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Confer AM, Vilbert AC, Dey A, Lancaster KM, Goldberg DP. A Mononuclear, Nonheme Fe II-Piloty's Acid (PhSO 2NHOH) Adduct: An Intermediate in the Production of {FeNO} 7/8 Complexes from Piloty's Acid. J Am Chem Soc 2019; 141:7046-7055. [PMID: 30994347 DOI: 10.1021/jacs.9b01700] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Reaction of the mononuclear nonheme complex [FeII(CH3CN)(N3PyS)]BF4 (1) with an HNO donor, Piloty's acid (PhSO2NHOH, P.A.), at low temperature affords a high-spin ( S = 2) FeII-P.A. intermediate (2), characterized by 57Fe Mössbauer and Fe K-edge X-ray absorption (XAS) spectroscopies, with interpretation of both supported by DFT calculations. The combined methods indicate that P.A. anion binds as the N-deprotonated tautomer (PhSO2NOH-) to [FeII(N3PyS)]+, leading to 2. Complex 2 is the first spectroscopically characterized example, to our knowledge, of P.A. anion bound to a redox-active metal center. Warming of 2 above -60 °C yields the stable {FeNO}7 complex [Fe(NO)(N3PyS)]BF4 (4), as evidenced by 1H NMR, ATR-IR, and Mössbauer spectroscopies. Isotope labeling experiments with 15N-labeled P.A. confirm that the nitrosyl ligand in 4 derives from P.A. In contrast, addition of a second equivalent of a strong base leads to S-N cleavage and production of an {FeNO}8 species, the deprotonated analog of an Fe-HNO complex. This work has implications for the targeted delivery of HNO/NO-/NO· to nonheme Fe centers in biological and synthetic applications, and suggests a new role for nonheme FeII complexes in the assisted degradation of HNO donor molecules.
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Affiliation(s)
- Alex M Confer
- Department of Chemistry , The Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Avery C Vilbert
- Baker Laboratory, Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
| | - Aniruddha Dey
- Department of Chemistry , The Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Kyle M Lancaster
- Baker Laboratory, Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
| | - David P Goldberg
- Department of Chemistry , The Johns Hopkins University , Baltimore , Maryland 21218 , United States
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2
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Kumar MR, Clover T, Olaitan AD, Becker C, Solouki T, Farmer PJ. The reaction between GSNO and H 2 S: On the generation of NO, HNO and N 2 O. Nitric Oxide 2018; 77:96-105. [DOI: 10.1016/j.niox.2018.04.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 04/20/2018] [Accepted: 04/24/2018] [Indexed: 12/17/2022]
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Lee T, Hwang S, Lim M. Picosecond Dynamics of Photoexcited DNO-Bound Myoglobin Probed by Femtosecond Vibrational Spectroscopy. J Phys Chem B 2015; 119:1814-22. [DOI: 10.1021/jp509644m] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Taegon Lee
- Department
of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan 609-735, Korea
| | - Sungu Hwang
- Department
of Applied Nanoscience, Pusan National University, Miryang 627-706, Korea
| | - Manho Lim
- Department
of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan 609-735, Korea
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4
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Montenegro AC, Bari SE, Olabe JA. Reactivity of iron(II)-bound nitrosyl hydride (HNO, nitroxyl) in aqueous solution. J Inorg Biochem 2012; 118:108-14. [PMID: 23153690 DOI: 10.1016/j.jinorgbio.2012.10.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 10/15/2012] [Accepted: 10/16/2012] [Indexed: 10/27/2022]
Abstract
The reactivity of coordinated nitroxyl (HNO) has been explored with the [Fe(II)(CN)(5)HNO](3-) complex in aqueous medium, pH 6. We discuss essential biorelevant issues as the thermal and photochemical decompositions, the reactivity toward HNO dissociation, the electrochemical behavior, and the reactions with oxidizing and reducing agents. The spontaneous decomposition in the absence of light yielded a two-electron oxidized species, the nitroprusside anion, [Fe(II)(CN)(5)NO](2-), and a negligible quantity of N(2)O, with k(obs)≈5×10(-7)s(-1), at 25.0°C. The value of k(obs) represents an upper limit for HNO release, comparable to values reported for other structurally related L ligands in the [Fe(II)(CN)(5)L](n-) series. These results reveal that the FeN bond is strong, suggesting a significant σ-π interaction, as already postulated for other HNO-complexes. The [Fe(II)(CN)(5)HNO](3-) ion showed a quasi-reversible oxidation wave at 0.32 V (vs normal hydrogen electrode), corresponding to the [Fe(II)(CN)(5)HNO](3-)/[Fe(II)(CN)(5)NO](3-),H(+) redox couple. Hexacyanoferrate(III), methylviologen and the nitroprusside ion have been selected as potential oxidants. Only the first reactant achieved a complete oxidation process, initiated by a proton-coupled electron transfer reaction at the HNO ligand, with nitroprusside as a final oxidation product. Dithionite acted as a reductant of [Fe(II)(CN)(5)HNO](3-), in a 4-electron process, giving NH(3). The high stability of bound HNO may resemble the properties in related Fe(II) centers of redox active enzymes. The very minor release of N(2)O shows that the redox conversions may evolve without disruption of the FeN bonds, under competitive conditions with the dissociation of HNO.
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Affiliation(s)
- Andrea C Montenegro
- Departamento de Química Inorgánica, Analítica y Química Física, and INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, Buenos Aires, C1428EHA, Argentina
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Zapata AL, Kumar MR, Pervitsky D, Farmer PJ. A singular value decomposition approach for kinetic analysis of reactions of HNO with myoglobin. J Inorg Biochem 2012; 118:171-8. [PMID: 23140900 DOI: 10.1016/j.jinorgbio.2012.10.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2012] [Revised: 10/03/2012] [Accepted: 10/04/2012] [Indexed: 12/01/2022]
Abstract
The reactions of several horse heart myoglobin species with nitrosyl hydride, HNO, derived from Angeli's salt (AS) and Piloty's acid (PA) have been followed by UV-visible, (1)H NMR and EPR spectroscopies. Spectral analysis of myoglobin-derived speciation during the reactions was obtained by using singular value decomposition methods combined with a global analysis to obtain the rate constants of complex sequential reactions. The analysis also provided spectra for the derived absorbers, which allowed self-consistent calibration to the spectra of known myoglobin species. Using this method, the determined rate for trapping of HNO by metmyoglobin, which produces NO-myoglobin, is found to be 2.7 × 10(5)M(-1)s(-1) at pH7.0 and 1.1 × 10(5)M(-1)s(-1) at pH9.4. The reaction of deoxymyoglobin with HNO generates the adduct HNO-myoglobin directly, but is followed by a secondary reaction of that product with HNO yielding NO-myoglobin; the determined bimolecular rate constants for these reactions are 3.7 × 10(5)M(-1)s(-1) and 1.67 × 10(4)M(-1)s(-1) respectively, and are independent of pH. The derived spectrum for HNO-myoglobin is characterized by a Soret absorbance maximum at 423 nm with an extinction coefficient of 1.66 × 10(5)M(-1)cm(-1). The rate constant for unimolecular loss of HNO from HNO-myoglobin was determined by competitive trapping with CO at 8.9 × 10(-5)s(-1), which gives the thermodynamic binding affinity of HNO to deoxymyoglobin as 4.2 × 10(9)M(-1). These results suggest that the formation of HNO-ferrous heme protein adducts represents an important consideration in the biological action of HNO-releasing drugs.
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Affiliation(s)
- Adrian L Zapata
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX 76796, USA
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Nitrosyl hydride (HNO) replaces dioxygen in nitroxygenase activity of manganese quercetin dioxygenase. Proc Natl Acad Sci U S A 2011; 108:18926-31. [PMID: 22084064 DOI: 10.1073/pnas.1111488108] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Quercetin dioxygenase (QDO) catalyzes the oxidation of the flavonol quercetin with dioxygen, cleaving the central heterocyclic ring and releasing CO. The QDO from Bacillus subtilis is unusual in that it has been shown to be active with several divalent metal cofactors such as Fe, Mn, and Co. Previous comparison of the catalytic activities suggest that Mn(II) is the preferred cofactor for this enzyme. We herein report the unprecedented substitution of nitrosyl hydride (HNO) for dioxygen in the activity of Mn-QDO, resulting in the incorporation of both N and O atoms into the product. Turnover is demonstrated by consumption of quercetin and other related substrates under anaerobic conditions in the presence of HNO-releasing compounds and the enzyme. As with dioxygenase activity, a nonenzymatic base-catalyzed reaction of quercetin with HNO is observed above pH 7, but no enhancement of this basal reactivity is found upon addition of divalent metal salts. Unique and regioselective N-containing products ((14)N/(15)N) have been characterized by MS analysis for both the enzymatic and nonenzymatic reactions. Of the several metallo-QDO enzymes examined for nitroxygenase activity under anaerobic condition, only the Mn(II) is active; the Fe(II) and Co(II) substituted enzymes show little or no activity. This result represents an enzymatic catalysis which we denote nitroxygenase activity; the unique reactivity of the Mn-QDO suggests a metal-mediated electron transfer mechanism rather than metal activation of the substrate's inherent base-catalyzed reactivity.
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Kumar MR, Fukuto JM, Miranda KM, Farmer PJ. Reactions of HNO with heme proteins: new routes to HNO-heme complexes and insight into physiological effects. Inorg Chem 2010; 49:6283-92. [PMID: 20666387 DOI: 10.1021/ic902319d] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The formation and interconversion of nitrogen oxides has been of interest in numerous contexts for decades. Early studies focused on gas-phase reactions, particularly with regard to industrial and atmospheric environments, and on nitrogen fixation. Additionally, investigation of the coordination chemistry of nitric oxide (NO) with hemoglobin dates back nearly a century. With the discovery in the early 1980s that NO is biosynthesized as a molecular signaling agent, the literature has been focused on the biological effects of nitrogen oxides, but the original concerns remain relevant. For instance, hemoglobin has long been known to react with nitrite, but this reductase activity has recently been considered to be important to produce NO under hypoxic conditions. The association of nitrosyl hydride (HNO; also commonly referred to as nitroxyl) with heme proteins can also produce NO by reductive nitrosylation. Furthermore, HNO is considered to be an intermediate in bacterial denitrification, but conclusive identification has been elusive. The authors of this article have approached the bioinorganic chemistry of HNO from different perspectives, which have converged because heme proteins are important biological targets of HNO.
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Affiliation(s)
- Murugaeson R Kumar
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76706, USA
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Farmer PJ, Kumar MR, Almaraz E. THE COORDINATION CHEMISTRY OF HNO: FROM WARREN ROPER TO HEMOGLOBIN. COMMENT INORG CHEM 2010. [DOI: 10.1080/02603594.2010.520257] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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9
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Roles of glutamates and metal ions in a rationally designed nitric oxide reductase based on myoglobin. Proc Natl Acad Sci U S A 2010; 107:8581-6. [PMID: 20421510 DOI: 10.1073/pnas.1000526107] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A structural and functional model of bacterial nitric oxide reductase (NOR) has been designed by introducing two glutamates (Glu) and three histidines (His) in sperm whale myoglobin. X-ray structural data indicate that the three His and one Glu (V68E) residues bind iron, mimicking the putative Fe(B) site in NOR, while the second Glu (I107E) interacts with a water molecule and forms a hydrogen bonding network in the designed protein. Unlike the first Glu (V68E), which lowered the heme reduction potential by approximately 110 mV, the second Glu has little effect on the heme potential, suggesting that the negatively charged Glu has a different role in redox tuning. More importantly, introducing the second Glu resulted in a approximately 100% increase in NOR activity, suggesting the importance of a hydrogen bonding network in facilitating proton delivery during NOR reactivity. In addition, EPR and X-ray structural studies indicate that the designed protein binds iron, copper, or zinc in the Fe(B) site, each with different effects on the structures and NOR activities, suggesting that both redox activity and an intermediate five-coordinate heme-NO species are important for high NOR activity. The designed protein offers an excellent model for NOR and demonstrates the power of using designed proteins as a simpler and more well-defined system to address important chemical and biological issues.
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Kumar MR, Pervitsky D, Chen L, Poulos T, Kundu S, Hargrove MS, Rivera EJ, Diaz A, Colón JL, Farmer PJ. Nitrosyl hydride (HNO) as an O2 analogue: long-lived HNO adducts of ferrous globins. Biochemistry 2009; 48:5018-25. [PMID: 19368336 DOI: 10.1021/bi900122r] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nitrosyl hydride, HNO or nitroxyl, is the one-electron reduced and protonated form of nitric oxide. HNO is isoelectronic to singlet O(2), and we have previously reported that deoxymyoglobin traps free HNO to form a stable adduct. In this report, we demonstrate that oxygen-binding hemoglobins from human, soy, and clam also trap HNO to form adducts which are stable over a period of weeks. The same species can be formed in higher yields by careful reduction of the ferrous nitrosyl adducts of the proteins. Like the analogous O(2)-Fe(II) adducts, the HNO adducts are diamagnetic, but with a characteristic HNO resonance in (1)H NMR at ca. 15 ppm that splits into doublets for H(15)NO adducts. The (1)H and (15)N NMR resonances, obtained by HSQC experiments, are shown to differentiate subunits and isoforms of proteins within mixtures. An apparent difference in the reduction rates of the NO adducts of the two subunits of human hemoglobin allows assignment of two distinct nitrosyl hydride peaks by a combination of UV-vis, NMR, and EPR analysis. The two peaks of the HNO-hHb adduct have a persistent 3:1 ratio during trapping reactions, demonstrating a kinetic difference between HNO binding at the two subunits. These results show NMR characterization of ferrous HNO adducts as a unique tool sensitive to structural changes within the oxygen-binding cavity, which may be of use in defining modes of oxygen binding in other heme proteins and enzymes.
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Affiliation(s)
- Murugaeson R Kumar
- Department of Chemistry, University of California, Irvine, California 92697, USA
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11
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Miller TW, Cherney MM, Lee AJ, Francoleon NE, Farmer PJ, King SB, Hobbs AJ, Miranda KM, Burstyn JN, Fukuto JM. The effects of nitroxyl (HNO) on soluble guanylate cyclase activity: interactions at ferrous heme and cysteine thiols. J Biol Chem 2009; 284:21788-21796. [PMID: 19531488 PMCID: PMC2755905 DOI: 10.1074/jbc.m109.014282] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
It has been previously proposed that nitric oxide (NO) is the only biologically relevant nitrogen oxide capable of activating the enzyme soluble guanylate cyclase (sGC). However, recent reports implicate HNO as another possible activator of sGC. Herein, we examine the affect of HNO donors on the activity of purified bovine lung sGC and find that, indeed, HNO is capable of activating this enzyme. Like NO, HNO activation appears to occur via interaction with the regulatory ferrous heme on sGC. Somewhat unexpectedly, HNO does not activate the ferric form of the enzyme. Finally, HNO-mediated cysteine thiol modification appears to also affect enzyme activity leading to inhibition. Thus, sGC activity can be regulated by HNO via interactions at both the regulatory heme and cysteine thiols.
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Affiliation(s)
- Thomas W Miller
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
| | - Melisa M Cherney
- the Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706
| | - Andrea J Lee
- the Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706
| | - Nestor E Francoleon
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
| | - Patrick J Farmer
- the Department of Chemistry, University of California, Irvine, California 92697
| | - S Bruce King
- the Department of Chemistry, Wake Forest University, Winston Salem, North Carolina 27109
| | - Adrian J Hobbs
- Department of Pharmacology, University College London, Medical Sciences Building, Gower Street, London WC1E 6BT, United Kingdom
| | - Katrina M Miranda
- the Department of Chemistry, University of Arizona, Tucson, Arizona 85721
| | - Judith N Burstyn
- the Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706
| | - Jon M Fukuto
- the Department of Chemistry, Sonoma State University, Rohnert Park, California 94928-3609
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