 72076 Tübingen, Germany
| | - H.-Jürgen Meyer
- Department of Inorganic Chemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Frank Jensen
- Department of Chemistry, Aarhus University, 8000 Aarhus, Denmark
| | - Peter R. Ogilby
- Department of Chemistry, Aarhus University, 8000 Aarhus, Denmark
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Chen X, Winters C, Crocker V, Lazarou M, Sousa AA, Leapman RD, Reese TS. Identification of PSD-95 in the Postsynaptic Density Using MiniSOG and EM Tomography. Front Neuroanat 2018; 12:107. [PMID: 30581381 PMCID: PMC6292990 DOI: 10.3389/fnana.2018.00107] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 11/20/2018] [Indexed: 12/21/2022] Open
Abstract
Combining tomography with electron microscopy (EM) produces images at definition sufficient to visualize individual protein molecules or molecular complexes in intact neurons. When freeze-substituted hippocampal cultures in plastic sections are imaged by EM tomography, detailed structures emerging from 3D reconstructions reveal putative glutamate receptors and membrane-associated filaments containing scaffolding proteins such as postsynaptic density (PSD)-95 family proteins based on their size, shape, and known distributions. In limited instances, structures can be identified with enhanced immuno-Nanogold labeling after light fixation and subsequent freeze-substitution. Molecular identification of structure can be corroborated in their absence after acute protein knockdown or gene knockout. However, additional labeling methods linking EM level structure to molecules in tomograms are needed. A recent development for labeling structures for TEM employs expression of endogenous proteins carrying a green fluorescent tag, miniSOG, to photoconvert diaminobenzidine (DAB) into osmiophilic polymers. This approach requires initial mild chemical fixation but many of structural features in neurons can still be discerned in EM tomograms. The photoreaction product, which appears as electron-dense, fine precipitates decorating protein structures in neurons, may diffuse to fill cytoplasm of spines, thus obscuring specific localization of proteins tagged with miniSOG. Here we develop an approach to minimize molecular diffusion of the DAB photoreaction product in neurons, which allows miniSOG tagged molecule/complexes to be identified in tomograms. The examples reveal electron-dense clusters of reaction product labeling membrane-associated vertical filaments, corresponding to the site of miniSOG fused at the C-terminal end of PSD-95-miniSOG, allowing identification of PSD-95 vertical filaments at the PSD. This approach, which results in considerable improvement in the precision of labeling PSD-95 in tomograms without complications due to the presence of antibody complexes in immunogold labeling, may be applicable for identifying other synaptic proteins in intact neurons.
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Affiliation(s)
- Xiaobing Chen
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Christine Winters
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Virginia Crocker
- EM Facility, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Michael Lazarou
- Surgical Neurology Branch, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Alioscka A Sousa
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, United States
| | - Richard D Leapman
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, United States
| | - Thomas S Reese
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States
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Bregnhøj M, Dichmann L, McLoughlin CK, Westberg M, Ogilby PR. Uric Acid: A Less-than-Perfect Probe for Singlet Oxygen. Photochem Photobiol 2018; 95:202-210. [DOI: 10.1111/php.12971] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 06/18/2018] [Indexed: 01/09/2023]
Affiliation(s)
| | - Lea Dichmann
- Department of Chemistry; Aarhus University; Aarhus Denmark
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Abstract
Sensory photoreceptors underpin light-dependent adaptations of organismal physiology, development, and behavior in nature. Adapted for optogenetics, sensory photoreceptors become genetically encoded actuators and reporters to enable the noninvasive, spatiotemporally accurate and reversible control by light of cellular processes. Rooted in a mechanistic understanding of natural photoreceptors, artificial photoreceptors with customized light-gated function have been engineered that greatly expand the scope of optogenetics beyond the original application of light-controlled ion flow. As we survey presently, UV/blue-light-sensitive photoreceptors have particularly allowed optogenetics to transcend its initial neuroscience applications by unlocking numerous additional cellular processes and parameters for optogenetic intervention, including gene expression, DNA recombination, subcellular localization, cytoskeleton dynamics, intracellular protein stability, signal transduction cascades, apoptosis, and enzyme activity. The engineering of novel photoreceptors benefits from powerful and reusable design strategies, most importantly light-dependent protein association and (un)folding reactions. Additionally, modified versions of these same sensory photoreceptors serve as fluorescent proteins and generators of singlet oxygen, thereby further enriching the optogenetic toolkit. The available and upcoming UV/blue-light-sensitive actuators and reporters enable the detailed and quantitative interrogation of cellular signal networks and processes in increasingly more precise and illuminating manners.
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Affiliation(s)
- Aba Losi
- Department of Mathematical, Physical and Computer Sciences , University of Parma , Parco Area delle Scienze 7/A-43124 Parma , Italy
| | - Kevin H Gardner
- Structural Biology Initiative, CUNY Advanced Science Research Center , New York , New York 10031 , United States.,Department of Chemistry and Biochemistry, City College of New York , New York , New York 10031 , United States.,Ph.D. Programs in Biochemistry, Chemistry, and Biology , The Graduate Center of the City University of New York , New York , New York 10016 , United States
| | - Andreas Möglich
- Lehrstuhl für Biochemie , Universität Bayreuth , 95447 Bayreuth , Germany.,Research Center for Bio-Macromolecules , Universität Bayreuth , 95447 Bayreuth , Germany.,Bayreuth Center for Biochemistry & Molecular Biology , Universität Bayreuth , 95447 Bayreuth , Germany
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31
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Hovan A, Datta S, Kruglik SG, Jancura D, Miskovsky P, Bánó G. Phosphorescence Kinetics of Singlet Oxygen Produced by Photosensitization in Spherical Nanoparticles. Part I. Theory. J Phys Chem B 2018; 122:5147-5153. [DOI: 10.1021/acs.jpcb.8b00658] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
| | | | - Sergei G. Kruglik
- Laboratoire Jean Perrin, Sorbonne Universités, UPMC Univ. Paris 6, CNRS UMR 8237, 4 Place Jussieu, 75005 Paris, France
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Westberg M, Bregnhøj M, Etzerodt M, Ogilby PR. No Photon Wasted: An Efficient and Selective Singlet Oxygen Photosensitizing Protein. J Phys Chem B 2017; 121:9366-9371. [PMID: 28892628 DOI: 10.1021/acs.jpcb.7b07831] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Optogenetics has been, and will continue to be, a boon to mechanistic studies of cellular processes. Genetically encodable proteins that sensitize the production of reactive oxygen species (ROS) are expected to play an increasingly important role, particularly in elucidating mechanisms of temporally and spatially dependent cell signaling. However, a substantial challenge in developing such photosensitizing proteins has been to funnel the optical excitation energy into the initial selective production of only one ROS. Singlet molecular oxygen, O2(a1Δg), is a ROS known to have a wide range of effects on cell function. Nevertheless, mechanistic details of singlet oxygen's behavior in a cell are lacking. On the basis of the rational optimization of a LOV-derived flavoprotein, we now report the development and photophysical characterization of a protein-encased photosensitizer that efficiently and selectively produces singlet oxygen at the expense of other ROS, especially ROS that derive from photoinduced electron transfer reactions. These results set the stage for a plethora of new experiments to elucidate ROS-mediated events in cells.
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Affiliation(s)
- Michael Westberg
- Department of Chemistry, Aarhus University , DK-8000 Aarhus, Denmark
| | - Mikkel Bregnhøj
- Department of Chemistry, Aarhus University , DK-8000 Aarhus, Denmark
| | - Michael Etzerodt
- Department of Molecular Biology and Genetics, Aarhus University , DK-8000 Aarhus, Denmark
| | - Peter R Ogilby
- Department of Chemistry, Aarhus University , DK-8000 Aarhus, Denmark
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