- Interrelationships between conformational dynamics and the redox chemistry of S-nitrosothiols
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An increasing number of biological roles are ascribed to S-nitrosothiol compounds. Their inherent instability in multicomponent solutions is recognized as forming the basis for their physiological effects, such as the release of nitric oxide or the posttr
- Arulsamy,Bohle,Butt,Irvine,Jordan,Sagan
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- Iron(II/III) Halide Complexes Promote the Interconversion of Nitric Oxide and S-Nitrosothiols through Reversible Fe-S Interaction
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Heme and non-heme iron in biology mediate the storage/release of NO? from S-nitrosothiols as a means to control the biological concentration of NO?. Despite their importance in many physiological processes, the mechanisms of N-S bond formation/cleavage at Fe centers have been controversial. Herein, we report the interconversion of NO? and S-nitrosothiols mediated by FeII/FeIII chloride complexes. The reaction of 2 equiv of S-nitrosothiol (Ph3CSNO) with [Cl6FeII2]2- results in facile release of NO? and formation of iron(III) halothiolate. Detailed spectroscopic studies, including in situ UV-vis, IR, and M?ssbauer spectroscopy, support the interaction of the S atom with the FeII center. This is in contrast to the proposed mechanism of NO? release from the well-studied red product κ1-N bound S-nitrosothiol FeII complex, [(CN)5Fe(κ1-N-RSNO)]3-. Additionally, FeIII chloride can mediate NO? storage through the formation of S-nitrosothiols. Treatment of iron(III) halothiolate with 2 equiv of NO? regenerates Ph3CSNO with the FeII source trapped as the S = 3/2 {FeNO}7 species [Cl3FeNO]-, which is inert toward further coordination and activation of S-nitrosothiols. Our work demonstrates how labile iron can mediate the interconversion of NO?/thiolate and S-nitrosothiol, which has important implications toward how Nature manages the biological concentration of free NO?.
- Poptic, Anna L.,Zhang, Shiyu
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supporting information
p. 5190 - 5197
(2021/04/06)
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- Four-Coordinate Copper Halonitrosyl {CuNO}10 Complexes
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While copper nitrosyl complexes are implicated in numerous biological systems, isolable examples remain limited. In this report, we show that [Cl3CuNO]?, with a {CuNO}10 electron configuration, can be generated by nitrite reduction at a copper(I) dichloride anion or by nitric oxide addition to a copper(II) trichloride precursor. The bromide analogue, [Br3CuNO]? was synthesized analogously, and both copper halonitrosyl complexes were characterized by X-ray diffraction and a variety of spectroscopic methods. Experimental data and multireference (CASSCF/NEVPT2) calculations provide strong evidence for a CuII–NO. ground state. Both [Cl3CuNO]? and [Br3CuNO]? release and recapture NO. reversibly, and exhibit nitrosative reactivities toward a wide range of biological nucleophiles, such as amines, alcohols, and thiols.
- Bower, Jamey K.,Sokolov, Alexander Yu.,Zhang, Shiyu
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supporting information
p. 10225 - 10229
(2019/07/03)
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- Copper(II) activation of nitrite: Nitrosation of nucleophiles and generation of NO by thiols
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Nitrite (NO2-) and nitroso compounds (E-NO, E = RS, RO, and R2N) in mammalian plasma and cells serve important roles in nitric oxide (NO) dependent as well as NO independent signaling. Employing an electron deficient β-diketiminato copper(II) nitrito complex [C12NNf6]Cu(κ2-O2N)-THF, thiols mediate reduction of nitrite to NO. In contrast to NO generation upon reaction of thiols at iron nitrite species, at copper this conversion proceeds through nucleophilic attack of thiol RSH on the bound nitrite in [CuII](κ2-O2N) that leads to S-nitrosation to give the S-nitrosothiol RSNO and copper(Il) hydroxide [CuII]-OH. This nitrosation pathway is general and results in the nitrosation of the amine Ph2NH and alcohol tBuOH to give Ph2NNO and tBuONO, respectively. NO formation from thiols occurs from the reaction of RSNO and a copper(II) thiolate [CuII]-SR intermediate formed upon reaction of an additional equiv thiol with [CuII]-OH.
- Kundu, Subrata,Kim, William Y.,Bertke, Jeffery A.,Warren, Timothy H.
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supporting information
p. 1045 - 1048
(2017/05/15)
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- Proline-based phosphoramidite reagents for the reductive ligation of S-nitrosothiols
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S-Nitrosothiols (RSNOs) have many biological implications but are rarely used in organic synthesis. In this work we report the development of proline-based phosphoramidite substrates that can effectively convert RSNOs to proline-based sulfenamides through
- Park, Chung-Min,Biggs, Tyler D.,Xian, Ming
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p. 313 - 318
(2016/05/09)
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- Establishment of the C-NO bond dissociation energy scale in solution and its application in analyzing the trend of NO transfer from C-nitroso compound to thiols
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(Chemical Equation Presented) The first set of experimentally determined C-NO bond homolytic and heterolytic dissociation enthalpies in solution is derived by using direct titration calorimetry combined with appropriate electrode potentials through thermodynamic cycles. The homolytic bond dissociation energy scale (BDEs) of the corresponding C-NO bonds in the gas phase was also calculated at the MP2/6-311+G**//B3LYP/6-31G* level and BP86/6-31G*//B3LYP/6-31G* level of theory for the purpose of comparison. The C-NO and S-NO bond thermodynamic parameters were used to predict the trend of NO transfer from C-nitroso substrates to thiols in acetonitrile solution.
- Li, Xin,Deng, Hui,Zhu, Xiao-Qing,Wang, Xiaoxiao,Liang, Hao,Cheng, Jin-Pei
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experimental part
p. 4472 - 4478
(2009/09/30)
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- Reactions of synthetic [2Fe-2S] and [4Fe-4S] clusters with nitric oxide and nitrosothiols
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The interaction of nitric oxide (NO) with iron-sulfur cluster proteins results in degradation and breakdown of the cluster to generate dinitrosyl iron complexes (DNICs). In some cases the formation of DNICs from such cluster systems can lead to activation
- Harrop, Todd C.,Tonzetich, Zachary J.,Reisner, Erwin,Lippard, Stephen J.
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experimental part
p. 15602 - 15610
(2009/03/12)
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- A kinetic study of S-nitrosothiol decomposition
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Under anaerobic conditions S-nitrosothiols 1a-e undergo thermal decomposition by homolytic cleavage of the S-N bond; the reaction leads to nitric oxide and sulfanyl radicals formed in a reversible manner. The rate constants, k1, have been determined at different temperatures from kinetic measurements performed in refluxing alkane solvents. The tertiary nitrosothiols 1c (k1(69°C) = 13 × 10-3 min-1) and 1d (k1(69°C) 91 × 10-3 min-1) decomposed faster than the primary nitrosothiols 1a (k1(69°C) = 3.0 × 10-3 min-1) and 1b (k1(69°C) = 6.5 × 10-3 min-1). The activation energies (E#= 20.5 - 22.8 Kcal mol-1) have been calculated from the Arrhenius equation. Under aerobic conditions the decay of S-nitrosothiols 1a-e takes place by an autocatalytic chain-decomposition process catalyzed by N2O3. The latter is formed by reaction of dioxygen with endogenous and/or exogenous nitric oxide. The autocatalytic decomposition is strongly inhibited by removing the endogenous nitric oxide or by the presence of antioxidants, such as pcresol, β-styrene, and BHT The rate of the chain reaction is independent of the RSNO concentration and decreases with increasing bulkiness of the alkyl group; this shows that steric effects are crucial in the propagation step.
- Grossi, Loris,Montevecchi, Pier Carlo
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p. 380 - 387
(2007/10/03)
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- The reaction of thionitrites with Barton esters: A convenient free radical chain reaction for decarboxylative nitrosation
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Tertiary thionitrite esters react with primary and secondary O-acyl derivatives of N-hydroxy-2-thiopyridone to give trans nitroso dimers as the principal products of a free radical chain reaction.
- Girard, Pierre,Guillot, Nadine,Motherwell, William B.,Hay-Motherwell, Robyn S.,Potier, Pierre
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p. 3573 - 3584
(2007/10/03)
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- ELECTRON SPIN RESONANCE SPIN TRAPPING OF THIYL RADICALS FROM THE DECOMPOSITION OF THIONITRITES
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Alkyl thiyl radicals produced by the homolytic decomposition of thionitrites are detected by ESR spin trapping using 5,5-dimethyl-1-Δ-pyrroline-N-oxide (DMPO).
- Josephy, P. David,Janzen, Edward G.,Rehork, Detlef
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p. 1685 - 1688
(2007/10/02)
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