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Tejero J, Gladwin MT. The globin superfamily: functions in nitric oxide formation and decay. Biol Chem 2014; 395:631-9. [PMID: 24477516 DOI: 10.1515/hsz-2013-0289] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 01/27/2014] [Indexed: 11/15/2022]
Abstract
Globin proteins are ubiquitous in living organisms and carry out a variety of functions related to the ability of their prosthetic heme group to bind gaseous ligands, such as oxygen, nitric oxide (NO), and CO. Moreover, they catalyze important reactions with nitrogen oxide species, such as NO dioxygenation and nitrite reduction. The formation of NO from nitrite is a reaction catalyzed by globins that has received increasing attention due to its potential as a hypoxic NO signaling mechanism. In this review, we revisit the current knowledge about the role of globins in NO formation and its physiological implications.
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52
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Du JF, Li W, Li L, Wen GB, Lin YW, Tan X. Regulating the coordination state of a heme protein by a designed distal hydrogen-bonding network. ChemistryOpen 2014; 4:97-101. [PMID: 25969804 PMCID: PMC4420578 DOI: 10.1002/open.201402108] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Indexed: 01/03/2023] Open
Abstract
Heme coordination state determines the functional diversity of heme proteins. Using myoglobin as a model protein, we designed a distal hydrogen-bonding network by introducing both distal glutamic acid (Glu29) and histidine (His43) residues and regulated the heme into a bis-His coordination state with native ligands His64 and His93. This resembles the heme site in natural bis-His coordinated heme proteins such as cytoglobin and neuroglobin. A single mutation of L29E or F43H was found to form a distinct hydrogen-bonding network involving distal water molecules, instead of the bis-His heme coordination, which highlights the importance of the combination of multiple hydrogen-bonding interactions to regulate the heme coordination state. Kinetic studies further revealed that direct coordination of distal His64 to the heme iron negatively regulates fluoride binding and hydrogen peroxide activation by competing with the exogenous ligands. The new approach developed in this study can be generally applicable for fine-tuning the structure and function of heme proteins.
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Affiliation(s)
- Jun-Fang Du
- School of Chemistry and Chemical Engineering, University of South China Hengyang, 421001, (P. R. China))
| | - Wei Li
- Department of Chemistry and Institute of Biomedical Science, Fudan University Shanghai, 200433, (P. R. China)
| | - Lianzhi Li
- School of Chemistry and Chemical Engineering, Liaocheng University Liaocheng, 252059, (P. R. China)
| | - Ge-Bo Wen
- Laboratory of Protein Structure and Function, University of South China Hengyang, 421001, (P. R. China)
| | - Ying-Wu Lin
- School of Chemistry and Chemical Engineering, University of South China Hengyang, 421001, (P. R. China)) ; Laboratory of Protein Structure and Function, University of South China Hengyang, 421001, (P. R. China)
| | - Xiangshi Tan
- Department of Chemistry and Institute of Biomedical Science, Fudan University Shanghai, 200433, (P. R. China)
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Uppal S, Salhotra S, Mukhi N, Zaidi FK, Seal M, Dey SG, Bhat R, Kundu S. Significantly enhanced heme retention ability of myoglobin engineered to mimic the third covalent linkage by nonaxial histidine to heme (vinyl) in synechocystis hemoglobin. J Biol Chem 2014; 290:1979-93. [PMID: 25451928 DOI: 10.1074/jbc.m114.603225] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Heme proteins, which reversibly bind oxygen and display a particular fold originally identified in myoglobin (Mb), characterize the "hemoglobin (Hb) superfamily." The long known and widely investigated Hb superfamily, however, has been enriched by the discovery and investigation of new classes and members. Truncated Hbs typify such novel classes and exhibit a distinct two-on-two α-helical fold. The truncated Hb from the freshwater cyanobacterium Synechocystis exhibits hexacoordinate heme chemistry and bears an unusual covalent bond between the nonaxial His(117) and a heme porphyrin 2-vinyl atom, which remains tightly associated with the globin unlike any other. It seems to be the most stable Hb known to date, and His(117) is the dominant force holding the heme. Mutations of amino acid residues in the vicinity did not influence this covalent linkage. Introduction of a nonaxial His into sperm whale Mb at the topologically equivalent position and in close proximity to vinyl group significantly increased the heme stability of this prototype globin. Reversed phase chromatography, electrospray ionization-MS, and MALDI-TOF analyses confirmed the presence of covalent linkage in Mb I107H. The Mb mutant with the engineered covalent linkage was stable to denaturants and exhibited ligand binding and auto-oxidation rates similar to the wild type protein. This indeed is a novel finding and provides a new perspective to the evolution of Hbs. The successful attempt at engineering heme stability holds promise for the production of stable Hb-based blood substitute.
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Affiliation(s)
- Sheetal Uppal
- From the Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | - Shikha Salhotra
- From the Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | - Nitika Mukhi
- From the Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | - Fatima Kamal Zaidi
- the School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India, and
| | - Manas Seal
- the Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Somdatta Ghosh Dey
- the Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Rajiv Bhat
- the School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India, and
| | - Suman Kundu
- From the Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India,
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54
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Ascenzi P, di Masi A, Tundo GR, Pesce A, Visca P, Coletta M. Nitrosylation mechanisms of Mycobacterium tuberculosis and Campylobacter jejuni truncated hemoglobins N, O, and P. PLoS One 2014; 9:e102811. [PMID: 25051055 PMCID: PMC4106858 DOI: 10.1371/journal.pone.0102811] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 06/23/2014] [Indexed: 01/19/2023] Open
Abstract
Truncated hemoglobins (trHbs) are widely distributed in bacteria and plants and have been found in some unicellular eukaryotes. Phylogenetic analysis based on protein sequences shows that trHbs branch into three groups, designated N (or I), O (or II), and P (or III). Most trHbs are involved in the O2/NO chemistry and/or oxidation/reduction function, permitting the survival of the microorganism in the host. Here, a detailed comparative analysis of kinetics and/or thermodynamics of (i) ferrous Mycobacterium tubertulosis trHbs N and O (Mt-trHbN and Mt-trHbO, respectively), and Campylobacter jejuni trHb (Cj-trHbP) nitrosylation, (ii) nitrite-mediated nitrosylation of ferrous Mt-trHbN, Mt-trHbO, and Cj-trHbP, and (iii) NO-based reductive nitrosylation of ferric Mt-trHbN, Mt-trHbO, and Cj-trHbP is reported. Ferrous and ferric Mt-trHbN and Cj-trHbP display a very high reactivity towards NO; however, the conversion of nitrite to NO is facilitated primarily by ferrous Mt-trHbN. Values of kinetic and/or thermodynamic parameters reflect specific trHb structural features, such as the ligand diffusion pathways to/from the heme, the heme distal pocket structure and polarity, and the ligand stabilization mechanisms. In particular, the high reactivity of Mt-trHbN and Cj-trHbP reflects the great ligand accessibility to the heme center by two protein matrix tunnels and the E7-path, respectively, and the penta-coordination of the heme-Fe atom. In contrast, the heme-Fe atom of Mt-trHbO the ligand accessibility to the heme center of Mt-trHbO needs large conformational readjustments, thus limiting the heme-based reactivity. These results agree with different roles of Mt-trHbN, Mt-trHbO, and Cj-trHbP in vivo.
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Affiliation(s)
- Paolo Ascenzi
- Interdepartmental Laboratory of Electron Microscopy, University Roma Tre, Roma, Italy
- * E-mail:
| | - Alessandra di Masi
- Interdepartmental Laboratory of Electron Microscopy, University Roma Tre, Roma, Italy
- Department of Sciences, University Roma Tre, Roma, Italy
| | - Grazia R. Tundo
- Department of Clinical Sciences and Translational Medicine, University of Roma “Tor Vergata”, Roma, Italy
- Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems, Bari, Italy
| | | | - Paolo Visca
- Interdepartmental Laboratory of Electron Microscopy, University Roma Tre, Roma, Italy
| | - Massimo Coletta
- Department of Clinical Sciences and Translational Medicine, University of Roma “Tor Vergata”, Roma, Italy
- Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems, Bari, Italy
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55
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Cardiolipin modulates allosterically the nitrite reductase activity of horse heart cytochrome c. J Biol Inorg Chem 2014; 19:1195-201. [DOI: 10.1007/s00775-014-1175-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 06/11/2014] [Indexed: 10/25/2022]
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56
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Ascenzi P, Leboffe L, Pesce A, Ciaccio C, Sbardella D, Bolognesi M, Coletta M. Nitrite-reductase and peroxynitrite isomerization activities of Methanosarcina acetivorans protoglobin. PLoS One 2014; 9:e95391. [PMID: 24827820 PMCID: PMC4020757 DOI: 10.1371/journal.pone.0095391] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 03/25/2014] [Indexed: 12/04/2022] Open
Abstract
Within the globin superfamily, protoglobins (Pgb) belong phylogenetically to the same cluster of two-domain globin-coupled sensors and single-domain sensor globins. Multiple functional roles have been postulated for Methanosarcina acetivorans Pgb (Ma-Pgb), since the detoxification of reactive nitrogen and oxygen species might co-exist with enzymatic activity(ies) to facilitate the conversion of CO to methane. Here, the nitrite-reductase and peroxynitrite isomerization activities of the CysE20Ser mutant of Ma-Pgb (Ma-Pgb*) are reported and analyzed in parallel with those of related heme-proteins. Kinetics of nitrite-reductase activity of ferrous Ma-Pgb* (Ma-Pgb*-Fe(II)) is biphasic and values of the second-order rate constant for the reduction of NO2– to NO and the concomitant formation of nitrosylated Ma-Pgb*-Fe(II) (Ma-Pgb*-Fe(II)-NO) are kapp1 = 9.6±0.2 M–1 s–1 and kapp2 = 1.2±0.1 M–1 s–1 (at pH 7.4 and 20°C). The kapp1 and kapp2 values increase by about one order of magnitude for each pH unit decrease, between pH 8.3 and 6.2, indicating that the reaction requires one proton. On the other hand, kinetics of peroxynitrite isomerization catalyzed by ferric Ma-Pgb* (Ma-Pgb*-Fe(III)) is monophasic and values of the second order rate constant for peroxynitrite isomerization by Ma-Pgb*-Fe(III) and of the first order rate constant for the spontaneous conversion of peroxynitrite to nitrate are happ = 3.8×104 M–1 s–1 and h0 = 2.8×10–1 s–1 (at pH 7.4 and 20°C). The pH-dependence of hon and h0 values reflects the acid-base equilibrium of peroxynitrite (pKa = 6.7 and 6.9, respectively; at 20°C), indicating that HOONO is the species that reacts preferentially with the heme-Fe(III) atom. These results highlight the potential role of Pgbs in the biosynthesis and scavenging of reactive nitrogen and oxygen species.
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Affiliation(s)
- Paolo Ascenzi
- Interdepartmental Laboratory of Electron Microscopy, University Roma Tre, Roma, Italy
- National Institute of Biostructures and Biosystems, Roma, Italy
- * E-mail:
| | - Loris Leboffe
- Interdepartmental Laboratory of Electron Microscopy, University Roma Tre, Roma, Italy
| | | | - Chiara Ciaccio
- Department of Clinical Sciences and Translational Medicine, University of Roma “Tor Vergata”, Roma, Italy
- Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems, Bari, Italy
| | - Diego Sbardella
- Department of Clinical Sciences and Translational Medicine, University of Roma “Tor Vergata”, Roma, Italy
- Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems, Bari, Italy
| | | | - Massimo Coletta
- Department of Clinical Sciences and Translational Medicine, University of Roma “Tor Vergata”, Roma, Italy
- Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems, Bari, Italy
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57
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Affiliation(s)
- Luisa B. Maia
- REQUIMTE/CQFB, Departamento
de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - José J. G. Moura
- REQUIMTE/CQFB, Departamento
de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
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58
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Gherasim C, Yadav PK, Kabil O, Niu WN, Banerjee R. Nitrite reductase activity and inhibition of H₂S biogenesis by human cystathionine ß-synthase. PLoS One 2014; 9:e85544. [PMID: 24416422 PMCID: PMC3885727 DOI: 10.1371/journal.pone.0085544] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 12/04/2013] [Indexed: 12/18/2022] Open
Abstract
Nitrite was recognized as a potent vasodilator >130 years and has more recently emerged as an endogenous signaling molecule and modulator of gene expression. Understanding the molecular mechanisms that regulate nitrite metabolism is essential for its use as a potential diagnostic marker as well as therapeutic agent for cardiovascular diseases. In this study, we have identified human cystathionine ß-synthase (CBS) as a new player in nitrite reduction with implications for the nitrite-dependent control of H2S production. This novel activity of CBS exploits the catalytic property of its unusual heme cofactor to reduce nitrite and generate NO. Evidence for the possible physiological relevance of this reaction is provided by the formation of ferrous-nitrosyl (FeII-NO) CBS in the presence of NADPH, the human diflavin methionine synthase reductase (MSR) and nitrite. Formation of FeII-NO CBS via its nitrite reductase activity inhibits CBS, providing an avenue for regulating biogenesis of H2S and cysteine, the limiting reagent for synthesis of glutathione, a major antioxidant. Our results also suggest a possible role for CBS in intracellular NO biogenesis particularly under hypoxic conditions. The participation of a regulatory heme cofactor in CBS in nitrite reduction is unexpected and expands the repertoire of proteins that can liberate NO from the intracellular nitrite pool. Our results reveal a potential molecular mechanism for cross-talk between nitrite, NO and H2S biology.
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Affiliation(s)
- Carmen Gherasim
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Pramod K. Yadav
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Omer Kabil
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Wei-Ning Niu
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- School of Life Science, Northwestern Polytechnical University, Xi’an, China
| | - Ruma Banerjee
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- * E-mail:
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59
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Manoli A, Begheldo M, Genre A, Lanfranco L, Trevisan S, Quaggiotti S. NO homeostasis is a key regulator of early nitrate perception and root elongation in maize. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:185-200. [PMID: 24220653 PMCID: PMC3883287 DOI: 10.1093/jxb/ert358] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Crop plant development is strongly dependent on nitrogen availability in the soil and on the efficiency of its recruitment by roots. For this reason, the understanding of the molecular events underlying root adaptation to nitrogen fluctuations is a primary goal to develop biotechnological tools for sustainable agriculture. However, knowledge about molecular responses to nitrogen availability is derived mainly from the study of model species. Nitric oxide (NO) has been recently proposed to be implicated in plant responses to environmental stresses, but its exact role in the response of plants to nutritional stress is still under evaluation. In this work, the role of NO production by maize roots after nitrate perception was investigated by focusing on the regulation of transcription of genes involved in NO homeostasis and by measuring NO production in roots. Moreover, its involvement in the root growth response to nitrate was also investigated. The results provide evidence that NO is produced by nitrate reductase as an early response to nitrate supply and that the coordinated induction of non-symbiotic haemoglobins (nsHbs) could finely regulate the NO steady state. This mechanism seems to be implicated on the modulation of the root elongation in response to nitrate perception. Moreover, an improved agar-plate system for growing maize seedlings was developed. This system, which allows localized treatments to be performed on specific root portions, gave the opportunity to discern between localized and systemic effects of nitrate supply to roots.
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Affiliation(s)
- Alessandro Manoli
- Department of Agriculture, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padua, Agripolis, Viale dell’Università, 16, 35020 Legnaro (PD), Italy
| | - Maura Begheldo
- Department of Agriculture, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padua, Agripolis, Viale dell’Università, 16, 35020 Legnaro (PD), Italy
| | - Andrea Genre
- Department of Life Sciences and Systems Biology, University of Turin, Viale Mattioli 25, 10125 Turin, Italy
| | - Luisa Lanfranco
- Department of Life Sciences and Systems Biology, University of Turin, Viale Mattioli 25, 10125 Turin, Italy
| | - Sara Trevisan
- Department of Agriculture, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padua, Agripolis, Viale dell’Università, 16, 35020 Legnaro (PD), Italy
| | - Silvia Quaggiotti
- Department of Agriculture, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padua, Agripolis, Viale dell’Università, 16, 35020 Legnaro (PD), Italy
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60
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Igamberdiev AU, Stasolla C, Hill RD. Low Oxygen Stress, Nonsymbiotic Hemoglobins, NO, and Programmed Cell Death. LOW-OXYGEN STRESS IN PLANTS 2014. [DOI: 10.1007/978-3-7091-1254-0_3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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61
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Wang X, Hargrove MS. Nitric oxide in plants: the roles of ascorbate and hemoglobin. PLoS One 2013; 8:e82611. [PMID: 24376554 PMCID: PMC3869716 DOI: 10.1371/journal.pone.0082611] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 11/04/2013] [Indexed: 11/18/2022] Open
Abstract
Ascorbic acid and hemoglobins have been linked to nitric oxide metabolism in plants. It has been hypothesized that ascorbic acid directly reduces plant hemoglobin in support of NO scavenging, producing nitrate and monodehydroascorbate. In this scenario, monodehydroascorbate reductase uses NADH to reduce monodehydroascorbate back to ascorbate to sustain the cycle. To test this hypothesis, rates of rice nonsymbiotic hemoglobin reduction by ascorbate were measured directly, in the presence and absence of purified rice monodehydroascorbate reductase and NADH. Solution NO scavenging was also measured methodically in the presence and absence of rice nonsymbiotic hemoglobin and monodehydroascorbate reductase, under hypoxic and normoxic conditions, in an effort to gauge the likelihood of these proteins affecting NO metabolism in plant tissues. Our results indicate that ascorbic acid slowly reduces rice nonsymbiotic hemoglobin at a rate identical to myoglobin reduction. The product of the reaction is monodehydroascorbate, which can be efficiently reduced back to ascorbate in the presence of monodehydroascorbate reductase and NADH. However, our NO scavenging results suggest that the direct reduction of plant hemoglobin by ascorbic acid is unlikely to serve as a significant factor in NO metabolism, even in the presence of monodehydroascorbate reductase. Finally, the possibility that the direct reaction of nitrite/nitrous acid and ascorbic acid produces NO was measured at various pH values mimicking hypoxic plant cells. Our results suggest that this reaction is a likely source of NO as the plant cell pH drops below 7, and as nitrite concentrations rise to mM levels during hypoxia.
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Affiliation(s)
- Xiaoguang Wang
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America
| | - Mark S. Hargrove
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America
- * E-mail:
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Groß F, Durner J, Gaupels F. Nitric oxide, antioxidants and prooxidants in plant defence responses. FRONTIERS IN PLANT SCIENCE 2013; 4:419. [PMID: 24198820 PMCID: PMC3812536 DOI: 10.3389/fpls.2013.00419] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 10/01/2013] [Indexed: 05/18/2023]
Abstract
In plant cells the free radical nitric oxide (NO) interacts both with anti- as well as prooxidants. This review provides a short survey of the central roles of ascorbate and glutathione-the latter alone or in conjunction with S-nitrosoglutathione reductase-in controlling NO bioavailability. Other major topics include the regulation of antioxidant enzymes by NO and the interplay between NO and reactive oxygen species (ROS). Under stress conditions NO regulates antioxidant enzymes at the level of activity and gene expression, which can cause either enhancement or reduction of the cellular redox status. For instance chronic NO production during salt stress induced the antioxidant system thereby increasing salt tolerance in various plants. In contrast, rapid NO accumulation in response to strong stress stimuli was occasionally linked to inhibition of antioxidant enzymes and a subsequent rise in hydrogen peroxide levels. Moreover, during incompatible Arabidopsis thaliana-Pseudomonas syringae interactions ROS burst and cell death progression were shown to be terminated by S-nitrosylation-triggered inhibition of NADPH oxidases, further highlighting the multiple roles of NO during redox-signaling. In chemical reactions between NO and ROS reactive nitrogen species (RNS) arise with characteristics different from their precursors. Recently, peroxynitrite formed by the reaction of NO with superoxide has attracted much attention. We will describe putative functions of this molecule and other NO derivatives in plant cells. Non-symbiotic hemoglobins (nsHb) were proposed to act in NO degradation. Additionally, like other oxidases nsHb is also capable of catalyzing protein nitration through a nitrite- and hydrogen peroxide-dependent process. The physiological significance of the described findings under abiotic and biotic stress conditions will be discussed with a special emphasis on pathogen-induced programmed cell death (PCD).
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Affiliation(s)
| | | | - Frank Gaupels
- German Research Center for Environmental Health, Institute of Biochemical Plant Pathology, Helmholtz-Zentrum MünchenMunich, Germany
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Warfarin modulates the nitrite reductase activity of ferrous human serum heme-albumin. J Biol Inorg Chem 2013; 18:939-46. [PMID: 24037275 DOI: 10.1007/s00775-013-1040-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 08/27/2013] [Indexed: 12/28/2022]
Abstract
Human serum heme-albumin (HSA-heme-Fe) displays reactivity and spectroscopic properties similar to those of heme proteins. Here, the nitrite reductase activity of ferrous HSA-heme-Fe [HSA-heme-Fe(II)] is reported. The value of the second-order rate constant for the reduction of [Formula: see text] to NO and the concomitant formation of nitrosylated HSA-heme-Fe(II) (i.e., k on) is 1.3 M(-1) s(-1) at pH 7.4 and 20 °C. Values of k on increase by about one order of magnitude for each pH unit decrease between pH 6.5 to 8.2, indicating that the reaction requires one proton. Warfarin inhibits the HSA-heme-Fe(II) reductase activity, highlighting the allosteric linkage between the heme binding site [also named the fatty acid (FA) binding site 1; FA1] and the drug-binding cleft FA2. The dissociation equilibrium constant for warfarin binding to HSA-heme-Fe(II) is (3.1 ± 0.4) × 10(-4) M at pH 7.4 and 20 °C. These results: (1) represent the first evidence for the [Formula: see text] reductase activity of HSA-heme-Fe(II), (2) highlight the role of drugs (e.g., warfarin) in modulating HSA(-heme-Fe) functions, and (3) strongly support the view that HSA acts not only as a heme carrier but also displays transient heme-based reactivity.
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64
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Matilla AJ, Rodríguez-Gacio MDC. Non-symbiotic hemoglobins in the life of seeds. PHYTOCHEMISTRY 2013; 87:7-15. [PMID: 23286879 DOI: 10.1016/j.phytochem.2012.11.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 11/13/2012] [Accepted: 11/21/2012] [Indexed: 06/01/2023]
Abstract
Non-symbiotic hemoglobins (nsHbs), ancestors of symbiotic-Hbs, are hexacoordinated dimeric proteins, for which the crystal structure is well described. According to the extent of hexacoordination, nsHbs are classified as belonging to class-1 (nsHbs1) or class-2 (nsHbs2). The nsHbs1 show weak hexacoordination, moderate rates of O(2)-binding, very small rates of O(2) dissociation, and a remarkably high affinity for O(2), all suggesting a function involving O(2) scavenging. In contrast, the nsHbs2 exhibit strong hexacoordination, low rates of O(2)-binding and moderately low O(2) dissociation and affinity, suggesting a sensing role for sustained low (μM) levels of O(2). The existence of spatial and specific expression of nsHbs1 suggests that nsHbs play tissue-specific rather than housekeeping functions. The permeation of O(2) into seeds is usually prevented during the desiccation phase and early imbibition, generating an internal hypoxic environment that leads to ATP limitation. During evolution, the seed has acquired mechanisms to prevent or reduce this hypoxic stress. The nsHbs1/NO cycle appear to be involved in modulating the redox state in the seed and in maintaining an active metabolism. Under O(2) deficit, NADH and NO are synthesized in the seed and nsHbs1 scavenges O(2), which is used to transform NO into NO(3)(-) with concomitant formation of Fe(3+)-nsHbs1. Expression of nsHbs1 is not detectable in dry viable seeds. However, in the seeds cross-talk occurs between nsHbs1 and NO during germination. This review considers the current status of our knowledge of seed nsHbs and considers key issues of further work to better understand their role in seed physiology.
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Affiliation(s)
- Angel J Matilla
- Department of Plant Physiology, University of Santiago de Compostela, 15782 Santiago de Compostela, A Coruña, Spain.
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65
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Abstract
Approximately, 20 years ago, a haemoglobin gene was identified within the genome of the cyanobacterium Nostoc commune. Haemoglobins have now been confirmed in multiple species of photosynthetic microbes beyond N. commune, and the diversity of these proteins has recently come under increased scrutiny. This chapter summarizes the state of knowledge concerning the phylogeny, physiology and chemistry of globins in cyanobacteria and green algae. Sequence information is by far the best developed and the most rapidly expanding aspect of the field. Structural and ligand-binding properties have been described for just a few proteins. Physiological data are available for even fewer. Although activities such as nitric oxide dioxygenation and oxygen scavenging are strong candidates for cellular function, dedicated studies will be required to complete the story on this intriguing and ancient group of proteins.
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Narsai R, Whelan J. How unique is the low oxygen response? An analysis of the anaerobic response during germination and comparison with abiotic stress in rice and Arabidopsis. FRONTIERS IN PLANT SCIENCE 2013; 4:349. [PMID: 24101922 PMCID: PMC3787303 DOI: 10.3389/fpls.2013.00349] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 08/19/2013] [Indexed: 05/04/2023]
Abstract
Plants face a variety of environmental stresses and have evolved molecular mechanisms to survive these challenges. One of these stresses is low oxygen conditions, which can occur under flooding conditions. Rice (Oryza sativa) is somewhat unique for its ability to tolerate and even germinate under low to no oxygen conditions. In this study, we examined global transcriptomic responses over the course of germination and in response to low oxygen and other abiotic stress in rice and Arabidopsis (Arabidopsis thaliana). Over 150 microarray datasets were analyzed in parallel to determine just how unique the low oxygen response is in rice. Comparison of aerobic germination in rice and Arabidopsis, with anaerobic germination in rice revealed conserved transcriptomic responses that are not only conserved across both species but also occur in the absence of oxygen in rice. Thus, these genes may represent functions necessary for the developmental progression of germination, whether or not oxygen is present in rice. Analysis of genes that responded differently in rice compared to Arabidopsis revealed responses specific to anaerobic germination in rice, including the down-regulation of genes encoding redox functions and up-regulation of receptor kinases. Comparison of a range of hypoxia/anoxia studies within and across Arabidopsis and rice revealed both conserved and species specific changes in gene expression (e.g., Arabidopsis specific up-regulation of WRKYs and rice specific down-regulation of heme), unveiling unique transcriptomic signatures of the low oxygen response. Lastly, a comparison of the low oxygen response with cold, salt, drought and heat stress revealed some similarity with the response to heat stress in Arabidopsis, which was not seen in rice. Comparison of these heat-responsive, abiotic stress marker genes in Arabidopsis with their rice orthologs revealed that while low oxygen may be perceived as an abiotic stress in Arabidopsis, this is not the case in rice.
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Affiliation(s)
- Reena Narsai
- Plant Energy Biology, Centre for Computational Systems Biology, University of Western AustraliaPerth, WA, Australia
- *Correspondence: Reena Narsai, Centre for Computation Systems Biology, ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, MCS Building M316, 35 Stirling Highway, Perth 6009, WA, Australia e-mail:
| | - James Whelan
- Department of Botany, School of Life Science, La Trobe UniversityMelbourne, VIC, Australia
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67
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Sun MH, Li W, Liu JH, Wen GB, Tan X, Lin YW. Structural and nitrite reductase activity comparisons of myoglobins with one to three distal histidines. RSC Adv 2013. [DOI: 10.1039/c3ra40839f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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68
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Mur LAJ, Mandon J, Persijn S, Cristescu SM, Moshkov IE, Novikova GV, Hall MA, Harren FJM, Hebelstrup KH, Gupta KJ. Nitric oxide in plants: an assessment of the current state of knowledge. AOB PLANTS 2013; 5:pls052. [PMID: 23372921 PMCID: PMC3560241 DOI: 10.1093/aobpla/pls052] [Citation(s) in RCA: 223] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 12/12/2012] [Indexed: 05/18/2023]
Abstract
BACKGROUND AND AIMS After a series of seminal works during the last decade of the 20th century, nitric oxide (NO) is now firmly placed in the pantheon of plant signals. Nitric oxide acts in plant-microbe interactions, responses to abiotic stress, stomatal regulation and a range of developmental processes. By considering the recent advances in plant NO biology, this review will highlight certain key aspects that require further attention. SCOPE AND CONCLUSIONS The following questions will be considered. While cytosolic nitrate reductase is an important source of NO, the contributions of other mechanisms, including a poorly defined arginine oxidizing activity, need to be characterized at the molecular level. Other oxidative pathways utilizing polyamine and hydroxylamine also need further attention. Nitric oxide action is dependent on its concentration and spatial generation patterns. However, no single technology currently available is able to provide accurate in planta measurements of spatio-temporal patterns of NO production. It is also the case that pharmaceutical NO donors are used in studies, sometimes with little consideration of the kinetics of NO production. We here include in planta assessments of NO production from diethylamine nitric oxide, S-nitrosoglutathione and sodium nitroprusside following infiltration of tobacco leaves, which could aid workers in their experiments. Further, based on current data it is difficult to define a bespoke plant NO signalling pathway, but rather NO appears to act as a modifier of other signalling pathways. Thus, early reports that NO signalling involves cGMP-as in animal systems-require revisiting. Finally, as plants are exposed to NO from a number of external sources, investigations into the control of NO scavenging by such as non-symbiotic haemoglobins and other sinks for NO should feature more highly. By crystallizing these questions the authors encourage their resolution through the concerted efforts of the plant NO community.
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Affiliation(s)
- Luis A. J. Mur
- Institute of Environmental and Rural Science, Aberystwyth University, Edward Llwyd Building, Aberystwyth SY23 3DA, UK
- Corresponding author's e-mail address:
| | - Julien Mandon
- Life Science Trace Gas Facility, Molecular and Laser Physics, Institute for Molecules and Materials, Radboud University, PO Box 9010, 6500 GL Nijmegen, The Netherlands
| | - Stefan Persijn
- Life Science Trace Gas Facility, Molecular and Laser Physics, Institute for Molecules and Materials, Radboud University, PO Box 9010, 6500 GL Nijmegen, The Netherlands
| | - Simona M. Cristescu
- Life Science Trace Gas Facility, Molecular and Laser Physics, Institute for Molecules and Materials, Radboud University, PO Box 9010, 6500 GL Nijmegen, The Netherlands
| | - Igor E. Moshkov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, ul. Botanicheskaya 35, Moscow 127276, Russia
| | - Galina V. Novikova
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, ul. Botanicheskaya 35, Moscow 127276, Russia
| | - Michael A. Hall
- Institute of Environmental and Rural Science, Aberystwyth University, Edward Llwyd Building, Aberystwyth SY23 3DA, UK
| | - Frans J. M. Harren
- Life Science Trace Gas Facility, Molecular and Laser Physics, Institute for Molecules and Materials, Radboud University, PO Box 9010, 6500 GL Nijmegen, The Netherlands
| | - Kim H. Hebelstrup
- Department of Molecular Biology and Genetics, Section of Crop Genetics and Biotechnology, Aarhus University, Forsøgsvej 1, DK-4200 Slagelse, Denmark
| | - Kapuganti J. Gupta
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
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69
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Gardner PR. Hemoglobin: a nitric-oxide dioxygenase. SCIENTIFICA 2012; 2012:683729. [PMID: 24278729 PMCID: PMC3820574 DOI: 10.6064/2012/683729] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 10/04/2012] [Indexed: 05/09/2023]
Abstract
Members of the hemoglobin superfamily efficiently catalyze nitric-oxide dioxygenation, and when paired with native electron donors, function as NO dioxygenases (NODs). Indeed, the NOD function has emerged as a more common and ancient function than the well-known role in O2 transport-storage. Novel hemoglobins possessing a NOD function continue to be discovered in diverse life forms. Unique hemoglobin structures evolved, in part, for catalysis with different electron donors. The mechanism of NOD catalysis by representative single domain hemoglobins and multidomain flavohemoglobin occurs through a multistep mechanism involving O2 migration to the heme pocket, O2 binding-reduction, NO migration, radical-radical coupling, O-atom rearrangement, nitrate release, and heme iron re-reduction. Unraveling the physiological functions of multiple NODs with varying expression in organisms and the complexity of NO as both a poison and signaling molecule remain grand challenges for the NO field. NOD knockout organisms and cells expressing recombinant NODs are helping to advance our understanding of NO actions in microbial infection, plant senescence, cancer, mitochondrial function, iron metabolism, and tissue O2 homeostasis. NOD inhibitors are being pursued for therapeutic applications as antibiotics and antitumor agents. Transgenic NOD-expressing plants, fish, algae, and microbes are being developed for agriculture, aquaculture, and industry.
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Affiliation(s)
- Paul R. Gardner
- Miami Valley Biotech, 1001 E. 2nd Street, Suite 2445, Dayton, OH 45402, USA
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70
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Zhou Q, Hu M, Zhang W, Jiang L, Perrett S, Zhou J, Wang J. Probing the function of the Tyr-Cys cross-link in metalloenzymes by the genetic incorporation of 3-methylthiotyrosine. Angew Chem Int Ed Engl 2012. [PMID: 23197358 DOI: 10.1002/anie.201207229] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Qing Zhou
- Laboratory of Non-coding RNA, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China
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71
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Zhou Q, Hu M, Zhang W, Jiang L, Perrett S, Zhou J, Wang J. Probing the Function of the Tyr-Cys Cross-Link in Metalloenzymes by the Genetic Incorporation of 3-Methylthiotyrosine. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201207229] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abstract
Nitric oxide (NO) has been demonstrated as an essential regulator of several physiological processes in plants. The understanding of the molecular mechanism underlying its critical role constitutes a major field of research. NO can exert its biological function through different ways, such as the modulation of gene expression, the mobilization of second messengers, or interplays with protein kinases. Besides this signaling events, NO can be responsible of the posttranslational modifications (PTM) of target proteins. Several modifications have been identified so far, whereas metal nitrosylation, the tyrosine nitration and the S-nitrosylation can be considered as the main ones. Recent data demonstrate that these PTM are involved in the control of a wide range of physiological processes in plants, such as the plant immune system. However, a great deal of effort is still necessary to pinpoint the role of each PTM in plant physiology. Taken together, these new advances in proteomic research provide a better comprehension of the role of NO in plant signaling.
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Affiliation(s)
- Jeremy Astier
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
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73
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Vázquez-Limón C, Hoogewijs D, Vinogradov SN, Arredondo-Peter R. The evolution of land plant hemoglobins. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2012; 191-192:71-81. [PMID: 22682566 DOI: 10.1016/j.plantsci.2012.04.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 04/24/2012] [Accepted: 04/25/2012] [Indexed: 05/04/2023]
Abstract
This review discusses the evolution of land plant hemoglobins within the broader context of eukaryote hemoglobins and the three families of bacterial globins. Most eukaryote hemoglobins, including metazoan globins and the symbiotic and non-symbiotic plant hemoglobins, are homologous to the bacterial 3/3-fold flavohemoglobins. The remaining plant hemoglobins are homologous to the bacterial 2/2-fold group 2 hemoglobins. We have proposed that all eukaryote globins were acquired via horizontal gene transfer concomitant with the endosymbiotic events responsible for the origin of mitochondria and chloroplasts. Although the 3/3 hemoglobins originated in the ancestor of green algae and plants prior to the emergence of embryophytes at about 450 mya, the 2/2 hemoglobins appear to have originated via horizontal gene transfer from a bacterium ancestral to present day Chloroflexi. Unlike the 2/2 hemoglobins, the evolution of the 3/3 hemoglobins was accompanied by duplication, diversification, and functional adaptations. Duplication of the ancestral plant nshb gene into the nshb-1 and nshb-2 lineages occurred prior to the monocot-dicot divergence at ca. 140 mya. It was followed by the emergence of symbiotic hemoglobins from a non-symbiotic hemoglobin precursor and further specialization, leading to leghemoglobins in N₂-fixing legume nodules concomitant with the origin of nodulation at ca. 60 mya. The transition of non-symbiotic to symbiotic hemoglobins (including to leghemoglobins) was accompanied by the alteration of heme-Fe coordination from hexa- to penta-coordination. Additional genomic information about Charophyte algae, the sister group to land plants, is required for the further clarification of plant globin phylogeny.
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Affiliation(s)
- Consuelo Vázquez-Limón
- Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, 62210 Cuernavaca, Morelos, Mexico
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Tiso M, Tejero J, Kenney C, Frizzell S, Gladwin MT. Nitrite reductase activity of nonsymbiotic hemoglobins from Arabidopsis thaliana. Biochemistry 2012; 51:5285-92. [PMID: 22620259 DOI: 10.1021/bi300570v] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Plant nonsymbiotic hemoglobins possess hexacoordinate heme geometry similar to that of the heme protein neuroglobin. We recently discovered that deoxygenated neuroglobin converts nitrite to nitric oxide (NO), an important signaling molecule involved in many processes in plants. We sought to determine whether Arabidopsis thaliana nonsymbiotic hemoglobins classes 1 and 2 (AHb1 and AHb2, respectively) might function as nitrite reductases. We found that the reaction of nitrite with deoxygenated AHb1 and AHb2 generates NO gas and iron-nitrosyl-hemoglobin species. The bimolecular rate constants for reduction of nitrite to NO are 19.8 ± 3.2 and 4.9 ± 0.2 M(-1) s(-1), respectively, at pH 7.4 and 25 °C. We determined the pH dependence of these bimolecular rate constants and found a linear correlation with the concentration of protons, indicating the requirement for one proton in the reaction. The release of free NO gas during the reaction under anoxic and hypoxic (2% oxygen) conditions was confirmed by chemiluminescence detection. These results demonstrate that deoxygenated AHb1 and AHb2 reduce nitrite to form NO via a mechanism analogous to that observed for hemoglobin, myoglobin, and neuroglobin. Our findings suggest that during severe hypoxia and in the anaerobic plant roots, especially in species submerged in water, nonsymbiotic hemoglobins provide a viable pathway for NO generation via nitrite reduction.
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Affiliation(s)
- Mauro Tiso
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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75
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Kristian KE, Bakac A. Reduction of nitrous acid with a macrocyclic rhodium complex that acts as a functional model of nitrite reductase. Inorg Chem 2012; 51:4877-82. [PMID: 22480334 DOI: 10.1021/ic300597n] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nitrous acid reacts with L(2)(H(2)O)Rh(2+) (L(2) = meso-hexamethylcyclam) in acidic aqueous solutions to generate a strongly absorbing intermediate Int-1 (λ(max) 400 nm, ε = 1200 M(-1) cm(-1)). The reaction follows a mixed second order rate law with k = (6.9 ± 0.3) × 10(4) M(-1) s(-1), independent of [H(+)]. The lack of acid dependence shows that Int-1 is a rhodium(II) complex of HNO(2), most reasonably assigned as L(2)(H(2)O)Rh(HNO(2))(2+). This species is analogous to the early iron and copper intermediates in the reduction of nitrite by nitrite reductases and by deoxyhemoglobin. In the presence of excess L(2)(H(2)O)Rh(2+), the lifetime of Int-1 is about 1 min. It decays to a 1:1 mixture of L(2)(H(2)O)RhNO(2+) and L(2)Rh(H(2)O)(2)(3+) with kinetics that are largely independent of the concentration of excess L(2)(H(2)O)Rh(2+) and of [H(+)] at [H(+)] < 0.03 M. At [H(+)] > 0.03 M, an acid-catalyzed pathway becomes effective, suggesting protonation and dehydration of Int-1 to generate L(2)(H(2)O)RhNO(3+) (Int-2) followed by rapid reduction of Int-2 by excess L(2)(H(2)O)Rh(2+). Int-2, which was generated and characterized independently, is an analog of the electrophilic intermediates in the mechanism of biological reduction of nitrite to (•)NO. Excess nitrite greatly reduces the lifetime of Int-1, which under such conditions decomposes on a millisecond time scale by nitrite-catalyzed disproportionation to yield L(2)(H(2)O)RhNO(2+) and L(2)Rh(III). This reaction provides additional support for the designation of Int-1 as a Rh(II) species. The complex reaction mechanism and the detection of Int-1 demonstrate the ability of inorganic complexes to perform the fundamental chemistry believed to take place in the biological reduction of HNO(2) to NO catalyzed by nitrite reductases or deoxyhemoglobin.
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76
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Leghemoglobin green derivatives with nitrated hemes evidence production of highly reactive nitrogen species during aging of legume nodules. Proc Natl Acad Sci U S A 2012; 109:2660-5. [PMID: 22308405 DOI: 10.1073/pnas.1116559109] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Globins constitute a superfamily of proteins widespread in all kingdoms of life, where they fulfill multiple functions, such as efficient O(2) transport and modulation of nitric oxide bioactivity. In plants, the most abundant Hbs are the symbiotic leghemoglobins (Lbs) that scavenge O(2) and facilitate its diffusion to the N(2)-fixing bacteroids in nodules. The biosynthesis of Lbs during nodule formation has been studied in detail, whereas little is known about the green derivatives of Lbs generated during nodule senescence. Here we characterize modified forms of Lbs, termed Lba(m), Lbc(m), and Lbd(m), of soybean nodules. These green Lbs have identical globins to the parent red Lbs but their hemes are nitrated. By combining UV-visible, MS, NMR, and resonance Raman spectroscopies with reconstitution experiments of the apoprotein with protoheme or mesoheme, we show that the nitro group is on the 4-vinyl. In vitro nitration of Lba with excess nitrite produced several isomers of nitrated heme, one of which is identical to those found in vivo. The use of antioxidants, metal chelators, and heme ligands reveals that nitration is contingent upon the binding of nitrite to heme Fe, and that the reactive nitrogen species involved derives from nitrous acid and is most probably the nitronium cation. The identification of these green Lbs provides conclusive evidence that highly oxidizing and nitrating species are produced in nodules leading to nitrosative stress. These findings are consistent with a previous report showing that the modified Lbs are more abundant in senescing nodules and have aberrant O(2) binding.
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77
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Sturms R, DiSpirito AA, Fulton DB, Hargrove MS. Hydroxylamine Reduction to Ammonium by Plant and Cyanobacterial Hemoglobins. Biochemistry 2011; 50:10829-35. [DOI: 10.1021/bi201425f] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ryan Sturms
- Department of Biochemistry,
Biophysics, and Molecular
Biology, Iowa State University, Ames, Iowa
50011, United States
| | - Alan A. DiSpirito
- Department of Biochemistry,
Biophysics, and Molecular
Biology, Iowa State University, Ames, Iowa
50011, United States
| | - D. Bruce Fulton
- Department of Biochemistry,
Biophysics, and Molecular
Biology, Iowa State University, Ames, Iowa
50011, United States
| | - Mark S. Hargrove
- Department of Biochemistry,
Biophysics, and Molecular
Biology, Iowa State University, Ames, Iowa
50011, United States
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78
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Gupta KJ, Hebelstrup KH, Mur LAJ, Igamberdiev AU. Plant hemoglobins: important players at the crossroads between oxygen and nitric oxide. FEBS Lett 2011; 585:3843-9. [PMID: 22036787 DOI: 10.1016/j.febslet.2011.10.036] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 10/17/2011] [Accepted: 10/18/2011] [Indexed: 11/16/2022]
Abstract
Plant hemoglobins constitute a diverse group of hemeproteins and evolutionarily belong to three different classes. Class 1 hemoglobins possess an extremely high affinity to oxygen and their main function consists in scavenging of nitric oxide (NO) at very low oxygen levels. Class 2 hemoglobins have a lower oxygen affinity and they facilitate oxygen supply to developing tissues. Symbiotic hemoglobins in nodules have mostly evolved from class 2 hemoglobins. Class 3 hemoglobins are truncated and represent a clade with a very low similarity to class 1 and 2 hemoglobins. They may regulate oxygen delivery at high O(2) concentrations. Depending on their physical properties, hemoglobins belong either to hexacoordinate non-symbiotic or pentacoordinate symbiotic groups. Plant hemoglobins are plausible targets for improving resistance to multiple stresses.
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Affiliation(s)
- Kapuganti J Gupta
- Department of Plant Physiology, University of Rostock, Rostock, Germany
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