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Lesanavičius M, Seo D, Maurutytė G, Čėnas N. Redox Properties of Bacillus subtilis Ferredoxin:NADP + Oxidoreductase: Potentiometric Characteristics and Reactions with Pro-Oxidant Xenobiotics. Int J Mol Sci 2024; 25:5373. [PMID: 38791410 PMCID: PMC11121358 DOI: 10.3390/ijms25105373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/03/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024] Open
Abstract
Bacillus subtilis ferredoxin:NADP+ oxidoreductase (BsFNR) is a thioredoxin reductase-type FNR whose redox properties and reactivity with nonphysiological electron acceptors have been scarcely characterized. On the basis of redox reactions with 3-acetylpyridine adenine dinucleotide phosphate, the two-electron reduction midpoint potential of the flavin adenine dinucleotide (FAD) cofactor was estimated to be -0.240 V. Photoreduction using 5-deazaflavin mononucleotide (5-deazaFMN) as a photosensitizer revealed that the difference in the redox potentials between the first and second single-electron transfer steps was 0.024 V. We examined the mechanisms of the reduction of several different groups of non-physiological electron acceptors catalyzed by BsFNR. The reactivity of quinones and aromatic N-oxides toward BsFNR increased when increasing their single-electron reduction midpoint redox potentials. The reactivity of nitroaromatic compounds was lower due to their lower electron self-exchange rate, but it exhibited the same trend. A mixed single- and two-electron reduction reaction was characteristic of quinones, whereas reactions involving nitroaromatics proceeded exclusively via the one-electron reduction reaction. The oxidation of FADH• to FAD is the rate-limiting step during the oxidation of fully reduced FAD. The calculated electron transfer distances in the reaction with nitroaromatics were close to those of other FNRs including the plant-type enzymes, thus demonstrating their similar active site accessibility to low-molecular-weight oxidants despite the fundamental differences in their structures.
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Affiliation(s)
- Mindaugas Lesanavičius
- Department of Xenobiotics Biochemistry, Institute of Biochemistry, Life Sciences Center, Vilnius University, Saulėtekio Av. 7, LT-10257 Vilnius, Lithuania; (M.L.); (G.M.)
| | - Daisuke Seo
- Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan;
| | - Gintarė Maurutytė
- Department of Xenobiotics Biochemistry, Institute of Biochemistry, Life Sciences Center, Vilnius University, Saulėtekio Av. 7, LT-10257 Vilnius, Lithuania; (M.L.); (G.M.)
| | - Narimantas Čėnas
- Department of Xenobiotics Biochemistry, Institute of Biochemistry, Life Sciences Center, Vilnius University, Saulėtekio Av. 7, LT-10257 Vilnius, Lithuania; (M.L.); (G.M.)
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2
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Kobayashi K, Ito YT, Kasu Y, Horitani M, Kozawa T. Intramolecular electron transfer from biopterin to Fe II-O 2 complex in nitric oxide synthases occurs at very different rates between bacterial and mammalian enzymes: Direct observation of a catalytically active intermediate. J Inorg Biochem 2023; 238:112035. [PMID: 36327499 DOI: 10.1016/j.jinorgbio.2022.112035] [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: 07/18/2022] [Revised: 10/05/2022] [Accepted: 10/17/2022] [Indexed: 11/21/2022]
Abstract
Nitric oxide synthase (NOS) is a cytochrome P450-type mono‑oxygenase that catalyzes the oxidation of L-arginine to nitric oxide. We previously observed that intramolecular electron transfer from biopterin to Fe2+-O2 in Deinococcus radiodurans NOS (DrNOS) using pulse radiolysis. However, the rate of electron transfer in DrNOS (2.2 × 103 s-1) contrasts with a reported corresponding rate (11 s-1) in a mammalian NOS determined using rapid freeze-quench (RFQ) EPR. We applied pulse radiolysis to Bacillus subtilis NOS (bsNOS) and to rat neural NOS oxygenase domain NOS (mNOS). Concurrently, RFQ EPR was used to trap a pterin radical during single-turnover enzyme reactions of the enzymes. By using the pulse radiolysis method, hydrated electrons (eaq-) reduced the heme iron of NOS enzymes. Subsequently, ferrous heme reacted with O2 to form a Fe2+-O2 intermediate. In the presence of pterin, the intermediate of bsNOS was found to convert to other intermediate in the time range of milliseconds. A similar process was determined to have occurred after pulse radiolysis of the pterin-bound mNOS, though the rate was much slower. The intermediates of all of the NOS enzymes further converted to the original ferric form in the time range of seconds. When using the RFQ method, pterin radicals were formed very rapidly in both DrNOS and bsNOS in the time range of milliseconds. In contrast, the pterin radical in mNOS was observed to form slowly, at a rate of ∼20 s-1.
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Affiliation(s)
- Kazuo Kobayashi
- The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan.
| | - Yuko Tsutsui Ito
- The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Yuri Kasu
- Department of Applied Biochemistry and Food Science, Saga University, Honjo-machi Saga, 840-8502, Japan
| | - Masaki Horitani
- Department of Applied Biochemistry and Food Science, Saga University, Honjo-machi Saga, 840-8502, Japan; The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima, Kagoshima 890-0065, Japan
| | - Takahiro Kozawa
- The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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3
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Overview of structurally homologous flavoprotein oxidoreductases containing the low M r thioredoxin reductase-like fold - A functionally diverse group. Arch Biochem Biophys 2021; 702:108826. [PMID: 33684359 DOI: 10.1016/j.abb.2021.108826] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 02/23/2021] [Accepted: 02/27/2021] [Indexed: 01/12/2023]
Abstract
Structural studies show that enzymes have a limited number of unique folds, although structurally related enzymes have evolved to perform a large variety of functions. In this review, we have focused on enzymes containing the low molecular weight thioredoxin reductase (low Mr TrxR) fold. This fold consists of two domains, both containing a three-layer ββα sandwich Rossmann-like fold, serving as flavin adenine dinucleotide (FAD) and, in most cases, pyridine nucleotide (NAD(P)H) binding-domains. Based on a search of the Protein Data Bank for all published structures containing the low Mr TrxR-like fold, we here present a comprehensive overview of enzymes with this structural architecture. These range from TrxR-like ferredoxin/flavodoxin NAD(P)+ oxidoreductases, through glutathione reductase, to NADH peroxidase. Some enzymes are solely composed of the low Mr TrxR-like fold, while others contain one or two additional domains. In this review, we give a detailed description of selected enzymes containing only the low Mr TrxR-like fold, however, catalyzing a diversity of chemical reactions. Our overview of this structurally similar, yet functionally distinct group of flavoprotein oxidoreductases highlights the fascinating and increasing number of studies describing the diversity among these enzymes, especially during the last decade(s).
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Zuo R, Ding Y. Direct Aromatic Nitration System for Synthesis of Nitrotryptophans in Escherichia coli. ACS Synth Biol 2019; 8:857-865. [PMID: 30865826 DOI: 10.1021/acssynbio.8b00534] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Nitrotryptophan and its analogues are useful building blocks for synthesizing bioactive and biotechnologically relevant chemicals, materials, and proteins. However, synthetic routes to enantiopure nitro-containing tryptophan derivatives are either complex and polluting or even unestablished yet. Herein, we describe microbial production of 4-NO2-l-tryptophan (Nitrotrp) and its analogues by designing and expressing the biosynthetic pathway in Escherichia coli. The biosynthetic pathway comprised one engineered self-sufficient P450 TB14 of Streptomyces origin for direct nitration of the C-4 of l-Trp indole and one nitric oxide synthase from Bacillus subtilis (BsNOS) for the production of nitric oxide (NO) from l-Arg to support the direct aromatic nitration. As both TB14 and BsNOS require reducing agent NADPH for their reactions, we also included one glucose dehydrogenase (GDH) from B. subtilis for in situ NADPH regeneration. The initially designed pathway led to 16.2 ± 2.3 mg/L of Nitrotrp by the engineered E. coli fermented in the M9 minimal medium for 3 days. A combination of the design and screening of three additional pathways, fermentation optimization and the knockout of competitive metabolic pathways together improved the Nitrotrp titer to around 192 mg/L within 20 h. Finally, the whole-cell biotransformation system produced eight Nitrotrp analogues with their titers varying from 2.5 to 61.5 mg/L. This work provides the first microbial direct aromatic nitration processes and sets the stage for the development of biocatalytic routes to other useful nitroaromatics in the future.
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Affiliation(s)
- Ran Zuo
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Yousong Ding
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
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5
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The Response of nor and nos Contributes to Staphylococcus aureus Virulence and Metabolism. J Bacteriol 2019; 201:JB.00107-19. [PMID: 30782631 DOI: 10.1128/jb.00107-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 02/06/2019] [Indexed: 12/21/2022] Open
Abstract
Staphylococcus aureus causes a wide spectrum of disease, with the site and severity of infection dependent on virulence traits encoded within genetically distinct clonal complexes (CCs) and bacterial responses to host innate immunity. The production of nitric oxide (NO) by activated phagocytes is a major host response to which S. aureus metabolically adapts through multiple strategies that are conserved in all CCs, including an S. aureus nitric oxide synthase (Nos). Previous genome analysis of CC30, a lineage associated with chronic endocardial and osteoarticular infections, revealed a putative NO reductase (Nor) not found in other CCs that potentially contributes to NO resistance and clinical outcome. Here, we demonstrate that Nor has true nitric oxide reductase activity, with nor expression enhanced by NO stress and anaerobic growth. Furthermore, we demonstrate that nor is regulated by MgrA and SrrAB, which modulate S. aureus virulence and hypoxic response. Transcriptome analysis of the S. aureus UAMS-1, UAMS-1 Δnor, and UAMS-1 Δnos strains under NO stress and anaerobic growth demonstrates that Nor contributes to nucleotide metabolism and Nos to glycolysis. We demonstrate that Nor and Nos contribute to enhanced survival in the presence of human human polymorphonuclear cells and have organ-specific seeding in a tail vein infection model. Nor contributes to abscess formation in an osteological implant model. We also demonstrate that Nor has a role in S. aureus metabolism and virulence. The regulation overlap between Nor and Nos points to an intriguing link between regulation of intracellular NO, metabolic adaptation, and persistence in the CC30 lineage.IMPORTANCE Staphylococcus aureus can cause disease at most body sites, and illness spans asymptomatic infection to death. The variety of clinical presentations is due to the diversity of strains, which are grouped into distinct clonal complexes (CCs) based on genetic differences. The ability of S. aureus CC30 to cause chronic infections relies on its ability to evade the oxidative/nitrosative defenses of the immune system and survive under different environmental conditions, including differences in oxygen and nitric oxide concentrations. The significance of this work is the exploration of unique genes involved in resisting NO stress and anoxia. A better understanding of the functions that control the response of S. aureus CC30 to NO and oxygen will guide the treatment of severe disease presentations.
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6
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Ras G, Leroy S, Talon R. Nitric oxide synthase: What is its potential role in the physiology of staphylococci in meat products? Int J Food Microbiol 2018; 282:28-34. [PMID: 29890305 DOI: 10.1016/j.ijfoodmicro.2018.06.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 05/23/2018] [Accepted: 06/06/2018] [Indexed: 12/17/2022]
Abstract
Coagulase-negative staphylococci are frequently isolated from meat products and two species are used as starter cultures in dry fermented sausages. In these products, they face various environmental conditions such as variation of redox potential and oxygen levels that can lead to oxidative stress. Furthermore, when nitrate and nitrite are added as curing salts, staphylococci also experience nitrosative stress. A nos gene encoding a nitric oxide synthase (NOS) is present in the genome of all staphylococci. NOS produces nitric oxide (NO) and citrulline from arginine, but its activity is still poorly characterized, particularly in coagulase-negative staphylococci. NO is highly reactive with a broad spectrum of activity resulting from targeting metal centres (heme and non-heme) and protein thiols. At low concentration, NO acts as a signalling molecule, while at higher concentration it generates stress. Thus, it was initially suggested that staphylococcal NOS counteract oxidative stress in relation to PerR and Fur regulators. In the physiology of staphylococci, it has recently been highlighted that NO controls the rate of aerobic respiration and regulates the transition from aerobic to nitrate respiration and also helps maintain the membrane potential in relation to the two-component systems SrrAB and AirRS. As NO interacts with heme centres, it binds the heme iron atom of myoglobin to form nitrosomyglobin, which is the typical red pigment of cured meat. However, the contribution of NOS to this reaction in meat products has yet to be evaluated.
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Affiliation(s)
- Geoffrey Ras
- Université Clermont Auvergne, INRA, MEDIS, Clermont-Ferrand, France; CHR. HANSEN SAS, Saint-Germain-les-Arpajon, France
| | - Sabine Leroy
- Université Clermont Auvergne, INRA, MEDIS, Clermont-Ferrand, France
| | - Régine Talon
- Université Clermont Auvergne, INRA, MEDIS, Clermont-Ferrand, France.
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7
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Holden JK, Lewis MC, Cinelli MA, Abdullatif Z, Pensa AV, Silverman RB, Poulos TL. Targeting Bacterial Nitric Oxide Synthase with Aminoquinoline-Based Inhibitors. Biochemistry 2016; 55:5587-5594. [PMID: 27607918 DOI: 10.1021/acs.biochem.6b00786] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Nitric oxide is produced in Gram-positive pathogens Bacillus anthracis and Staphylococcus aureus by the bacterial isoform of nitric oxide synthase (NOS). Inhibition of bacterial nitric oxide synthase (bNOS) has been identified as a promising antibacterial strategy for targeting methicillin-resistant S. aureus [Holden, J. K., et al. (2015) Chem. Biol. 22, 785-779]. One class of NOS inhibitors that demonstrates antimicrobial efficacy utilizes an aminoquinoline scaffold. Here we report on a variety of aminoquinolines that target the bacterial NOS active site, in part, by binding to a hydrophobic patch that is unique to bNOS. Through mutagenesis and crystallographic studies, our findings demonstrate that aminoquinolines are an excellent scaffold for further aiding in the development of bNOS specific inhibitors.
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Affiliation(s)
- Jeffrey K Holden
- Department of Molecular Biology and Biochemistry, ‡Department of Pharmaceutical Sciences, and §Department of Chemistry, University of California , Irvine, California 92697-3900, United States.,Departments of Chemistry and Molecular Biosciences, ⊥Chemistry of Life Processes Institute, and #Center for Molecular Innovation and Drug Discovery, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Matthew C Lewis
- Department of Molecular Biology and Biochemistry, ‡Department of Pharmaceutical Sciences, and §Department of Chemistry, University of California , Irvine, California 92697-3900, United States.,Departments of Chemistry and Molecular Biosciences, ⊥Chemistry of Life Processes Institute, and #Center for Molecular Innovation and Drug Discovery, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Maris A Cinelli
- Department of Molecular Biology and Biochemistry, ‡Department of Pharmaceutical Sciences, and §Department of Chemistry, University of California , Irvine, California 92697-3900, United States.,Departments of Chemistry and Molecular Biosciences, ⊥Chemistry of Life Processes Institute, and #Center for Molecular Innovation and Drug Discovery, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Ziad Abdullatif
- Department of Molecular Biology and Biochemistry, ‡Department of Pharmaceutical Sciences, and §Department of Chemistry, University of California , Irvine, California 92697-3900, United States.,Departments of Chemistry and Molecular Biosciences, ⊥Chemistry of Life Processes Institute, and #Center for Molecular Innovation and Drug Discovery, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Anthony V Pensa
- Department of Molecular Biology and Biochemistry, ‡Department of Pharmaceutical Sciences, and §Department of Chemistry, University of California , Irvine, California 92697-3900, United States.,Departments of Chemistry and Molecular Biosciences, ⊥Chemistry of Life Processes Institute, and #Center for Molecular Innovation and Drug Discovery, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Richard B Silverman
- Department of Molecular Biology and Biochemistry, ‡Department of Pharmaceutical Sciences, and §Department of Chemistry, University of California , Irvine, California 92697-3900, United States.,Departments of Chemistry and Molecular Biosciences, ⊥Chemistry of Life Processes Institute, and #Center for Molecular Innovation and Drug Discovery, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Thomas L Poulos
- Department of Molecular Biology and Biochemistry, ‡Department of Pharmaceutical Sciences, and §Department of Chemistry, University of California , Irvine, California 92697-3900, United States.,Departments of Chemistry and Molecular Biosciences, ⊥Chemistry of Life Processes Institute, and #Center for Molecular Innovation and Drug Discovery, Northwestern University , Evanston, Illinois 60208-3113, United States
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8
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Lofstad M, Gudim I, Hammerstad M, Røhr ÅK, Hersleth HP. Activation of the Class Ib Ribonucleotide Reductase by a Flavodoxin Reductase in Bacillus cereus. Biochemistry 2016; 55:4998-5001. [DOI: 10.1021/acs.biochem.6b00699] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marie Lofstad
- Section
for Biochemistry and Molecular Biology, Department of Biosciences, University of Oslo, P.O.
Box 1066, Blindern, NO-0316 Oslo, Norway
| | - Ingvild Gudim
- Section
for Biochemistry and Molecular Biology, Department of Biosciences, University of Oslo, P.O.
Box 1066, Blindern, NO-0316 Oslo, Norway
| | - Marta Hammerstad
- Section
for Biochemistry and Molecular Biology, Department of Biosciences, University of Oslo, P.O.
Box 1066, Blindern, NO-0316 Oslo, Norway
| | - Åsmund Kjendseth Røhr
- Department
of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway
| | - Hans-Petter Hersleth
- Section
for Biochemistry and Molecular Biology, Department of Biosciences, University of Oslo, P.O.
Box 1066, Blindern, NO-0316 Oslo, Norway
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9
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Holden JK, Kang S, Beasley FC, Cinelli MA, Li H, Roy SG, Dejam D, Edinger AL, Nizet V, Silverman RB, Poulos TL. Nitric Oxide Synthase as a Target for Methicillin-Resistant Staphylococcus aureus. ACTA ACUST UNITED AC 2016; 22:785-92. [PMID: 26091171 DOI: 10.1016/j.chembiol.2015.05.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 04/20/2015] [Accepted: 05/17/2015] [Indexed: 02/04/2023]
Abstract
Bacterial infections associated with methicillin-resistant Staphylococcus aureus (MRSA) are a major economic burden to hospitals, and confer high rates of morbidity and mortality among those infected. Exploitation of novel therapeutic targets is thus necessary to combat this dangerous pathogen. Here, we report on the identification and characterization, including crystal structures, of two nitric oxide synthase (NOS) inhibitors that function as antimicrobials against MRSA. These data provide the first evidence that bacterial NOS (bNOS) inhibitors can work synergistically with oxidative stress to enhance MRSA killing. Crystal structures show that each inhibitor contacts an active site Ile residue in bNOS that is Val in the mammalian NOS isoforms. Mutagenesis studies show that the additional nonpolar contacts provided by the Ile in bNOS contribute to tighter binding toward the bacterial enzyme.
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Affiliation(s)
- Jeffrey K Holden
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California, Irvine, CA 92697-3900, USA
| | - Soosung Kang
- Departments of Chemistry and Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL 60208-3113, USA
| | - Federico C Beasley
- Departments of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, CA 92093, USA
| | - Maris A Cinelli
- Departments of Chemistry and Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL 60208-3113, USA
| | - Huiying Li
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California, Irvine, CA 92697-3900, USA
| | - Saurabh G Roy
- Department of Developmental and Cell Biology, University of California, Irvine, CA 92697, USA
| | - Dillon Dejam
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California, Irvine, CA 92697-3900, USA
| | - Aimee L Edinger
- Department of Developmental and Cell Biology, University of California, Irvine, CA 92697, USA
| | - Victor Nizet
- Departments of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, CA 92093, USA
| | - Richard B Silverman
- Departments of Chemistry and Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL 60208-3113, USA.
| | - Thomas L Poulos
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California, Irvine, CA 92697-3900, USA.
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10
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Seo D, Soeta T, Sakurai H, Sétif P, Sakurai T. Pre-steady-state kinetic studies of redox reactions catalysed by Bacillus subtilis ferredoxin-NADP(+) oxidoreductase with NADP(+)/NADPH and ferredoxin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:678-87. [PMID: 26965753 DOI: 10.1016/j.bbabio.2016.03.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 02/12/2016] [Accepted: 03/01/2016] [Indexed: 11/30/2022]
Abstract
Ferredoxin-NADP(+) oxidoreductase ([EC1.18.1.2], FNR) from Bacillus subtilis (BsFNR) is a homodimeric flavoprotein sharing structural homology with bacterial NADPH-thioredoxin reductase. Pre-steady-state kinetics of the reactions of BsFNR with NADP(+), NADPH, NADPD (deuterated form) and B. subtilis ferredoxin (BsFd) using stopped-flow spectrophotometry were studied. Mixing BsFNR with NADP(+) and NADPH yielded two types of charge-transfer (CT) complexes, oxidized FNR (FNR(ox))-NADPH and reduced FNR (FNR(red))-NADP(+), both having CT absorption bands centered at approximately 600n m. After mixing BsFNR(ox) with about a 10-fold molar excess of NADPH (forward reaction), BsFNR was almost completely reduced at equilibrium. When BsFNR(red) was mixed with NADP(+), the amount of BsFNR(ox) increased with increasing NADP(+) concentration, but BsFNR(red) remained as the major species at equilibrium even with about 50-fold molar excess NADP(+). In both directions, the hydride-transfer was the rate-determining step, where the forward direction rate constant (~500 s(-1)) was much higher than the reverse one (<10 s(-1)). Mixing BsFd(red) with BsFNR(ox) induced rapid formation of a neutral semiquinone form. This process was almost completed within 1 ms. Subsequently the neutral semiquinone form was reduced to the hydroquinone form with an apparent rate constant of 50 to 70 s(-1) at 10°C, which increased as BsFd(red) increased from 40 to 120 μM. The reduction rate of BsFNR(ox) by BsFd(red) was markedly decreased by premixing BsFNR(ox) with BsFd(ox), indicating that the dissociation of BsFd(ox) from BsFNR(sq) is rate-limiting in the reaction. The characteristics of the BsFNR reactions with NADP(+)/NADPH were compared with those of other types of FNRs.
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Affiliation(s)
- Daisuke Seo
- Division of Material Science, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan.
| | - Takahiro Soeta
- Division of Material Science, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
| | - Hidehiro Sakurai
- Research Institute for Photobiological Hydrogen Production, Kanagawa University, Tsuchiya, Hiratsuka, Kanagawa 259-1293, Japan
| | - Pierre Sétif
- CEA, iBiTecS, 91191 Gif sur Yvette, France; CNRS/Université Paris-Sud/CEA, I2BC, 91190 Gif sur Yvette, France
| | - Takeshi Sakurai
- Division of Material Science, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
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11
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Holden JK, Dejam D, Lewis MC, Huang H, Kang S, Jing Q, Xue F, Silverman RB, Poulos TL. Inhibitor Bound Crystal Structures of Bacterial Nitric Oxide Synthase. Biochemistry 2015; 54:4075-82. [PMID: 26062720 DOI: 10.1021/acs.biochem.5b00431] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nitric oxide generated by bacterial nitric oxide synthase (NOS) increases the susceptibility of Gram-positive pathogens Staphylococcus aureus and Bacillus anthracis to oxidative stress, including antibiotic-induced oxidative stress. Not surprisingly, NOS inhibitors also improve the effectiveness of antimicrobials. Development of potent and selective bacterial NOS inhibitors is complicated by the high active site sequence and structural conservation shared with the mammalian NOS isoforms. To exploit bacterial NOS for the development of new therapeutics, recognition of alternative NOS surfaces and pharmacophores suitable for drug binding is required. Here, we report on a wide number of inhibitor-bound bacterial NOS crystal structures to identify several compounds that interact with surfaces unique to the bacterial NOS. Although binding studies indicate that these inhibitors weakly interact with the NOS active site, many of the inhibitors reported here provide a revised structural framework for the development of new antimicrobials that target bacterial NOS. In addition, mutagenesis studies reveal several key residues that unlock access to bacterial NOS surfaces that could provide the selectivity required to develop potent bacterial NOS inhibitors.
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Affiliation(s)
- Jeffrey K Holden
- Departments of †Molecular Biology and Biochemistry, ‡Pharmaceutical Sciences, and §Chemistry, University of California, Irvine, California 92697-3900, United States.,∥Departments of Chemistry and Molecular Biosciences, ⊥Chemistry of Life Processes Institute, #Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Dillon Dejam
- Departments of †Molecular Biology and Biochemistry, ‡Pharmaceutical Sciences, and §Chemistry, University of California, Irvine, California 92697-3900, United States.,∥Departments of Chemistry and Molecular Biosciences, ⊥Chemistry of Life Processes Institute, #Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Matthew C Lewis
- Departments of †Molecular Biology and Biochemistry, ‡Pharmaceutical Sciences, and §Chemistry, University of California, Irvine, California 92697-3900, United States.,∥Departments of Chemistry and Molecular Biosciences, ⊥Chemistry of Life Processes Institute, #Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - He Huang
- Departments of †Molecular Biology and Biochemistry, ‡Pharmaceutical Sciences, and §Chemistry, University of California, Irvine, California 92697-3900, United States.,∥Departments of Chemistry and Molecular Biosciences, ⊥Chemistry of Life Processes Institute, #Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Soosung Kang
- Departments of †Molecular Biology and Biochemistry, ‡Pharmaceutical Sciences, and §Chemistry, University of California, Irvine, California 92697-3900, United States.,∥Departments of Chemistry and Molecular Biosciences, ⊥Chemistry of Life Processes Institute, #Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Qing Jing
- Departments of †Molecular Biology and Biochemistry, ‡Pharmaceutical Sciences, and §Chemistry, University of California, Irvine, California 92697-3900, United States.,∥Departments of Chemistry and Molecular Biosciences, ⊥Chemistry of Life Processes Institute, #Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Fengtian Xue
- Departments of †Molecular Biology and Biochemistry, ‡Pharmaceutical Sciences, and §Chemistry, University of California, Irvine, California 92697-3900, United States.,∥Departments of Chemistry and Molecular Biosciences, ⊥Chemistry of Life Processes Institute, #Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Richard B Silverman
- Departments of †Molecular Biology and Biochemistry, ‡Pharmaceutical Sciences, and §Chemistry, University of California, Irvine, California 92697-3900, United States.,∥Departments of Chemistry and Molecular Biosciences, ⊥Chemistry of Life Processes Institute, #Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Thomas L Poulos
- Departments of †Molecular Biology and Biochemistry, ‡Pharmaceutical Sciences, and §Chemistry, University of California, Irvine, California 92697-3900, United States.,∥Departments of Chemistry and Molecular Biosciences, ⊥Chemistry of Life Processes Institute, #Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, Illinois 60208-3113, United States
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Holden JK, Kang S, Hollingsworth SA, Li H, Lim N, Chen S, Huang H, Xue F, Tang W, Silverman RB, Poulos TL. Structure-based design of bacterial nitric oxide synthase inhibitors. J Med Chem 2015; 58:994-1004. [PMID: 25522110 PMCID: PMC4306518 DOI: 10.1021/jm501723p] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
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Inhibition
of bacterial nitric oxide synthase (bNOS) has the potential to improve
the efficacy of antimicrobials used to treat infections by Gram-positive
pathogens Staphylococcus aureus and Bacillus anthracis. However, inhibitor specificity
toward bNOS over the mammalian NOS (mNOS) isoforms remains a challenge
because of the near identical NOS active sites. One key structural
difference between the NOS isoforms is the amino acid composition
of the pterin cofactor binding site that is adjacent to the NOS active
site. Previously, we demonstrated that a NOS inhibitor targeting both
the active and pterin sites was potent and functioned as an antimicrobial
(Holden, , Proc. Natl. Acad.
Sci. U.S.A.2013, 110, 1812724145412). Here we present additional crystal structures, binding
analyses, and bacterial killing studies of inhibitors that target
both the active and pterin sites of a bNOS and function as antimicrobials.
Together, these data provide a framework for continued development
of bNOS inhibitors, as each molecule represents an excellent chemical
scaffold for the design of isoform selective bNOS inhibitors.
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Affiliation(s)
- Jeffrey K Holden
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences and Chemistry, University of California , 2206 Nat. Sci. 1, Irvine, California 92697-3900, United States
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