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Complementary Roles of Two DNA Protection Proteins from Deinococcus geothermalis. Int J Mol Sci 2022; 24:ijms24010469. [PMID: 36613913 PMCID: PMC9820295 DOI: 10.3390/ijms24010469] [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] [Received: 11/10/2022] [Revised: 12/17/2022] [Accepted: 12/22/2022] [Indexed: 12/29/2022] Open
Abstract
The roles of two interrelated DNA protection protein in starved cells (Dps)-putative Dps Dgeo_0257 and Dgeo_0281-as orthologous proteins to DrDps1 for DNA binding, protection, and metal ion sensing were characterised in a Deinococcus geothermalis strain. Dgeo_0257 exhibited high DNA-binding affinity and formed a multimeric structure but lacked the conserved amino acid sequence for ferroxidase activity. In contrast, the Dgeo_0281 (DgDps1) protein was abundant in the early exponential phase, had a lower DNA-binding activity than Dgeo_0257, and was mainly observed in its monomeric or dimeric forms. Electrophoretic mobility shift assays demonstrated that both purified proteins bound nonspecifically to DNA, and their binding ability was affected by certain metal ions. For example, in the presence of ferrous and ferric ions, neither Dgeo_0257 nor Dgeo_0281 could readily bind to DNA. In contrast, both proteins exhibited more stable DNA binding in the presence of zinc and manganese ions. Mutants in which the dps gene was disrupted exhibited higher sensitivity to oxidative stress than the wild-type strain. Furthermore, the expression levels of each gene showed an opposite correlation under H2O2 treatment conditions. Collectively, these findings indicate that the putative Dps Dgeo_0257 and DgDps1 from D. geothermalis are involved in DNA binding and protection in complementary interplay ways compared to known Dps.
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Abstract
The DNA-binding protein from starved cells, Dps, is a universally conserved prokaryotic ferritin that, in many species, also binds DNA. Dps homologs have been identified in the vast majority of bacterial species and several archaea. Dps also may play a role in the global regulation of gene expression, likely through chromatin reorganization. Dps has been shown to use both its ferritin and DNA-binding functions to respond to a variety of environmental pressures, including oxidative stress. One mechanism that allows Dps to achieve this is through a global nucleoid restructuring event during stationary phase, resulting in a compact, hexacrystalline nucleoprotein complex called the biocrystal that occludes damaging agents from DNA. Due to its small size, hollow spherical structure, and high stability, Dps is being developed for applications in biotechnology.
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Samanta L, Stensjö K, Lindblad P, Bhattacharya J. Differential catalase activity and tolerance to hydrogen peroxide in the filamentous cyanobacteria Nostoc punctiforme ATCC 29133 and Anabaena sp. PCC 7120. Arch Microbiol 2022; 204:121. [PMID: 34993618 DOI: 10.1007/s00203-021-02643-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 10/03/2021] [Accepted: 10/29/2021] [Indexed: 11/28/2022]
Abstract
Photoautotrophic cyanobacteria often confront hydrogen peroxide (H2O2), a reactive oxygen species potentially toxic to cells when present in sufficiently high concentrations. In this study, H2O2 tolerance ability of filamentous cyanobacteria Nostoc punctiforme ATCC 29133 (Nostoc 29133) and Anabaena sp. PCC 7120 (Anabaena 7120) was investigated at increasing concentrations of H2O2 (0-0.5 mM). In Nostoc 29133, 0.25 and 0.5 mM H2O2 caused a reduction in chlorophyll a content by 12 and 20%, respectively, whereas with similar treatments, a total loss of chlorophyll a was detected in Anabaena 7120. Further, Nostoc 29133 was able to maintain its photosystem II performance in the presence of H2O2 up to a concentration of 0.5 mM, whereas in Anabaena 7120, 0.25 mM H2O2 caused a complete reduction of photosystem II performance. The intracellular hydroperoxide level (indicator of oxidative status) did not increase to the same high level in Nostoc 29133, as compared to in Anabaena 7120 after H2O2 treatment. This might be explained by that Nostoc 29133 showed a 20-fold higher intrinsic constitutive catalase activity than Anabaena 7120, thus indicating that the superior tolerance of Nostoc 29133 to H2O2 stems from its higher ability to decompose H2O2. It is suggested that difference in H2O2 tolerance between closely related filamentous cyanobacteria, as revealed in this study, may be taken into account for judicious selection and effective use of strains in biotechnological applications.
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Affiliation(s)
- Loknath Samanta
- Department of Biotechnology, Mizoram University, PB No. 190, Aizawl, 796004, Mizoram, India
| | - Karin Stensjö
- Microbial Chemistry-Ångström Laboratory, Uppsala University, Box 523, 751 20, Uppsala, Sweden
| | - Peter Lindblad
- Microbial Chemistry-Ångström Laboratory, Uppsala University, Box 523, 751 20, Uppsala, Sweden
| | - Jyotirmoy Bhattacharya
- Department of Biotechnology, Mizoram University, PB No. 190, Aizawl, 796004, Mizoram, India.
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Rai R, Singh S, Rai KK, Raj A, Sriwastaw S, Rai LC. Regulation of antioxidant defense and glyoxalase systems in cyanobacteria. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 168:353-372. [PMID: 34700048 DOI: 10.1016/j.plaphy.2021.09.037] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 09/09/2021] [Accepted: 09/28/2021] [Indexed: 05/19/2023]
Abstract
Oxidative stress is common consequence of abiotic stress in plants as well as cyanobacteria caused by generation of reactive oxygen species (ROS), an inevitable product of respiration and photosynthetic electron transport. ROS act as signalling molecule at low concentration however, when its production exceeds the endurance capacity of antioxidative defence system, the organisms suffer oxidative stress. A highly toxic metabolite, methylglyoxal (MG) is also produced in cyanobacteria in response to various abiotic stresses which consequently augment the ensuing oxidative damage. Taking recourse to the common lineage of eukaryotic plants and cyanobacteria, it would be worthwhile to explore the regulatory role of glyoxalase system and antioxidative defense mechanism in combating abiotic stress in cyanobacteria. This review provides comprehensive information on the complete glyoxalase system (GlyI, GlyII and GlyIII) in cyanobacteria. Furthermore, it elucidates the recent understanding regarding the production of ROS and MG, noteworthy link between intracellular MG and ROS and its detoxification via synchronization of antioxidants (enzymatic and non-enzymatic) and glyoxalase systems using glutathione (GSH) as common co-factor.
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Affiliation(s)
- Ruchi Rai
- Molecular Biology Section, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Shilpi Singh
- Molecular Biology Section, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Krishna Kumar Rai
- Molecular Biology Section, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Alka Raj
- Molecular Biology Section, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Sonam Sriwastaw
- Molecular Biology Section, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - L C Rai
- Molecular Biology Section, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
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5
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Bradley JM, Svistunenko DA, Wilson MT, Hemmings AM, Moore GR, Le Brun NE. Bacterial iron detoxification at the molecular level. J Biol Chem 2021; 295:17602-17623. [PMID: 33454001 PMCID: PMC7762939 DOI: 10.1074/jbc.rev120.007746] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 10/07/2020] [Indexed: 01/18/2023] Open
Abstract
Iron is an essential micronutrient, and, in the case of bacteria, its availability is commonly a growth-limiting factor. However, correct functioning of cells requires that the labile pool of chelatable "free" iron be tightly regulated. Correct metalation of proteins requiring iron as a cofactor demands that such a readily accessible source of iron exist, but overaccumulation results in an oxidative burden that, if unchecked, would lead to cell death. The toxicity of iron stems from its potential to catalyze formation of reactive oxygen species that, in addition to causing damage to biological molecules, can also lead to the formation of reactive nitrogen species. To avoid iron-mediated oxidative stress, bacteria utilize iron-dependent global regulators to sense the iron status of the cell and regulate the expression of proteins involved in the acquisition, storage, and efflux of iron accordingly. Here, we survey the current understanding of the structure and mechanism of the important members of each of these classes of protein. Diversity in the details of iron homeostasis mechanisms reflect the differing nutritional stresses resulting from the wide variety of ecological niches that bacteria inhabit. However, in this review, we seek to highlight the similarities of iron homeostasis between different bacteria, while acknowledging important variations. In this way, we hope to illustrate how bacteria have evolved common approaches to overcome the dual problems of the insolubility and potential toxicity of iron.
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Affiliation(s)
- Justin M Bradley
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich, United Kingdom.
| | | | - Michael T Wilson
- School of Life Sciences, University of Essex, Colchester, United Kingdom
| | - Andrew M Hemmings
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich, United Kingdom; Centre for Molecular and Structural Biochemistry, School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Geoffrey R Moore
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich, United Kingdom
| | - Nick E Le Brun
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich, United Kingdom.
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Li X, Mustila H, Magnuson A, Stensjö K. Homologous overexpression of NpDps2 and NpDps5 increases the tolerance for oxidative stress in the multicellular cyanobacterium Nostoc punctiforme. FEMS Microbiol Lett 2019; 365:5071947. [PMID: 30107525 PMCID: PMC6116882 DOI: 10.1093/femsle/fny198] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 08/10/2018] [Indexed: 12/30/2022] Open
Abstract
The filamentous cyanobacterium Nostoc punctiforme has several oxidative stress-managing systems, including Dps proteins. Dps proteins belong to the ferritin superfamily and are involved in abiotic stress management in prokaryotes. Previously, we found that one of the five Dps proteins in N. punctiforme, NpDps2, was critical for H2O2 tolerance. Stress induced by high light intensities is aggravated in N. punctiforme strains deficient of either NpDps2, or the bacterioferritin-like NpDps5. Here, we have investigated the capacity of NpDps2 and NpDps5 to enhance stress tolerance by homologous overexpression of these two proteins in N. punctiforme. Both overexpression strains were found to tolerate twice as high concentrations of added H2O2 as the control strain, indicating that overexpression of either NpDps2 or NpDps5 will enhance the capacity for H2O2 tolerance. Under high light intensities, the overexpression of the two NpDps did not enhance the tolerance against general light-induced stress. However, overexpression of the heterocyst-specific NpDps5 in all cells of the filament led to a higher amount of chlorophyll-binding proteins per cell during diazotrophic growth. The OENpDps5 strain also showed an increased tolerance to ammonium-induced oxidative stress. Our results provide information of how Dps proteins may be utilised for engineering of cyanobacteria with enhanced stress tolerance.
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Affiliation(s)
- Xin Li
- Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE 75120 Uppsala, Swedens
| | - Henna Mustila
- Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE 75120 Uppsala, Swedens
| | - Ann Magnuson
- Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE 75120 Uppsala, Swedens
| | - Karin Stensjö
- Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE 75120 Uppsala, Swedens
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Structural diffusion properties of two atypical Dps from the cyanobacterium Nostoc punctiforme disclose interactions with ferredoxins and DNA. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:148063. [PMID: 31419396 DOI: 10.1016/j.bbabio.2019.148063] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 08/06/2019] [Accepted: 08/10/2019] [Indexed: 12/14/2022]
Abstract
Ferritin-like proteins, Dps (DNA-binding protein from starved cells), store iron and play a key role in the iron homeostasis in bacteria, yet their iron releasing machinery remains largely unexplored. The electron donor proteins that may interact with Dps and promote the mobilization of the stored iron have hitherto not been identified. Here, we investigate the binding capacity of the two atypical Dps proteins NpDps4 and NpDps5 from Nostoc punctiforme to isolated ferredoxins. We report NpDps-ferredoxin interactions by fluorescence correlation spectroscopy (FCS) and fluorescence resonance energy transfer (FRET) methods. Dynamic light scattering, size exclusion chromatography and native gel electrophoresis results show that NpDps4 forms a dodecamer at both pH 6.0 and pH 8.0, while NpDps5 forms a dodecamer only at pH 6.0. In addition, FCS data clearly reveal that the non-canonical NpDps5 interacts with DNA at pH 6.0. Our spectroscopic analysis shows that [FeS] centers of the three recombinantly expressed and isolated ferredoxins are properly incorporated and are consistent with their respective native states. The results support our hypothesis that ferredoxins could be involved in cellular iron homeostasis by interacting with Dps and assisting the release of stored iron.
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Howe C, Moparthi VK, Ho FM, Persson K, Stensjö K. The Dps4 from Nostoc punctiforme ATCC 29133 is a member of His-type FOC containing Dps protein class that can be broadly found among cyanobacteria. PLoS One 2019; 14:e0218300. [PMID: 31369577 PMCID: PMC6675082 DOI: 10.1371/journal.pone.0218300] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 07/18/2019] [Indexed: 11/18/2022] Open
Abstract
Dps proteins (DNA-binding proteins from starved cells) have been found to detoxify H2O2. At their catalytic centers, the ferroxidase center (FOC), Dps proteins utilize Fe2+ to reduce H2O2 and therefore play an essential role in the protection against oxidative stress and maintaining iron homeostasis. Whereas most bacteria accommodate one or two Dps, there are five different Dps proteins in Nostoc punctiforme, a phototrophic and filamentous cyanobacterium. This uncommonly high number of Dps proteins implies a sophisticated machinery for maintaining complex iron homeostasis and for protection against oxidative stress. Functional analyses and structural information on cyanobacterial Dps proteins are rare, but essential for understanding the function of each of the NpDps proteins. In this study, we present the crystal structure of NpDps4 in its metal-free, iron- and zinc-bound forms. The FOC coordinates either two iron atoms or one zinc atom. Spectroscopic analyses revealed that NpDps4 could oxidize Fe2+ utilizing O2, but no evidence for its use of the oxidant H2O2 could be found. We identified Zn2+ to be an effective inhibitor of the O2-mediated Fe2+ oxidation in NpDps4. NpDps4 exhibits a FOC that is very different from canonical Dps, but structurally similar to the atypical one from DpsA of Thermosynechococcus elongatus. Sequence comparisons among Dps protein homologs to NpDps4 within the cyanobacterial phylum led us to classify a novel FOC class: the His-type FOC. The features of this special FOC have not been identified in Dps proteins from other bacterial phyla and it might be unique to cyanobacterial Dps proteins.
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Affiliation(s)
- Christoph Howe
- Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Vamsi K. Moparthi
- Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Felix M. Ho
- Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Karina Persson
- Department of Chemistry, Umeå University, Umeå, Sweden
- * E-mail: (KS); (KP)
| | - Karin Stensjö
- Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
- * E-mail: (KS); (KP)
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Babele PK, Kumar J, Chaturvedi V. Proteomic De-Regulation in Cyanobacteria in Response to Abiotic Stresses. Front Microbiol 2019; 10:1315. [PMID: 31263458 PMCID: PMC6584798 DOI: 10.3389/fmicb.2019.01315] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 05/27/2019] [Indexed: 11/13/2022] Open
Abstract
Cyanobacteria are oxygenic photoautotrophs, exhibiting a cosmopolitan distribution in almost all possible environments and are significantly responsible for half of the global net primary productivity. They are well adapted to the diverse environments including harsh conditions by evolving a range of fascinating repertoires of unique biomolecules and secondary metabolites to support their growth and survival. These phototrophs are proved as excellent models for unraveling the mysteries of basic biochemical and physiological processes taking place in higher plants. Several known species of cyanobacteria have tremendous biotechnological applications in diverse fields such as biofuels, biopolymers, secondary metabolites and much more. Due to their potential biotechnological and commercial applications in various fields, there is an imperative need to engineer robust cyanobacteria in such a way that they can tolerate and acclimatize to ever-changing environmental conditions. Adaptations to stress are mainly governed by a precise gene regulation pathways resulting in the expression of novel protein/enzymes and metabolites. Despite the demand, till date few proteins/enzymes have been identified which play a potential role in improving tolerance against abiotic stresses. Therefore, it is utmost important to study environmental stress responses related to post-genomic investigations, including proteomic changes employing advanced proteomics, synthetic and structural biology workflows. In this respect, the study of stress proteomics offers exclusive advantages to scientists working on these aspects. Advancements on these fields could be helpful in dissecting, characterization and manipulation of physiological and metabolic systems of cyanobacteria to understand the stress induced proteomic responses. Till date, it remains ambiguous how cyanobacteria perceive changes in the ambient environment that lead to the stress-induced proteins thus metabolic deregulation. This review briefly describes the current major findings in the fields of proteome research on the cyanobacteria under various abiotic stresses. These findings may improve and advance the information on the role of different class of proteins associated with the mechanism(s) of stress mitigation in cyanobacteria under harsh environmental conditions.
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Affiliation(s)
- Piyoosh Kumar Babele
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, India
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Jay Kumar
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Venkatesh Chaturvedi
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
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Pernil R, Schleiff E. Metalloproteins in the Biology of Heterocysts. Life (Basel) 2019; 9:E32. [PMID: 30987221 PMCID: PMC6616624 DOI: 10.3390/life9020032] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 03/18/2019] [Accepted: 03/28/2019] [Indexed: 12/15/2022] Open
Abstract
Cyanobacteria are photoautotrophic microorganisms present in almost all ecologically niches on Earth. They exist as single-cell or filamentous forms and the latter often contain specialized cells for N₂ fixation known as heterocysts. Heterocysts arise from photosynthetic active vegetative cells by multiple morphological and physiological rearrangements including the absence of O₂ evolution and CO₂ fixation. The key function of this cell type is carried out by the metalloprotein complex known as nitrogenase. Additionally, many other important processes in heterocysts also depend on metalloproteins. This leads to a high metal demand exceeding the one of other bacteria in content and concentration during heterocyst development and in mature heterocysts. This review provides an overview on the current knowledge of the transition metals and metalloproteins required by heterocysts in heterocyst-forming cyanobacteria. It discusses the molecular, physiological, and physicochemical properties of metalloproteins involved in N₂ fixation, H₂ metabolism, electron transport chains, oxidative stress management, storage, energy metabolism, and metabolic networks in the diazotrophic filament. This provides a detailed and comprehensive picture on the heterocyst demands for Fe, Cu, Mo, Ni, Mn, V, and Zn as cofactors for metalloproteins and highlights the importance of such metalloproteins for the biology of cyanobacterial heterocysts.
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Affiliation(s)
- Rafael Pernil
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue-Straβe 9, 60438 Frankfurt am Main, Germany.
| | - Enrico Schleiff
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue-Straβe 9, 60438 Frankfurt am Main, Germany.
- Frankfurt Institute for Advanced Studies, Ruth-Moufang-Straße 1, 60438 Frankfurt am Main, Germany.
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue-Straβe 15, 60438 Frankfurt am Main, Germany.
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An optogenetic toolbox of LOV-based photosensitizers for light-driven killing of bacteria. Sci Rep 2018; 8:15021. [PMID: 30301917 PMCID: PMC6177443 DOI: 10.1038/s41598-018-33291-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 09/26/2018] [Indexed: 01/04/2023] Open
Abstract
Flavin-binding fluorescent proteins (FPs) are genetically encoded in vivo reporters, which are derived from microbial and plant LOV photoreceptors. In this study, we comparatively analyzed ROS formation and light-driven antimicrobial efficacy of eleven LOV-based FPs. In particular, we determined singlet oxygen (1O2) quantum yields and superoxide photosensitization activities via spectroscopic assays and performed cell toxicity experiments in E. coli. Besides miniSOG and SOPP, which have been engineered to generate 1O2, all of the other tested flavoproteins were able to produce singlet oxygen and/or hydrogen peroxide but exhibited remarkable differences in ROS selectivity and yield. Accordingly, most LOV-FPs are potent photosensitizers, which can be used for light-controlled killing of bacteria. Furthermore, the two variants Pp2FbFP and DsFbFP M49I, exhibiting preferential photosensitization of singlet oxygen or singlet oxygen and superoxide, respectively, were shown to be new tools for studying specific ROS-induced cell signaling processes. The tested LOV-FPs thus further expand the toolbox of optogenetic sensitizers usable for a broad spectrum of microbiological and biomedical applications.
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Howe C, Ho F, Nenninger A, Raleiras P, Stensjö K. Differential biochemical properties of three canonical Dps proteins from the cyanobacterium Nostoc punctiforme suggest distinct cellular functions. J Biol Chem 2018; 293:16635-16646. [PMID: 30171072 DOI: 10.1074/jbc.ra118.002425] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 08/29/2018] [Indexed: 11/06/2022] Open
Abstract
DNA-binding proteins from starved cells (Dps, EC: 1.16.3.1) have a variety of different biochemical activities such as DNA-binding, iron sequestration, and H2O2 detoxification. Most bacteria commonly feature one or two Dps enzymes, whereas the cyanobacterium Nostoc punctiforme displays an unusually high number of five Dps proteins (NpDps1-5). Our previous studies have indicated physiological differences, as well as cell-specific expression, among these five proteins. Three of the five NpDps proteins, NpDps1, -2, and -3, were classified as canonical Dps proteins. To further investigate their properties and possible importance for physiological function, here we characterized and compared them in vitro Nondenaturing PAGE, gel filtration, and dynamic light-scattering experiments disclosed that the three NpDps proteins exist as multimeric protein species in the bacterial cell. We also demonstrate Dps-mediated iron oxidation catalysis in the presence of H2O2 However, no iron oxidation with O2 as the electron acceptor was detected under our experimental conditions. In modeled structures of NpDps1, -2, and -3, protein channels were identified that could serve as the entrance for ferrous iron into the dodecameric structures. Furthermore, we could demonstrate pH-dependent DNA-binding properties for NpDps2 and -3. This study adds critical insights into the functions and stabilities of the three canonical Dps proteins from N. punctiforme and suggests that each of the Dps proteins within this bacterium has a specific biochemical property and function.
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Affiliation(s)
- Christoph Howe
- From the Department of Chemistry, Molecular Biomimetics, Ångström Laboratory, Uppsala University, SE-751 20 Uppsala, Sweden
| | - Felix Ho
- From the Department of Chemistry, Molecular Biomimetics, Ångström Laboratory, Uppsala University, SE-751 20 Uppsala, Sweden
| | - Anja Nenninger
- From the Department of Chemistry, Molecular Biomimetics, Ångström Laboratory, Uppsala University, SE-751 20 Uppsala, Sweden
| | - Patrícia Raleiras
- From the Department of Chemistry, Molecular Biomimetics, Ångström Laboratory, Uppsala University, SE-751 20 Uppsala, Sweden
| | - Karin Stensjö
- From the Department of Chemistry, Molecular Biomimetics, Ångström Laboratory, Uppsala University, SE-751 20 Uppsala, Sweden
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13
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Arosio P, Elia L, Poli M. Ferritin, cellular iron storage and regulation. IUBMB Life 2017; 69:414-422. [DOI: 10.1002/iub.1621] [Citation(s) in RCA: 165] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 02/28/2017] [Indexed: 12/19/2022]
Affiliation(s)
- Paolo Arosio
- Laboratory of Molecular Biology, Department of Molecular and Translational MedicineUniversity of BresciaBrescia Italy
| | - Leonardo Elia
- Laboratory of Molecular Biology, Department of Molecular and Translational MedicineUniversity of BresciaBrescia Italy
- Humanitas Clinical and Research CenterRozzano MI Italy
| | - Maura Poli
- Laboratory of Molecular Biology, Department of Molecular and Translational MedicineUniversity of BresciaBrescia Italy
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