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Thompson MEH, Raizada MN. The Microbiome of Fertilization-Stage Maize Silks (Style) Encodes Genes and Expresses Traits That Potentially Promote Survival in Pollen/Style Niches and Host Reproduction. Microorganisms 2024; 12:1473. [PMID: 39065240 PMCID: PMC11278993 DOI: 10.3390/microorganisms12071473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Revised: 07/16/2024] [Accepted: 07/17/2024] [Indexed: 07/28/2024] Open
Abstract
Within flowers, the style channel receives pollen and transmits male gametes inside elongating pollen tubes to ovules. The styles of maize/corn are called silks. Fertilization-stage silks possess complex microbiomes, which may partially derive from pollen. These microbiomes lack functional analysis. We hypothesize that fertilization-stage silk microbiomes promote host fertilization to ensure their own vertical transmission. We further hypothesize that these microbes encode traits to survive stresses within the silk (water/nitrogen limitation) and pollen (dehydration/aluminum) habitats. Here, bacteria cultured from fertilization-stage silks of 14 North American maize genotypes underwent genome mining and functional testing, which revealed osmoprotection, nitrogen-fixation, and aluminum-tolerance traits. Bacteria contained auxin biosynthesis genes, and testing confirmed indole compound secretion, which is relevant, since pollen delivers auxin to silks to stimulate egg cell maturation. Some isolates encoded biosynthetic/transport compounds known to regulate pollen tube guidance/growth. The isolates encoded ACC deaminase, which degrades the precursor for ethylene that otherwise accelerates silk senescence. The findings suggest that members of the microbiome of fertilization-stage silks encode adaptations to survive the stress conditions of silk/pollen and have the potential to express signaling compounds known to impact reproduction. Overall, whereas these microbial traits have traditionally been assumed to primarily promote vegetative plant growth, this study proposes they may also play selfish roles during host reproduction.
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Affiliation(s)
| | - Manish N. Raizada
- Department of Plant Agriculture, University of Guelph, Guelph, ON N1G 2W1, Canada;
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2
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Anju BS, Nair NR, Kundu S. Nitrite and Nitric Oxide Interconversion at Mononuclear Copper(II): Insight into the Role of the Red Copper Site in Denitrification. Angew Chem Int Ed Engl 2023; 62:e202311523. [PMID: 37800603 DOI: 10.1002/anie.202311523] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/04/2023] [Accepted: 10/06/2023] [Indexed: 10/07/2023]
Abstract
Nitrite (NO2 - ) and nitric oxide (NO) interconversion is crucial for maintaining optimum NO flux in mammalian physiology. Herein we demonstrate that [L2 CuII (nitrite)]+ moieties (in 2 a and 2 b; where, L = Me2 PzPy and Me2 PzQu) with distorted octahedral geometry undergo facile reduction to provide tetrahedral [L2 CuI ]+ (in 3 a and 3 b) and NO in the presence of biologically relevant reductants, such as 4-methoxy-2,6-di-tert-butylphenol (4-MeO-2,6-DTBP, a tyrosine model) and N-benzyl-1,4-dihydronicotinamide (BNAH, a NAD(P)H model). Interestingly, the reaction of excess NO gas with [L2 CuII (MeCN)2 ]2+ (in 1 a) provides a putative {CuNO}10 species, which is effective in mediating the nitrosation of various nucleophiles, such as thiol and amine. Generation of the transient {CuNO}10 species in wet acetonitrile leads to NO2 - as assessed by Griess assay and 14 N/15 N-FTIR analyses. A detailed study reveals that the bidirectional NOx -reactivity, namely, nitrite reductase (NIR) and NO oxidase (NOO), at a common CuII site, is governed by the geometric-preference-driven facile CuII /CuI redox process. Of broader interest, this study not only highlights potential strategies for the design of copper-based catalysts for nitrite reduction, but also strengthens the previous postulates regarding the involvement of red copper proteins in denitrification.
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Affiliation(s)
- Balakrishnan S Anju
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER-Tvm) Thiruvananthapuram, 695551, Kerala, India
| | - Neeraja R Nair
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER-Tvm) Thiruvananthapuram, 695551, Kerala, India
| | - Subrata Kundu
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER-Tvm) Thiruvananthapuram, 695551, Kerala, India
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3
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Mondal P, Tolbert GB, Wijeratne GB. Bio-inspired nitrogen oxide (NO x) interconversion reactivities of synthetic heme Compound-I and Compound-II intermediates. J Inorg Biochem 2021; 226:111633. [PMID: 34749065 DOI: 10.1016/j.jinorgbio.2021.111633] [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: 07/17/2021] [Revised: 10/06/2021] [Accepted: 10/12/2021] [Indexed: 10/20/2022]
Abstract
Dioxygen activating heme enzymes have long predicted to be powerhouses for nitrogen oxide interconversion, especially for nitric oxide (NO) oxidation which has far-reaching biological and/or environmental impacts. Lending credence, reactivity of NO with high-valent heme‑oxygen intermediates of globin proteins has recently been implicated in the regulation of a variety of pivotal physiological events such as modulating catalytic activities of various heme enzymes, enhancing antioxidant activity to inhibit oxidative damage, controlling inflammatory and infectious properties within the local heme environments, and NO scavenging. To reveal insights into such crucial biological processes, we have investigated low temperature NO reactivities of two classes of synthetic high-valent heme intermediates, Compound-II and Compound-I. In that, Compound-II rapidly reacts with NO yielding the six-coordinate (NO bound) heme ferric nitrite complex, which upon warming to room temperature converts into the five-coordinate heme ferric nitrite species. These ferric nitrite complexes mediate efficient substrate oxidation reactions liberating NO; i.e., shuttling NO2- back to NO. In contrast, Compound-I and NO proceed through an oxygen-atom transfer process generating the strong nitrating agent NO2, along with the corresponding ferric nitrosyl species that converts to the naked heme ferric parent complex upon warmup. All reaction components have been fully characterized by UV-vis, 2H NMR and EPR spectroscopic methods, mass spectrometry, elemental analyses, and semi-quantitative determination of NO2- anions. The clean, efficient, potentially catalytic NOx interconversions driven by high-valent heme species presented herein illustrate the strong prospects of a heme enzyme/O2/NOx dependent unexplored territory that is central to human physiology, pathology, and therapeutics.
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Affiliation(s)
- Pritam Mondal
- Department of Chemistry and O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL 35205, United States
| | - Garrett B Tolbert
- Department of Chemistry and O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL 35205, United States
| | - Gayan B Wijeratne
- Department of Chemistry and O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL 35205, United States.
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4
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Tewari RK, Horemans N, Watanabe M. Evidence for a role of nitric oxide in iron homeostasis in plants. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:990-1006. [PMID: 33196822 DOI: 10.1093/jxb/eraa484] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/13/2020] [Indexed: 05/27/2023]
Abstract
Nitric oxide (NO), once regarded as a poisonous air pollutant, is now understood as a regulatory molecule essential for several biological functions in plants. In this review, we summarize NO generation in different plant organs and cellular compartments, and also discuss the role of NO in iron (Fe) homeostasis, particularly in Fe-deficient plants. Fe is one of the most limiting essential nutrient elements for plants. Plants often exhibit Fe deficiency symptoms despite sufficient tissue Fe concentrations. NO appears to not only up-regulate Fe uptake mechanisms but also makes Fe more bioavailable for metabolic functions. NO forms complexes with Fe, which can then be delivered into target cells/tissues. NO generated in plants can alleviate oxidative stress by regulating antioxidant defense processes, probably by improving functional Fe status and by inducing post-translational modifications in the enzymes/proteins involved in antioxidant defense responses. It is hypothesized that NO acts in cooperation with transcription factors such as bHLHs, FIT, and IRO to regulate the expression of enzymes and proteins essential for Fe homeostasis. However, further investigations are needed to disentangle the interaction of NO with intracellular target molecules that leads to enhanced internal Fe availability in plants.
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Affiliation(s)
| | - Nele Horemans
- Biosphere Impact Studies, Belgian Nuclear Research Center (SCK•CEN), Boeretang, Mol, Belgium
- Centre for Environmental Sciences, Hasselt University, Agoralaan gebouw D, Diepenbeek, Belgium
| | - Masami Watanabe
- Laboratory of Plant Biochemistry, Chiba University, Inage-ward, Yayoicho, Chiba, Japan
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5
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Tejero J, Hunt AP, Santolini J, Lehnert N, Stuehr DJ. Mechanism and regulation of ferrous heme-nitric oxide (NO) oxidation in NO synthases. J Biol Chem 2019; 294:7904-7916. [PMID: 30926606 DOI: 10.1074/jbc.ra119.007810] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 03/27/2019] [Indexed: 12/12/2022] Open
Abstract
Nitric oxide (NO) synthases (NOSs) catalyze the formation of NO from l-arginine. We have shown previously that the NOS enzyme catalytic cycle involves a large number of reactions but can be characterized by a global model with three main rate-limiting steps. These are the rate of heme reduction by the flavin domain (kr ), of dissociation of NO from the ferric heme-NO complex (kd ), and of oxidation of the ferrous heme-NO complex (k ox). The reaction of oxygen with the ferrous heme-NO species is part of a futile cycle that does not directly contribute to NO synthesis but allows a population of inactive enzyme molecules to return to the catalytic cycle, and thus, enables a steady-state NO synthesis rate. Previously, we have reported that this reaction does involve the reaction of oxygen with the NO-bound ferrous heme complex, but the mechanistic details of the reaction, that could proceed via either an inner-sphere or an outer-sphere mechanism, remained unclear. Here, we present additional experiments with neuronal NOS (nNOS) and inducible NOS (iNOS) variants (nNOS W409F and iNOS K82A and V346I) and computational methods to study how changes in heme access and electronics affect the reaction. Our results support an inner-sphere mechanism and indicate that the particular heme-thiolate environment of the NOS enzymes can stabilize an N-bound FeIII-N(O)OO- intermediate species and thereby catalyze this reaction, which otherwise is not observed or favorable in proteins like globins that contain a histidine-coordinated heme.
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Affiliation(s)
- Jesús Tejero
- From the Department of Pathobiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195 and
| | - Andrew P Hunt
- the Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109
| | - Jérôme Santolini
- From the Department of Pathobiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195 and
| | - Nicolai Lehnert
- the Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109
| | - Dennis J Stuehr
- From the Department of Pathobiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195 and
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6
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Cao GJ, Fisher CM, Jiang X, Chong Y, Zhang H, Guo H, Zhang Q, Zheng J, Knolhoff AM, Croley TR, Yin JJ. Platinum nanoparticles: an avenue for enhancing the release of nitric oxide from S-nitroso-N-acetylpenicillamine and S-nitrosoglutathione. NANOSCALE 2018; 10:11176-11185. [PMID: 29873378 DOI: 10.1039/c8nr03874k] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Nitric oxide (NO) is an endogenous bioregulator with established roles in diverse fields. The difficulty in the modulation of NO release is still a significant obstacle to achieving successful clinical applications. We report herein our initial work using electron spin resonance (ESR) spectroscopy to detect NO generated from S-nitroso-N-acetylpenicillamine (SNAP) and S-nitrosoglutathione (GSNO) donors catalyzed by platinum nanoparticles (Pt NPs, 3 nm) under physiological conditions. With ESR spectroscopy coupled with spin trapping and spin labeling techniques, we identified that Pt NPs can significantly promote the generation of NO from SNAP and GSNO under physiological conditions. A classic NO colorimetric detection kit was also employed to verify that Pt NPs truly triggered the release of NO from its donors. Pt NPs can act as promising delivery vehicles for on-demand NO delivery based on time and dosage. These results, along with the detection of the resulting disulfide product, were confirmed with mass spectrometry. In addition, cellular experiments provided a convincing demonstration that the triggered release of NO from its donors by Pt NPs is efficient in killing human cancer cells in vitro. The catalytic mechanism was elucidated by X-ray photo-electron spectroscopy (XPS) and ultra-high performance liquid chromatography/high-resolution mass spectrometry (UHPLC-HRMS), which suggested that Pt-S bond formation occurs in the solution of Pt NPs and NO donors. Identification of Pt NPs capable of generating NO from S-nitrosothiols (RSNOs) is an important step in harnessing NO for investigations into its clinical applications and therapies.
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Affiliation(s)
- Gao-Juan Cao
- Department of Applied Chemistry, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
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7
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Marvasi M. Potential use and perspectives of nitric oxide donors in agriculture. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2017; 97:1065-1072. [PMID: 27786356 DOI: 10.1002/jsfa.8117] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 08/03/2016] [Accepted: 10/25/2016] [Indexed: 06/06/2023]
Abstract
Nitric oxide (NO) has emerged in the last 30 years as a key molecule involved in many physiological processes in plants, animals and bacteria. Current research has shown that NO can be delivered via donor molecules. In such cases, the NO release rate is dependent on the chemical structure of the donor itself and on the chemical environment. Despite NO's powerful signaling effect in plants and animals, the application of NO donors in agriculture is currently not implemented and research remains mainly at the experimental level. Technological development in the field of NO donors is rapidly expanding in scope to include controlling seed germination, plant development, ripening and increasing shelf-life of produce. Potential applications in animal production have also been identified. This concise review focuses on the use of donors that have shown potential biotechnological applications in agriculture. Insights are provided into (i) the role of donors in plant production, (ii) the potential use of donors in animal production and (iii) future approaches to explore the use and applications of donors for the benefit of agriculture. © 2016 Society of Chemical Industry.
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Affiliation(s)
- Massimiliano Marvasi
- Department of Natural Sciences, Faculty of Science and Technology, Middlesex University, The Burroughs, London, NW4 4BT, UK
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8
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Wang ZQ, Haque MM, Binder K, Sharma M, Wei CC, Stuehr DJ. Engineering nitric oxide synthase chimeras to function as NO dioxygenases. J Inorg Biochem 2016; 158:122-130. [PMID: 27013266 DOI: 10.1016/j.jinorgbio.2016.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 03/10/2016] [Accepted: 03/12/2016] [Indexed: 10/22/2022]
Abstract
Nitric oxide synthases (NOSs) catalyze a two-step oxidation of l-arginine to form nitric oxide (NO) and l-citrulline. NOS contains a N-terminal oxygenase domain (NOSoxy) that is the site of NO synthesis, and a C-terminal reductase domain (NOSred) that binds nicotinamide adenine dinucleotide phosphate (NADPH), flavin adenine dinucleotide (FAD), and flavin mononucleotide (FMN) and provides electrons to the NOSoxy heme during catalysis. The three NOS isoforms in mammals inducible NOS (iNOS), neuronal NOS (nNOS), and endothelial NOS (eNOS) share high structural similarity but differ in NO release rates and catalytic properties due to differences in enzyme kinetic parameters. These parameters must be balanced for NOS enzymes to release NO, rather than consume it in a competing, inherent NO dioxygenase reaction. To improve understanding, we drew on a global catalytic model and previous findings to design three NOS chimeras that may predominantly function as NO dioxygenases: iNOSoxy/nNOSred (Wild type (WT) chimera), V346I iNOSoxy/nNOSred (V346I chimera) and iNOSoxy/S1412D nNOSred (S1412D chimera). The WT and S1412D chimeras had higher NO release than the parent iNOS, while the V346I chimera exhibited much lower NO release, consistent with expectations. Measurements indicated that a greater NO dioxygenase activity was achieved, particularly in the V346I chimera, which dioxygenated an estimated two to four NO per NO that it released, while the other chimeras had nearly equivalent NO dioxygenase and NO release activities. Computer simulations of the global catalytic model using the measured kinetic parameters produced results that mimicked the measured outcomes, and this provided further insights on the catalytic behaviors of the chimeras and basis of their increased NO dioxygenase activities.
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Affiliation(s)
- Zhi-Qiang Wang
- Department of Chemistry and Biochemistry, Kent State University Geauga, Burton, OH 44021, United States.
| | - Mohammad Mahfuzul Haque
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, United States
| | - Katherine Binder
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, United States
| | - Manisha Sharma
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, United States
| | - Chin-Chuan Wei
- Department of Chemistry, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Dennis J Stuehr
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, United States.
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9
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Hematian S, Kenkel I, Shubina TE, Dürr M, Liu JJ, Siegler MA, Ivanovic-Burmazovic I, Karlin KD. Nitrogen Oxide Atom-Transfer Redox Chemistry; Mechanism of NO(g) to Nitrite Conversion Utilizing μ-oxo Heme-Fe(III)-O-Cu(II)(L) Constructs. J Am Chem Soc 2015; 137:6602-15. [PMID: 25974136 DOI: 10.1021/jacs.5b02174] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
While nitric oxide (NO, nitrogen monoxide) is a critically important signaling agent, its cellular concentrations must be tightly controlled, generally through its oxidative conversion to nitrite (NO2(-)) where it is held in reserve to be reconverted as needed. In part, this reaction is mediated by the binuclear heme a3/CuB active site of cytochrome c oxidase. In this report, the oxidation of NO(g) to nitrite is shown to occur efficiently in new synthetic μ-oxo heme-Fe(III)-O-Cu(II)(L) constructs (L being a tridentate or tetradentate pyridyl/alkylamino ligand), and spectroscopic and kinetic investigations provide detailed mechanistic insights. Two new X-ray structures of μ-oxo complexes have been determined and compared to literature analogs. All μ-oxo complexes react with 2 mol equiv NO(g) to give 1:1 mixtures of discrete [(L)Cu(II)(NO2(-))](+) plus ferrous heme-nitrosyl compounds; when the first NO(g) equiv reduces the heme center and itself is oxidized to nitrite, the second equiv of NO(g) traps the ferrous heme thus formed. For one μ-oxo heme-Fe(III)-O-Cu(II)(L) compound, the reaction with NO(g) reveals an intermediate species ("intermediate"), formally a bis-NO adduct, [(NO)(porphyrinate)Fe(II)-(NO2(-))-Cu(II)(L)](+) (λmax = 433 nm), confirmed by cryo-spray ionization mass spectrometry and EPR spectroscopy, along with the observation that cooling a 1:1 mixture of [(L)Cu(II)(NO2(-))](+) and heme-Fe(II)(NO) to -125 °C leads to association and generation of the key 433 nm UV-vis feature. Kinetic-thermodynamic parameters obtained from low-temperature stopped-flow measurements are in excellent agreement with DFT calculations carried out which describe the sequential addition of NO(g) to the μ-oxo complex.
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Affiliation(s)
- Shabnam Hematian
- †Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21211, United States
| | - Isabell Kenkel
- ‡Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Erlangen 91058, Germany
| | - Tatyana E Shubina
- ‡Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Erlangen 91058, Germany
| | - Maximilian Dürr
- ‡Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Erlangen 91058, Germany
| | - Jeffrey J Liu
- †Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21211, United States
| | - Maxime A Siegler
- †Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21211, United States
| | | | - Kenneth D Karlin
- †Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21211, United States
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10
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Nitrite reduction by molybdoenzymes: a new class of nitric oxide-forming nitrite reductases. J Biol Inorg Chem 2015; 20:403-33. [DOI: 10.1007/s00775-014-1234-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 12/14/2014] [Indexed: 02/07/2023]
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Experimental and statistical analysis of nutritional requirements for the growth of the extremophile Deinococcus geothermalis DSM 11300. Extremophiles 2014; 18:1009-21. [PMID: 25209745 DOI: 10.1007/s00792-014-0671-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 07/06/2014] [Indexed: 10/24/2022]
Abstract
Few studies concerning the nutritional requirements of Deinococcus geothermalis DSM 11300 have been conducted to date. Three defined media compositions have been published for the growth of this strain but they were found to be inadequate to achieve growth without limitation. Furthermore, growth curves, biomass concentration and growth rates were generally not available. Analysis in Principal Components was used in this work to compare and consequently to highlight the main compounds which differ between published chemically defined media. When available, biomass concentration, and/or growth rate were superimposed to the PCA analysis. The formulations of the media were collected from existing literature; media compositions designed for the growth of several strains of Deinococcaceae or Micrococcaceae were included. The results showed that a defined medium adapted from Holland et al. (Appl Microbiol Biotechnol 72:1074-1082, 2006) was the best basal medium and was chosen for further studies. A growth rate of 0.03 h(-1) and a final OD600nm of 0.55 were obtained, but the growth was linear. Then, the effects of several medium components on oxygen uptake and biomass production by Deinococcus geothermalis DSM 11300 were studied using a respirometry-based method, to search for the nutritional limitation. The results revealed that the whole yeast extract in the medium with glucose is necessary to obtain a non-limiting growth of Deinococcus geothermalis DSM 11300 at a maximum growth rate of 0.64 h(-1) at 45 °C.
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Arasimowicz-Jelonek M, Floryszak-Wieczorek J. Nitric oxide: an effective weapon of the plant or the pathogen? MOLECULAR PLANT PATHOLOGY 2014; 15:406-16. [PMID: 24822271 PMCID: PMC6638900 DOI: 10.1111/mpp.12095] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
An explosion of research in plant nitric oxide (NO) biology during the last two decades has revealed that NO is a key signal involved in plant development, abiotic stress responses and plant immunity. During the course of evolutionary changes, microorganisms parasitizing plants have developed highly effective offensive strategies, in which NO also seems to be implicated. NO production has been demonstrated in several plant pathogens, including fungi, but the origin of NO seems to be as puzzling as in plants. So far, published studies have been spread over multiple species of pathogenic microorganisms in various developmental stages; however, the data clearly indicate that pathogen-derived NO is an important regulatory molecule involved not only in developmental processes, but also in pathogen virulence and its survival in the host. This review also focuses on the search for potential mechanisms by which pathogens convert NO messages into a physiological response or detoxify both endo- and exogenous NO. Finally, taking into account the data available from model bacteria and yeast, a basic draft for the mode of NO action in phytopathogenic microorganisms is proposed.
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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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14
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Nitric oxide generation from heme/copper assembly mediated nitrite reductase activity. J Biol Inorg Chem 2014; 19:515-28. [PMID: 24430198 DOI: 10.1007/s00775-013-1081-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/18/2013] [Indexed: 01/03/2023]
Abstract
Nitric oxide (NO) as a cellular signaling molecule and vasodilator regulates a range of physiological and pathological processes. Nitrite (NO2 (-)) is recycled in vivo to generate nitric oxide, particularly in physiologic hypoxia and ischemia. The cytochrome c oxidase binuclear heme a 3/CuB active site is one entity known to be responsible for conversion of cellular nitrite to nitric oxide. We recently reported that a partially reduced heme/copper assembly reduces nitrite ion, producing nitric oxide; the heme serves as the reductant and the cupric ion provides a Lewis acid interaction with nitrite, facilitating nitrite (N-O) bond cleavage (Hematian et al., J. Am. Chem. Soc. 134:18912-18915, 2012). To further investigate this nitrite reductase chemistry, copper(II)-nitrito complexes with tridentate and tetradentate ligands were used in this study, where either O,O'-bidentate or O-unidentate modes of nitrite binding to the cupric center are present. To study the role of the reducing ability of the ferrous heme center, two different tetraarylporphyrinate-iron(II) complexes, one with electron-donating para-methoxy peripheral substituents and the other with electron-withdrawing 2,6-difluorophenyl substituents, were used. The results show that differing modes of nitrite coordination to the copper(II) ion lead to differing kinetic behavior. Here, also, the ferrous heme is in all cases the source of the reducing equivalent required to convert nitrite to nitric oxide, but the reduction ability of the heme center does not play a key role in the observed overall reaction rate. On the basis of our observations, reaction mechanisms are proposed and discussed in terms of heme/copper heterobinuclear structures.
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15
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Antioxidant Functions of Nitric Oxide Synthase in a Methicillin Sensitive Staphylococcus aureus. Int J Microbiol 2013; 2013:312146. [PMID: 23690783 PMCID: PMC3638668 DOI: 10.1155/2013/312146] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 03/11/2013] [Indexed: 12/21/2022] Open
Abstract
Nitric oxide and its derivative peroxynitrites are generated by host defense system to control bacterial infection. However certain Gram positive bacteria including Staphylococcus aureus possess a gene encoding nitric oxide synthase (SaNOS) in their chromosome. In this study it was determined that under normal growth conditions, expression of SaNOS was highest during early exponential phase of the bacterial growth. In oxidative stress studies, deletion of SaNOS led to increased susceptibility of the mutant cells compared to wild-type S. aureus. While inhibition of SaNOS activity by the addition of L-NAME increased sensitivity of the wild-type S. aureus to oxidative stress, the addition of a nitric oxide donor, sodium nitroprusside, restored oxidative stress tolerance of the SaNOS mutant. The SaNOS mutant also showed reduced survival after phagocytosis by PMN cells with respect to wild-type S. aureus.
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16
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Chung MC, Narayanan A, Popova TG, Kashanchi F, Bailey CL, Popov SG. Bacillus anthracis-derived nitric oxide induces protein S-nitrosylation contributing to macrophage death. Biochem Biophys Res Commun 2013. [DOI: 10.1016/j.bbrc.2012.11.042] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Hannibal L, Somasundaram R, Tejero J, Wilson A, Stuehr DJ. Influence of heme-thiolate in shaping the catalytic properties of a bacterial nitric-oxide synthase. J Biol Chem 2011; 286:39224-35. [PMID: 21921039 PMCID: PMC3234747 DOI: 10.1074/jbc.m111.286351] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 08/26/2011] [Indexed: 12/26/2022] Open
Abstract
Nitric-oxide synthases (NOS) are heme-thiolate enzymes that generate nitric oxide (NO) from L-arginine. Mammalian and bacterial NOSs contain a conserved tryptophan (Trp) that hydrogen bonds with the heme-thiolate ligand. We mutated Trp(66) to His and Phe (W66H, W66F) in B. subtilis NOS to investigate how heme-thiolate electronic properties control enzyme catalysis. The mutations had opposite effects on heme midpoint potential (-302, -361, and -427 mV for W66H, wild-type (WT), and W66F, respectively). These changes were associated with rank order (W66H < WT < W66F) changes in the rates of oxygen activation and product formation in Arg hydroxylation and N-hydroxyarginine (NOHA) oxidation single turnover reactions, and in the O(2) reactivity of the ferrous heme-NO product complex. However, enzyme ferrous heme-O(2) autoxidation showed an opposite rank order. Tetrahydrofolate supported NO synthesis by WT and the mutant NOS. All three proteins showed similar extents of product formation (L-Arg → NOHA or NOHA → citrulline) in single turnover studies, but the W66F mutant showed a 2.5 times lower activity when the reactions were supported by flavoproteins and NADPH. We conclude that Trp(66) controls several catalytic parameters by tuning the electron density of the heme-thiolate bond. A greater electron density (as in W66F) improves oxygen activation and reactivity toward substrate, but decreases heme-dioxy stability and lowers the driving force for heme reduction. In the WT enzyme the Trp(66) residue balances these opposing effects for optimal catalysis.
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Affiliation(s)
- Luciana Hannibal
- From the Department of Pathobiology, Lerner
Research Institute, Cleveland Clinic, Cleveland, Ohio 44195 and
| | - Ramasamy Somasundaram
- From the Department of Pathobiology, Lerner
Research Institute, Cleveland Clinic, Cleveland, Ohio 44195 and
| | - Jesús Tejero
- From the Department of Pathobiology, Lerner
Research Institute, Cleveland Clinic, Cleveland, Ohio 44195 and
| | - Adjele Wilson
- the Laboratoire Stress Oxidant et Detoxication
(LSOD), CEA-IBITEC-S, Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Dennis J. Stuehr
- From the Department of Pathobiology, Lerner
Research Institute, Cleveland Clinic, Cleveland, Ohio 44195 and
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Lang J, Santolini J, Couture M. The conserved Trp-Cys hydrogen bond dampens the "push effect" of the heme cysteinate proximal ligand during the first catalytic cycle of nitric oxide synthase. Biochemistry 2011; 50:10069-81. [PMID: 22023145 DOI: 10.1021/bi200965e] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Residues surrounding and interacting with the heme proximal ligand are important for efficient catalysis by heme proteins. The nitric oxide synthases (NOSs) are thiolate-coordinated enzymes that catalyze the hydroxylation of l-Arg in the first of the two catalytic cycles needed to synthesize nitric oxide. In NOSs, the indole NH group of a conserved tryptophan [W56 of the bacterial NOS-like protein from Staphylococcus aureus (saNOS)] forms a hydrogen bond with the heme proximal cysteinate ligand. The purpose of this study was to determine the impact of increasing (W56F and W56Y variants) or decreasing (W56H variant) the electron density of the proximal cysteinate ligand on molecular oxygen (O(2)) activation using saNOS as a model. We show that the removal of the indole NH···S(-) bond for W56F and W56Y caused an increase in the electron density of the cysteinate. This was probed by the decrease of the midpoint reduction potential (E(1/2)) along with weakened σ-bonding and strengthened π-backbonding with distal ligands (CO and O(2)). On the other hand, the W56H variant showed stronger Fe-OO and Fe-CO bonds (strengthened σ-bonding) along with an elevated E(1/2), which is consistent with the formation of a strong NH···S(-) hydrogen bond from H56. We also show here that changing the electron density of the proximal thiolate controls its "push effect"; whereas the rates of both O(2) activation and autoxidation of the Fe(II)O(2) complex increase with the stronger push effect created by removing the indole NH···S(-) hydrogen bond (W56F and W56Y variants), the W56H variant showed an increased stability of the complex against autoxidation and a slower rate of O(2) activation. These results are discussed with regard to the roles played by the conserved tryptophan-cysteinate interaction in the first catalytic cycle of NOS.
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Affiliation(s)
- Jérôme Lang
- Département de biochimie, de microbiologie et de bioinformatique, PROTEO and IBIS, pavillon Charles-Eugène Marchand, room 3163, Université Laval, Québec, Canada G1V 0A6
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Schopfer MP, Wang J, Karlin KD. Bioinspired heme, heme/nonheme diiron, heme/copper, and inorganic NOx chemistry: *NO((g)) oxidation, peroxynitrite-metal chemistry, and *NO((g)) reductive coupling. Inorg Chem 2010; 49:6267-82. [PMID: 20666386 DOI: 10.1021/ic100033y] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The focus of this Forum Article highlights work from our own laboratories and those of others in the area of biochemical and biologically inspired inorganic chemistry dealing with nitric oxide [nitrogen monoxide, *NO((g))] and its biological roles and reactions. The latter focus is on (i) oxidation of *NO((g)) to nitrate by nitric oxide dioxygenases (NODs) and (ii) reductive coupling of two molecules of *NO((g)) to give N(2)O(g). In the former case, NODs are described, and the highlighting of possible peroxynitrite/heme intermediates and the consequences of this are given by a discussion of recent works with myoglobin and a synthetic heme model system for NOD action. Summaries of recent copper complex chemistries with *NO((g)) and O(2)(g), leading to peroxynitrite species, are given. The coverage of biological reductive coupling of *NO((g)) deals with bacterial nitric oxide reductases (NORs) with heme/nonheme diiron active sites and on heme/copper oxidases such as cytochrome c oxidase, which can mediate the same chemistry. Recently designed protein and synthetic model compounds (heme/nonheme/diiron or heme/copper) as functional mimics are discussed in some detail. We also highlight examples from the chemical literature, not necessarily involving biologically relevant metal ions, that describe the oxidation of *NO((g)) to nitrate (or nitrite) and possible peroxynitrite intermediates or reductive coupling of *NO((g)) to give nitrous oxide.
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Affiliation(s)
- Mark P Schopfer
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA
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Abstract
Unlike mammalian NO synthases, bacterial NO synthases do not contain a reductase domain. The only exception from this rule is the NO synthase from myxobacterium Sorangium cellulosum, but its reductase domain has unusual structure and location in the enzyme molecule. Recent achievements in bacterial genome sequencing have revealed the gene coding NO synthase (represented as an oxygenase domain) in some bacteria and have advanced the study of structure and functions of bacterial NO synthases. Important features of structure, sources of reducing equivalents, evolutionary connections, and functions of bacterial NO synthases (i.e. participation in nitration of the indole ring of Trp, in reparation of UV-radiation damage, role in adaptation of bacteria to oxidative stress, participation in the synthesis of cGMP, and resistance of bacteria against antibiotics) are described.
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Affiliation(s)
- S Iu Filippovich
- Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow, Russia.
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Affiliation(s)
| | | | - Bhumit A. Patel
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853;
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Schopfer MP, Mondal B, Lee DH, Sarjeant AAN, Karlin KD. Heme/O2/*NO nitric oxide dioxygenase (NOD) reactivity: phenolic nitration via a putative heme-peroxynitrite intermediate. J Am Chem Soc 2009; 131:11304-5. [PMID: 19627146 DOI: 10.1021/ja904832j] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
An oxy-heme complex, the heme-superoxo species (tetrahydrofuran)(F(8))Fe(III)-(O(2)(*-)) (2) (F(8) = an ortho-difluoro substituted tetraarylporphyrinate), reacts with nitrogen monoxide (*NO; nitric oxide) to produce a nitrato-iron(III) compound (F(8))Fe(III)-(NO(3)(-)) (3) (X-ray). The chemistry mimics the action of *NO Dioxygenases (NODs), microbial and mammalian heme proteins which facilitate *NO detoxification/homeostasis. A peroxynitrite intermediate complex is implicated; if 2,4-di-tert-butylphenol is added prior to *NO reaction with 2, o-nitration occurs giving 2,4-di-tert-butyl-6-nitrophenol. The iron product is (F(8))Fe(III)-(OH) (4). The results suggest that heme/O(2)/*NO chemistry may lead to peroxynitrite leakage and/or exogenous substrate oxidative/nitrative reactivity.
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Affiliation(s)
- Mark P Schopfer
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA
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Cloning, Expression, and Purification of a Nitric Oxide Synthase-Like Protein from Bacillus cereus. Biochem Res Int 2009; 2010:489892. [PMID: 21188074 PMCID: PMC3005942 DOI: 10.1155/2010/489892] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2009] [Accepted: 09/02/2009] [Indexed: 01/11/2023] Open
Abstract
The nitric oxide synthase-like protein from Bacillus cereus (bcNOS) has been cloned, expressed, and characterized. This small hemeprotein (356 amino acids in length) has a mass of 43 kDa and forms a dimer. The recombinant protein showed similar spectral shifts to the mammalian NOS proteins and could bind the substrates L-arginine and N(G)-hydroxy-L-arginine as well as the ligand imidazole. Low levels of activity were recorded for the hydrogen peroxide-dependent oxidation of N(G)-hydroxy-L-arginine and L-arginine by bcNOS, while a reconstituted system with the rat neuronal NOS reductase domain showed no activity. The recombinant bcNOS protein adds to the complement of bacterial NOS-like proteins that are used for the investigation of the mechanism and function of NO in microorganisms.
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Abstract
During catalysis, the heme in nitric oxide synthase (NOS) binds NO before releasing it to the environment. Oxidation of the NOS ferrous heme-NO complex by O2 is key for catalytic cycling, but the mechanism is unclear. We utilized stopped-flow methods to study the reaction of O2 with ferrous heme-NO complexes of inducible and neuronal NOS enzymes. We found that the reaction does not involve heme-NO dissociation, but instead proceeds by a rapid direct reaction of O2 with the ferrous heme-NO complex. This behavior is novel and may distinguish heme-thiolate enzymes, such as NOS, from related heme proteins.
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Affiliation(s)
- Jesús Tejero
- Department of Pathobiology, The Cleveland Clinic Foundation, Lerner Research Institute, 9500 Euclid Ave., Cleveland, OH 44195, USA
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