1
|
Filice F, Henderson JD, Li MSM, Ding Z. Correlating Live Cell Viability with Membrane Permeability Disruption Induced by Trivalent Chromium. ACS OMEGA 2019; 4:2142-2151. [PMID: 30775648 PMCID: PMC6374964 DOI: 10.1021/acsomega.8b02113] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 12/18/2018] [Indexed: 06/09/2023]
Abstract
Cr(III) is often regarded as a trace essential micronutrient that can be found in many dietary supplements due to its participation in blood glucose regulation. However, increased levels of exposure have been linked to adverse health effects in living organisms. Herein, scanning electrochemical microscopy (SECM) was used to detect variation in membrane permeability of single cells (T24) resulting from exposure to a trivalent Cr-salt, CrCl3. By employing electrochemical mediators, ferrocenemethanol (FcMeOH) and ferrocenecarboxylic acid (FcCOO-), initially semipermeable and impermeable, respectively, complementary information was obtained. Three-dimensional COMSOL finite element analysis simulations were successfully used to quantify the permeability coefficients of each mediator by matching experimental and simulated results. Depending on the concentration of Cr(III) administered, three regions of membrane response were detected. Following exposure to low concentrations (up to 500 μM Cr(III)), their permeability coefficients were comparable to that of control cells, 80 μm/s for FcMeOH and 0 μm/s for FcCOO-. This was confirmed for both mediators. As the incubation concentrations were increased, the ability of FcMeOH to permeate the membrane decreased to a minimum of 17 μm/s at 7500 μM Cr(III), while FcCOO- remained impermeable. At the highest examined concentrations, both mediators were found to demonstrate increased membrane permeability. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cell viability studies were also conducted on Cr(III)-treated T24 cells to correlate the SECM findings with the toxicity effects of the metal. The viability experiments revealed a similar concentration-dependent trend to the SECM cell membrane permeability study.
Collapse
Affiliation(s)
| | | | | | - Zhifeng Ding
- E-mail: . Tel: +1 519 661 2111x86161. Fax: +1 519 661
3022
| |
Collapse
|
2
|
Olsbu IK, Zoppellaro G, Andersson KK, Boucher JL, Hersleth HP. Importance of Val567 on heme environment and substrate recognition of neuronal nitric oxide synthase. FEBS Open Bio 2018; 8:1553-1566. [PMID: 30186754 PMCID: PMC6120233 DOI: 10.1002/2211-5463.12503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 07/22/2018] [Accepted: 08/01/2018] [Indexed: 12/02/2022] Open
Abstract
Nitric oxide (NO) produced by mammalian nitric oxide synthases (mNOSs) is an important mediator in a variety of physiological functions. Crystal structures of mNOSs have shown strong conservation of the active‐site residue Val567 (numbering for rat neuronal NOS, nNOS). NOS‐like proteins have been identified in several bacterial pathogens, and these display striking sequence identity to the oxygenase domain of mNOS (NOSoxy), with the exception of a Val to Ile mutation at the active site. Preliminary studies have highlighted the importance of this Val residue in NO‐binding, substrate recognition, and oxidation in mNOSs. To further elucidate the role of this valine in substrate and substrate analogue recognition, we generated five Val567 mutants of the oxygenase domain of the neuronal NOS (nNOSoxy) and used UV‐visible and EPR spectroscopy to investigate the effects of these mutations on the heme distal environment, the stability of the heme‐FeII‐CO complexes, and the binding of a series of substrate analogues. Our results are consistent with Val567 playing an important role in preserving the integrity of the active site for substrate binding, stability of heme‐bound gaseous ligands, and potential NO production.
Collapse
Affiliation(s)
- Inger K Olsbu
- Department of Biosciences Section for Biochemistry and Molecular Biology University of Oslo Norway
| | - Giorgio Zoppellaro
- Regional Centre of Advanced Technologies and Materials Department of Physical Chemistry Faculty of Science Palacky University in Olomouc Czech Republic
| | - K Kristoffer Andersson
- Department of Biosciences Section for Biochemistry and Molecular Biology University of Oslo Norway
| | | | - Hans-Petter Hersleth
- Department of Biosciences Section for Biochemistry and Molecular Biology University of Oslo Norway.,Department of Chemistry Section for Chemical Life Sciences University of Oslo Norway
| |
Collapse
|
3
|
Tsutsui Y, Kobayashi K, Takeuchi F, Tsubaki M, Kozawa T. Reaction Intermediates of Nitric Oxide Synthase from Deinococcus radiodurans as Revealed by Pulse Radiolysis: Evidence for Intramolecular Electron Transfer from Biopterin to Fe II-O 2 Complex. Biochemistry 2018; 57:1611-1619. [PMID: 29320163 DOI: 10.1021/acs.biochem.7b00887] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Nitric oxide synthase (NOS) is a cytochrome P450-type mono-oxygenase that catalyzes the oxidation of l-arginine (Arg) to nitric oxide (NO) through a reaction intermediate N-hydroxy-l-arginine (NHA). The mechanism underlying the reaction catalyzed by NOS from Deinococcus radiodurans was investigated using pulse radiolysis. Radiolytically generated hydrated electrons reduced the heme iron of NOS within 2 μs. Subsequently, ferrous heme reacted with O2 to form a ferrous-dioxygen intermediate with a second-order rate constant of 2.8 × 108 M-1 s-1. In the tetrahydrofolate (H4F)-bound enzyme, the ferrous-dioxygen intermediate was found to decay an another intermediate with a first-order rate constant of 2.2 × 103 s-1. The spectrum of the intermediate featured an absorption maximum at 440 nm and an absorption minimum at 390 nm. In the absence of H4F, this step did not proceed, suggesting that H4F was reduced with the ferrous-dioxygen intermediate to form a second intermediate. The intermediate further converted to the original ferric form with a first-order rate constant of 4 s-1. A similar intermediate could be detected after pulse radiolysis in the presence of NHA, although the intermediate decayed more slowly (0.5 s-1). These data suggested that a common catalytically active intermediate involved in the substrate oxidation of both Arg and NHA may be formed during catalysis. In addition, we investigated the solvent isotope effects on the kinetics of the intermediate after pulse radiolysis. Our experiments revealed dramatic kinetic solvent isotope effects on the conversion of the intermediate to the ferric form, of 10.5 and 2.5 for Arg and NHA, respectively, whereas the faster phases were not affected. These data suggest that the proton transfer in DrNOS is the rate-limiting reaction of the intermediate with the substrates.
Collapse
Affiliation(s)
- Yuko Tsutsui
- The Institute of Scientific and Industrial Research , Osaka University , Mihogaoka 8-1 , Ibaraki , Osaka 567-0047 , Japan
| | - Kazuo Kobayashi
- The Institute of Scientific and Industrial Research , Osaka University , Mihogaoka 8-1 , Ibaraki , Osaka 567-0047 , Japan
| | - Fusako Takeuchi
- Institute for Promotion of Higher Education , Kobe University , 1-2-1 Tsurukabuto , Nada-ku, Kobe , Hyogo 657-8501 , Japan
| | - Motonari Tsubaki
- Graduate School of Science, Department of Chemistry , Kobe University , 1-1 Rokkodai-cho , Nada-ku, Kobe , Hyogo 657-8501 , Japan
| | - Takahiro Kozawa
- The Institute of Scientific and Industrial Research , Osaka University , Mihogaoka 8-1 , Ibaraki , Osaka 567-0047 , Japan
| |
Collapse
|
4
|
Weisslocker-Schaetzel M, André F, Touazi N, Foresi N, Lembrouk M, Dorlet P, Frelet-Barrand A, Lamattina L, Santolini J. The NOS-like protein from the microalgae Ostreococcus tauri is a genuine and ultrafast NO-producing enzyme. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2017; 265:100-111. [PMID: 29223331 DOI: 10.1016/j.plantsci.2017.09.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 09/21/2017] [Accepted: 09/24/2017] [Indexed: 05/03/2023]
Abstract
The exponential increase of genomes' sequencing has revealed the presence of NO-Synthases (NOS) throughout the tree of life, uncovering an extraordinary diversity of genetic structure and biological functions. Although NO has been shown to be a crucial mediator in plant physiology, NOS sequences seem present solely in green algae genomes, with a first identification in the picoplankton species Ostreococcus tauri. There is no rationale so far to account for the presence of NOS in this early-diverging branch of the green lineage and its absence in land plants. To address the biological function of algae NOS, we cloned, expressed and characterized the NOS oxygenase domain from Ostreococcus tauri (OtNOSoxy). We launched a phylogenetic and structural analysis of algae NOS, and achieved a 3D model of OtNOSoxy by homology modeling. We used a combination of various spectroscopies to characterize the structural and electronic fingerprints of some OtNOSoxy reaction intermediates. The analysis of OtNOSoxy catalytic activity and kinetic efficiency was achieved by stoichiometric stopped-flow. Our results highlight the conserved and particular features of OtNOSoxy structure that might explain its ultrafast NO-producing capacity. This integrative Structure-Catalysis-Function approach could be extended to the whole NOS superfamily and used for predicting potential biological activity for any new NOS.
Collapse
Affiliation(s)
- Marine Weisslocker-Schaetzel
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, F-91198, Gif-sur-Yvette cedex, France
| | - François André
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, F-91198, Gif-sur-Yvette cedex, France
| | - Nabila Touazi
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, F-91198, Gif-sur-Yvette cedex, France
| | - Noelia Foresi
- Instituto de Investigaciones Biologicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC 1245, 7600 Mar del Plata, Argentina, Argentina
| | - Mehdi Lembrouk
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, F-91198, Gif-sur-Yvette cedex, France
| | - Pierre Dorlet
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, F-91198, Gif-sur-Yvette cedex, France
| | - Annie Frelet-Barrand
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, F-91198, Gif-sur-Yvette cedex, France
| | - Lorenzo Lamattina
- Instituto de Investigaciones Biologicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC 1245, 7600 Mar del Plata, Argentina, Argentina
| | - Jérôme Santolini
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, F-91198, Gif-sur-Yvette cedex, France.
| |
Collapse
|
5
|
Weisslocker-Schaetzel M, Lembrouk M, Santolini J, Dorlet P. Revisiting the Val/Ile Mutation in Mammalian and Bacterial Nitric Oxide Synthases: A Spectroscopic and Kinetic Study. Biochemistry 2017; 56:748-756. [PMID: 28074650 DOI: 10.1021/acs.biochem.6b01018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Nitric oxide is produced in mammals by the nitric oxide synthase (NOS) isoforms at a catalytic site comprising a heme associated with a biopterin cofactor. Through genome sequencing, proteins that are highly homologous to the oxygenase domain of NOSs have been identified, in particular in bacteria. The active site is highly conserved except for a valine residue in the distal pocket that is replaced with an isoleucine in bacteria. This switch was previously reported to influence the kinetics of the reaction. We have used the V346I mutant of the mouse inducible NOS (iNOS) as well as the I224V mutant of the NOS from Bacillus subtilis (bsNOS) to study their spectroscopic signatures in solution and look for potential structural differences compared to their respective wild types. Both mutants seem destabilized in the absence of substrate and cofactor. When both substrate and cofactor are present, small differences can be detected with Nω-hydroxy-l-arginine compared to arginine, which is likely due to the differences in the hydrogen bonding network of the distal pocket. Stopped-flow experiments evidence significant changes in the kinetics of the reaction due to the mutation as was already known. We found these effects particularly marked for iNOS. On the basis of these results, we performed rapid freeze-quench experiments to trap the biopterin radical and found the same results that we had obtained for the wild types. Despite differences in kinetics, a radical could be trapped in both steps for the iNOS mutant but only for the first step in the mutant of bsNOS. This strengthens the hypothesis that mammalian and bacterial NOSs may have a different mechanism during the second catalytic step.
Collapse
Affiliation(s)
- Marine Weisslocker-Schaetzel
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay , F-91198 Gif-sur-Yvette cedex, France
| | - Mehdi Lembrouk
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay , F-91198 Gif-sur-Yvette cedex, France
| | - Jérôme Santolini
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay , F-91198 Gif-sur-Yvette cedex, France
| | - Pierre Dorlet
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay , F-91198 Gif-sur-Yvette cedex, France
| |
Collapse
|
6
|
Nitric oxide synthase in plants: Where do we stand? Nitric Oxide 2016; 63:30-38. [PMID: 27658319 DOI: 10.1016/j.niox.2016.09.005] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 09/13/2016] [Accepted: 09/16/2016] [Indexed: 12/31/2022]
Abstract
Over the past twenty years, nitric oxide (NO) has emerged as an important player in various plant physiological processes. Although many advances in the understanding of NO functions have been made, the question of how NO is produced in plants is still challenging. It is now generally accepted that the endogenous production of NO is mainly accomplished through the reduction of nitrite via both enzymatic and non-enzymatic mechanisms which remain to be fully characterized. Furthermore, experimental arguments in favour of the existence of plant nitric oxide synthase (NOS)-like enzymes have been reported. However, recent investigations revealed that land plants do not possess animal NOS-like enzymes while few algal species do. Phylogenetic and structural analyses reveals interesting features specific to algal NOS-like proteins.
Collapse
|
7
|
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.
Collapse
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.
| |
Collapse
|
8
|
Santolini J, Maréchal A, Boussac A, Dorlet P. EPR characterisation of the ferrous nitrosyl complex formed within the oxygenase domain of NO synthase. Chembiochem 2013; 14:1852-7. [PMID: 23943262 PMCID: PMC4159581 DOI: 10.1002/cbic.201300233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Indexed: 11/10/2022]
Abstract
Nitric oxide is produced in mammals by a class of enzymes called NO synthases (NOSs). It plays a central role in cellular signalling but also has deleterious effects, as it leads to the production of reactive oxygen and nitrogen species. NO forms a relatively stable adduct with ferrous haem proteins, which, in the case of NOS, is also a key catalytic intermediate. Despite extensive studies on the ferrous nitrosyl complex of other haem proteins (in particular myoglobin), little characterisation has been performed in the case of NOS. We report here a temperature-dependent EPR study of the ferrous nitrosyl complex of the inducible mammalian NOS and the bacterial NOS-like protein from Bacillus subtilis. The results show that the overall behaviours are similar to those observed for other haem proteins, but with distinct ratios between axial and rhombic forms in the case of the two NOS proteins. The distal environment appears to control the existence of the axial form and the evolution of the rhombic form.
Collapse
Affiliation(s)
- Jérôme Santolini
- CNRS, UMR 8221, CEA/iBiTec-S/SB2SM, Bât. 532, CEA Saclay, 91191 Gif-sur-Yvette Cedex (France).
| | | | | | | |
Collapse
|
9
|
Whited CA, Warren JJ, Lavoie KD, Weinert EE, Agapie T, Winkler JR, Gray HB. Gating NO release from nitric oxide synthase. J Am Chem Soc 2011; 134:27-30. [PMID: 22148177 DOI: 10.1021/ja2069533] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have investigated the kinetics of NO escape from Geobacillus stearothermophilus nitric oxide synthase (gsNOS). Previous work indicated that NO release was gated at position 223 in mammalian enzymes; our kinetics experiments include mutants at that position along with measurements on the wild type enzyme. Employing stopped-flow UV-vis methods, reactions were triggered by mixing a reduced enzyme/N-hydroxy-l-arginine complex with an aerated buffer solution. NO release kinetics were obtained for wt NOS and three mutants (H134S, I223V, H134S/I223V). We have confirmed that wt gsNOS has the lowest NO release rate of known NOS enzymes, whether bacterial or mammalian. We also have found that steric clashes at positions 223 and 134 hinder NO escape, as judged by enhanced rates in the single mutants. The empirical rate of NO release from the gsNOS double mutant (H134/I223V) is nearly as rapid as that of the fastest mammalian enzymes, demonstrating that both positions 223 and 134 function as gates for escape of the product diatomic molecule.
Collapse
Affiliation(s)
- Charlotte A Whited
- Beckman Institute and Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | | | | | | | | | | | | |
Collapse
|
10
|
Feng C, Tollin G. Regulation of interdomain electron transfer in the NOS output state for NO production. Dalton Trans 2009:6692-700. [PMID: 19690675 DOI: 10.1039/b902884f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
There is still much that is unknown about how nitric oxide (NO) biosynthesis by NO synthase (NOS) isoform is tightly regulated at the molecular level. This is remarkable because deviated NO production in vivo has been implicated in an increasing number of diseases that currently lack effective treatments, including stroke and cancer. Given the significant public health burden of these diseases, the NOS enzyme family is a key target for development of new pharmaceuticals. Three NOS isoforms, inducible, endothelial and neuronal NOS (iNOS, eNOS and nNOS, respectively), achieve their key biological functions via stringent regulations of interdomain electron transfer (IET) processes. Unlike iNOS, eNOS and nNOS isoforms are controlled by calmodulin (CaM) binding through facilitating catalytically significant IET processes. The CaM-modulated NOS output state is an IET-competent complex between the flavin mononucleotide (FMN) domain and the catalytic heme domain. The output state facilitates the catalytically essential FMN-heme IET, and thereby enables NO production by NOS. Due to lack of reliable techniques for specifically determining the inter-domain FMN-heme interactions and their direct effects on the catalytic heme center, the molecular mechanism that underlies the output state formation remains elusive. The recent developments in our understanding of mechanisms of the NOS output state formation that are driven by a combination of molecular biology, laser flash photolysis, and spectroscopic techniques are the subject of this perspective.
Collapse
Affiliation(s)
- Changjian Feng
- College of Pharmacy, University of New Mexico, Albuquerque, NM 87131, USA.
| | | |
Collapse
|
11
|
Sudhamsu J, Crane BR. Bacterial nitric oxide synthases: what are they good for? Trends Microbiol 2009; 17:212-8. [DOI: 10.1016/j.tim.2009.02.003] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Revised: 02/09/2009] [Accepted: 02/11/2009] [Indexed: 11/26/2022]
|
12
|
Abstract
Mammalian NOSs (nitric oxide synthases) are haem-based monoxygenases that oxidize the amino acid arginine to the intracellular signal and protective cytotoxin nitric oxide (NO). Certain strains of mostly Gram-positive bacteria contain homologues of the mammalian NOS catalytic domain that can act as NOSs when suitable reductants are supplied. Crystallographic analyses of bacterial NOSs, with substrates and haem-ligands, have disclosed important features of assembly and active-centre chemistry, both general to the NOS family and specific to the bacterial proteins. The slow reaction profiles and especially stable haem-oxygen species of NOSs derived from bacterial thermophiles have facilitated the study of NOS reaction intermediates. Functionally, bacterial NOSs are distinct from their mammalian counterparts. In certain strains of Streptomyces, they participate in the biosynthetic nitration of plant toxins. In the radiation-resistant bacterium Deinococcus radiodurans, NOSs are also likely to be involved in biosynthetic nitration reactions, but, furthermore, appear to play an important role in the recovery from damage induced by UV radiation.
Collapse
|
13
|
Woodward JJ, Chang MM, Martin NI, Marletta MA. The Second Step of the Nitric Oxide Synthase Reaction: Evidence for Ferric-Peroxo as the Active Oxidant. J Am Chem Soc 2008; 131:297-305. [DOI: 10.1021/ja807299t] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joshua J. Woodward
- Departments of Chemistry, Molecular and Cellular Biology, QB3 Institute, and Division of Physical Biosciences, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720-3220
| | - Michelle M. Chang
- Departments of Chemistry, Molecular and Cellular Biology, QB3 Institute, and Division of Physical Biosciences, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720-3220
| | - Nathaniel I. Martin
- Departments of Chemistry, Molecular and Cellular Biology, QB3 Institute, and Division of Physical Biosciences, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720-3220
| | - Michael A. Marletta
- Departments of Chemistry, Molecular and Cellular Biology, QB3 Institute, and Division of Physical Biosciences, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720-3220
| |
Collapse
|