1
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Wulansari D, Jeelani G, Yazaki E, Nozaki T. Identification and characterization of archaeal-type FAD synthase as a novel tractable drug target from the parasitic protozoa Entamoeba histolytica. mSphere 2024:e0034724. [PMID: 39189775 DOI: 10.1128/msphere.00347-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Accepted: 07/29/2024] [Indexed: 08/28/2024] Open
Abstract
Flavin adenine dinucleotide (FAD) is an essential cofactor for numerous flavoenzymes present in all living organisms. The biosynthesis of FAD from riboflavin involves two sequential reactions catalyzed by riboflavin kinase and flavin adenine dinucleotide synthase (FADS). Entamoeba histolytica, the protozoan parasite responsible for amebiasis, apparently lacks a gene encoding FADS that share similarity with bacterial and eukaryotic canonical FADS, yet it can synthesize FAD. In this study, we have identified the gene responsible for FADS and thoroughly characterized physiological and biochemical properties of FADS from E. histolytica. Phylogenetic analysis revealed that the gene was likely laterally transferred from archaea. The kinetic properties of recombinant EhFADS were consistent with the notion that EhFADS is of archaeal origin, exhibiting KM and kcat values similar to those of the arachaeal enzyme while significantly differing from the human counterpart. Repression of gene expression of EhFADS by epigenetic gene silencing caused substantial reduction in FAD levels and parasite growth, underscoring the importance of EhFADS for the parasite. Furthermore, we demonstrated that EhFADS gene silencing reduced thioredoxin reductase activity, which requires FAD as a cofactor and makes the ameba more susceptible to metronidazole. In summary, this study unveils unique evolutionary and biochemical features of EhFADS and underscores its significance as a promising drug target in combating human amebiasis.IMPORTANCEFAD is important for all forms of life, yet its role and metabolism are still poorly studied in E. histolytica, the protozoan parasite causing human amebiasis. Our study uncovers the evolutionary unique key enzyme, archaeal-type FADS for FAD biosynthesis from E. histolytica for the first time. Additionally, we showed the essentiality of this enzyme for parasite survival, highlighting its potential as target for drug development against E. histolytica infections.
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Affiliation(s)
- Dewi Wulansari
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- National Research and Innovation Agency, Jakarta, Indonesia
| | - Ghulam Jeelani
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Euki Yazaki
- Research Center for Advanced Analysis, National Agriculture and Food Research Organization, Ibaraki, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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2
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Blomberg MRA, Ädelroth P. Reduction of molecular oxygen in flavodiiron proteins - Catalytic mechanism and comparison to heme-copper oxidases. J Inorg Biochem 2024; 255:112534. [PMID: 38552360 DOI: 10.1016/j.jinorgbio.2024.112534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 03/15/2024] [Accepted: 03/18/2024] [Indexed: 04/16/2024]
Abstract
The family of flavodiiron proteins (FDPs) plays an important role in the scavenging and detoxification of both molecular oxygen and nitric oxide. Using electrons from a flavin mononucleotide cofactor molecular oxygen is reduced to water and nitric oxide is reduced to nitrous oxide and water. While the mechanism for NO reduction in FDPs has been studied extensively, there is very little information available about O2 reduction. Here we use hybrid density functional theory (DFT) to study the mechanism for O2 reduction in FDPs. An important finding is that a proton coupled reduction is needed after the O2 molecule has bound to the diferrous diiron active site and before the OO bond can be cleaved. This is in contrast to the mechanism for NO reduction, where both NN bond formation and NO bond cleavage occurs from the same starting structure without any further reduction, according to both experimental and computational results. This computational result for the O2 reduction mechanism should be possible to evaluate experimentally. Another difference between the two substrates is that the actual OO bond cleavage barrier is low, and not involved in rate-limiting the reduction process, while the barrier connected with bond cleavage/formation in the NO reduction process is of similar height as the rate-limiting steps. We suggest that these results may be part of the explanation for the generally higher activity for O2 reduction as compared to NO reduction in most FDPs. Comparisons are also made to the O2 reduction reaction in the family of heme‑copper oxidases.
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Affiliation(s)
- Margareta R A Blomberg
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden.
| | - Pia Ädelroth
- Department of Biochemistry and Biophysics, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
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3
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Bracken AJ, Dong HT, Lengel MO, Lehnert N. Exploring second coordination sphere effects in flavodiiron nitric oxide reductase model complexes. Dalton Trans 2023; 52:17360-17374. [PMID: 37938109 DOI: 10.1039/d3dt02828c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
Flavodiiron nitric oxide reductases (FNORs) equip pathogens with resistance to nitric oxide (NO), an important immune defense agent in mammals, allowing these pathogens to proliferate in the human body, potentially causing chronic infections. Understanding the mechanism of how FNORs mediate the reduction of NO contributes to the greater goal of developing new therapeutic approaches against drug-resistant strains. Recent density functional theory calculations suggest that a second coordination sphere (SCS) tyrosine residue provides a hydrogen bond that is critical for the reduction of NO to N2O at the active site of FNORs [J. Lu, B. Bi, W. Lai and H. Chen, Origin of Nitric Oxide Reduction Activity in Flavo-Diiron NO Reductase: Key Roles of the Second Coordination Sphere, Angew. Chem., Int. Ed., 2019, 58, 3795-3799]. Specifically, this H-bond stabilizes the hyponitrite intermediate and reduces the energetic barrier for the N-N coupling step. At the same time, the role of the Fe⋯Fe distance and its effect on the N-N coupling step has not been fully investigated. In this study, we equipped the H[BPMP] (= 2,6-bis[[bis(2-pyridylmethyl)amino]methyl]-4-methylphenol) ligand with SCS amide groups and investigated the corresponding diiron complexes with 0-2 bridging acetate ligands. These amide groups can form hydrogen bonds with the bridging acetate ligand(s) and potentially the coordinated NO groups in these model complexes. At the same time, by changing the number of bridging acetate ligands, we can systematically vary the Fe⋯Fe distance. The reactivity of these complexes with NO was then investigated, and the formation of stable iron(II)-NO complexes was observed. Upon one-electron reduction, these NO complexes form Dinitrosyl Iron Complexes (DNICs), which were further characterized using IR and EPR spectroscopy.
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Affiliation(s)
- Abigail J Bracken
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA.
| | - Hai T Dong
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA.
| | - Michael O Lengel
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA.
| | - Nicolai Lehnert
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA.
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4
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Okabe S, Ye S, Lan X, Nukada K, Zhang H, Kobayashi K, Oshiki M. Oxygen tolerance and detoxification mechanisms of highly enriched planktonic anaerobic ammonium-oxidizing (anammox) bacteria. ISME COMMUNICATIONS 2023; 3:45. [PMID: 37137967 PMCID: PMC10156729 DOI: 10.1038/s43705-023-00251-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 04/11/2023] [Accepted: 04/19/2023] [Indexed: 05/05/2023]
Abstract
Oxygen is a key regulatory factor of anaerobic ammonium oxidation (anammox). Although the inhibitory effect of oxygen is evident, a wide range of oxygen sensitivities of anammox bacteria have been reported so far, which makes it difficult to model the marine nitrogen loss and design anammox-based technologies. Here, oxygen tolerance and detoxification mechanisms of four genera of anammox bacteria; one marine species ("Ca. Scalindua sp.") and four freshwater anammox species ("Ca. Brocadia sinica", "Ca. Brocadia sapporoensis", "Ca. Jettenia caeni", and "Ca. Kuenenia stuttgartiensis") were determined and then related to the activities of anti-oxidative enzymes. Highly enriched planktonic anammox cells were exposed to various levels of oxygen, and oxygen inhibition kinetics (50% inhibitory concentration (IC50) and upper O2 limits (DOmax) of anammox activity) were quantitatively determined. A marine anammox species, "Ca. Scalindua sp.", exhibited much higher oxygen tolerance capability (IC50 = 18.0 µM and DOmax = 51.6 µM) than freshwater species (IC50 = 2.7-4.2 µM and DOmax = 10.9-26.6 µM). The upper DO limit of "Ca. Scalindua sp." was much higher than the values reported so far (~20 µM). Furthermore, the oxygen inhibition was reversible even after exposed to ambient air for 12-24 h. The comparative genome analysis confirmed that all anammox species commonly possess the genes considered to function for reduction of O2, superoxide anion (O2•-), and H2O2. However, the superoxide reductase (Sor)-peroxidase dependent detoxification system alone may not be sufficient for cell survival under microaerobic conditions. Despite the fact that anaerobes normally possess no or little superoxide dismutase (Sod) or catalase (Cat), only Scalindua exhibited high Sod activity of 22.6 ± 1.9 U/mg-protein with moderate Cat activity of 1.6 ± 0.7 U/mg-protein, which was consistent with the genome sequence analysis. This Sod-Cat dependent detoxification system could be responsible for the higher O2 tolerance of Scalindua than other freshwater anammox species lacking the Sod activity.
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Affiliation(s)
- Satoshi Okabe
- Department of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan.
| | - Shaoyu Ye
- Department of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan
| | - Xi Lan
- Department of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan
| | - Keishi Nukada
- Department of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan
| | - Haozhe Zhang
- Department of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan
| | - Kanae Kobayashi
- Department of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan
- Super-cutting-edge Grand and Advanced Research (SUGAR) Program, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa, 237-0061, Japan
| | - Mamoru Oshiki
- Department of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido, 060-8628, Japan
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5
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Abdulaziz EN, Bell TA, Rashid B, Heacock ML, Begic T, Skinner OS, Yaseen MA, Chao LH, Mootha VK, Pierik AJ, Cracan V. A natural fusion of flavodiiron, rubredoxin, and rubredoxin oxidoreductase domains is a self-sufficient water-forming oxidase of Trichomonas vaginalis. J Biol Chem 2022; 298:102210. [PMID: 35780837 PMCID: PMC9364112 DOI: 10.1016/j.jbc.2022.102210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 06/23/2022] [Accepted: 06/24/2022] [Indexed: 11/29/2022] Open
Abstract
Microaerophilic pathogens such as Giardia lamblia, Entamoeba histolytica, and Trichomonas vaginalis have robust oxygen consumption systems to detoxify oxygen and maintain intracellular redox balance. This oxygen consumption results from H2O-forming NADH oxidase (NOX) activity of two distinct flavin-containing systems: H2O-forming NOXes and multicomponent flavodiiron proteins (FDPs). Neither system is membrane bound, and both recycle NADH into oxidized NAD+ while simultaneously removing O2 from the local environment. However, little is known about the specific contributions of these systems in T. vaginalis. In this study, we use bioinformatics and biochemical analyses to show that T. vaginalis lacks a NOX-like enzyme and instead harbors three paralogous genes (FDPF1-3), each encoding a natural fusion product between the N-terminal FDP, central rubredoxin (Rb), and C-terminal NADH:Rb oxidoreductase domains. Unlike a "stand-alone" FDP that lacks Rb and oxidoreductase domains, this natural fusion protein with fully populated flavin redox centers directly accepts reducing equivalents of NADH to catalyze the four-electron reduction of oxygen to water within a single polypeptide with an extremely high turnover. Furthermore, using single-particle cryo-EM, we present structural insights into the spatial organization of the FDP core within this multidomain fusion protein. Together, these results contribute to our understanding of systems that allow protozoan parasites to maintain optimal redox balance and survive transient exposure to oxic conditions.
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Affiliation(s)
- Evana N Abdulaziz
- Redox Biology and Metabolism Laboratory, Scintillon Institute, San Diego, California, USA
| | - Tristan A Bell
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Bazlur Rashid
- Faculty of Chemistry, University of Kaiserslautern, Kaiserslautern, Germany
| | - Mina L Heacock
- Redox Biology and Metabolism Laboratory, Scintillon Institute, San Diego, California, USA
| | - Tarik Begic
- Faculty of Chemistry, University of Kaiserslautern, Kaiserslautern, Germany
| | - Owen S Skinner
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA; Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Mohammad A Yaseen
- Department of Bioengineering, Northeastern University, Boston, Massachusetts, USA
| | - Luke H Chao
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Vamsi K Mootha
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA; Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Antonio J Pierik
- Faculty of Chemistry, University of Kaiserslautern, Kaiserslautern, Germany
| | - Valentin Cracan
- Redox Biology and Metabolism Laboratory, Scintillon Institute, San Diego, California, USA; Department of Chemistry, The Scripps Research Institute, La Jolla, California, USA.
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6
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White CJ, Lengel MO, Bracken AJ, Kampf JW, Speelman AL, Alp EE, Hu MY, Zhao J, Lehnert N. Distortion of the [FeNO] 2 Core in Flavodiiron Nitric Oxide Reductase Models Inhibits N-N Bond Formation and Promotes Formation of Unusual Dinitrosyl Iron Complexes: Implications for Catalysis and Reactivity. J Am Chem Soc 2022; 144:3804-3820. [PMID: 35212523 DOI: 10.1021/jacs.1c10388] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Flavodiiron nitric oxide reductases (FNORs) carry out the reduction of nitric oxide (NO) to nitrous oxide (N2O), allowing infectious pathogens to mitigate toxic levels of NO generated in the human immune response. We previously reported the model complex [Fe2(BPMP)(OPr)(NO)2](OTf)2 (1, OPr- = propionate) that contains two coplanar NO ligands and that is capable of quantitative NO reduction to N2O [White et al. J. Am. Chem. Soc. 2018, 140, 2562-2574]. Here we investigate, for the first time, how a distortion of the active site affects the ability of the diiron core to mediate N2O formation. For this purpose, we prepared several analogues of 1 that contain two monodentate ligands in place of the bridging carboxylate, [Fe2(BPMP)(X)2(NO)2]3+/1+ (2-X; X = triflate, 1-methylimidazole, or methanol). Structural data of 2-X show that without the bridging carboxylate, the diiron core expands, leading to elongated (O)N-N(O) distances (from 2.80 Å in 1 to 3.00-3.96 Å in 2-X) and distorted (O)N-Fe-Fe-N(O) dihedral angles (from coplanarity (5.9°) in 1 to 52.9-85.1° in 2-X). Whereas 1 produces quantitative amounts of N2O upon one-electron reduction, N2O production is substantially impeded in 2-X, to an initial 5-10% N2O yield. The main products after reduction are unprecedented hs-FeII/{Fe(NO)2}9/10 dinitrosyl iron complexes (DNICs). Even though mononuclear DNICs are stable and do not show N-N coupling (since it is a spin-forbidden process), the hs-FeII/{Fe(NO)2}9/10 DNICs obtained from 2-X show unexpected reactivity and produce up to quantitative N2O yields after 2 h. The implications of these results for the active site structure of FNORs are discussed.
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Affiliation(s)
- Corey J White
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Michael O Lengel
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Abigail J Bracken
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Jeff W Kampf
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Amy L Speelman
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - E Ercan Alp
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Michael Y Hu
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Jiyong Zhao
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Nicolai Lehnert
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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7
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Martínez-Pérez Y, Nequiz-Avendaño M, García-Torres I, Gudiño-Zayas ME, López-Velázquez G, Enríquez-Flores S, Mendoza E, Saavedra E, Pérez-Tamayo R, León-Avila G, Olivos-García A. Rabeprazole inhibits several functions of Entamoeba histolytica related with its virulence. Parasitol Res 2020; 119:3491-3502. [PMID: 32886229 DOI: 10.1007/s00436-020-06868-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/26/2020] [Indexed: 11/24/2022]
Abstract
Amoebiasis is a human parasitic disease caused by Entamoeba histolytica. The parasite can invade the large intestine and other organs such as liver; resistance to the host tissue oxygen is a condition for parasite invasion and survival. Thioredoxin reductase of E. histolytica (EhTrxR) is a critical enzyme mainly involved in maintaining reduced the redox system and detoxifying the intracellular oxygen; therefore, it is necessary for E. histolytica survival under both aerobic in vitro and in vivo conditions. In the present work, it is reported that rabeprazole (Rb), a drug widely used to treat heartburn, was able to inhibit the EhTrxR recombinant enzyme. Moreover, Rb affected amoebic proliferation and several functions required for parasite virulence such as cytotoxicity, oxygen reduction to hydrogen peroxide, erythrophagocytosis, proteolysis, and oxygen and complement resistances. In addition, amoebic pre-incubation with sublethal Rb concentration (600 μM) promoted amoebic death during early liver infection in hamsters. Despite the high Rb concentration used to inhibit amoebic virulence, the wide E. histolytica pathogenic-related functions affected by Rb strongly suggest that its molecular structure can be used as scaffold to design new antiamoebic compounds with lower IC50 values.
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Affiliation(s)
- Yoalli Martínez-Pérez
- Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Casco de Santo Tomás, Ciudad de México, 11340, México. .,Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México.
| | - Mario Nequiz-Avendaño
- Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México
| | - Itzhel García-Torres
- Grupo de Investigación en Biomoléculas y Salud Infantil, Laboratorio de EIMyT, Instituto Nacional de Pediatría, Ciudad de México, 04530, México
| | - Marco E Gudiño-Zayas
- Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México
| | - Gabriel López-Velázquez
- Grupo de Investigación en Biomoléculas y Salud Infantil, Laboratorio de EIMyT, Instituto Nacional de Pediatría, Ciudad de México, 04530, México
| | - Sergio Enríquez-Flores
- Grupo de Investigación en Biomoléculas y Salud Infantil, Laboratorio de EIMyT, Instituto Nacional de Pediatría, Ciudad de México, 04530, México
| | - Edith Mendoza
- Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México
| | - Emma Saavedra
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez, Ciudad de México, 14080, México
| | - Ruy Pérez-Tamayo
- Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México
| | - Gloria León-Avila
- Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Casco de Santo Tomás, Ciudad de México, 11340, México
| | - Alfonso Olivos-García
- Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México
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8
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Biswas S, Kurtz DM, Montoya SR, Hendrich MP, Bominaar EL. The Catalytic Role of a Conserved Tyrosine in Nitric Oxide-Reducing Non-heme Diiron Enzymes. ACS Catal 2020. [DOI: 10.1021/acscatal.0c01884] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Saborni Biswas
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Donald M. Kurtz
- Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Samuel R. Montoya
- Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Michael P. Hendrich
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Emile L. Bominaar
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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9
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Ferousi C, Majer SH, DiMucci IM, Lancaster KM. Biological and Bioinspired Inorganic N-N Bond-Forming Reactions. Chem Rev 2020; 120:5252-5307. [PMID: 32108471 PMCID: PMC7339862 DOI: 10.1021/acs.chemrev.9b00629] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The metallobiochemistry underlying the formation of the inorganic N-N-bond-containing molecules nitrous oxide (N2O), dinitrogen (N2), and hydrazine (N2H4) is essential to the lifestyles of diverse organisms. Similar reactions hold promise as means to use N-based fuels as alternative carbon-free energy sources. This review discusses research efforts to understand the mechanisms underlying biological N-N bond formation in primary metabolism and how the associated reactions are tied to energy transduction and organismal survival. These efforts comprise studies of both natural and engineered metalloenzymes as well as synthetic model complexes.
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Affiliation(s)
- Christina Ferousi
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Sean H Majer
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Ida M DiMucci
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Kyle M Lancaster
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
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10
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Lehnert N, Fujisawa K, Camarena S, Dong HT, White CJ. Activation of Non-Heme Iron-Nitrosyl Complexes: Turning Up the Heat. ACS Catal 2019. [DOI: 10.1021/acscatal.9b03219] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Nicolai Lehnert
- Department of Chemistry and Department of Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
| | - Kiyoshi Fujisawa
- Department of Chemistry, Ibaraki University, Mito 310-8512, Japan
| | - Stephanie Camarena
- Department of Chemistry and Department of Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
| | - Hai T. Dong
- Department of Chemistry and Department of Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
| | - Corey J. White
- Department of Chemistry and Department of Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
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11
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Folgosa F, Martins MC, Teixeira M. Diversity and complexity of flavodiiron NO/O2 reductases. FEMS Microbiol Lett 2019; 365:4733271. [PMID: 29240952 DOI: 10.1093/femsle/fnx267] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 12/11/2017] [Indexed: 11/14/2022] Open
Abstract
Flavodiiron proteins (FDPs) are a family of enzymes endowed with nitric oxide (NO) or oxygen reductase activities, forming the innocuous nitrous oxide (N2O) or water molecules, respectively. FDPs are widespread in the three life kingdoms, and have a modular nature, being each monomer minimally constituted by a metallo-β-lactamase-like domain containing a catalytic diiron centre, followed by a flavodoxin one, with a flavin mononucleotide. Since their discovery, additional domains have been found in FDPs, attached to the C-terminus, and containing either extra metal (iron) centers or extra flavin binding modules. Following an extensive analysis of genomic databases, we identified novel domain compositions, and proposed a new classification of FDPs in eight classes based on the nature and number of extra domains.
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12
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Martins MC, Romão CV, Folgosa F, Borges PT, Frazão C, Teixeira M. How superoxide reductases and flavodiiron proteins combat oxidative stress in anaerobes. Free Radic Biol Med 2019; 140:36-60. [PMID: 30735841 DOI: 10.1016/j.freeradbiomed.2019.01.051] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 01/14/2019] [Accepted: 01/31/2019] [Indexed: 12/31/2022]
Abstract
Microbial anaerobes are exposed in the natural environment and in their hosts, even if transiently, to fluctuating concentrations of oxygen and its derived reactive species, which pose a considerable threat to their anoxygenic lifestyle. To counteract these stressful conditions, they contain a multifaceted array of detoxifying systems that, in conjugation with cellular repairing mechanisms and in close crosstalk with metal homeostasis, allow them to survive in the presence of O2 and reactive oxygen species. Some of these systems are shared with aerobes, but two families of enzymes emerged more recently that, although not restricted to anaerobes, are predominant in anaerobic microbes. These are the iron-containing superoxide reductases, and the flavodiiron proteins, endowed with O2 and/or NO reductase activities, which are the subject of this Review. A detailed account of their physicochemical, physiological and molecular mechanisms will be presented, highlighting their unique properties in allowing survival of anaerobes in oxidative stress conditions, and comparing their properties with the most well-known detoxifying systems.
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Affiliation(s)
- Maria C Martins
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Célia V Romão
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Filipe Folgosa
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Patrícia T Borges
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Carlos Frazão
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Miguel Teixeira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal.
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Dong HT, White CJ, Zhang B, Krebs C, Lehnert N. Non-Heme Diiron Model Complexes Can Mediate Direct NO Reduction: Mechanistic Insight into Flavodiiron NO Reductases. J Am Chem Soc 2018; 140:13429-13440. [DOI: 10.1021/jacs.8b08567] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hai T. Dong
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Corey J. White
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Bo Zhang
- Department of Chemistry and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Carsten Krebs
- Department of Chemistry and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Nicolai Lehnert
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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The multidomain flavodiiron protein from Clostridium difficile 630 is an NADH:oxygen oxidoreductase. Sci Rep 2018; 8:10164. [PMID: 29977056 PMCID: PMC6033852 DOI: 10.1038/s41598-018-28453-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 06/20/2018] [Indexed: 01/05/2023] Open
Abstract
Flavodiiron proteins (FDPs) are enzymes with a minimal core of two domains: a metallo-β-lactamase-like, harbouring a diiron center, and a flavodoxin, FMN containing, domains. FDPs are O2 or NO reducing enzymes; for many pathogens, they help mitigate the NO produced by the immune system of the host, and aid survival during fluctuating concentrations concentrations of oxygen. FDPs have a mosaic structure, being predicted to contain multiple extra domains. Clostridium difficile, a threatening human pathogen, encodes two FDPs: one with the two canonical domains, and another with a larger polypeptide chain of 843 amino acids, CD1623, with two extra domains, predicted to be a short-rubredoxin-like and an NAD(P)H:rubredoxin oxidoreductase. This multi-domain protein is the most complex FDP characterized thus far. Each of the predicted domains was characterized and the presence of the predicted cofactors confirmed by biochemical and spectroscopic analysis. Results show that this protein operates as a standalone FDP, receiving electrons directly from NADH, and reducing oxygen to water, precluding the need for extra partners. CD1623 displayed negligible NO reductase activity, and is thus considered an oxygen selective FDP, that may contribute to the survival of C. difficile in the human gut and in the environment.
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Romão CV, Vicente JB, Borges PT, Victor BL, Lamosa P, Silva E, Pereira L, Bandeiras TM, Soares CM, Carrondo MA, Turner D, Teixeira M, Frazão C. Structure of Escherichia coli Flavodiiron Nitric Oxide Reductase. J Mol Biol 2016; 428:4686-4707. [PMID: 27725182 DOI: 10.1016/j.jmb.2016.10.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 10/02/2016] [Accepted: 10/04/2016] [Indexed: 01/08/2023]
Abstract
Flavodiiron proteins (FDPs) are present in organisms from all domains of life and have been described so far to be involved in the detoxification of oxygen or nitric oxide (NO), acting as O2 and/or NO reductases. The Escherichia coli FDP, named flavorubredoxin (FlRd), is the most extensively studied FDP. Biochemical and in vivo studies revealed that FlRd is involved in NO detoxification as part of the bacterial defense mechanisms against reactive nitrogen species. E. coli FlRd has a clear preference for NO as a substrate in vitro, exhibiting a very low reactivity toward O2. To contribute to the understanding of the structural features defining this substrate selectivity, we determined the crystallographic structure of E. coli FlRd, both in the isolated and reduced states. The overall tetrameric structure revealed a highly conserved flavodiiron core domain, with a metallo-β-lactamase-like domain containing a diiron center, and a flavodoxin domain with a flavin mononucleotide cofactor. The metal center in the oxidized state has a μ-hydroxo bridge coordinating the two irons, while in the reduced state, this moiety is not detected. Since only the flavodiiron domain was observed in these crystal structures, the structure of the rubredoxin domain was determined by NMR. Tunnels for the substrates were identified, and through molecular dynamics simulations, no differences for O2 or NO permeation were found. The present data represent the first structure for a NO-selective FDP.
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Affiliation(s)
- Célia V Romão
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Av. da República, 2780-157 Oeiras, Portugal
| | - João B Vicente
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Av. da República, 2780-157 Oeiras, Portugal
| | - Patrícia T Borges
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Av. da República, 2780-157 Oeiras, Portugal
| | - Bruno L Victor
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Av. da República, 2780-157 Oeiras, Portugal
| | - Pedro Lamosa
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Av. da República, 2780-157 Oeiras, Portugal
| | - Elísio Silva
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Av. da República, 2780-157 Oeiras, Portugal
| | - Luís Pereira
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Av. da República, 2780-157 Oeiras, Portugal
| | - Tiago M Bandeiras
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Av. da República, 2780-157 Oeiras, Portugal; Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal
| | - Cláudio M Soares
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Av. da República, 2780-157 Oeiras, Portugal
| | - Maria A Carrondo
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Av. da República, 2780-157 Oeiras, Portugal
| | - David Turner
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Av. da República, 2780-157 Oeiras, Portugal
| | - Miguel Teixeira
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Av. da República, 2780-157 Oeiras, Portugal.
| | - Carlos Frazão
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Av. da República, 2780-157 Oeiras, Portugal.
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Antioxidant defence systems in the protozoan pathogen Giardia intestinalis. Mol Biochem Parasitol 2016; 206:56-66. [DOI: 10.1016/j.molbiopara.2015.12.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 11/26/2015] [Accepted: 12/01/2015] [Indexed: 01/03/2023]
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Romão CV, Vicente JB, Borges PT, Frazão C, Teixeira M. The dual function of flavodiiron proteins: oxygen and/or nitric oxide reductases. J Biol Inorg Chem 2016; 21:39-52. [PMID: 26767750 DOI: 10.1007/s00775-015-1329-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 12/28/2015] [Indexed: 12/27/2022]
Abstract
Flavodiiron proteins have emerged in the last two decades as a newly discovered family of oxygen and/or nitric oxide reductases widespread in the three life domains, and present in both aerobic and anaerobic organisms. Herein we present the main features of these fascinating enzymes, with a particular emphasis on the metal sites, as more appropriate for this special issue in memory of the exceptional bioinorganic scientist R. J. P. Williams who pioneered the notion of (metal) element availability-driven evolution. We also compare the flavodiiron proteins with the other oxygen and nitric oxide reductases known until now, highlighting how throughout evolution Nature arrived at different solutions for similar functions, in some cases adding extra features, such as energy conservation. These enzymes are an example of the (bioinorganic) unpredictable diversity of the living world.
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Affiliation(s)
- Célia V Romão
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República (EAN), 2780-157, Oeiras, Portugal
| | - João B Vicente
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República (EAN), 2780-157, Oeiras, Portugal
| | - Patrícia T Borges
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República (EAN), 2780-157, Oeiras, Portugal
| | - Carlos Frazão
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República (EAN), 2780-157, Oeiras, Portugal
| | - Miguel Teixeira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República (EAN), 2780-157, Oeiras, Portugal.
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18
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Ansell BRE, McConville MJ, Ma'ayeh SY, Dagley MJ, Gasser RB, Svärd SG, Jex AR. Drug resistance in Giardia duodenalis. Biotechnol Adv 2015; 33:888-901. [PMID: 25922317 DOI: 10.1016/j.biotechadv.2015.04.009] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 04/21/2015] [Accepted: 04/21/2015] [Indexed: 02/07/2023]
Abstract
Giardia duodenalis is a microaerophilic parasite of the human gastrointestinal tract and a major contributor to diarrheal and post-infectious chronic gastrointestinal disease world-wide. Treatment of G. duodenalis infection currently relies on a small number of drug classes. Nitroheterocyclics, in particular metronidazole, have represented the front line treatment for the last 40 years. Nitroheterocyclic-resistant G. duodenalis have been isolated from patients and created in vitro, prompting considerable research into the biomolecular mechanisms of resistance. These compounds are redox-active and are believed to damage proteins and DNA after being activated by oxidoreductase enzymes in metabolically active cells. In this review, we explore the molecular phenotypes of nitroheterocyclic-resistant G. duodenalis described to date in the context of the protist's unusual glycolytic and antioxidant systems. We propose that resistance mechanisms are likely to extend well beyond currently described resistance-associated enzymes (i.e., pyruvate ferredoxin oxidoreductases and nitroreductases), to include NAD(P)H- and flavin-generating pathways, and possibly redox-sensitive epigenetic regulation. Mechanisms that allow G. duodenalis to tolerate oxidative stress may lead to resistance against both oxygen and nitroheterocyclics, with implications for clinical control. The present review highlights the potential for systems biology tools and advanced bioinformatics to further investigate the multifaceted mechanisms of nitroheterocyclic resistance in this important pathogen.
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Affiliation(s)
- Brendan R E Ansell
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Cnr Park Dr and Flemington Rd, Parkville, VIC 3010, Australia.
| | - Malcolm J McConville
- Bio21 Institute, University of Melbourne, 30 Flemington Rd, Parkville, VIC 3010, Australia
| | - Showgy Y Ma'ayeh
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Box 596, SE-751 24 Uppsala, Sweden
| | - Michael J Dagley
- Bio21 Institute, University of Melbourne, 30 Flemington Rd, Parkville, VIC 3010, Australia
| | - Robin B Gasser
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Cnr Park Dr and Flemington Rd, Parkville, VIC 3010, Australia
| | - Staffan G Svärd
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Box 596, SE-751 24 Uppsala, Sweden
| | - Aaron R Jex
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Cnr Park Dr and Flemington Rd, Parkville, VIC 3010, Australia
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Frederick RE, Caranto JD, Masitas CA, Gebhardt LL, MacGowan CE, Limberger RJ, Kurtz DM. Dioxygen and nitric oxide scavenging by Treponema denticola flavodiiron protein: a mechanistic paradigm for catalysis. J Biol Inorg Chem 2015; 20:603-13. [PMID: 25700637 PMCID: PMC4768905 DOI: 10.1007/s00775-015-1248-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 02/13/2015] [Indexed: 10/24/2022]
Abstract
Flavodiiron proteins (FDPs) contain a unique active site consisting of a non-heme diiron carboxylate site proximal to a flavin mononucleotide (FMN). FDPs serve as the terminal components for reductive scavenging of dioxygen (to water) or nitric oxide (to nitrous oxide), which combats oxidative or nitrosative stress in many bacteria. Characterizations of FDPs from spirochetes or from any oral microbes have not been previously reported. Here, we report characterization of an FDP from the anaerobic spirochete, Treponema (T.) denticola, which is associated with chronic periodontitis. The isolated T. denticola FDP exhibited efficient four-electron dioxygen reductase activity and lower but significant anaerobic nitric oxide reductase activity. A mutant T. denticola strain containing the inactivated FDP-encoding gene was significantly more air-sensitive than the wild-type strain. Single turnover reactions of the four-electron-reduced FDP (FMNH2-Fe(II)Fe(II)) (FDPred) with O2 monitored on the milliseconds to seconds time scale indicated initial rapid formation of a spectral feature consistent with a cis-μ-1,2-peroxo-diferric intermediate, which triggered two-electron oxidation of FMNH2. Reaction of FDPred with NO showed apparent cooperativity between binding of the first and second NO to the diferrous site. The resulting diferrous dinitrosyl complex triggered two-electron oxidation of the FMNH2. Our cumulative results on this and other FDPs indicate that smooth two-electron FMNH2 oxidation triggered by the FDPred/substrate complex and overall four-electron oxidation of FDPred to FDPox constitutes a mechanistic paradigm for both dioxygen and nitric oxide reductase activities of FDPs. Four-electron reductive O2 scavenging by FDPs could contribute to oxidative stress protection in many other oral bacteria.
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Affiliation(s)
- Rosanne E. Frederick
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Jonathan D. Caranto
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Cesar A. Masitas
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Linda L. Gebhardt
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
| | - Charles E. MacGowan
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
| | - Ronald J. Limberger
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
| | - Donald M. Kurtz
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
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Cabeza MS, Guerrero SA, Iglesias AA, Arias DG. New enzymatic pathways for the reduction of reactive oxygen species in Entamoeba histolytica. Biochim Biophys Acta Gen Subj 2015; 1850:1233-44. [PMID: 25725270 DOI: 10.1016/j.bbagen.2015.02.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Revised: 02/13/2015] [Accepted: 02/17/2015] [Indexed: 11/26/2022]
Abstract
BACKGROUND Entamoeba histolytica, an intestinal parasite that is the causative agent of amoebiasis, is exposed to elevated amounts of highly toxic reactive oxygen and nitrogen species during tissue invasion. A flavodiiron protein and a rubrerythrin have been characterized in this human pathogen, although their physiological reductants have not been identified. METHODS The present work deals with biochemical studies performed to reach a better understanding of the kinetic and structural properties of rubredoxin reductase and two ferredoxins from E. histolytica. RESULTS We complemented the characterization of two different metabolic pathways for O2 and H2O2 detoxification in E. histolytica. We characterized a novel amoebic protein with rubredoxin reductase activity that is able to catalyze the NAD(P)H-dependent reduction of heterologous rubredoxins, amoebic rubrerythrin and flavodiiron protein but not ferredoxins. In addition, the protein exhibited an NAD(P)H oxidase activity, which generates hydrogen peroxide from molecular oxygen. We describe how different ferredoxins were also efficient reducing substrates for both flavodiiron protein and rubrerythrin. CONCLUSIONS The enzymatic systems herein characterized could contribute to the in vivo detoxification of O2 and H2O2, playing a key role for the parasite defense against reactive oxidant species. GENERAL SIGNIFICANCE To the best of our knowledge this is the first characterization of a eukaryotic rubredoxin reductase, including a novel kinetic study on ferredoxin-dependent reduction of flavodiiron and rubrerythrin proteins.
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Affiliation(s)
- Matías S Cabeza
- Instituto de Agrobiotecnología del Litoral-Facultad de Bioquímica y Ciencias Biológicas (CONICET-Universidad Nacional del Litoral), Santa Fe, Argentina
| | - Sergio A Guerrero
- Instituto de Agrobiotecnología del Litoral-Facultad de Bioquímica y Ciencias Biológicas (CONICET-Universidad Nacional del Litoral), Santa Fe, Argentina
| | - Alberto A Iglesias
- Instituto de Agrobiotecnología del Litoral-Facultad de Bioquímica y Ciencias Biológicas (CONICET-Universidad Nacional del Litoral), Santa Fe, Argentina
| | - Diego G Arias
- Instituto de Agrobiotecnología del Litoral-Facultad de Bioquímica y Ciencias Biológicas (CONICET-Universidad Nacional del Litoral), Santa Fe, Argentina.
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