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Püllmann P, Homann D, Karl TA, König B, Weissenborn MJ. Light-Controlled Biocatalysis by Unspecific Peroxygenases with Genetically Encoded Photosensitizers. Angew Chem Int Ed Engl 2023; 62:e202307897. [PMID: 37597259 DOI: 10.1002/anie.202307897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 08/16/2023] [Accepted: 08/16/2023] [Indexed: 08/21/2023]
Abstract
Fungal unspecific peroxygenases (UPOs) have gained substantial attention for their versatile oxyfunctionalization chemistry paired with impressive catalytic capabilities. A major drawback, however, remains their sensitivity towards their co-substrate hydrogen peroxide, necessitating the use of smart in situ hydrogen peroxide generation methods to enable efficient catalysis setups. Herein, we introduce flavin-containing protein photosensitizers as a new general tool for light-controlled in situ hydrogen peroxide production. By genetically fusing flavin binding fluorescent proteins and UPOs, we have created two virtually self-sufficient photo-enzymes (PhotUPO). Subsequent testing of a versatile substrate panel with the two divergent PhotUPOs revealed two stereoselective conversions. The catalytic performance of the fusion protein was optimized through enzyme and substrate loading variation, enabling up to 24300 turnover numbers (TONs) for the sulfoxidation of methyl phenyl sulfide. The PhotUPO concept was upscaled to a 100 mg substrate preparative scale, enabling the extraction of enantiomerically pure alcohol products.
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Affiliation(s)
- Pascal Püllmann
- Research Group Bioorganic Chemistry, Leibniz Institute for Plant Biochemistry, Weinberg 3, 06120, Halle (Saale), Germany
- Present address: Molecular Design and Engineering, Bayer AG, Aprather Weg 18 A, 42113, Wuppertal, Germany
| | - Dominik Homann
- Research Group Bioorganic Chemistry, Leibniz Institute for Plant Biochemistry, Weinberg 3, 06120, Halle (Saale), Germany
- Institute of Chemistry, Martin-Luther-University Halle-Wittenberg, Weinbergweg 22, 06120, Halle (Saale), Germany
| | - Tobias A Karl
- Institute for Organic Chemistry, University of Regensburg, Universitätstr. 31, 93053, Regensburg, Germany
| | - Burkhard König
- Institute for Organic Chemistry, University of Regensburg, Universitätstr. 31, 93053, Regensburg, Germany
| | - Martin J Weissenborn
- Research Group Bioorganic Chemistry, Leibniz Institute for Plant Biochemistry, Weinberg 3, 06120, Halle (Saale), Germany
- Institute of Chemistry, Martin-Luther-University Halle-Wittenberg, Weinbergweg 22, 06120, Halle (Saale), Germany
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Hsu TI. Editorial: Metabolic reprogramming for acquiring therapeutic resistance in glioblastoma. Front Oncol 2023; 13:1220063. [PMID: 37519794 PMCID: PMC10382683 DOI: 10.3389/fonc.2023.1220063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 07/03/2023] [Indexed: 08/01/2023] Open
Affiliation(s)
- Tsung-I Hsu
- Ph.D. Program in Medical Neuroscience, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes, Taipei, Taiwan
- International Master Program in Medical Neuroscience, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
- Taipei Medical University Research Center of Neuroscience, Taipei, Taiwan
- Taipei Medical University Research Center of Cancer Translational Medicine, Taipei, Taiwan
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Püschel D, Hédé S, Maisuls I, Höfert SP, Woschko D, Kühnemuth R, Felekyan S, Seidel CAM, Czekelius C, Weingart O, Strassert CA, Janiak C. Enhanced Solid-State Fluorescence of Flavin Derivatives by Incorporation in the Metal-Organic Frameworks MIL-53(Al) and MOF-5. Molecules 2023; 28:molecules28062877. [PMID: 36985849 PMCID: PMC10055669 DOI: 10.3390/molecules28062877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 03/14/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
The flavin derivatives 10-methyl-isoalloxazine (MIA) and 6-fluoro-10-methyl-isoalloxazine (6F-MIA) were incorporated in two alternative metal-organic frameworks, (MOFs) MIL-53(Al) and MOF-5. We used a post-synthetic, diffusion-based incorporation into microcrystalline MIL-53 powders with one-dimensional (1D) pores and an in-situ approach during the synthesis of MOF-5 with its 3D channel network. The maximum amount of flavin dye incorporation is 3.9 wt% for MIA@MIL-53(Al) and 1.5 wt% for 6F-MIA@MIL-53(Al), 0.85 wt% for MIA@MOF-5 and 5.2 wt% for 6F-MIA@MOF-5. For the high incorporation yields the probability to have more than one dye molecule in a pore volume is significant. As compared to the flavins in solution, the fluorescence spectrum of these flavin@MOF composites is broadened at the bathocromic side especially for MIA. Time-resolved spectroscopy showed that multi-exponential fluorescence lifetimes were needed to describe the decays. The fluorescence-weighted lifetime of flavin@MOF of 4 ± 1 ns also corresponds to those in solution but is significantly prolonged compared to the solid flavin dyes with less than 1 ns, thereby confirming the concept of "solid solutions" for dye@MOF composites. The fluorescence quantum yield (ΦF) of the flavin@MOF composites is about half of the solution but is significantly higher compared to the solid flavin dyes. Both the fluorescence lifetime and quantum yield of flavin@MOF decrease with the flavin loading in MIL-53 due to the formation of various J-aggregates. Theoretical calculations using plane-wave and QM/MM methods are in good correspondence with the experimental results and explain the electronic structures as well as the photophysical properties of crystalline MIA and the flavin@MOF composites. In the solid flavins, π-stacking interactions of the molecules lead to a charge transfer state with low oscillator strength resulting in aggregation-caused quenching (ACQ) with low lifetimes and quantum yields. In the MOF pores, single flavin molecules represent a major population and the computed MIA@MOF structures do not find π-stacking interactions with the pore walls but only weak van-der-Waals contacts which reasons the enhanced fluorescence lifetime and quantum yield of the flavins in the composites compared to their neat solid state. To analyze the orientation of flavins in MOFs, we measured fluorescence anisotropy images of single flavin@MOF-5 crystals and a static ensemble flavin@MIL53 microcrystals, respectively. Based on image information, anisotropy distributions and overall curve of the time-resolved anisotropy curves combined with theoretical calculations, we can prove that all fluorescent flavins species have a defined and rather homogeneous orientation in the MOF framework. In MIL-53, the transition dipole moments of flavins are orientated along the 1D channel axis, whereas in MOF-5 we resolved an average orientation that is tilted with respect to the cubic crystal lattice. Notably, the more hydrophobic 6F-MIA exhibits a higher degree order than MIA. The flexible MOF MIL-53(Al) was optimized essentially to the experimental large-pore form in the guest-free state with QuantumEspresso (QE) and with MIA molecules in the pores the structure contracted to close to the experimental narrow-pore form which was also confirmed by PXRD. In summary, the incorporation of flavins in MOFs yields solid-state materials with enhanced rigidity, stabilized conformation, defined orientation and reduced aggregations of the flavins, leading to increased fluorescence lifetime and quantum yield as controllable photo-luminescent and photo-physical properties.
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Affiliation(s)
- Dietrich Püschel
- Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany
| | - Simon Hédé
- Institut für Theoretische Chemie und Computerchemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany
| | - Iván Maisuls
- Institut für Anorganische und Analytische Chemie, CeNTech, CiMIC, SoN, Westfälische Wilhelms-Universität Münster, Heisenbergstraße 11, D-48149 Münster, Germany
| | - Simon-Patrick Höfert
- Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany
| | - Dennis Woschko
- Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany
| | - Ralf Kühnemuth
- Institut für Physikalische Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany
| | - Suren Felekyan
- Institut für Physikalische Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany
| | - Claus A M Seidel
- Institut für Physikalische Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany
| | - Constantin Czekelius
- Institut für Organische Chemie und Makromolekulare Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany
| | - Oliver Weingart
- Institut für Theoretische Chemie und Computerchemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany
| | - Cristian A Strassert
- Institut für Anorganische und Analytische Chemie, CeNTech, CiMIC, SoN, Westfälische Wilhelms-Universität Münster, Heisenbergstraße 11, D-48149 Münster, Germany
| | - Christoph Janiak
- Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany
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Tolar JG, Li S, Ajo-Franklin CM. The Differing Roles of Flavins and Quinones in Extracellular Electron Transfer in Lactiplantibacillus plantarum. Appl Environ Microbiol 2023; 89:e0131322. [PMID: 36533923 DOI: 10.1128/aem.01313-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Lactiplantibacillus plantarum is a lactic acid bacterium that is commonly found in the human gut and fermented food products. Despite its overwhelmingly fermentative metabolism, this microbe can perform extracellular electron transfer (EET) when provided with an exogenous quinone, 1,4-dihydroxy-2-naphthoic acid (DHNA), and riboflavin. However, the separate roles of DHNA and riboflavin in EET in L. plantarum have remained unclear. Here, we seek to understand the role of quinones and flavins in EET by monitoring iron and anode reduction in the presence and absence of these small molecules. We found that addition of either DHNA or riboflavin can support robust iron reduction, indicating electron transfer to extracellular iron occurs through both flavin-dependent and DHNA-dependent routes. Using genetic mutants of L. plantarum, we found that flavin-dependent iron reduction requires Ndh2 and EetA, while DHNA-dependent iron reduction largely relies on Ndh2 and PplA. In contrast to iron reduction, DHNA-containing medium supported more robust anode reduction than riboflavin-containing medium, suggesting electron transfer to an anode proceeds most efficiently through the DHNA-dependent pathway. Furthermore, we found that flavin-dependent anode reduction requires EetA, Ndh2, and PplA, while DHNA-dependent anode reduction requires Ndh2 and PplA. Taken together, we identify multiple EET routes utilized by L. plantarum and show that the EET route depends on access to environmental biomolecules and on the electron acceptor. This work expands our molecular-level understanding of EET in Gram-positive microbes and provides additional opportunities to manipulate EET for biotechnology. IMPORTANCE Lactic acid bacteria are named because of their nearly exclusive fermentative metabolism. Thus, the recent observation of EET activity-typically associated with anaerobic respiration-in this class of organisms has forced researchers to rethink the rules governing microbial metabolic strategies. Our identification of multiple routes for EET in L. plantarum that depend on two different redox active small molecules expands our understanding of how microbes metabolically adapt to different environments to gain an energetic edge and how these processes can be manipulated for biotechnological uses. Understanding the role of EET in lactic acid bacteria is of great importance due to the significance of lactic acid bacteria in agriculture, bioremediation, food production, and gut health. Furthermore, the maintenance of multiple EET routes speaks to the importance of this process to function under a variety of environmental conditions.
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Liu Y, Chaudhari AS, Chatterjee A, Andrikopoulos PC, Picchiotti A, Rebarz M, Kloz M, Lorenz-Fonfria VA, Schneider B, Fuertes G. Sub-Millisecond Photoinduced Dynamics of Free and EL222-Bound FMN by Stimulated Raman and Visible Absorption Spectroscopies. Biomolecules 2023; 13. [PMID: 36671546 DOI: 10.3390/biom13010161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/05/2023] [Accepted: 01/08/2023] [Indexed: 01/15/2023] Open
Abstract
Time-resolved femtosecond-stimulated Raman spectroscopy (FSRS) provides valuable information on the structural dynamics of biomolecules. However, FSRS has been applied mainly up to the nanoseconds regime and above 700 cm-1, which covers only part of the spectrum of biologically relevant time scales and Raman shifts. Here we report on a broadband (~200-2200 cm-1) dual transient visible absorption (visTA)/FSRS set-up that can accommodate time delays from a few femtoseconds to several hundreds of microseconds after illumination with an actinic pump. The extended time scale and wavenumber range allowed us to monitor the complete excited-state dynamics of the biological chromophore flavin mononucleotide (FMN), both free in solution and embedded in two variants of the bacterial light-oxygen-voltage (LOV) photoreceptor EL222. The observed lifetimes and intermediate states (singlet, triplet, and adduct) are in agreement with previous time-resolved infrared spectroscopy experiments. Importantly, we found evidence for additional dynamical events, particularly upon analysis of the low-frequency Raman region below 1000 cm-1. We show that fs-to-sub-ms visTA/FSRS with a broad wavenumber range is a useful tool to characterize short-lived conformationally excited states in flavoproteins and potentially other light-responsive proteins.
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Knowles OJ, Johannissen LO, Crisenza GEM, Hay S, Leys D, Procter DJ. A Vitamin B 2 -Photocatalysed Approach to Methionine Analogues. Angew Chem Int Ed Engl 2022; 61:e202212158. [PMID: 36250805 PMCID: PMC10100050 DOI: 10.1002/anie.202212158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Indexed: 11/05/2022]
Abstract
Access to new non-canonical amino acid residues is crucial for medicinal chemistry and chemical biology. Analogues of the amino acid methionine have been far less explored-despite their use in biochemistry, pharmacology and peptide bioconjugation. This is largely due to limited synthetic access. Herein, we exploit a new disconnection to access non-natural methionines through the development of a photochemical method for the radical α-C-H functionalization of sulfides with alkenes, in water, using inexpensive and commercially-available riboflavin (vitamin B2 ) as a photocatalyst. Our photochemical conditions allow the two-step synthesis of novel methionine analogues-by radical addition to unsaturated amino acid derivatives-and the chemoselective modification of peptide side-chains to yield non-natural methionine residues within small peptides. The mechanism of the bio-inspired flavin photocatalysis has been probed by experimental, DFT and TDDFT studies.
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Affiliation(s)
- Oliver J Knowles
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Linus O Johannissen
- Manchester Institute of Biotechnology and Department of Chemistry, University of Manchester, Princess Street, Manchester, M1 7DN, UK
| | - Giacomo E M Crisenza
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Sam Hay
- Manchester Institute of Biotechnology and Department of Chemistry, University of Manchester, Princess Street, Manchester, M1 7DN, UK
| | - David Leys
- Manchester Institute of Biotechnology and Department of Chemistry, University of Manchester, Princess Street, Manchester, M1 7DN, UK
| | - David J Procter
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
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Knowles OJ, Johannissen LO, Crisenza GEM, Hay S, Leys D, Procter DJ. A Vitamin B 2-Photocatalysed Approach to Methionine Analogues. Angew Chem Weinheim Bergstr Ger 2022; 134:e202212158. [PMID: 38505624 PMCID: PMC10946832 DOI: 10.1002/ange.202212158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Indexed: 11/11/2022]
Abstract
Access to new non-canonical amino acid residues is crucial for medicinal chemistry and chemical biology. Analogues of the amino acid methionine have been far less explored-despite their use in biochemistry, pharmacology and peptide bioconjugation. This is largely due to limited synthetic access. Herein, we exploit a new disconnection to access non-natural methionines through the development of a photochemical method for the radical α-C-H functionalization of sulfides with alkenes, in water, using inexpensive and commercially-available riboflavin (vitamin B2) as a photocatalyst. Our photochemical conditions allow the two-step synthesis of novel methionine analogues-by radical addition to unsaturated amino acid derivatives-and the chemoselective modification of peptide side-chains to yield non-natural methionine residues within small peptides. The mechanism of the bio-inspired flavin photocatalysis has been probed by experimental, DFT and TDDFT studies.
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Affiliation(s)
- Oliver J. Knowles
- Department of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
| | - Linus O. Johannissen
- Manchester Institute of Biotechnology and Department of ChemistryUniversity of ManchesterPrincess StreetManchesterM1 7DNUK
| | | | - Sam Hay
- Manchester Institute of Biotechnology and Department of ChemistryUniversity of ManchesterPrincess StreetManchesterM1 7DNUK
| | - David Leys
- Manchester Institute of Biotechnology and Department of ChemistryUniversity of ManchesterPrincess StreetManchesterM1 7DNUK
| | - David J. Procter
- Department of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
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Yurgel SN, Johnson SA, Rice J, Sa N, Bailes C, Baumgartner J, Pitzer JE, Roop RM, Roje S. A novel formamidase is required for riboflavin biosynthesis in invasive bacteria. J Biol Chem 2022; 298:102377. [PMID: 35970388 PMCID: PMC9478397 DOI: 10.1016/j.jbc.2022.102377] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 11/03/2022] Open
Abstract
Biosynthesis of riboflavin, the precursor of the redox cofactors FMN and FAD, was thought to be well understood in bacteria, with all the pathway enzymes presumed to be known and essential. Our previous research has challenged this view by showing that, in the bacterium Sinorhizobium meliloti, deletion of the ribBA gene encoding the enzyme that catalyzes the initial steps on the riboflavin biosynthesis pathway only causes a reduction in flavin secretion rather than riboflavin auxotrophy. This finding led us to hypothesize that RibBA participates in the biosynthesis of flavins destined for secretion, while S. meliloti has another enzyme that performs this function for internal cellular metabolism. Here, we identify and biochemically characterize a novel formamidase (SMc02977) involved in the production of riboflavin for intracellular functions in S. meliloti. This catalyst, which we named Sm-BrbF, releases formate from the early riboflavin precursor 2-amino-5-formylamino-6-ribosylamino-4(3H)-pyrimidinone 5'-phosphate (AFRPP) to yield 2,5-diamino-6-ribosylamino-4(3H)-pyrimidinone 5'-phosphate (DARoPP). We show that homologs of this enzyme are present in many bacteria, are highly abundant in the Rhizobiales order, and that sequence homologs from Brucella abortus and Liberobacter solanacearum complement the riboflavin auxotrophy of the Sm1021ΔSMc02977 mutant. Furthermore, we show that the B. abortus enzyme (Bab2_0247, Ba-BrbF) is also an AFRPP formamidase, and that the bab2_0247 mutant is a riboflavin auxotroph exhibiting a lower level of intracellular infection than the wild-type strain. Finally, we show that Sm-BrbF and Ba-BrbF directly interact with other riboflavin biosynthesis pathway enzymes. Together, our results provide novel insight into the intricacies of riboflavin biosynthesis in bacteria.
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Affiliation(s)
- Svetlana N Yurgel
- Grain Legume Genetics and Physiology Research Unit, USDA, ARS, Prosser, WA, USA.
| | - Skylar A Johnson
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Jennifer Rice
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Na Sa
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Clayton Bailes
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - John Baumgartner
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Josh E Pitzer
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - R Martin Roop
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Sanja Roje
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
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Zhao X, Tebbe L, Naash MI, Al-Ubaidi MR. The Neuroprotective Role of Retbindin, a Metabolic Regulator in the Neural Retina. Front Pharmacol 2022; 13:919667. [PMID: 35873559 PMCID: PMC9298789 DOI: 10.3389/fphar.2022.919667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 06/10/2022] [Indexed: 11/13/2022] Open
Abstract
Dysregulation of retinal metabolism is emerging as one of the major reasons for many inherited retinal diseases (IRDs), a leading cause of blindness worldwide. Thus, the identification of a common regulator that can preserve or revert the metabolic ecosystem to homeostasis is a key step in developing a treatment for different forms of IRDs. Riboflavin (RF) and its derivatives (flavins), flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), are essential cofactors for a wide range of cellular metabolic processes; hence, they are particularly critical in highly metabolically active tissues such as the retina. Patients with RF deficiency (ariboflavinosis) often display poor photosensitivity resulting in impaired low-light vision. We have identified a novel retina-specific RF binding protein called retbindin (Rtbdn), which plays a key role in retaining flavin levels in the neural retina. This role is mediated by its specific localization at the interface between the neural retina and retinal pigment epithelium (RPE), which is essential for metabolite and nutrient exchange. As a consequence of this vital function, Rtbdn's role in flavin utilization and metabolism in retinal degeneration is discussed. The principal findings are that Rtbdn helps maintain high levels of retinal flavins, and its ablation leads to an early-onset retinal metabolic dysregulation, followed by progressive degeneration of rod and cone photoreceptors. Lack of Rtbdn reduces flavin levels, forcing the neural retina to repurpose glucose to reduce the production of free radicals during ATP production. This leads to metabolic breakdown followed by retinal degeneration. Assessment of the role of Rtbdn in several preclinical retinal disease models revealed upregulation of its levels by several folds prior to and during the degenerative process. Ablation of Rtbdn in these models accelerated the rate of retinal degeneration. In agreement with these in vivo studies, we have also demonstrated that Rtbdn protects immortalized cone photoreceptor cells (661W cells) from light damage in vitro. This indicates that Rtbdn plays a neuroprotective role during retinal degeneration. Herein, we discussed the specific function of Rtbdn and its neuroprotective role in retinal metabolic homeostasis and its role in maintaining retinal health.
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Affiliation(s)
| | | | - Muna I. Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | - Muayyad R. Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
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Müllerová L, Marková K, Obruča S, Mravec F. Use of Flavin-Related Cellular Autofluorescence to Monitor Processes in Microbial Biotechnology. Microorganisms 2022; 10:microorganisms10061179. [PMID: 35744697 PMCID: PMC9231254 DOI: 10.3390/microorganisms10061179] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 06/06/2022] [Indexed: 11/16/2022] Open
Abstract
Cellular autofluorescence is usually considered to be a negative phenomenon because it can affect the sensitivity of fluorescence microscopic or flow cytometric assays by interfering with the signal of various fluorescent probes. Nevertheless, in our work, we adopted a different approach, and green autofluorescence induced by flavins was used as a tool to monitor fermentation employing the bacterium Cupriavidus necator. The autofluorescence was used to distinguish microbial cells from abiotic particles in flow cytometry assays, and it was also used for the determination of viability or metabolic characteristics of the microbial cells. The analyses using two complementary techniques, namely fluorescence microscopy and flow cytometry, are simple and do not require labor sample preparation. Flavins and their autofluorescence can also be used in a combination with other fluorophores when the need for multi-parametrical analyses arises, but it is wise to use dyes that do not emit a green light in order to not interfere with flavins' emission band (500-550 nm).
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11
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Kung JW, Meier AK, Willistein M, Weidenweber S, Demmer U, Ermler U, Boll M. Structural Basis of Cyclic 1,3-Diene Forming Acyl-Coenzyme A Dehydrogenases. Chembiochem 2021; 22:3173-3177. [PMID: 34555236 PMCID: PMC9293079 DOI: 10.1002/cbic.202100421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/15/2021] [Indexed: 11/20/2022]
Abstract
The biologically important, FAD‐containing acyl‐coenzyme A (CoA) dehydrogenases (ACAD) usually catalyze the anti‐1,2‐elimination of a proton and a hydride of aliphatic CoA thioesters. Here, we report on the structure and function of an ACAD from anaerobic bacteria catalyzing the unprecedented 1,4‐elimination at C3 and C6 of cyclohex‐1‐ene‐1‐carboxyl‐CoA (Ch1CoA) to cyclohex‐1,5‐diene‐1‐carboxyl‐CoA (Ch1,5CoA) and at C3 and C4 of the latter to benzoyl‐CoA. Based on high‐resolution Ch1CoA dehydrogenase crystal structures, the unorthodox reactivity is explained by the presence of a catalytic aspartate base (D91) at C3, and by eliminating the catalytic glutamate base at C1. Moreover, C6 of Ch1CoA and C4 of Ch1,5CoA are positioned towards FAD‐N5 to favor the biologically relevant C3,C6‐ over the C3,C4‐dehydrogenation activity. The C1,C2‐dehydrogenation activity was regained by structure‐inspired amino acid exchanges. The results provide the structural rationale for the extended catalytic repertoire of ACADs and offer previously unknown biocatalytic options for the synthesis of cyclic 1,3‐diene building blocks.
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Affiliation(s)
- Johannes W Kung
- Faculty of Biology - Microbiology, Albert-Ludwigs-Universität Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany
| | - Anne-Katrin Meier
- Faculty of Biology - Microbiology, Albert-Ludwigs-Universität Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany
| | - Max Willistein
- Faculty of Biology - Microbiology, Albert-Ludwigs-Universität Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany
| | - Sina Weidenweber
- Max-Planck-Institute for Biophysics, Max-von-Laue-Strasse 3, 60438, Frankfurt, Germany
| | - Ulrike Demmer
- Max-Planck-Institute for Biophysics, Max-von-Laue-Strasse 3, 60438, Frankfurt, Germany
| | - Ulrich Ermler
- Max-Planck-Institute for Biophysics, Max-von-Laue-Strasse 3, 60438, Frankfurt, Germany
| | - Matthias Boll
- Faculty of Biology - Microbiology, Albert-Ludwigs-Universität Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany
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12
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Tan TCY, Mahbub SB, Campbell JM, Habibalahi A, Campugan CA, Rose RD, Chow DJX, Mustafa S, Goldys EM, Dunning KR. Non-invasive, label-free optical analysis to detect aneuploidy within the inner cell mass of the preimplantation embryo. Hum Reprod 2021; 37:14-29. [PMID: 34741175 DOI: 10.1093/humrep/deab233] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 09/28/2021] [Indexed: 11/13/2022] Open
Abstract
STUDY QUESTION Can label-free, non-invasive optical imaging by hyperspectral autofluorescence microscopy discern between euploid and aneuploid cells within the inner cell mass (ICM) of the mouse preimplantation embryo? SUMMARY ANSWER Hyperspectral autofluorescence microscopy enables discrimination between euploid and aneuploid ICM in mouse embryos. WHAT IS KNOWN ALREADY Euploid/aneuploid mosaicism affects up to 17.3% of human blastocyst embryos with trophectoderm biopsy or spent media currently utilized to diagnose aneuploidy and mosaicism in clinical in vitro fertilization. Based on their design, these approaches will fail to diagnose the presence or proportion of aneuploid cells within the foetal lineage ICM of some blastocyst embryos. STUDY DESIGN, SIZE, DURATION The impact of aneuploidy on cellular autofluorescence and metabolism of primary human fibroblast cells and mouse embryos was assessed using a fluorescence microscope adapted for imaging with multiple spectral channels (hyperspectral imaging). Primary human fibroblast cells with known ploidy were subjected to hyperspectral imaging to record native cell fluorescence (4-6 independent replicates, euploid n = 467; aneuploid n = 969). For mouse embryos, blastomeres from the eight-cell stage (five independent replicates: control n = 39; reversine n = 44) and chimeric blastocysts (eight independent replicates: control n = 34; reversine n = 34; 1:1 (control:reversine) n = 30 and 1:3 (control:reversine) n = 37) were utilized for hyperspectral imaging. The ICM from control and reversine-treated embryos were mechanically dissected and their karyotype confirmed by whole genome sequencing (n = 13 euploid and n = 9 aneuploid). PARTICIPANTS/MATERIALS, SETTING, METHODS Two models were employed: (i) primary human fibroblasts with known karyotype and (ii) a mouse model of embryo aneuploidy where mouse embryos were treated with reversine, a reversible spindle assembly checkpoint inhibitor, during the four- to eight-cell division. Individual blastomeres were dissociated from control and reversine-treated eight-cell embryos and either imaged directly or used to generate chimeric blastocysts with differing ratios of control:reversine-treated cells. Individual blastomeres and embryos were interrogated by hyperspectral imaging. Changes in cellular metabolism were determined by quantification of metabolic co-factors (inferred from their autofluorescence signature): NAD(P)H and flavins with the subsequent calculation of the optical redox ratio (ORR: flavins/[NAD(P)H + flavins]). Autofluorescence signals obtained from hyperspectral imaging were examined mathematically to extract features from each cell/blastomere/ICM. This was used to discriminate between different cell populations. MAIN RESULTS AND THE ROLE OF CHANCE An increase in the relative abundance of NAD(P)H and decrease in flavins led to a significant reduction in the ORR for aneuploid cells in primary human fibroblasts and reversine-treated mouse blastomeres (P < 0.05). Mathematical analysis of endogenous cell autofluorescence achieved separation between (i) euploid and aneuploid primary human fibroblast cells, (ii) control and reversine-treated mouse blastomeres cells, (iii) control and reversine-treated chimeric blastocysts, (iv) 1:1 and 1:3 chimeric blastocysts and (v) confirmed euploid and aneuploid ICM from mouse blastocysts. The accuracy of these separations was supported by receiver operating characteristic curves with areas under the curve of 0.97, 0.99, 0.87, 0.88 and 0.93, respectively. We believe that the role of chance is low as mathematical features separated euploid from aneuploid in both human fibroblasts and ICM of mouse blastocysts. LARGE SCALE DATA N/A. LIMITATIONS, REASONS FOR CAUTION Although we were able to discriminate between euploid and aneuploid ICM in mouse blastocysts, confirmation of this approach in human embryos is required. While we show this approach is safe in mouse, further validation is required in large animal species prior to implementation in a clinical setting. WIDER IMPLICATIONS OF THE FINDINGS We have developed an original, accurate and non-invasive optical approach to assess aneuploidy within the ICM of mouse embryos in the absence of fluorescent tags. Hyperspectral autofluorescence imaging was able to discriminate between euploid and aneuploid human fibroblast and mouse blastocysts (ICM). This approach may potentially lead to a new diagnostic for embryo analysis. STUDY FUNDING/COMPETING INTEREST(S) K.R.D. is supported by a Mid-Career Fellowship from the Hospital Research Foundation (C-MCF-58-2019). This study was funded by the Australian Research Council Centre of Excellence for Nanoscale Biophotonics (CE140100003) and the National Health and Medical Research Council (APP2003786). The authors declare that there is no conflict of interest.
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Affiliation(s)
- Tiffany C Y Tan
- Robinson Research Institute, School of Biomedicine, The University of Adelaide, Adelaide, SA, Australia.,Australian Research Council Centre of Excellence for Nanoscale Biophotonics, The University of Adelaide, Adelaide, SA, Australia
| | - Saabah B Mahbub
- The Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Kensington, NSW, Australia.,Australian Research Council Centre of Excellence Centre for Nanoscale Biophotonics, University of New South Wales, Kensington, NSW, Australia
| | - Jared M Campbell
- The Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Kensington, NSW, Australia.,Australian Research Council Centre of Excellence Centre for Nanoscale Biophotonics, University of New South Wales, Kensington, NSW, Australia
| | - Abbas Habibalahi
- The Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Kensington, NSW, Australia.,Australian Research Council Centre of Excellence Centre for Nanoscale Biophotonics, University of New South Wales, Kensington, NSW, Australia
| | - Carl A Campugan
- Robinson Research Institute, School of Biomedicine, The University of Adelaide, Adelaide, SA, Australia.,Australian Research Council Centre of Excellence for Nanoscale Biophotonics, The University of Adelaide, Adelaide, SA, Australia
| | - Ryan D Rose
- Robinson Research Institute, School of Biomedicine, The University of Adelaide, Adelaide, SA, Australia.,Fertility SA, St. Andrews Hospital, Adelaide, SA, Australia
| | - Darren J X Chow
- Robinson Research Institute, School of Biomedicine, The University of Adelaide, Adelaide, SA, Australia.,Australian Research Council Centre of Excellence for Nanoscale Biophotonics, The University of Adelaide, Adelaide, SA, Australia
| | - Sanam Mustafa
- Robinson Research Institute, School of Biomedicine, The University of Adelaide, Adelaide, SA, Australia.,Australian Research Council Centre of Excellence for Nanoscale Biophotonics, The University of Adelaide, Adelaide, SA, Australia
| | - Ewa M Goldys
- The Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Kensington, NSW, Australia.,Australian Research Council Centre of Excellence Centre for Nanoscale Biophotonics, University of New South Wales, Kensington, NSW, Australia
| | - Kylie R Dunning
- Robinson Research Institute, School of Biomedicine, The University of Adelaide, Adelaide, SA, Australia.,Australian Research Council Centre of Excellence for Nanoscale Biophotonics, The University of Adelaide, Adelaide, SA, Australia
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13
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Wong NGK, Rhodes C, Dessent CEH. Photodegradation of Riboflavin under Alkaline Conditions: What Can Gas-Phase Photolysis Tell Us about What Happens in Solution? Molecules 2021; 26:6009. [PMID: 34641554 PMCID: PMC8512791 DOI: 10.3390/molecules26196009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/25/2021] [Accepted: 09/30/2021] [Indexed: 11/16/2022] Open
Abstract
The application of electrospray ionisation mass spectrometry (ESI-MS) as a direct method for detecting reactive intermediates is a technique of developing importance in the routine monitoring of solution-phase reaction pathways. Here, we utilise a novel on-line photolysis ESI-MS approach to detect the photoproducts of riboflavin in aqueous solution under mildly alkaline conditions. Riboflavin is a constituent of many food products, so its breakdown processes are of wide interest. Our on-line photolysis setup allows for solution-phase photolysis to occur within a syringe using UVA LEDs, immediately prior to being introduced into the mass spectrometer via ESI. Gas-phase photofragmentation studies via laser-interfaced mass spectrometry of deprotonated riboflavin, [RF - H]-, the dominant solution-phase species under the conditions of our study, are presented alongside the solution-phase photolysis. The results obtained illustrate the extent to which gas-phase photolysis methods can inform our understanding of the corresponding solution-phase photochemistry. We determine that the solution-phase photofragmentation observed for [RF - H]- closely mirrors the gas-phase photochemistry, with the dominant m/z 241 condensed-phase photoproduct also being observed in gas-phase photodissociation. Further gas-phase photoproducts are observed at m/z 255, 212, and 145. The value of exploring both the gas- and solution-phase photochemistry to characterise photochemical reactions is discussed.
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Affiliation(s)
| | | | - Caroline E. H. Dessent
- Department of Chemistry, University of York, Heslington YO10 5DD, UK; (N.G.K.W.); (C.R.)
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14
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Min D, Liu DF, Wu J, Cheng L, Zhang F, Cheng ZH, Li WW, Yu HQ. Extracellular electron transfer via multiple electron shuttles in waterborne Aeromonas hydrophila for bioreduction of pollutants. Biotechnol Bioeng 2021; 118:4760-4770. [PMID: 34546573 DOI: 10.1002/bit.27940] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 08/22/2021] [Accepted: 09/14/2021] [Indexed: 12/17/2022]
Abstract
Members of the genus Aeromonas prevail in aquatic habitats and have a great potential in biological wastewater treatment because of their unique extracellular electron transfer (EET) capabilities. However, the mediated EET mechanisms of Aeromonas have not been fully understood yet, hindering their applications in biological wastewater treatment processes. In this study, the electron shuttles in Aeromonas hydrophila, a model and widespread strain in aquatic environments and wastewater treatment plants, were explored. A. hydrophila was found to produce both flavins and 2-amino-3-carboxy-1,4-naphthoquinone (ACNQ) as electron shuttles and utilize them to accelerate its EET for the bioreduction of various pollutants. The Mtr-like respiratory pathway was essential for the reduction of flavins, but not involved in the ACNQ reduction. The electron shuttle activity of ACNQ for pollutant bioreduction involved the redox reactions that occurred inside the cell. These findings deepen our understanding about the underlying EET mechanisms in dissimilatory metal reducing bacteria and provide new insights into the roles of the genus Aeromonas in biological wastewater treatment.
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Affiliation(s)
- Di Min
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, China
| | - Dong-Feng Liu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, China
| | - Jie Wu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, China
| | - Lei Cheng
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Feng Zhang
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, China
| | - Zhou-Hua Cheng
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Wen-Wei Li
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, China
| | - Han-Qing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, China
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15
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Sinha T, Du J, Makia MS, Hurley JB, Naash MI, Al-Ubaidi MR. Absence of retbindin blocks glycolytic flux, disrupts metabolic homeostasis, and leads to photoreceptor degeneration. Proc Natl Acad Sci U S A 2021; 118:e2018956118. [PMID: 33526685 DOI: 10.1073/pnas.2018956118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
We previously reported a model of progressive retinal degeneration resulting from the knockout of the retina-specific riboflavin binding protein, retbindin (Rtbdn -/- ). We also demonstrated a reduction in neural retinal flavins as a result of the elimination of RTBDN. Given the role of flavins in metabolism, herein we investigated the underlying mechanism of this retinal degeneration by performing metabolomic analyses on predegeneration at postnatal day (P) 45 and at the onset of functional degeneration in the P120 retinas. Metabolomics of hydrophilic metabolites revealed that individual glycolytic products accumulated in the P45 Rtbdn -/- neural retinas along with the elevation of pentose phosphate pathway, while TCA cycle intermediates remained unchanged. This was confirmed by using 13C-labeled flux measurements and immunoblotting, revealing that the key regulatory step of phosphoenolpyruvate to pyruvate was inhibited via down-regulation of the tetrameric pyruvate kinase M2 (PKM2). Separate metabolite assessments revealed that almost all intermediates of acylcarnitine fatty acid oxidation, ceramides, sphingomyelins, and multiple toxic metabolites were significantly elevated in the predegeneration Rtbdn -/- neural retina. Our data show that lack of RTBDN, and hence reduction in flavins, forced the neural retina into repurposing glucose for free-radical mitigation over ATP production. However, such sustained metabolic reprogramming resulted in an eventual metabolic collapse leading to neurodegeneration.
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16
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Abstract
We demonstrate, by direct, single-cell imaging kinetic measurements, that endogenous autofluorescence in HeLa cells is sensitive to the application of external magnetic fields of 25 mT and less. We provide spectroscopic and mechanistic evidence that our findings can be explained in terms of magnetic field effects on photoinduced electron transfer reactions to flavins, through the radical pair mechanism. The observed magnetic field dependence is consistent with a triplet-born radical pair and a B1/2 value of 18.0 mT with a saturation value of 3.7%.
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17
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Jakubec M, Novák D, Zatloukalová M, Císařová I, Cibulka R, Favereau L, Crassous J, Cytryniak A, Bilewicz R, Hrbáč J, Storch J, Žádný J, Vacek J. Flavin-Helicene Amphiphilic Hybrids: Synthesis, Characterization, and Preparation of Surface-Supported Films. Chempluschem 2021; 86:982-990. [PMID: 33977667 DOI: 10.1002/cplu.202100092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/20/2021] [Indexed: 11/07/2022]
Abstract
This work reports on the preparation and structural characterization of flavo[7]helicene 1 (flavin-[7]helicene conjugate), which was subsequently characterized at the molecular level in either an aqueous environment or an organic phase, at the supramolecular level in the form of polymeric layers, and also embedded in a lipidic mesophase environment to study the resulting properties of such a hybrid relative to its parent molecules. The flavin benzo[g]pteridin-2,4-dione (isoalloxazine) was selected for conjugation because of its photoactivity and reversible redox behavior. Compound 1 was prepared from 2-nitroso[6]helicene and 6-methylamino-3-methyluracil, and characterized using common structural and spectroscopic tools: circular dichroism (CD), circularly polarized luminescence (CPL) spectroscopy, cyclic voltammetry (CV), and DFT quantum calculations. In addition, a methodology that allows the loading of 1 enantiomers into an internally nanostructured lipid (1-monoolein) matrix was developed.
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Affiliation(s)
- Martin Jakubec
- Institute of Chemical Process Fundamentals of the Czech Academy of Sciences, v.v.i., Rozvojová 135, 165 02, Prague 6, Czech Republic
| | - David Novák
- Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacký University, Hněvotínská 3, 775 15, Olomouc, Czech Republic
| | - Martina Zatloukalová
- Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacký University, Hněvotínská 3, 775 15, Olomouc, Czech Republic
| | - Ivana Císařová
- Department of Inorganic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, 128 40, Prague 2, Czech Republic
| | - Radek Cibulka
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28, Prague, Czech Republic
| | - Ludovic Favereau
- Univ. Rennes, CNRS, ISCR-UMR 6226, Campus de Beaulieu, 35042, Rennes Cedex, France
| | - Jeanne Crassous
- Univ. Rennes, CNRS, ISCR-UMR 6226, Campus de Beaulieu, 35042, Rennes Cedex, France
| | - Adrianna Cytryniak
- Faculty of Chemistry, University of Warsaw, Pasteura 1, Warsaw, 02-093, Poland
| | - Renata Bilewicz
- Faculty of Chemistry, University of Warsaw, Pasteura 1, Warsaw, 02-093, Poland
| | - Jan Hrbáč
- Institute of Chemistry, Masaryk University, Kamenice 5, Brno, 725 00, Czech Republic
| | - Jan Storch
- Institute of Chemical Process Fundamentals of the Czech Academy of Sciences, v.v.i., Rozvojová 135, 165 02, Prague 6, Czech Republic
| | - Jaroslav Žádný
- Institute of Chemical Process Fundamentals of the Czech Academy of Sciences, v.v.i., Rozvojová 135, 165 02, Prague 6, Czech Republic
| | - Jan Vacek
- Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacký University, Hněvotínská 3, 775 15, Olomouc, Czech Republic
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18
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Abstract
Hydrogen sulfide (H2 S) is an environmental toxin and a heritage of ancient microbial metabolism that has stimulated new interest following its discovery as a neuromodulator. While many physiological responses have been attributed to low H2 S levels, higher levels inhibit complex IV in the electron transport chain. To prevent respiratory poisoning, a dedicated set of enzymes that make up the mitochondrial sulfide oxidation pathway exists to clear H2 S. The committed step in this pathway is catalyzed by sulfide quinone oxidoreductase (SQOR), which couples sulfide oxidation to coenzyme Q10 reduction in the electron transport chain. The SQOR reaction prevents H2 S accumulation and generates highly reactive persulfide species as products; these can be further oxidized or can modify cysteine residues in proteins by persulfidation. Here, we review the kinetic and structural characteristics of human SQOR, and how its unconventional redox cofactor configuration and substrate promiscuity lead to sulfide clearance and potentially expand the signaling potential of H2 S. This dual role of SQOR makes it a promising target for H2 S-based therapeutics.
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Affiliation(s)
- Aaron P. Landry
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - David P. Ballou
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Ruma Banerjee
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
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19
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Lopez-Adams R, Newsome L, Moore KL, Lyon IC, Lloyd JR. Dissimilatory Fe(III) Reduction Controls on Arsenic Mobilization: A Combined Biogeochemical and NanoSIMS Imaging Approach. Front Microbiol 2021; 12:640734. [PMID: 33692773 PMCID: PMC7938665 DOI: 10.3389/fmicb.2021.640734] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 01/22/2021] [Indexed: 11/13/2022] Open
Abstract
Microbial metabolism plays a key role in controlling the fate of toxic groundwater contaminants, such as arsenic. Dissimilatory metal reduction catalyzed by subsurface bacteria can facilitate the mobilization of arsenic via the reductive dissolution of As(V)-bearing Fe(III) mineral assemblages. The mobility of liberated As(V) can then be amplified via reduction to the more soluble As(III) by As(V)-respiring bacteria. This investigation focused on the reductive dissolution of As(V) sorbed onto Fe(III)-(oxyhydr)oxide by model Fe(III)- and As(V)-reducing bacteria, to elucidate the mechanisms underpinning these processes at the single-cell scale. Axenic cultures of Shewanella sp. ANA-3 wild-type (WT) cells [able to respire both Fe(III) and As(V)] were grown using 13C-labeled lactate on an arsenical Fe(III)-(oxyhydr)oxide thin film, and after colonization, the distribution of Fe and As in the solid phase was assessed using nanoscale secondary ion mass spectrometry (NanoSIMS), complemented with aqueous geochemistry analyses. Parallel experiments were conducted using an arrA mutant, able to respire Fe(III) but not As(V). NanoSIMS imaging showed that most metabolically active cells were not in direct contact with the Fe(III) mineral. Flavins were released by both strains, suggesting that these cell-secreted electron shuttles mediated extracellular Fe(III)-(oxyhydr)oxide reduction, but did not facilitate extracellular As(V) reduction, demonstrated by the presence of flavins yet lack of As(III) in the supernatants of the arrA deletion mutant strain. 3D reconstructions of NanoSIMS depth-profiled single cells revealed that As and Fe were associated with the cell surface in the WT cells, whereas for the arrA mutant, only Fe was associated with the biomass. These data were consistent with Shewanella sp. ANA-3 respiring As(V) in a multistep process; first, the reductive dissolution of the Fe(III) mineral released As(V), and once in solution, As(V) was respired by the cells to As(III). As well as highlighting Fe(III) reduction as the primary release mechanism for arsenic, our data also identified unexpected cellular As(III) retention mechanisms that require further investigation.
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Affiliation(s)
- Rebeca Lopez-Adams
- Department of Earth and Environmental Sciences, University of Manchester, Manchester, United Kingdom
| | - Laura Newsome
- Department of Earth and Environmental Sciences, University of Manchester, Manchester, United Kingdom.,Camborne School of Mines, Environment and Sustainability Institute, University of Exeter, Exeter, United Kingdom
| | - Katie L Moore
- Department of Materials, University of Manchester, Manchester, United Kingdom.,Photon Science Institute, University of Manchester, Manchester, United Kingdom
| | - Ian C Lyon
- Department of Earth and Environmental Sciences, University of Manchester, Manchester, United Kingdom.,Photon Science Institute, University of Manchester, Manchester, United Kingdom
| | - Jonathan R Lloyd
- Department of Earth and Environmental Sciences, University of Manchester, Manchester, United Kingdom
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20
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Morici P, Battisti A, Tortora G, Menciassi A, Checcucci G, Ghetti F, Sgarbossa A. The in vitro Photoinactivation of Helicobacter pylori by a Novel LED-Based Device. Front Microbiol 2020; 11:283. [PMID: 32153551 PMCID: PMC7047934 DOI: 10.3389/fmicb.2020.00283] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 02/07/2020] [Indexed: 12/22/2022] Open
Abstract
The rise of antibiotic resistance is the main cause for the failure of conventional antibiotic therapy of Helicobacter pylori infection, which is often associated with severe gastric diseases, including gastric cancer. In the last years, alternative non-pharmacological approaches have been considered in the treatment of H. pylori infection. Among these, antimicrobial PhotoDynamic Therapy (aPDT), a light-based treatment able to photoinactivate a wide range of bacteria, viruses, fungal and protozoan parasites, could represent a promising therapeutic strategy. In the case of H. pylori, aPDT can exploit photoactive endogenous porphyrins, such as protoporphyrin IX and coproporphyrin I and III, to induce photokilling, without any other exogenous photosensitizers. With the aim of developing an ingestible LED-based robotic pill for minimally invasive intragastric treatment of H. pylori infection, it is crucial to determine the best illumination parameters to activate the endogenous photosensitizers. In this study the photokilling effect on H. pylori has been evaluated by using a novel LED-based device, designed for testing the appropriate LEDs for the pill and suitable to perform in vitro irradiation experiments. Exposure to visible light induced bacterial photokilling most effectively at 405 nm and 460 nm. Sub-lethal light dose at 405 nm caused morphological changes on bacterial surface indicating the cell wall as one of the main targets of photodamage. For the first time endogenous photosensitizing molecules other than porphyrins, such as flavins, have been suggested to be involved in the 460 nm H. pylori photoinactivation.
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Affiliation(s)
- Paola Morici
- Nanoscience Institute, CNR and NEST, Scuola Normale Superiore, Pisa, Italy
| | - Antonella Battisti
- Nanoscience Institute, CNR and NEST, Scuola Normale Superiore, Pisa, Italy
| | - Giuseppe Tortora
- The BioRobotics Institute, Polo Sant'Anna Valdera, Scuola Superiore Sant'Anna, Pontedera, Italy
| | - Arianna Menciassi
- The BioRobotics Institute, Polo Sant'Anna Valdera, Scuola Superiore Sant'Anna, Pontedera, Italy
| | - Giovanni Checcucci
- Nanoscience Institute, CNR and NEST, Scuola Normale Superiore, Pisa, Italy
| | - Francesco Ghetti
- Nanoscience Institute, CNR and NEST, Scuola Normale Superiore, Pisa, Italy
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21
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Schmid J, Hoenes K, Vatter P, Hessling M. Antimicrobial Effect of Visible Light-Photoinactivation of Legionella rubrilucens by Irradiation at 450, 470, and 620 nm. Antibiotics (Basel) 2019; 8:E187. [PMID: 31618994 DOI: 10.3390/antibiotics8040187] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/11/2019] [Accepted: 10/13/2019] [Indexed: 01/12/2023] Open
Abstract
Despite the high number of legionella infections, there are currently no convincing preventive measures. Photoinactivation with visible light is a promising new approach and the photoinactivation sensitivity properties of planktonic Legionella rubrilucens to 450, 470, and 620 nm irradiation were thus investigated and compared to existing 405 nm inactivation data for obtaining information on responsible endogenous photosensitizers. Legionella were streaked on agar plates and irradiated with different doses by light emitting diodes (LEDs) of different visible wavelengths. When irradiating bacterial samples with blue light of 450 nm, a 5-log reduction could be achieved by applying a dose of 300 J cm−2, whereas at 470 nm, a comparable reduction required about 500 J cm−2. For red irradiation at 620 nm, no inactivation could be observed, even at 500 J cm−2. The declining photoinactivation sensitivity with an increasing wavelength is consistent with the assumption of porphyrins and flavins being among the relevant photosensitizers. These results were obtained for L. rubrilucens, but there is reason to believe that its inactivation behavior is similar to that of pathogenic legionella species. Therefore, this photoinactivation might lead to new future concepts for legionella reduction and prevention in technical applications or even on or inside the human body.
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22
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Liu S, Diao N, Wang Z, Lu W, Tang YJ, Chen T. Modular Engineering of the Flavin Pathway in Escherichia coli for Improved Flavin Mononucleotide and Flavin Adenine Dinucleotide Production. J Agric Food Chem 2019; 67:6532-6540. [PMID: 31099250 DOI: 10.1021/acs.jafc.9b02646] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In this work, modular engineering of Escherichia coli was peformed to improve flavin production and the conversion ratio of riboflavin (RF) to FMN/FAD. The RF operon and the bifunctional RF kinase/FAD synthetase were divided into two separate modules. The two modules were expressed at different levels to produce RF: ribF ratios ranging from 2:20 to 7:5. The best strain respectively produced 324.1 and 171.6 mg/L of FAD and FMN in shake flask fermentation, and the titers reached 1899.3 and 872.7 mg/L in a fed-batch process. Furthermore, error-prone PCR (epPCR) of the E. coli ribF gene was performed. The highest FMN production of the best mutant reached 586.1 mg/L in shake flask cultivation. Moreover, this mutant produced 1017.5 mg/L FMN with a greatly reduced proportion of FAD in fermenter culture. To the best of our knowledge, this is the highest production of FAD and FMN in a microbial fermentation process reported to date.
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Affiliation(s)
- Shuang Liu
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology , Tianjin University , Tianjin 300072 , People's Republic of China
| | - Na Diao
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology , Tianjin University , Tianjin 300072 , People's Republic of China
| | - Zhiwen Wang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology , Tianjin University , Tianjin 300072 , People's Republic of China
| | - Wenyu Lu
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology , Tianjin University , Tianjin 300072 , People's Republic of China
| | - Ya-Jie Tang
- State Key Laboratory of Microbial Technology , Shandong University , Qingdao 266237 , People's Republic of China
- Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Key Laboratory of Industrial Microbiology, Hubei Provincial Cooperative Innovation Center of Industrial Fermentation , Hubei University of Technology , Wuhan 430068 , People's Republic of China
| | - Tao Chen
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology , Tianjin University , Tianjin 300072 , People's Republic of China
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23
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Wang Y, Ferrer-Espada R, Baglo Y, Gu Y, Dai T. Antimicrobial Blue Light Inactivation of Neisseria gonorrhoeae: Roles of Wavelength, Endogenous Photosensitizer, Oxygen, and Reactive Oxygen Species. Lasers Surg Med 2019; 51:815-823. [PMID: 31157931 DOI: 10.1002/lsm.23104] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/02/2019] [Indexed: 01/09/2023]
Abstract
BACKGROUND AND OBJECTIVES The aim of this study was to investigate the efficacy, safety, and mechanism of action of antimicrobial blue light (aBL) for the inactivation of Neisseria gonorrhoeae, the etiological agent of gonorrhea. STUDY DESIGN/MATERIALS AND METHODS The susceptibilities of N. gonorrhoeae (ATCC 700825) in planktonic suspensions to aBL at 405- and 470-nm wavelengths were compared. The roles of oxygen in the anti-gonococcal activity of aBL were studied by examining the effects of hypoxic condition (blowing N2 ) on the anti-gonococcal efficiency of 405-nm aBL. The presence, identification, and quantification of endogenous photosensitizers in N. gonorrhoeae cells and human vaginal epithelial cells (VK2/E6E7 cells) were determined using fluorescence spectroscopy and ultra-performance liquid chromatography (UPLC). Finally, the selectivity of aBL inactivation of N. gonorrhoeae over the host cells were investigated by irradiating the co-cultures of N. gonorrhoeae and human vaginal epithelial cells using 405-nm aBL. RESULTS About 3.12-log10 reduction of bacterial colony forming units (CFU) was achieved by 27 J/cm 2 exposure at 405 nm, while about 3.70-log10 reduction of bacterial CFU was achieved by 234 J/cm2 exposure at 470 nm. The anti-gonococcal efficacy of 405-nm aBL was significantly suppressed under hypoxic condition. Spectroscopic and UPLC analyses revealed the presence of endogenous porphyrins and flavins in N. gonorrhoeae. The concentrations of endogenous photosensitizers in N. gonorrhoeae (ATCC 700825) cells were more than 10 times higher than those in the VK2/E6E7 cells. In the co-cultures of N. gonorrhoeae and VK2/E6E7 cells, 405-nm aBL at 108 J/cm2 preferentially inactivated N. gonorrhoeae cells while sparing the vaginal epithelial cells. CONCLUSIONS aBL at 405-nm wavelength is more effective than 470-nm wavelength in inactivating N. gonorrhoeae while sparing the vaginal epithelial cells. Reactive oxygen species generated from the photochemical reactions between aBL and endogenous photosensitizers play a vital role in the anti-gonococcal activity of 405-nm aBL. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Ying Wang
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, Massachusetts, 02114.,Department of Laser Medicine, Chinese PLA General Hospital, Medical School of Chinese PLA, 28 Fuxing Road, 100853, Beijing, China
| | - Raquel Ferrer-Espada
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, Massachusetts, 02114.,Vaccine and Immunotherapy Center, Massachusetts General Hospital, Harvard Medical School, 149 13th St, Charlestown, Massachusetts, 02129
| | - Yan Baglo
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, Massachusetts, 02114
| | - Ying Gu
- Department of Laser Medicine, Chinese PLA General Hospital, Medical School of Chinese PLA, 28 Fuxing Road, 100853, Beijing, China
| | - Tianhong Dai
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, Massachusetts, 02114.,Vaccine and Immunotherapy Center, Massachusetts General Hospital, Harvard Medical School, 149 13th St, Charlestown, Massachusetts, 02129
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24
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Ludwig P, Sévin DC, Busche T, Kalinowski J, Bourdeaux F, Grininger M, Mack M. Characterization of the small flavin-binding dodecin in the roseoflavin producer Streptomyces davawensis. Microbiology (Reading) 2019; 164:908-919. [PMID: 29856311 DOI: 10.1099/mic.0.000662] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Genes encoding dodecin proteins are present in almost 20 % of archaeal and in more than 50 % of bacterial genomes. Archaeal dodecins bind riboflavin (vitamin B2), are thought to play a role in flavin homeostasis and possibly also help to protect cells from radical or oxygenic stress. Bacterial dodecins were found to bind riboflavin-5'-phosphate (also called flavin mononucleotide or FMN) and coenzyme A, but their physiological function remained unknown. In this study, we set out to investigate the relevance of dodecins for flavin metabolism and oxidative stress management in the phylogenetically related bacteria Streptomyces coelicolor and Streptomyces davawensis. Additionally, we explored the role of dodecins with regard to resistance against the antibiotic roseoflavin, a riboflavin analogue produced by S. davawensis. Our results show that the dodecin of S. davawensis predominantly binds FMN and is neither involved in roseoflavin biosynthesis nor in roseoflavin resistance. In contrast to S. davawensis, growth of S. coelicolor was not reduced in the presence of plumbagin, a compound, which induces oxidative stress. Plumbagin treatment stimulated expression of the dodecin gene in S. davawensis but not in S. coelicolor. Deletion of the dodecin gene in S. davawensis generated a recombinant strain which, in contrast to the wild-type, was fully resistant to plumbagin. Subsequent metabolome analyses revealed that the S. davawensis dodecin deletion strain exhibited a very different stress response when compared to the wild-type indicating that dodecins broadly affect cellular physiology.
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Affiliation(s)
- Petra Ludwig
- Institute for Technical Microbiology, Mannheim University of Applied Sciences, 68163 Mannheim, Germany
| | - Daniel C Sévin
- Institute of Molecular Systems Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Tobias Busche
- Center for Biotechnology, Bielefeld University, 33615 Bielefeld, Germany
| | - Jörn Kalinowski
- Center for Biotechnology, Bielefeld University, 33615 Bielefeld, Germany
| | - Florian Bourdeaux
- Institute of Organic Chemistry and Chemical Biology, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Martin Grininger
- Institute of Organic Chemistry and Chemical Biology, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Matthias Mack
- Institute for Technical Microbiology, Mannheim University of Applied Sciences, 68163 Mannheim, Germany
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25
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Arinda T, Philipp LA, Rehnlund D, Edel M, Chodorski J, Stöckl M, Holtmann D, Ulber R, Gescher J, Sturm-Richter K. Addition of Riboflavin-Coupled Magnetic Beads Increases Current Production in Bioelectrochemical Systems via the Increased Formation of Anode-Biofilms. Front Microbiol 2019; 10:126. [PMID: 30804910 PMCID: PMC6370747 DOI: 10.3389/fmicb.2019.00126] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 01/21/2019] [Indexed: 11/17/2022] Open
Abstract
Shewanella oneidensis is one of the best-understood model organisms for extracellular electron transfer. Endogenously produced and exported flavin molecules seem to play an important role in this process and mediate the connection between respiratory enzymes on the cell surface and the insoluble substrate by acting as electron shuttle and cytochrome-bound cofactor. Consequently, the addition of riboflavin to a bioelectrochemical system (BES) containing S. oneidensis cells as biocatalyst leads to a strong current increase. Still, an external application of riboflavin to increase current production in continuously operating BESs does not seem to be applicable due to the constant washout of the soluble flavin compound. In this study, we developed a recyclable electron shuttle to overcome the limitation of mediator addition to BES. Riboflavin was coupled to magnetic beads that can easily be recycled from the medium. The effect on current production and cell distribution in a BES as well as the recovery rate and the stability of the beads was investigated. The addition of synthesized beads leads to a more than twofold higher current production, which was likely caused by increased biofilm production. Moreover, 90% of the flavin-coupled beads could be recovered from the BESs using a magnetic separator.
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Affiliation(s)
- Tutut Arinda
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Laura-Alina Philipp
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - David Rehnlund
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Miriam Edel
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Jonas Chodorski
- Chair of Bioprocess Engineering, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Markus Stöckl
- Electrochemistry, DECHEMA-Forschungsinstitut, Frankfurt, Germany
| | - Dirk Holtmann
- Industrial Biotechnology, DECHEMA-Forschungsinstitut, Frankfurt, Germany
| | - Roland Ulber
- Chair of Bioprocess Engineering, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Johannes Gescher
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany.,Institute for Biological Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Katrin Sturm-Richter
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
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26
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Dundas CM, Graham AJ, Romanovicz DK, Keitz BK. Extracellular Electron Transfer by Shewanella oneidensis Controls Palladium Nanoparticle Phenotype. ACS Synth Biol 2018; 7:2726-2736. [PMID: 30396267 DOI: 10.1021/acssynbio.8b00218] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The relative scarcity of well-defined genetic and metabolic linkages to material properties impedes biological production of inorganic materials. The physiology of electroactive bacteria is intimately tied to inorganic transformations, which makes genetically tractable and well-studied electrogens, such as Shewanella oneidensis, attractive hosts for material synthesis. Notably, this species is capable of reducing a variety of transition-metal ions into functional nanoparticles, but exact mechanisms of nanoparticle biosynthesis remain ill-defined. We report two key factors of extracellular electron transfer by S. oneidensis, the outer membrane cytochrome, MtrC, and soluble redox shuttles (flavins), that affect Pd nanoparticle formation. Changes in the expression and availability of these electron transfer components drastically modulated particle synthesis rate and phenotype, including their structure and cellular localization. These relationships may serve as the basis for biologically tailoring Pd nanoparticle catalysts and could potentially be used to direct the biogenesis of other metal nanomaterials.
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27
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Huang L, Tang J, Chen M, Liu X, Zhou S. Two Modes of Riboflavin-Mediated Extracellular Electron Transfer in Geobacter uraniireducens. Front Microbiol 2018; 9:2886. [PMID: 30538691 PMCID: PMC6277576 DOI: 10.3389/fmicb.2018.02886] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 11/12/2018] [Indexed: 12/31/2022] Open
Abstract
Anaerobes respire extracellular electron acceptors by extracellular electron transfer (EET). It is widely recognized that flavins can act as electron shuttles to facilitate this process. Flavin synthesis genes are widely distributed in Geobacter species. However, the functions of flavins in the EET of Geobacter species are unclear. Here, we demonstrate that G. uraniireducens can secrete abundant riboflavin (up to 270 nM) to facilitate EET. When an electrode was used as the electron acceptor, the quick recovery of anodizing current after anolyte replacement and the electrochemical behavior of the G. uraniireducens biofilm characterized by differential pulse voltammetry suggest that the self-secreted riboflavin promoted EET by serving as bound redox cofactors for cytochromes. On the contrary, when Fe(III) oxide was the electron acceptor, free riboflavin acted as electron shuttle to mediate the reduction of Fe(III) oxide. The results demonstrate the flexibility of flavins in EET, suggesting that the properties of electron acceptors can affect the binding mode of extracellular flavins, and broaden the knowledge of the EET of Geobacter species.
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Affiliation(s)
- Lingyan Huang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jiahuan Tang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Man Chen
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xing Liu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shungui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
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28
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Richtar J, Heinrichova P, Apaydin DH, Schmiedova V, Yumusak C, Kovalenko A, Weiter M, Sariciftci NS, Krajcovic J. Novel Riboflavin-Inspired Conjugated Bio-Organic Semiconductors. Molecules 2018; 23:E2271. [PMID: 30189689 PMCID: PMC6225382 DOI: 10.3390/molecules23092271] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 08/27/2018] [Accepted: 08/31/2018] [Indexed: 11/23/2022] Open
Abstract
Flavins are known to be extremely versatile, thus enabling routes to innumerable modifications in order to obtain desired properties. Thus, in the present paper, the group of bio-inspired conjugated materials based on the alloxazine core is synthetized using two efficient novel synthetic approaches providing relatively high reaction yields. The comprehensive characterization of the materials, in order to evaluate the properties and application potential, has shown that the modification of the initial alloxazine core with aromatic substituents allows fine tuning of the optical bandgap, position of electronic orbitals, absorption and emission properties. Interestingly, the compounds possess multichromophoric behavior, which is assumed to be the results of an intramolecular proton transfer.
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Affiliation(s)
- Jan Richtar
- Faculty of Chemistry, Materials Research Centre, Brno University of Technology, Purkyňova 118, 612 00 Brno, Czech Republic.
| | - Patricie Heinrichova
- Faculty of Chemistry, Materials Research Centre, Brno University of Technology, Purkyňova 118, 612 00 Brno, Czech Republic.
| | - Dogukan Hazar Apaydin
- Linz Institute for Organic Solar Cells (LIOS), Physical Chemistry, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria.
| | - Veronika Schmiedova
- Faculty of Chemistry, Materials Research Centre, Brno University of Technology, Purkyňova 118, 612 00 Brno, Czech Republic.
| | - Cigdem Yumusak
- Linz Institute for Organic Solar Cells (LIOS), Physical Chemistry, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria.
| | - Alexander Kovalenko
- Faculty of Chemistry, Materials Research Centre, Brno University of Technology, Purkyňova 118, 612 00 Brno, Czech Republic.
| | - Martin Weiter
- Faculty of Chemistry, Materials Research Centre, Brno University of Technology, Purkyňova 118, 612 00 Brno, Czech Republic.
| | - Niyazi Serdar Sariciftci
- Linz Institute for Organic Solar Cells (LIOS), Physical Chemistry, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria.
| | - Jozef Krajcovic
- Faculty of Chemistry, Materials Research Centre, Brno University of Technology, Purkyňova 118, 612 00 Brno, Czech Republic.
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29
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Keinänen TA, Grigorenko N, Khomutov AR, Huang Q, Uimari A, Alhonen L, Hyvönen MT, Vepsäläinen J. Controlling the regioselectivity and stereospecificity of FAD-dependent polyamine oxidases with the use of amine-attached guide molecules as conformational modulators. Biosci Rep 2018; 38:BSR20180527. [PMID: 30006473 PMCID: PMC6131205 DOI: 10.1042/bsr20180527] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 07/03/2018] [Accepted: 07/05/2018] [Indexed: 01/03/2023] Open
Abstract
Enzymes generally display strict stereospecificity and regioselectivity for their substrates. Here by using FAD-dependent human acetylpolyamine oxidase (APAO), human spermine (Spm) oxidase (SMOX) and yeast polyamine oxidase (Fms1), we demonstrate that these fundamental properties of the enzymes may be regulated using simple guide molecules, being either covalently attached to polyamines or used as a supplement to the substrate mixtures. APAO, which naturally metabolizes achiral N1-acetylated polyamines, displays aldehyde-controllable stereospecificity with chiral 1-methylated polyamines, like (R)- and (S)-1-methylspermidine (1,8-diamino-5-azanonane) (1-MeSpd). Among the novel N1-acyl derivatives of MeSpd, isonicotinic acid (P4) or benzoic acid (Bz) with (R)-MeSpd had Km of 3.6 ± 0.6/1.2 ± 0.7 µM and kcat of 5.2 ± 0.6/4.6 ± 0.7 s-1 respectively, while N1 -AcSpd had Km 8.2 ± 0.4 µM and kcat 2.7 ± 0.0 s-1 On the contrary, corresponding (S)-MeSpd amides were practically inactive (kcat < 0.03 s-1) but they retained micromole level Km for APAO. SMOX did not metabolize any of the tested compounds (kcat < 0.05 s-1) that acted as non-competitive inhibitors having Ki ≥ 155 µM for SMOX. In addition, we tested (R,R)-1,12-bis-methylspermine (2,13-diamino-5,10-diazatetradecane) (R,R)-(Me2Spm) and (S,S)-Me2Spm as substrates for Fms1. Fms1 preferred (S,S)- to (R,R)-diastereoisomer, but with notably lower kcat in comparison with spermine. Interestingly, Fms1 was prone to aldehyde supplementation in its regioselectivity, i.e. the cleavage site of spermidine. Thus, aldehyde supplementation to generate aldimines or N-terminal substituents in polyamines, i.e. attachment of guide molecule, generates novel ligands with altered charge distribution changing the binding and catalytic properties with polyamine oxidases. This provides means for exploiting hidden capabilities of polyamine oxidases for controlling their regioselectivity and stereospecificity.
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Affiliation(s)
- Tuomo A Keinänen
- School of Pharmacy, Biocenter Kuopio, University of Eastern Finland, Kuopio Campus, P.O. Box 1627, Kuopio FI-70211, Finland
| | - Nikolay Grigorenko
- BASF Schweiz AG, Dispersions and Pigments Division, Klybeckstrasse 141, P.O. Box CH 4002, Basel, Switzerland
| | - Alex R Khomutov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov St 32, Moscow 119991, Russia
| | - Qingqiu Huang
- MacCHESS at the Cornell High Energy Synchrotron Source, Cornell University Ithaca, NY 14853-8001, U.S.A
| | - Anne Uimari
- Natural Resources Institute Finland, Natural Resources Division, Neulaniementie 5, Kuopio FI-70210, Finland
| | - Leena Alhonen
- School of Pharmacy, Biocenter Kuopio, University of Eastern Finland, Kuopio Campus, P.O. Box 1627, Kuopio FI-70211, Finland
| | - Mervi T Hyvönen
- School of Pharmacy, Biocenter Kuopio, University of Eastern Finland, Kuopio Campus, P.O. Box 1627, Kuopio FI-70211, Finland
| | - Jouko Vepsäläinen
- School of Pharmacy, Biocenter Kuopio, University of Eastern Finland, Kuopio Campus, P.O. Box 1627, Kuopio FI-70211, Finland
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30
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Lefèvre F, Fourmeau J, Pottier M, Baijot A, Cornet T, Abadía J, Álvarez-Fernández A, Boutry M. The Nicotiana tabacum ABC transporter NtPDR3 secretes O-methylated coumarins in response to iron deficiency. J Exp Bot 2018; 69:4419-4431. [PMID: 29893871 PMCID: PMC6093371 DOI: 10.1093/jxb/ery221] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 06/04/2018] [Indexed: 05/18/2023]
Abstract
Although iron is present in large amounts in the soil, its poor solubility means that plants have to use various strategies to facilitate its uptake. In this study, we show that expression of NtPDR3/NtABCG3, a Nicotiana tabacum plasma-membrane ABC transporter in the pleiotropic drug resistance (PDR) subfamily, is strongly induced in the root epidermis under iron deficiency conditions. Prevention of NtPDR3 expression resulted in N. tabacum plants that were less tolerant to iron-deficient conditions, displaying stronger chlorosis and slower growth than those of the wild-type when not supplied with iron. Metabolic profiling of roots and root exudates revealed that, upon iron deficiency, secretion of catechol-bearing O-methylated coumarins such as fraxetin, hydroxyfraxetin, and methoxyfraxetin to the rhizosphere was compromised in NtPDR3-silenced plants. However, exudation of flavins such as riboflavin was not markedly affected by NtPDR3-silencing. Expression of NtPDR3 in N. tabacum Bright Yellow-2 (BY-2) cells resulted in altered intra- and extracellular coumarin pools, supporting coumarin transport by this transporter. The results demonstrate that N. tabacum secretes both coumarins and flavins in response to iron deficiency and that NtPDR3 plays an essential role in the plant response to iron deficiency by mediating secretion of O-methylated coumarins to the rhizosphere.
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Affiliation(s)
- François Lefèvre
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud, Louvain-la-Neuve, Belgium
| | - Justine Fourmeau
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud, Louvain-la-Neuve, Belgium
| | - Mathieu Pottier
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud, Louvain-la-Neuve, Belgium
| | - Amandine Baijot
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud, Louvain-la-Neuve, Belgium
| | - Thomas Cornet
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud, Louvain-la-Neuve, Belgium
| | - Javier Abadía
- Department of Plant Nutrition, Estación Experimental de Aula Dei, Consejo Superior de Investigaciones Científicas (CSIC), Zaragoza, Spain
| | - Ana Álvarez-Fernández
- Department of Plant Nutrition, Estación Experimental de Aula Dei, Consejo Superior de Investigaciones Científicas (CSIC), Zaragoza, Spain
| | - Marc Boutry
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud, Louvain-la-Neuve, Belgium
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Beaudoin GAW, Li Q, Bruner SD, Hanson AD. An unusual diphosphatase from the PhnP family cleaves reactive FAD photoproducts. Biochem J 2018; 475:261-72. [PMID: 29229761 DOI: 10.1042/BCJ20170817] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 12/02/2017] [Accepted: 12/07/2017] [Indexed: 12/12/2022]
Abstract
Flavins are notoriously photolabile, but while the photoproducts derived from the iso-alloxazine ring are well known the other photoproducts are not. In the case of FAD, typically the main cellular flavin, the other photoproducts are predicted to include four- and five-carbon sugars linked to ADP. These FAD photoproducts were shown to be potent glycating agents, more so than ADP-ribose. Such toxic compounds would require disposal via an ADP-sugar diphosphatase or other route. Comparative analysis of bacterial genomes uncovered a candidate disposal gene that is chromosomally clustered with genes for FAD synthesis or transport and is predicted to encode a protein of the PhnP cyclic phosphodiesterase family. The representative PhnP family enzyme from Koribacter versatilis (here named Fpd, FAD photoproduct diphosphatase) was found to have high, Mn2+-dependent diphosphatase activity against FAD photoproducts, FAD, and ADP-ribose, but almost no phosphodiesterase activity against riboflavin 4',5'-cyclic phosphate, a chemical breakdown product of FAD. To provide a structural basis of the unique Fpd activity, the crystal structure of K. versatilis Fpd was determined. The results place Fpd in the broad metallo-β-lactamase-like family of hydrolases, a diverse family commonly using two metals for hydrolytic catalysis. The active site of Fpd contains two Mn2+ ions and a bound phosphate, consistent with a diphosphatase mechanism. Our results characterize the first PhnP family member that is a diphosphatase rather than a cyclic phosphodiesterase and suggest its involvement in a cellular damage-control system that efficiently hydrolyzes the reactive, ADP-ribose-like products of FAD photodegradation.
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32
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Dourado DFAR, Swart M, Carvalho ATP. Why the Flavin Adenine Dinucleotide (FAD) Cofactor Needs To Be Covalently Linked to Complex II of the Electron-Transport Chain for the Conversion of FADH 2 into FAD. Chemistry 2017; 24:5246-5252. [PMID: 29124817 PMCID: PMC5969107 DOI: 10.1002/chem.201704622] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/07/2017] [Indexed: 11/10/2022]
Abstract
A covalently bound flavin cofactor is predominant in the succinate‐ubiquinone oxidoreductase (SQR; Complex II), an essential component of aerobic electron transport, and in the menaquinol‐fumarate oxidoreductase (QFR), the anaerobic counterpart, although it is only present in approximately 10 % of the known flavoenzymes. This work investigates the role of this 8α‐N3‐histidyl linkage between the flavin adenine dinucleotide (FAD) cofactor and the respiratory Complex II. After parameterization with DFT calculations, classical molecular‐dynamics simulations and quantum‐mechanics calculations for Complex II:FAD and Complex II:FADH2, with and without the covalent bond, were performed. It was observed that the covalent bond is essential for the active‐center arrangement of the FADH2/FAD cofactor. Removal of this bond causes a displacement of the isoalloxazine group, which influences interactions with the protein, flavin solvation, and possible proton‐transfer pathways. Specifically, for the noncovalently bound FADH2 cofactor, the N1 atom moves away from the His‐A365 and His‐A254 residues and the N5 atom moves away from the glutamine‐62A residue. Both of the histidine and glutamine residues interact with a chain of water molecules that cross the enzyme, which is most likely involved in proton transfer. Breaking this chain of water molecules could thereby compromise proton transfer across the two active sites of Complex II.
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Affiliation(s)
- Daniel F A R Dourado
- School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Stranmillis Road, Belfast, BT9 5AG, Northern Ireland, UK.,Almac Sciences, Department of Biocatalysis and Isotope Chemistry, Almac House, 20 Seagoe Industrial Estate, Craigavon, BT63 5QD, Northern Ireland, UK
| | - Marcel Swart
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, 17003, Girona, Spain.,ICREA, Pg. Lluís Companys 23, 08010, Barcelona, Spain
| | - Alexandra T P Carvalho
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal
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Xiao Y, Zhang E, Zhang J, Dai Y, Yang Z, Christensen HEM, Ulstrup J, Zhao F. Extracellular polymeric substances are transient media for microbial extracellular electron transfer. Sci Adv 2017; 3:e1700623. [PMID: 28695213 PMCID: PMC5498105 DOI: 10.1126/sciadv.1700623] [Citation(s) in RCA: 287] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 05/18/2017] [Indexed: 05/19/2023]
Abstract
Microorganisms exploit extracellular electron transfer (EET) in growth and information exchange with external environments or with other cells. Every microbial cell is surrounded by extracellular polymeric substances (EPS). Understanding the roles of three-dimensional (3D) EPS in EET is essential in microbiology and microbial exploitation for mineral bio-respiration, pollutant conversion, and bioenergy production. We have addressed these challenges by comparing pure and EPS-depleted samples of three representative electrochemically active strains viz Gram-negative Shewanella oneidensis MR-1, Gram-positive Bacillus sp. WS-XY1, and yeast Pichia stipites using technology from electrochemistry, spectroscopy, atomic force microscopy, and microbiology. Voltammetry discloses redox signals from cytochromes and flavins in intact MR-1 cells, whereas stronger signals from cytochromes and additional signals from both flavins and cytochromes are found after EPS depletion. Flow cytometry and fluorescence microscopy substantiated by N-acetylglucosamine and electron transport system activity data showed less than 1.5% cell damage after EPS extraction. The electrochemical differences between normal and EPS-depleted cells therefore originate from electrochemical species in cell walls and EPS. The 35 ± 15-nm MR-1 EPS layer is also electrochemically active itself, with cytochrome electron transfer rate constants of 0.026 and 0.056 s-1 for intact MR-1 and EPS-depleted cells, respectively. This surprisingly small rate difference suggests that molecular redox species at the core of EPS assist EET. The combination of all the data with electron transfer analysis suggests that electron "hopping" is the most likely molecular mechanism for electrochemical electron transfer through EPS.
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Affiliation(s)
- Yong Xiao
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- Department of Chemistry, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - Enhua Zhang
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- Key Laboratory of Environmental Biology and Pollution Control, College of Environmental Science and Engineering, Hunan University, Changsha 410082, China
| | - Jingdong Zhang
- Department of Chemistry, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - Youfen Dai
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Zhaohui Yang
- Key Laboratory of Environmental Biology and Pollution Control, College of Environmental Science and Engineering, Hunan University, Changsha 410082, China
| | | | - Jens Ulstrup
- Department of Chemistry, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - Feng Zhao
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
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Hluska T, Šebela M, Lenobel R, Frébort I, Galuszka P. Purification of Maize Nucleotide Pyrophosphatase/Phosphodiesterase Casts Doubt on the Existence of Zeatin Cis- Trans Isomerase in Plants. Front Plant Sci 2017; 8:1473. [PMID: 28878803 PMCID: PMC5572937 DOI: 10.3389/fpls.2017.01473] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/08/2017] [Indexed: 05/14/2023]
Abstract
Almost 25 years ago, an enzyme named zeatin cis-trans isomerase from common bean has been described by Bassil et al. (1993). The partially purified enzyme required an external addition of FAD and dithiothreitol for the conversion of cis-zeatin to its trans- isomer that occurred only under light. Although an existence of this important enzyme involved in the metabolism of plant hormones cytokinins was generally accepted by plant biologists, the corresponding protein and encoding gene have not been identified to date. Based on the original paper, we purified and identified an enzyme from maize, which shows the described zeatin cis-trans isomerase activity. The enzyme belongs to nucleotide pyrophosphatase/phosphodiesterase family, which is well characterized in mammals, but less known in plants. Further experiments with the recombinant maize enzyme obtained from yeast expression system showed that rather than the catalytic activity of the enzyme itself, a non-enzymatic flavin induced photoisomerization is responsible for the observed zeatin cis-trans interconversion in vitro. An overexpression of the maize nucleotide pyrophosphatase/phosphodiesterase gene led to decreased FAD and increased FMN and riboflavin contents in transgenic Arabidopsis plants. However, neither contents nor the ratio of zeatin isomers was altered suggesting that the enzyme is unlikely to catalyze the interconversion of zeatin isomers in vivo. Using enhanced expression of a homologous gene, functional nucleotide pyrophosphatase/phosphodiesterase was also identified in rice.
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Affiliation(s)
- Tomáš Hluska
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University OlomoucOlomouc, Czechia
| | - Marek Šebela
- Department of Protein Biochemistry and Proteomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University OlomoucOlomouc, Czechia
| | - René Lenobel
- Department of Protein Biochemistry and Proteomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University OlomoucOlomouc, Czechia
| | - Ivo Frébort
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University OlomoucOlomouc, Czechia
| | - Petr Galuszka
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University OlomoucOlomouc, Czechia
- *Correspondence: Petr Galuszka,
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Affiliation(s)
- Tilo Mathes
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam Amsterdam, Netherlands
| | - John T M Kennis
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam Amsterdam, Netherlands
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Hering T, Mühldorf B, Wolf R, König B. Halogenase-Inspired Oxidative Chlorination Using Flavin Photocatalysis. Angew Chem Int Ed Engl 2016; 55:5342-5. [PMID: 26991557 PMCID: PMC5069574 DOI: 10.1002/anie.201600783] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 01/23/2016] [Indexed: 11/22/2022]
Abstract
Chlorine gas or electropositive chlorine reagents are used to prepare chlorinated aromatic compounds, which are found in pharmaceuticals, agrochemicals, and polymers, and serve as synthetic precursors for metal‐catalyzed cross‐couplings. Nature chlorinates with chloride anions, FAD‐dependent halogenases, and O2 as the oxidant. A photocatalytic oxidative chlorination is described based on the organic dye riboflavin tetraacetate mimicking the enzymatic process. The chemical process allows within the suitable arene redox potential window a broader substrate scope compared to the specific activation in the enzymatic binding pocket.
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Affiliation(s)
- Thea Hering
- Universität Regensburg, Fakultät für Chemie und Pharmazie, 93040, Regensburg, Germany
| | - Bernd Mühldorf
- Universität Regensburg, Fakultät für Chemie und Pharmazie, 93040, Regensburg, Germany
| | - Robert Wolf
- Universität Regensburg, Fakultät für Chemie und Pharmazie, 93040, Regensburg, Germany.
| | - Burkhard König
- Universität Regensburg, Fakultät für Chemie und Pharmazie, 93040, Regensburg, Germany.
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Sisó-Terraza P, Rios JJ, Abadía J, Abadía A, Álvarez-Fernández A. Flavins secreted by roots of iron-deficient Beta vulgaris enable mining of ferric oxide via reductive mechanisms. New Phytol 2016; 209:733-45. [PMID: 26351005 DOI: 10.1111/nph.13633] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 08/03/2015] [Indexed: 05/07/2023]
Abstract
Iron (Fe) is abundant in soils but generally poorly soluble. Plants, with the exception of Graminaceae, take up Fe using an Fe(III)-chelate reductase coupled to an Fe(II) transporter. Whether or not nongraminaceous species can convert scarcely soluble Fe(III) forms into soluble Fe forms has deserved little attention so far. We have used Beta vulgaris, one among the many species whose roots secrete flavins upon Fe deficiency, to study whether or not flavins are involved in Fe acquisition. Flavins secreted by Fe-deficient plants were removed from the nutrient solution, and plants were compared with Fe-sufficient plants and Fe-deficient plants without flavin removal. Solubilization of a scarcely soluble Fe(III)-oxide was assessed in the presence or absence of flavins, NADH (nicotinamide adenine dinucleotide, reduced form) or plant roots, and an Fe(II) trapping agent. The removal of flavins from the nutrient solution aggravated the Fe deficiency-induced leaf chlorosis. Flavins were able to dissolve an Fe(III)-oxide in the presence of NADH. The addition of extracellular flavins enabled roots of Fe-deficient plants to reductively dissolve an Fe(III)-oxide. We concluded that root-secretion of flavins improves Fe nutrition in B. vulgaris. Flavins allow B. vulgaris roots to mine Fe from Fe(III)-oxides via reductive mechanisms.
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Affiliation(s)
- Patricia Sisó-Terraza
- Department of Plant Nutrition, Estación Experimental de Aula Dei (CSIC), Av. Montañana 1005, E-50080, Zaragoza, Spain
| | - Juan J Rios
- Department of Plant Nutrition, Estación Experimental de Aula Dei (CSIC), Av. Montañana 1005, E-50080, Zaragoza, Spain
| | - Javier Abadía
- Department of Plant Nutrition, Estación Experimental de Aula Dei (CSIC), Av. Montañana 1005, E-50080, Zaragoza, Spain
| | - Anunciación Abadía
- Department of Plant Nutrition, Estación Experimental de Aula Dei (CSIC), Av. Montañana 1005, E-50080, Zaragoza, Spain
| | - Ana Álvarez-Fernández
- Department of Plant Nutrition, Estación Experimental de Aula Dei (CSIC), Av. Montañana 1005, E-50080, Zaragoza, Spain
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Suzuki H, Inoue R, Kawamorita S, Komiya N, Imada Y, Naota T. Highly fluorescent flavins: rational molecular design for quenching protection based on repulsive and attractive control of molecular alignment. Chemistry 2015; 21:9171-8. [PMID: 25962532 DOI: 10.1002/chem.201406346] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Indexed: 11/05/2022]
Abstract
Unprecedented intense fluorescent emission was observed for a variety of flavin compounds bearing a perpendicular cyclic imide moiety at the C7 position of an isoalloxazine platform. A series of alloxan-substituted flavins was prepared selectively by reduction of the corresponding N-aryl-2-nitro-5-alkoxyanilines with zinc dust and subsequent reaction with alloxan monohydrate in the presence of boric acid. Analogues bearing oxazolidine-2,4-dione functionality were obtained on methylation of the alloxan-substituted flavins with methyl iodide and subsequent rearrangement in the presence of an inorganic base. The flavin compounds exhibit intense white-green fluorescent emission in the solution state under UV excitation at 298 K, with emission efficiencies Φ298 K greater than 0.55 in CH3 CN, which are higher than the values for all reported flavin compounds under similar conditions. The highest Φ298 K value of 0.70 was obtained in CH3 CN for isoalloxazine bearing C7-alloxan and N10-2,6-diisopropylphenyl groups. The temperature dependence of the emission intensities indicates that the pronounced emission properties at 298 K are attributable to the highly heat resistant properties towards emission decay with increasing temperature. Mechanistic studies, including X-ray diffraction analysis, revealed that the good emission properties and high heat resistance of the alloxan-substituted flavins are due to a synergetic effect of the associative nature of the C7-alloxan unit and the repulsive nature of the perpendicular bulky substituents at the C7 and N10 positions.
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Affiliation(s)
- Haruka Suzuki
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)
| | - Ryo Inoue
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)
| | - Soichiro Kawamorita
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)
| | - Naruyoshi Komiya
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)
| | - Yasushi Imada
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Machikaneyama, Toyonaka, Osaka 560-8531 (Japan).,Present address: Department of Chemical Science and Technology, Institute of Technology and Science, Tokushima University, Minamijosanjima, Tokushima 770-8506 (Japan)
| | - Takeshi Naota
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Machikaneyama, Toyonaka, Osaka 560-8531 (Japan).
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Repič M, Vianello R, Purg M, Duarte F, Bauer P, Kamerlin SCL, Mavri J. Empirical valence bond simulations of the hydride transfer step in the monoamine oxidase B catalyzed metabolism of dopamine. Proteins 2014; 82:3347-55. [PMID: 25220264 DOI: 10.1002/prot.24690] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 09/10/2014] [Indexed: 01/05/2023]
Abstract
Monoamine oxidases (MAOs) A and B are flavoenzymes responsible for the metabolism of biogenic amines such as dopamine, serotonin and noradrenaline. In this work, we present a comprehensive study of the rate-limiting step of dopamine degradation by MAO B, which consists in the hydride transfer from the methylene group of the substrate to the flavin moiety of the FAD prosthetic group. This article builds on our previous quantum chemical study of the same reaction using a cluster model (Vianello et al., Eur J Org Chem 2012; 7057), but now considering the full dimensionality of the hydrated enzyme with extensive configurational sampling. We show that MAO B is specifically tuned to catalyze the hydride transfer step from the substrate to the flavin moiety of the FAD prosthetic group and that it lowers the activation barrier by 12.3 kcal mol⁻¹ compared to the same reaction in aqueous solution, a rate enhancement of more than nine orders of magnitude. Taking into account the deprotonation of the substrate prior to the hydride transfer reaction, the activation barrier in the enzyme is calculated to be 16.1 kcal mol⁻¹, in excellent agreement with the experimental value of 16.5 kcal mol⁻¹. Additionally, we demonstrate that the protonation state of the active site residue Lys296 does not have an influence on the hydride transfer reaction.
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Affiliation(s)
- Matej Repič
- Laboratory for Biocomputing and Bioinformatics, National Institute of Chemistry, Hajdrihova 19, SI-1000, Ljubljana, Slovenia
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Langer J, Günther A, Seidenbecher S, Berden G, Oomens J, Dopfer O. Probing protonation sites of isolated flavins using IR spectroscopy: from lumichrome to the cofactor flavin mononucleotide. Chemphyschem 2014; 15:2550-62. [PMID: 24895155 DOI: 10.1002/cphc.201402146] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Indexed: 11/06/2022]
Abstract
Infrared spectra of the isolated protonated flavin molecules lumichrome, lumiflavin, riboflavin (vitamin B2), and the biologically important cofactor flavin mononucleotide are measured in the fingerprint region (600-1850 cm(-1)) by means of IR multiple-photon dissociation (IRMPD) spectroscopy. Using density functional theory calculations, the geometries, relative energies, and linear IR absorption spectra of several low-energy isomers are calculated. Comparison of the calculated IR spectra with the measured IRMPD spectra reveals that the N10 substituent on the isoalloxazine ring influences the protonation site of the flavin. Lumichrome, with a hydrogen substituent, is only stable as the N1-protonated tautomer and protonates at N5 of the pyrazine ring. The presence of the ribityl unit in riboflavin leads to protonation at N1 of the pyrimidinedione moiety, and methyl substitution in lumiflavin stabilizes the tautomer that is protonated at O2. In contrast, flavin mononucleotide exists as both the O2- and N1-protonated tautomers. The frequencies and relative intensities of the two C=O stretch vibrations in protonated flavins serve as reliable indicators for their protonation site.
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Affiliation(s)
- Judith Langer
- Technische Universität Berlin, Institut für Optik und Atomare Physik, Hardenbergstraße 36, D-10623 Berlin (Germany); Current address: Parque Tecnologico de San Sebastian, Paseo Miramon 182, Edif C, 20009 San Sebastian (Spain)
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Sainz M, Pérez-Rontomé C, Ramos J, Mulet JM, James EK, Bhattacharjee U, Petrich JW, Becana M. Plant hemoglobins may be maintained in functional form by reduced flavins in the nuclei, and confer differential tolerance to nitro-oxidative stress. Plant J 2013; 76:875-87. [PMID: 24118423 DOI: 10.1111/tpj.12340] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 09/09/2013] [Accepted: 09/27/2013] [Indexed: 05/09/2023]
Abstract
The heme of bacteria, plant and animal hemoglobins (Hbs) must be in the ferrous state to bind O(2) and other physiological ligands. Here we have characterized the full set of non-symbiotic (class 1 and 2) and 'truncated' (class 3) Hbs of Lotus japonicus. Class 1 Hbs are hexacoordinate, but class 2 and 3 Hbs are pentacoordinate. Three of the globins, Glb1-1, Glb2 and Glb3-1, are nodule-enhanced proteins. The O(2) affinity of Glb1-1 (50 pm) was the highest known for any Hb, and the protein may function as an O(2) scavenger. The five globins were reduced by free flavins, which transfer electrons from NAD(P)H to the heme iron under aerobic and anaerobic conditions. Class 1 Hbs were reduced at very fast rates by FAD, class 2 Hbs at slower rates by both FMN and FAD, and class 3 Hbs at intermediate rates by FMN. The members of the three globin classes were immunolocalized predominantly in the nuclei. Flavins were quantified in legume nodules and nuclei, and their concentrations were sufficient to maintain Hbs in their functional state. All Hbs, except Glb1-1, were expressed in a flavohemoglobin-deficient yeast mutant and found to confer tolerance to oxidative stress induced by methyl viologen, copper or low temperature, indicating an anti-oxidative role for the hemes. However, only Glb1-2 and Glb2 afforded protection against nitrosative stress induced by S-nitrosoglutathione. Because this compound is specifically involved in transnitrosylation reactions with thiol groups, our results suggest a contribution of the single cysteine residues of both proteins in the stress response.
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Affiliation(s)
- Martha Sainz
- Departamento de Nutrición Vegetal, Estación Experimental de Aula Dei, Consejo Superior de Investigaciones Científicas, Apartado 13034, 50080, Zaragoza, Spain
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Rodríguez-Celma J, Schmidt W. Reduction-based iron uptake revisited: on the role of secreted iron-binding compounds. Plant Signal Behav 2013; 8:e26116. [PMID: 23989491 PMCID: PMC4091243 DOI: 10.4161/psb.26116] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 08/12/2013] [Indexed: 05/19/2023]
Abstract
With the exception of the grasses, plants rely on a reduction-based iron (Fe) uptake system that is compromised by high soil pH, leading to severe chlorosis and reduced yield in crop plants. We recently reported that iron deficiency triggers the production of secondary metabolites that are beneficial for Fe uptake in particular at high external pH when iron is present but not readily available. The exact function of these metabolites, however, remains enigmatic. Here, we speculate on the mechanism by which secondary metabolites secreted by roots from Fe-deficient plants improve Fe acquisition. We suggest that the production and excretion of Iron Binding Compounds (IBCs) constitute an integrative, pH-insensitive component of the reduction-based iron uptake strategy in plants.
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Silva MR, Mansurova M, Gärtner W, Thiel W. Photophysics of structurally modified flavin derivatives in the blue-light photoreceptor YtvA: a combined experimental and theoretical study. Chembiochem 2013; 14:1648-61. [PMID: 23940057 DOI: 10.1002/cbic.201300217] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Indexed: 11/10/2022]
Abstract
The light-induced processes of two flavin mononucleotide derivatives (1- and 5-deaza flavin mononucleotide, 1DFMN and 5DFMN), incorporated into the LOV domain of YtvA protein from Bacillus subtilis, were studied by a combination of experimental and computational methods. Quantum mechanics/molecular mechanics (QM/MM) calculations were carried out in which the QM part was treated by density functional theory (DFT) using the B3LYP functional for geometry optimizations and the DFT/MRCI method for spectroscopic properties, whereas the MM part was described by the CHARMM force field. 1DFMN is incorporated into the protein binding site, yielding a red-shifted absorption band (λ(max) =530 nm compared to YtvA wild-type λ(max) =445 nm), but does not undergo any LOV-typical photoreactions such as triplet and photoadduct formation. QM/MM computations confirmed the absence of a channel for triplet formation and located a radiation-free channel (through an S₁/S₀ conical intersection) along a hydrogen transfer path that might allow for fast deactivation. By contrast, 5DFMN-YtvA-LOV shows a blue-shifted absorption (λ(max) =410 nm) and undergoes similar photochemical processes to FMN in the wild-type protein, both with regard to the photophysics and the formation of a photoadduct with a flavin-cysteinyl covalent bond. The QM/MM calculations predict a mechanism that involves hydrogen transfer in the T₁ state, followed by intersystem crossing and adduct formation in the S₀ state for the forward reaction. Experimentally, in contrast to wild-type YtvA, dark-state recovery in 5DFMN-YtvA-LOV is not thermally driven but can only be accomplished after absorption of a second photon by the photoadduct, again via the triplet state. The QM/MM calculations suggest a photochemical mechanism for dark-state recovery that is accessible only for the adduct with a C4a--S bond but not for alternative adducts with a C5--S bond.
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Affiliation(s)
- Mario R Silva
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany)
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Xu N, Ahuja EG, Janning P, Mavrodi DV, Thomashow LS, Blankenfeldt W. Trapped intermediates in crystals of the FMN-dependent oxidase PhzG provide insight into the final steps of phenazine biosynthesis. Acta Crystallogr D Biol Crystallogr 2013; 69:1403-13. [PMID: 23897464 DOI: 10.1107/s0907444913008354] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 03/26/2013] [Indexed: 11/10/2022]
Abstract
Phenazines are redox-active secondary metabolites that many bacteria produce and secrete into the environment. They are broad-specificity antibiotics, but also act as virulence and survival factors in infectious diseases. Phenazines are derived from chorismic acid, but important details of their biosynthesis are still unclear. For example, three two-electron oxidations seem to be necessary in the final steps of the pathway, while only one oxidase, the FMN-dependent PhzG, is conserved in the phenazine-biosynthesis phz operon. Here, crystal structures of PhzG from Pseudomonas fluorescens 2-79 and from Burkholderia lata 383 in complex with excess FMN and with the phenazine-biosynthesis intermediates hexahydrophenazine-1,6-dicarboxylate and tetrahydrophenazine-1-carboxylate generated in situ are reported. Corroborated with biochemical data, these complexes demonstrate that PhzG is the terminal enzyme in phenazine biosynthesis and that its relaxed substrate specificity lets it participate in the generation of both phenazine-1,6-dicarboxylic acid (PDC) and phenazine-1-carboxylic acid (PCA). This suggests that competition between flavin-dependent oxidations through PhzG and spontaneous oxidative decarboxylations determines the ratio of PDC, PCA and unsubstituted phenazine as the products of phenazine biosynthesis. Further, the results indicate that PhzG synthesizes phenazines in their reduced form. These reduced molecules, and not the fully aromatized derivatives, are the likely end products in vivo, explaining why only one oxidase is required in the phenazine-biosynthesis pathway.
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Affiliation(s)
- Ningna Xu
- Lehrstuhl für Biochemie, Universität Bayreuth, Universitätsstrasse 30, 95447 Bayreuth, Germany
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Staudt H, Hoesl MG, Dreuw A, Serdjukow S, Oesterhelt D, Budisa N, Wachtveitl J, Grininger M. Directed manipulation of a flavoprotein photocycle. Angew Chem Int Ed Engl 2013; 52:8463-6. [PMID: 23818044 DOI: 10.1002/anie.201302334] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Indexed: 11/06/2022]
Affiliation(s)
- Heike Staudt
- Institut für Physikalische and Theoretische Chemie, Exzellenzcluster Makromolekulare Komplexe, Goethe Universität Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt am Main, Germany
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Lee M, Hong J, Seo DH, Nam DH, Nam KT, Kang K, Park CB. Redox cofactor from biological energy transduction as molecularly tunable energy-storage compound. Angew Chem Int Ed Engl 2013; 52:8322-8. [PMID: 23784869 DOI: 10.1002/anie.201301850] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Minah Lee
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
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Iyanagi T, Xia C, Kim JJP. NADPH-cytochrome P450 oxidoreductase: prototypic member of the diflavin reductase family. Arch Biochem Biophys 2012; 528:72-89. [PMID: 22982532 PMCID: PMC3606592 DOI: 10.1016/j.abb.2012.09.002] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Revised: 09/01/2012] [Accepted: 09/03/2012] [Indexed: 12/31/2022]
Abstract
NADPH-cytochrome P450 oxidoreductase (CYPOR) and nitric oxide synthase (NOS), two members of the diflavin oxidoreductase family, are multi-domain enzymes containing distinct FAD and FMN domains connected by a flexible hinge. FAD accepts a hydride ion from NADPH, and reduced FAD donates electrons to FMN, which in turn transfers electrons to the heme center of cytochrome P450 or NOS oxygenase domain. Structural analysis of CYPOR, the prototype of this enzyme family, has revealed the exact nature of the domain arrangement and the role of residues involved in cofactor binding. Recent structural and biophysical studies of CYPOR have shown that the two flavin domains undergo large domain movements during catalysis. NOS isoforms contain additional regulatory elements within the reductase domain that control electron transfer through Ca(2+)-dependent calmodulin (CaM) binding. The recent crystal structure of an iNOS Ca(2+)/CaM-FMN construct, containing the FMN domain in complex with Ca(2+)/CaM, provided structural information on the linkage between the reductase and oxgenase domains of NOS, making it possible to model the holo iNOS structure. This review summarizes recent advances in our understanding of the dynamics of domain movements during CYPOR catalysis and the role of the NOS diflavin reductase domain in the regulation of NOS isozyme activities.
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Affiliation(s)
- Takashi Iyanagi
- Department of Biochemistry, Medical College of Wisconsin, USA
- Department of Life Science, The Himeji Institute of Technology, University of Hyogo, Japan
| | - Chuanwu Xia
- Department of Biochemistry, Medical College of Wisconsin, USA
| | - Jung-Ja P. Kim
- Department of Biochemistry, Medical College of Wisconsin, USA
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Forneris F, Rovida S, Heuts DPHM, Fraaije MW, Mattevi A. Crystallization and preliminary X-ray analysis of an alditol oxidase from Streptomyces coelicolor A3(2). Acta Crystallogr Sect F Struct Biol Cryst Commun 2006; 62:1298-300. [PMID: 17142922 PMCID: PMC2225352 DOI: 10.1107/s1744309106051128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2006] [Accepted: 11/27/2006] [Indexed: 11/10/2022]
Abstract
Alditol oxidase is a 45 kDa enzyme containing a covalently bound FAD cofactor. This oxidase efficiently oxidizes a range of alditols to the corresponding aldoses. Owing to its substrate range and regioselectivity, this enzyme is an interesting candidate for biotechnological applications. Crystals of alditol oxidase from Streptomyces coelicolor A3(2) were obtained by the hanging-drop vapour-diffusion method and diffracted to 1.1 A resolution. The crystals belong to space group C2, with unit-cell parameters a = 107, b = 68, c = 58 A, beta = 94 degrees. Crystals of seleno-L-methionine-labelled alditol oxidase were obtained after seeding the crystallization drops with native microcrystals and showed a diffraction limit of 2.4 A.
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Affiliation(s)
- Federico Forneris
- Department of Genetics and Microbiology, University of Pavia, Via Ferrata 1, 27100 Pavia, Italy
| | - Stefano Rovida
- Department of Genetics and Microbiology, University of Pavia, Via Ferrata 1, 27100 Pavia, Italy
| | - Dominic P. H. M. Heuts
- Laboratory of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG, The Netherlands
| | - Marco W. Fraaije
- Laboratory of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG, The Netherlands
| | - Andrea Mattevi
- Department of Genetics and Microbiology, University of Pavia, Via Ferrata 1, 27100 Pavia, Italy
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Jäger-Vottero P, Dorne AJ, Jordanov J, Douce R, Joyard J. Redox chains in chloroplast envelope membranes: spectroscopic evidence for the presence of electron carriers, including iron-sulfur centers. Proc Natl Acad Sci U S A 1997; 94:1597-602. [PMID: 11038604 PMCID: PMC19837 DOI: 10.1073/pnas.94.4.1597] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have shown that envelope membranes from spinach chloroplasts contain (i) semiquinone and flavosemiquinone radicals, (ii) a series of iron-containing electron-transfer centers, and (iii) flavins (mostly FAD) loosely associated with proteins. In contrast, we were unable to detect any cytochrome in spinach chloroplast envelope membranes. In addition to a high spin [1Fe]3+ type protein associated with an EPR signal at g = 4.3, we observed two iron-sulfur centers, a [4Fe-4S]1+ and a [2Fe-2S]1+, associated with features, respectively, at g = 1.921 and g = 1.935, which were detected after reduction by NADPH and NADH, respectively. The [4Fe-4S] center, but not the [2Fe-2S] center, was also reduced by dithionite or 5-deazaflavin/oxalate. An unusual Fe-S center, named X, associated with a signal at g = 2.057, was also detected, which was reduced by dithionite but not by NADH or NADPH. Extremely fast spin-relaxation rates of flavin- and quinone-free radicals suggest their close proximity to the [4Fe-4S] cluster or the high-spin [1Fe]3+ center. Envelope membranes probably contain enzymatic activities involved in the formation and reduction of semiquinone radicals (quinol oxidase, NADPH-quinone, and NADPH-semiquinone reductases). The physiological significance of our results is discussed with respect to (i) the presence of desaturase activities in envelope membranes and (ii) the mechanisms involved in the export of protons to the cytosol, which partially regulate the stromal pH during photosynthesis. The characterization of such a wide variety of electron carriers in envelope membranes opens new fields of research on the functions of this membrane system within the plant cell.
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Affiliation(s)
- P Jäger-Vottero
- Département de Biologie Moléculaire et Structurale, Unité de Recherche Associée Centre National de la Recherche Scientifique n degrees 576, Université Joseph Fourier et Commissariat à l'Energie Atomique-Grenoble, F-38054, Grenoble cédex 9, France
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