1
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Gao Q, Grzyb K, Gamon LF, Ogilby PR, Pędziński T, Davies MJ. The structure of model and peptide disulfides markedly affects their reactivity and products formed with singlet oxygen. Free Radic Biol Med 2023; 207:320-329. [PMID: 37633403 DOI: 10.1016/j.freeradbiomed.2023.08.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/22/2023] [Accepted: 08/23/2023] [Indexed: 08/28/2023]
Abstract
Disulfide bonds are critical structural elements in proteins and stabilize folded structures. Modification of these linkages is associated with a loss of structure and function. Previous studies have reported large variations in the rate of disulfide oxidation by hypohalous acids, due to stabilization of reaction intermediates. In this study we hypothesized that considerable variation (and hence selective oxidation) would occur with singlet oxygen (1O2), a key intermediate in photo-oxidation reactions. The kinetics of disulfide-mediated 1O2 removal were monitored using the time-resolved 1270 nm phosphorescence of 1O2. Stern-Volmer plots of these data showed a large variation (∼103) in the quenching rate constants kq (from 2 × 107 for α-lipoic acid to 3.6 × 104 M-1s-1 for cystamine). The time course of disulfide loss and product formation (determined by LC-MS) support a role for 1O2, with mono- and di-oxygenated products detected. Elevated levels of these latter species were generated in D2O- compared to H2O buffers, which is consistent with solvent effects on the 1O2 lifetime. These data are interpreted in terms of the intermediacy of a zwitterion [-S+(OO-)-S-], which either isomerizes to a thiosulfonate [-S(O)2-S-] or reacts with another parent molecule to give two thiosulfinates [-S(O)-S-]. The variation in quenching rates and product formation are ascribed to zwitterion stabilization by neighboring, or remote, lone pairs of electrons. These data suggest that some disulfides, including some present within or attached to proteins (e.g., α-lipoic acid), may be selectively modified, and undergo subsequent cleavage, with adverse effects on protein structure and function.
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Affiliation(s)
- Qing Gao
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Katarzyna Grzyb
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznanskiego 8, 61-614, Poznań, Poland
| | - Luke F Gamon
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Peter R Ogilby
- Department of Chemistry, Aarhus University, DK-8000, Aarhus, Denmark
| | - Tomasz Pędziński
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznanskiego 8, 61-614, Poznań, Poland
| | - Michael J Davies
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark.
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2
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Trammell SAJ, Gamon LF, Gotfryd K, Michler KT, Alrehaili BD, Rix I, Knop FK, Gourdon P, Lee YK, Davies MJ, Gillum MP, Grevengoed TJ. Identification of bile acid-CoA:amino acid N-acyltransferase as the hepatic N-acyl taurine synthase for polyunsaturated fatty acids. J Lipid Res 2023; 64:100361. [PMID: 36958721 PMCID: PMC10470208 DOI: 10.1016/j.jlr.2023.100361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/17/2023] [Accepted: 03/19/2023] [Indexed: 03/25/2023] Open
Abstract
N-acyl taurines (NATs) are bioactive lipids with emerging roles in glucose homeostasis and lipid metabolism. The acyl chains of hepatic and biliary NATs are enriched in polyunsaturated fatty acids (PUFAs). Dietary supplementation with a class of PUFAs, the omega-3 fatty acids, increases their cognate NATs in mice and humans. However, the synthesis pathway of the PUFA-containing NATs remains undiscovered. Here, we report that human livers synthesize NATs and that the acyl-chain preference is similar in murine liver homogenates. In the mouse, we found that hepatic NAT synthase activity localizes to the peroxisome and depends upon an active-site cysteine. Using unbiased metabolomics and proteomics, we identified bile acid-CoA:amino acid N-acyltransferase (BAAT) as the likely hepatic NAT synthase in vitro. Subsequently, we confirmed that BAAT knockout livers lack up to 90% of NAT synthase activity and that biliary PUFA-containing NATs are significantly reduced compared with wildtype. In conclusion, we identified the in vivo PUFA-NAT synthase in the murine liver and expanded the known substrates of the bile acid-conjugating enzyme, BAAT, beyond classic bile acids to the synthesis of a novel class of bioactive lipids.
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Affiliation(s)
- Samuel A J Trammell
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Luke F Gamon
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kamil Gotfryd
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Katja Thorøe Michler
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bandar D Alrehaili
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA; Department of Pharmacology and Toxicology, Pharmacy College, Taibah University, Medina, Saudi Arabia
| | - Iben Rix
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Filip K Knop
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Steno Diabetes Center Copenhagen, Herlev, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Pontus Gourdon
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Yoon-Kwang Lee
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Michael J Davies
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Matthew P Gillum
- Global Obesity and Liver Disease Research, Novo Nordisk A/S, Måløv, Denmark
| | - Trisha J Grevengoed
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
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3
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Sauerland MB, Helm C, Lorentzen LG, Manandhar A, Ulven T, Gamon LF, Davies MJ. Identification of galectin-1 and other cellular targets of alpha,beta-unsaturated carbonyl compounds, including dimethylfumarate, by use of click-chemistry probes. Redox Biol 2022; 59:102560. [PMID: 36493513 PMCID: PMC9731849 DOI: 10.1016/j.redox.2022.102560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 11/26/2022] [Accepted: 11/26/2022] [Indexed: 12/02/2022] Open
Abstract
α,β-Unsaturated carbonyls are a common motif in environmental toxins (e.g. acrolein) as well as therapeutic drugs, including dimethylfumarate (DMFU) and monomethylfumarate (MMFU), which are used to treat multiple sclerosis and psoriasis. These compounds form adducts with protein Cys residues as well as other nucleophiles. The specific targets ('adductome') that give rise to their therapeutic or toxic activities are poorly understood. This is due, at least in part, to the absence of antigens or chromophores/fluorophores in these compounds. We have recently reported click-chemistry probes of DMFU and MMFU (Redox Biol., 2022, 52, 102299) that allow adducted proteins to be visualized and enriched for further characterization. In the current study, we hypothesized that adducted proteins could be 'clicked' to agarose beads and thereby isolated for LC-MS analysis of DMFU/MMFU targets in primary human coronary artery smooth muscle cells. We show that the probes react with thiols with similar rate constants to the parent drugs, and give rise to comparable patterns of gene induction, confirming similar biological actions. LC-MS proteomic analysis identified ∼2970 cellular targets of DMFU, ∼1440 for MMFU, and ∼140 for the control (succinate-probe) treated samples. The most extensively modified proteins were galectin-1, annexin-A2, voltage dependent anion channel-2 and vimentin. Other previously postulated DMFU targets, including glyceraldehyde-3-phosphate dehydrogenase (GAPDH), cofilin, p65 (RELA) and Keap1 were also identified as adducted species, though at lower levels with the exception of GAPDH. These data demonstrate the utility of the click-chemistry approach to the identification of cellular protein targets of both exogenous and endogenous compounds.
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Affiliation(s)
- Max B. Sauerland
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Christina Helm
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Lasse G. Lorentzen
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Asmita Manandhar
- Department of Drug Design and Pharmacology, Jagtvej 162, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Trond Ulven
- Department of Drug Design and Pharmacology, Jagtvej 162, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Luke F. Gamon
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Michael J. Davies
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark,Corresponding author.
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4
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Bolding JE, Martín‐Gago P, Rajabi N, Gamon LF, Hansen TN, Bartling CRO, Strømgaard K, Davies MJ, Olsen CA. Aryl Fluorosulfate Based Inhibitors That Covalently Target the SIRT5 Lysine Deacylase. Angew Chem Int Ed Engl 2022; 61:e202204565. [PMID: 36130196 PMCID: PMC9828517 DOI: 10.1002/anie.202204565] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Indexed: 01/12/2023]
Abstract
The sirtuin enzymes are a family of lysine deacylases that regulate gene transcription and metabolism. Sirtuin 5 (SIRT5) hydrolyzes malonyl, succinyl, and glutaryl ϵ-N-carboxyacyllysine posttranslational modifications and has recently emerged as a vulnerability in certain cancers. However, chemical probes to illuminate its potential as a pharmacological target have been lacking. Here we report the harnessing of aryl fluorosulfate-based electrophiles as an avenue to furnish covalent inhibitors that target SIRT5. Alkyne-tagged affinity-labeling agents recognize and capture overexpressed SIRT5 in cultured HEK293T cells and can label SIRT5 in the hearts of mice upon intravenous injection of the compound. This work demonstrates the utility of aryl fluorosulfate electrophiles for targeting of SIRT5 and suggests this as a means for the development of potential covalent drug candidates. It is our hope that these results will serve as inspiration for future studies investigating SIRT5 and general sirtuin biology in the mitochondria.
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Affiliation(s)
- Julie E. Bolding
- Center for Biopharmaceuticals & Department of Drug Design and PharmacologyFaculty of Health and Medical SciencesUniversity of CopenhagenUniversitetsparken 2DK-2100CopenhagenDenmark
| | - Pablo Martín‐Gago
- Center for Biopharmaceuticals & Department of Drug Design and PharmacologyFaculty of Health and Medical SciencesUniversity of CopenhagenUniversitetsparken 2DK-2100CopenhagenDenmark
| | - Nima Rajabi
- Center for Biopharmaceuticals & Department of Drug Design and PharmacologyFaculty of Health and Medical SciencesUniversity of CopenhagenUniversitetsparken 2DK-2100CopenhagenDenmark
| | - Luke F. Gamon
- Department of Biomedical SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenBlegdamsvej 3DK-2200CopenhagenDenmark
| | - Tobias N. Hansen
- Center for Biopharmaceuticals & Department of Drug Design and PharmacologyFaculty of Health and Medical SciencesUniversity of CopenhagenUniversitetsparken 2DK-2100CopenhagenDenmark
| | - Christian R. O. Bartling
- Center for Biopharmaceuticals & Department of Drug Design and PharmacologyFaculty of Health and Medical SciencesUniversity of CopenhagenUniversitetsparken 2DK-2100CopenhagenDenmark
| | - Kristian Strømgaard
- Center for Biopharmaceuticals & Department of Drug Design and PharmacologyFaculty of Health and Medical SciencesUniversity of CopenhagenUniversitetsparken 2DK-2100CopenhagenDenmark
| | - Michael J. Davies
- Department of Biomedical SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenBlegdamsvej 3DK-2200CopenhagenDenmark
| | - Christian A. Olsen
- Center for Biopharmaceuticals & Department of Drug Design and PharmacologyFaculty of Health and Medical SciencesUniversity of CopenhagenUniversitetsparken 2DK-2100CopenhagenDenmark
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5
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Xu S, Chuang CY, Malle E, Gamon LF, Hawkins CL, Davies MJ. Influence of plasma halide, pseudohalide and nitrite ions on myeloperoxidase-mediated protein and extracellular matrix damage. Free Radic Biol Med 2022; 188:162-174. [PMID: 35718304 DOI: 10.1016/j.freeradbiomed.2022.06.222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 06/11/2022] [Indexed: 01/15/2023]
Abstract
Myeloperoxidase (MPO) mediates pathogen destruction by generating the bactericidal oxidant hypochlorous acid (HOCl). Formation of this oxidant is however associated with host tissue damage and disease. MPO also utilizes H2O2 to oxidize other substrates, and we hypothesized that mixtures of other plasma anions, including bromide (Br-), iodide (I-), thiocyanate (SCN-) and nitrite (NO2-), at normal or supplemented concentrations, might modulate MPO-mediated HOCl damage. For the (pseudo)halide anions, only SCN- significantly modulated HOCl formation (IC50 ∼33 μM), which is within the normal physiological range, as judged by damage to human plasma fibronectin or extracellular matrix preparations detected by ELISA and LC-MS. NO2- modulated HOCl-mediated damage, in a dose-dependent manner, at physiologically-attainable anion concentrations. However, this was accompanied by increased tyrosine and tryptophan nitration (detected by ELISA and LC-MS), and the overall extent of damage remained approximately constant. Increasing NO2- concentrations (0.5-20 μM) diminished HOCl-mediated modification of tyrosine and methionine, whereas tryptophan loss was enhanced. At higher NO2- concentrations, enhanced tyrosine and methionine loss was detected. These analytical data were confirmed in studies of cell adhesion and metabolic activity. Together, these data indicate that endogenous plasma levels of SCN- (but not Br- or I-) can modulate protein modification induced by MPO, including the extent of chlorination. In contrast, NO2- alters the type of modification, but does not markedly decrease its extent, with chlorination replaced by nitration. These data also indicate that MPO could be a major source of nitration in vivo, and particularly at inflammatory sites where NO2- levels are often elevated.
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Affiliation(s)
- Shuqi Xu
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - Christine Y Chuang
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - Ernst Malle
- Division of Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Luke F Gamon
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - Clare L Hawkins
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark.
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6
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Morozzi C, Sauerland M, Gamon LF, Manandhar A, Ulven T, Davies MJ. Synthesis and cellular evaluation of click-chemistry probes to study the biological effects of alpha, beta-unsaturated carbonyls. Redox Biol 2022; 52:102299. [PMID: 35358849 PMCID: PMC8966197 DOI: 10.1016/j.redox.2022.102299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 11/18/2022] Open
Abstract
Humans are commonly exposed to α,β-unsaturated carbonyls as both environmental toxins (e.g. acrolein) and therapeutic drugs (e.g. dimethylfumarate, DMFU, a front-line drug for the treatment of multiple sclerosis and psoriasis). These compounds undergo rapid Michael addition reactions with amine, imidazole and thiol groups on biological targets, with reaction at protein Cys residues being a major reaction pathway. However, the cellular targets of these species (the ‘adductome’) are poorly understood due to the absence of readily identifiable tags or reporter groups (chromophores/fluorophores or antigens) on many α,β-unsaturated carbonyls. Here we report a ‘proof of concept’ study in which we synthesize novel α,β-unsaturated carbonyls containing an alkyne function introduced at remote sites on the α,β-unsaturated carbonyl compounds (e.g. one of the methyl groups of dimethylfumarate). The presence of this tag allows ‘click-chemistry’ to be used to visualize, isolate, enrich and characterize the cellular targets of such compounds. The probes show similar selectivity and reactivity to the parent compounds, and compete for cellular targets, yielding long-lived (stable) adducts that can be visualized in intact cells (such as primary human coronary artery smooth muscle cells), and extracted and enriched for subsequent target analysis. It is shown using this approach that dimethylfumarate forms adducts with multiple intracellular targets including cytoskeletal, organelle and nuclear species, with these including the rate-limiting glycolytic enzyme, glyceraldehyde-3-phosphate dehydrogenase (GAPDH). This approach should be amenable to use with multiple α,β-unsaturated carbonyls and a wide variety of targets containing nucleophilic sites. Humans are widely exposed to α,β-unsaturated carbonyls via drugs and environmental toxins. These compounds react with cellular targets, and particularly Cys residues, via Michael addition. Alkyne tagged derivatives have been synthesized to allow click chemistry detection. These tags allow visualization, extraction, enrichment and identification of adducted proteins. GAPDH reacts with dimethylfumarate, with adducts detected in both the cytosol and nucleus.
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Affiliation(s)
- Chiara Morozzi
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Max Sauerland
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Luke F Gamon
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Asmita Manandhar
- Department of Drug Design and Pharmacology, Jagtvej 162, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Trond Ulven
- Department of Drug Design and Pharmacology, Jagtvej 162, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark.
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7
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Fuentes-Lemus E, Reyes JS, Gamon LF, López-Alarcón C, Davies MJ. Effect of macromolecular crowding on protein oxidation: Consequences on the rate, extent and oxidation pathways. Redox Biol 2021; 48:102202. [PMID: 34856437 PMCID: PMC8640551 DOI: 10.1016/j.redox.2021.102202] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 11/25/2021] [Accepted: 11/26/2021] [Indexed: 12/02/2022] Open
Abstract
Biological systems are heterogeneous and crowded environments. Such packed milieus are expected to modulate reactions both inside and outside the cell, including protein oxidation. In this work, we explored the effect of macromolecular crowding on the rate and extent of oxidation of Trp and Tyr, in free amino acids, peptides and proteins. These species were chosen as they are readily oxidized and contribute to damage propagation. Dextran was employed as an inert crowding agent, as this polymer decreases the fraction of volume available to other (macro)molecules. Kinetic analysis demonstrated that dextran enhanced the rate of oxidation of free Trp, and peptide Trp, elicited by AAPH-derived peroxyl radicals. For free Trp, the rates of oxidation were 15.0 ± 2.1 and 30.5 ± 3.4 μM min-1 without and with dextran (60 mg mL-1) respectively. Significant increases were also detected for peptide-incorporated Trp. Dextran increased the extent of Trp consumption (up to 2-fold) and induced short chain reactions. In contrast, Tyr oxidation was not affected by the presence of dextran. Studies on proteins, using SDS-PAGE and LC-MS, indicated that oxidation was also affected by crowding, with enhanced amino acid loss (45% for casein), chain reactions and altered extents of oligomer formation. The overall effects of dextran-mediated crowding were however dependent on the protein structure. Overall, these data indicate that molecular crowding, as commonly encountered in biological systems affect the rates, and extents of oxidation, and particularly of Trp residues, illustrating the importance of appropriate choice of in vitro systems to study biological oxidations.
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Affiliation(s)
- Eduardo Fuentes-Lemus
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, Copenhagen, 2200, Denmark.
| | - Juan Sebastián Reyes
- Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Luke F Gamon
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, Copenhagen, 2200, Denmark
| | - Camilo López-Alarcón
- Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Michael J Davies
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, Copenhagen, 2200, Denmark.
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8
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Sauerland M, Mertes R, Morozzi C, Eggler AL, Gamon LF, Davies MJ. Kinetic assessment of Michael addition reactions of alpha, beta-unsaturated carbonyl compounds to amino acid and protein thiols. Free Radic Biol Med 2021; 169:1-11. [PMID: 33819622 DOI: 10.1016/j.freeradbiomed.2021.03.040] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/23/2021] [Accepted: 03/29/2021] [Indexed: 12/14/2022]
Abstract
Humans have extensive adverse exposure to alpha,beta-unsaturated carbonyl compounds (ABuCs) as these are major toxins in smoke and exhaust fumes, as well as products of lipid peroxidation. In contrast, another ABuC, dimethylfumarate, is used to treat psoriasis and multiple sclerosis. ABuCs undergo Michael adduction with amine, imidazole and thiol groups, with reaction at Cys residues predominating. Here we report rate constants, k2, for ABuCs (acrolein, crotonaldehyde, dimethylfumarate, cyclohex-1-en-2-one, cyclopent-1-en-2-one) with Cys residues present on N-Ac-Cys, GSH, bovine serum albumin, creatine kinase, papain, glyceraldehyde-3-phosphate dehydrogenase, and both wild-type and the C151S mutant of Keap-1. k2 values for N-Ac-Cys and GSH vary by > 250-fold, indicating a marked ABuC structure dependence, with acrolein the most reactive. There is also considerable variation in k2 between protein Cys groups, with these significantly greater than for GSH. A linear inverse correlation for acrolein with the thiol pKa indicates that the thiolate anion is the reactive species. The modest k2 for GSH rationalizes the detection of protein adducts of ABuCs in cells. The k2 values for dimethylfumarate also vary markedly, with the Cys151 residue on Keap-1 being particularly reactive, with the C151S mutant giving a much lower k2 value. The data for crotonaldehyde, dimethylfumarate, and cyclohex-1-en-2-one show little correlation with the Cys pKa values, indicating that steric/electronic interactions, rather than Cys ionization are important. These data indicate that protein Cys residues, and particularly Cys151 on Keap-1, react readily with dimethylfumarate, and this may help rationalize the use of this compound as a therapeutic agent.
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Affiliation(s)
- Max Sauerland
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Ralf Mertes
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Chiara Morozzi
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Aimee L Eggler
- Department of Chemistry, Villanova University, Villanova, PA, 19085, USA
| | - Luke F Gamon
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark.
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9
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He J, Becares ER, Thulstrup PW, Gamon LF, Pedersen JN, Otzen D, Gourdon P, Davies MJ, Hägglund P. Peroxynitrous acid (ONOOH) modifies the structure of anastellin and influences its capacity to polymerize fibronectin. Redox Biol 2020; 36:101631. [PMID: 32807731 PMCID: PMC7364157 DOI: 10.1016/j.redox.2020.101631] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/18/2020] [Accepted: 06/28/2020] [Indexed: 11/27/2022] Open
Abstract
Anastellin (AN), a fragment of the first type III module in fibronectin (FN), initiates formation of superfibronectin, a polymer which resembles the native cell-derived fibrillar FN found in the extracellular matrix of many tissues, but which displays remarkably different functional properties. Here we demonstrate that exposure of AN to the biologically-important inflammatory oxidant, peroxynitrous acid (ONOOH), either as a bolus or formed at low levels in a time-dependent manner from SIN-1, impairs the capability of AN to polymerize FN. In contrast, exposure of FN to ONOOH does not seem to affect superfibronectin formation to the same extent. This oxidant-induced loss-of-function in AN occurs in a dose-dependent manner, and correlates with structural perturbations, loss of the amino acid tyrosine and tryptophan, and dose-dependent formation of modified amino acid side-chains (3-nitrotyrosine, di-tyrosine and 6-nitrotryptophan). Reagent ONOOH also induces formation of oligomeric species which decrease in the presence of bicarbonate, whereas SIN-1 mainly generates dimers. Modifications were detected at sub-stoichiometric (0.1-fold), or greater, molar excesses of oxidant compared to AN. These species have been localized to specific sites by peptide mass mapping. With high levels of oxidant (>100 times molar excess), ONOOH also induces unfolding of the beta-sheet structure of AN, thermal destabilization, and formation of high molecular mass aggregates. These results have important implications for the understanding of FN fibrillogenesis in vivo, and indicates that AN is highly sensitive to pathophysiological levels of oxidants such as ONOOH.
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Affiliation(s)
- Jianfei He
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Eva Ramos Becares
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Luke F Gamon
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jannik Nedergaard Pedersen
- Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Daniel Otzen
- Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Pontus Gourdon
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Per Hägglund
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
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10
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Gamon LF, Guo C, He J, Hägglund P, Hawkins CL, Davies MJ. Absolute quantitative analysis of intact and oxidized amino acids by LC-MS without prior derivatization. Redox Biol 2020; 36:101586. [PMID: 32505089 PMCID: PMC7276450 DOI: 10.1016/j.redox.2020.101586] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/11/2020] [Accepted: 05/14/2020] [Indexed: 01/15/2023] Open
Abstract
The precise characterization and quantification of oxidative protein damage is a significant challenge due to the low abundance, large variety, and heterogeneity of modifications. Mass spectrometry (MS)-based techniques at the peptide level (proteomics) provide a detailed but limited picture due to incomplete sequence coverage and imperfect enzymatic digestion. This is particularly problematic with oxidatively modified and cross-linked/aggregated proteins. There is a pressing need for methods that can quantify large numbers of modified amino acids, which are often present in low abundance compared to the high background of non-damaged amino acids, in a rapid and reliable fashion. We have developed a protocol using zwitterionic ion-exchange chromatography coupled with LC-MS to simultaneously quantify both parent amino acids and their respective oxidation products. Proteins are hydrolyzed with methanesulfonic acid in the presence of tryptamine and purified by strong cation exchange solid phase extraction. The method was validated for the common amino acids (excluding Gln, Asn, Cys) and the oxidation products 3-chlorotyrosine (3-ClTyr), 3-nitrotyrosine (3-NO2Tyr), di-tyrosine, Nε-(1-carboxymethyl)-l-lysine, o,o’-di-tyrosine, 3,4,-dihydroxyphenylalanine, hydroxy-tryptophan and kynurenine. Linear standard curves were observed over ~3 orders of magnitude dynamic range (2–1000 pmol for parent amino acids, 80 fmol–20 pmol for oxidation products) with limit-of-quantification values as low as 200 fmol (o,o’-di-tyrosine). The validated method was used to quantify Tyr and Trp loss, and formation of 3-NO2Tyr on the isolated protein anastellin treated with peroxynitrous acid, and for 3-ClTyr formation (over a 2 orders of magnitude range) in cell lysates and complex protein mixtures treated with hypochlorous acid. Identification and quantification of oxidative protein damage is a major challenge. A versatile LC-MS assay is reported that involves hydrolysis to free amino acids. Quantification is possible for both parent amino acids and products in single runs. A dynamic range of 2-3 orders of magnitude is available for most analytes. Example of use with pure proteins, extracellular matrix and cell lysates are given.
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Affiliation(s)
- Luke F Gamon
- Dept. of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Chaorui Guo
- Dept. of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jianfei He
- Dept. of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Per Hägglund
- Dept. of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Clare L Hawkins
- Dept. of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael J Davies
- Dept. of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
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Ávila F, Ravello N, Zanocco AL, Gamon LF, Davies MJ, Silva E. 3-Hydroxykynurenine bound to eye lens proteins induces oxidative modifications in crystalline proteins through a type I photosensitizing mechanism. Free Radic Biol Med 2019; 141:103-114. [PMID: 31128239 DOI: 10.1016/j.freeradbiomed.2019.05.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 04/19/2019] [Accepted: 05/21/2019] [Indexed: 12/27/2022]
Abstract
Photosensitized reactions mediated by endogenous chromophores have been associated with the etiology of age-related cataract disease. Endogenous chromophores such as 3-hydroxykynurenine (3OHKN) can be found in both free form, and bound to crystallin proteins. However, their efficiency in generating photo-induced oxidative modifications on eye lens proteins is not completely understood. In this work, the efficiency and photodynamic activity of 3OHKN bound to both lysine (3OHKN-Lys) and bovine lens proteins (3OHKN-BLP) was assessed and compared with the photosensitizing activity of the major chromophore arising from glucose degradation (GDC). The photosensitizing activity of 3OHKN-Lys, 3OHKN-BLP and GDC was characterized by measurement of singlet oxygen quantum yields, O2 consumption, SDS-PAGE and amino acid analysis of the photo-oxidized proteins. Singlet oxygen quantum yields under 20% O2 atmosphere were 0.02, 0.01, and 0.27 for 3OHKN-Lys, 3OHKN-BLP and GDC, respectively. O2 consumption by photosensitized reactions was more efficient for 3OHKN-BLP, with the extent of O2 consumption being ∼28% higher than for 3OHKN-Lys and GDC under both 5 and 20% O2. SDS-PAGE showed that protein crosslinking is dependent on the O2 concentration, and more extensive at 5 than 20% O2. GDC and 3OHKN-Lys were the most efficient crosslinkers at 20 and 5% O2, respectively. Amino acid analysis of the irradiated proteins showed consumption of Trp, His, Tyr and Phe, and formation of kynurenine (from Trp), methionine sulfoxide (from Met) and DOPA (from Tyr). Kynurenine formation was dependent on the O2 concentration with higher amounts detected at 5 than 20% O2 for 3OHKN-BLP and 3OHKN-Lys, with 3OHKN-BLP the most efficient sensitizer. Our results suggest that 3OHKN-BLP can elicit photo-oxidative damage mainly by a type I photosensitizing mechanism, with this likely to be the most prevalent pathway at the low physiologic O2 concentrations in the eye lens.
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Affiliation(s)
- Felipe Ávila
- Escuela de Nutrición y Dietética, Facultad de Ciencias de la Salud, Universidad de Talca, Talca, Chile; Interdisciplinary Center on Aging, Universidad de Talca, Talca, Chile.
| | - Natalia Ravello
- Escuela de Nutrición y Dietética, Facultad de Ciencias de la Salud, Universidad de Talca, Talca, Chile; Interdisciplinary Center on Aging, Universidad de Talca, Talca, Chile
| | - Antonio L Zanocco
- Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Luke F Gamon
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - Eduardo Silva
- Departamento de Química Física, Facultad de Química, Pontificia Universidad Católica de Chile, Santiago, Chile
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Chen Z, Kondrashina A, Greco I, Gamon LF, Lund MN, Giblin L, Davies MJ. Effects of Protein-Derived Amino Acid Modification Products Present in Infant Formula on Metabolic Function, Oxidative Stress, and Intestinal Permeability in Cell Models. J Agric Food Chem 2019; 67:5634-5646. [PMID: 31017422 DOI: 10.1021/acs.jafc.9b01324] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Proteins present in infant formulas are modified by oxidation and glycation during processing. Modified amino acid residues released from proteins may be absorbed in the gastrointestinal tract, and pose a health risk to infants. In this study, the markers of glycation furosine (1.7-3.5 μg per milligram of protein) and Nε-(carboxymethyl)lysine (28-81 ng per milligram of protein) were quantitated in infant formulas. The effects of these species, and other amino acid modifications, at the levels detected in infant formulas, on 3T3-L1 (murine preadipocyte) and Caco-2 (human intestinal epithelial) cells were assessed. Incubation of 3T3-L1 cells for 48 h with amino acid side chain oxidation and glycation products (1 and 10 μM) resulted in a loss (up to 40%, p < 0.05) of cell thiols and decreased metabolic activity compared with those of the controls. In contrast, Caco-2 cells showed a stimulation (10-50%, p < 0.05) of cellular metabolism on exposure to these products for 24 or 48 h. A 28% ( p < 0.05) increase in protein carbonyls was detected upon incubation with 200 μM modified amino acids for 48 h, although no alteration in transepithelial electrical resistance was detected. Oxidation products were detected in the basolateral compartments of Caco-2 monolayers when modified amino acids were applied to the apical side, consistent with limited permeability (up to 3.4%) across the monolayer. These data indicate that modified amino acids present in infant formulas can induce effects on different cell types, with evidence of bioavailability and induction of cellular stress. This may lead to potential health risks for infants consistently exposed to high levels of infant formulas.
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Affiliation(s)
- Zhifei Chen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen 2200 , Denmark
| | - Alina Kondrashina
- Teagasc Food Research Centre , Moorepark, Fermoy , County Cork , Ireland
| | - Ines Greco
- Department of Food Science, Faculty of Science , University of Copenhagen , Copenhagen 2200 , Denmark
| | - Luke F Gamon
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen 2200 , Denmark
| | - Marianne N Lund
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen 2200 , Denmark
- Department of Food Science, Faculty of Science , University of Copenhagen , Copenhagen 2200 , Denmark
| | - Linda Giblin
- Teagasc Food Research Centre , Moorepark, Fermoy , County Cork , Ireland
| | - Michael J Davies
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen 2200 , Denmark
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13
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Nybo T, Cai H, Chuang CY, Gamon LF, Rogowska-Wrzesinska A, Davies MJ. Chlorination and oxidation of human plasma fibronectin by myeloperoxidase-derived oxidants, and its consequences for smooth muscle cell function. Redox Biol 2018; 19:388-400. [PMID: 30237127 PMCID: PMC6142189 DOI: 10.1016/j.redox.2018.09.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 08/28/2018] [Accepted: 09/03/2018] [Indexed: 12/11/2022] Open
Abstract
Fibronectin (FN) occurs as both a soluble form, in plasma and at sites of tissue injury, and a cellular form in tissue extracellular matrices (ECM). FN is critical to wound repair, ECM structure and assembly, cell adhesion and proliferation. FN is reported to play a critical role in the development, progression and stability of cardiovascular atherosclerotic lesions, with high FN levels associated with a thick fibrotic cap, stable disease and a low risk of rupture. Evidence has been presented for FN modification by inflammatory oxidants, and particularly myeloperoxidase (MPO)-derived species including hypochlorous acid (HOCl). The targets and consequences of FN modification are poorly understood. Here we show, using a newly-developed MS protocol, that HOCl and an enzymatic MPO system, generate site-specific dose-dependent Tyr chlorination and dichlorination (up to 16 of 100 residues modified), and oxidation of Trp (7 of 39 residues), Met (3 of 26) and His (1 of 55) within selected FN domains, and particularly the heparin- and cell-binding regions. These alterations increase FN binding to heparin-containing columns. Studies using primary human coronary artery smooth muscle cells (HCASMC) show that exposure to HOCl-modified FN, results in decreased adherence, increased proliferation and altered expression of genes involved in ECM synthesis and remodelling. These findings indicate that the presence of modified fibronectin may play a major role in the formation, development and stabilisation of fibrous caps in atherosclerotic lesions and may play a key role in the switching of quiescent contractile smooth muscle cells to a migratory, synthetic and proliferative phenotype.
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Affiliation(s)
- Tina Nybo
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Huan Cai
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Christine Y Chuang
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Luke F Gamon
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Adelina Rogowska-Wrzesinska
- Department of Biochemistry and Molecular Biology and VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark.
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Nathanael JG, Gamon LF, Cordes M, Rablen PR, Bally T, Fromm KM, Giese B, Wille U. Amide Neighbouring-Group Effects in Peptides: Phenylalanine as Relay Amino Acid in Long-Distance Electron Transfer. Chembiochem 2018; 19:922-926. [PMID: 29460322 DOI: 10.1002/cbic.201800098] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Indexed: 12/27/2022]
Abstract
In nature, proteins serve as media for long-distance electron transfer (ET) to carry out redox reactions in distant compartments. This ET occurs either by a single-step superexchange or through a multi-step charge hopping process, which uses side chains of amino acids as stepping stones. In this study we demonstrate that Phe can act as a relay amino acid for long-distance electron hole transfer through peptides. The considerably increased susceptibility of the aromatic ring to oxidation is caused by the lone pairs of neighbouring amide carbonyl groups, which stabilise the Phe radical cation. This neighbouring-amide-group effect helps improve understanding of the mechanism of extracellular electron transfer through conductive protein filaments (pili) of anaerobic bacteria during mineral respiration.
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Affiliation(s)
- Joses G Nathanael
- School of Chemistry, Bio21 Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria, 3010, Australia
| | - Luke F Gamon
- School of Chemistry, Bio21 Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria, 3010, Australia
| | - Meike Cordes
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Paul R Rablen
- Department of Chemistry and Biochemistry, Swarthmore College, 500 College Avenue, Swarthmore, PA, 19081-1397, USA
| | - Thomas Bally
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700, Fribourg, Switzerland
| | - Katharina M Fromm
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700, Fribourg, Switzerland
| | - Bernd Giese
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700, Fribourg, Switzerland
| | - Uta Wille
- School of Chemistry, Bio21 Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria, 3010, Australia
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Abstract
Air pollution is responsible for the premature death of about 7 million people every year. Ozone (O3) and nitrogen dioxide (NO2•) are the key gaseous pollutants in the troposphere, which predominantly result from combustion processes. Their inhalation leads to reactions with constituents in the airway surface fluids (ASF) of the respiratory tract and/or lungs. ASF contain small molecular-weight antioxidants, which protect the underlying epithelial cells against oxidative damage. When this defense system is overwhelmed, proteins and lipids present on cell surfaces or within the ASF become vulnerable to attack. The resulting highly reactive protein and lipid oxidation products could subsequently damage the epithelial cells through secondary reactions, thereby causing inflammation. While reactions of NO2• with biological molecules are considered to proceed through radical pathways, the biological effect of O3 is attributed to its high reactivity with π systems. Because O3 and NO2• always coexist in the polluted ambient atmosphere, synergistic effects resulting from in situ formed strongly oxidizing nitrate radicals (NO3•) may also require consideration. For example, in vitro product studies revealed that phenylalanine, which is inert not only to oxidants produced through biochemical processes, but also to NO2• or O3 in isolation, is damaged by NO3•. The reaction is initiated by oxidation of the aromatic ring and, depending on the availability of NO2•, leads to formation of nitrophenylalanine or β-nitrooxyphenylalanine, which could serve as marker for NO3•-induced oxidative damage in peptides. More easily oxidizable aromatic amino acids are directly attacked by NO2• and are converted to the same products independent of whether O3 is also present. Remarkably, NO2•-induced oxidative damage in peptides occurs not only through the well-established radical oxidation of peptide side chains, but also through an unprecedented fragmentation/rearrangement of the peptide backbone. This process is initiated by a nonradical N-nitrosation of a peptide bond involving the dimer of NO2•, i.e., N2O4, and contracts the peptide chain in the N → C direction by expelling one amino acid residue with simultaneous fusion of the remaining molecular termini, thereby forming a new peptide bond. This peptide cleavage could potentially be highly relevant for peptide segments with "nonvulnerable" side chains closer to the terminus that are not tied up in complex secondary and tertiary structures and therefore accessible for environmental oxidants. Likewise, NO2• reacts with cholesterol at the C═C moiety through an ionic mechanism, which leads to formation of 6-nitrocholesterol in the presence of moisture. Contrary to common belief, this clearly shows that ionic chemistry, in particular nitrosation reactions by intermediately formed NO+, requires consideration when assessing NO2• toxicity. This conclusion is supported by recent work by Colussi et al. (Enami, S.; Hoffmann, M. R.; Colussi, A. J. Absorption of inhaled NO2. J. Phys. Chem. B. 2009, 113, 7977-7981), who showed that anions in the airway surfaces fluids mediate NO2• absorption by catalyzing its hydrolytic disproportionation into NO2-/HNO2 and NO3-. These findings could be the key to our understanding why NO2•, despite its low water solubility, has such pronounced biological effects in vivo.
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Affiliation(s)
- Luke F. Gamon
- School of Chemistry and Bio21
Institute, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Uta Wille
- School of Chemistry and Bio21
Institute, The University of Melbourne, Parkville, VIC 3010, Australia
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Leeming MG, Gamon LF, Wille U, Donald WA, O'Hair RAJ. What Are the Potential Sites of Protein Arylation by N-Acetyl-p-benzoquinone Imine (NAPQI)? Chem Res Toxicol 2015; 28:2224-33. [PMID: 26523953 DOI: 10.1021/acs.chemrestox.5b00373] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Acetaminophen (paracetamol, APAP) is a safe and widely used analgesic medication when taken at therapeutic doses. However, APAP can cause potentially fatal hepatotoxicity when taken in overdose or in patients with metabolic irregularities. The production of the electrophilic and putatively toxic compound N-acetyl-p-benzoquinone imine (NAPQI), which cannot be efficiently detoxicated at high doses, is implicated in APAP toxicity. Numerous studies have identified that excess NAPQI can form covalent linkages to the thiol side chains of cysteine residues in proteins; however, the reactivity of NAPQI toward other amino acid side chains is largely unexplored. Here, we report a survey of the reactivity of NAPQI toward 11 N-acetyl amino acid methyl esters and four peptides. (1)H NMR analysis reveals that NAPQI forms covalent bonds to the side-chain functional groups of cysteine, methionine, tyrosine, and tryptophan residues. Analogous reaction products were observed when NAPQI was reacted with synthetic model peptides GAIL-X-GAILR for X = Cys, Met, Tyr, and Trp. Tandem mass spectrometry peptide sequencing showed that the NAPQI modification sites are located on the "X" residue in each case. However, when APAP and the GAIL-X-GAILR peptide were incubated with rat liver microsomes that contain many metabolic enzymes, NAPQI formed by oxidative metabolism reacted with GAIL-C-GAILR exclusively. For the peptides where X = Met, Tyr, and Trp, competing reactions between NAPQI and alternative nucleophiles precluded arylation of the target peptide by NAPQI. Although Cys residues are favorably targeted under these conditions, these data suggest that NAPQI can, in principle, also damage proteins at Met, Tyr, and Trp residues.
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Affiliation(s)
- Michael G Leeming
- School of Chemistry and ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne , Parkville, Victoria 3010, Australia
| | - Luke F Gamon
- School of Chemistry and ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne , Parkville, Victoria 3010, Australia
| | - Uta Wille
- School of Chemistry and ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne , Parkville, Victoria 3010, Australia
| | - William A Donald
- School of Chemistry, University of New South Wales , Sydney, NSW 2052, Australia
| | - Richard A J O'Hair
- School of Chemistry and ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne , Parkville, Victoria 3010, Australia
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Gamon LF, Nathanael JG, Taggert BI, Henry FA, Bogena J, Wille U. Fragmentation-Rearrangement of Peptide Backbones Mediated by the Air Pollutant NO2. Chemistry 2015; 21:14924-30. [DOI: 10.1002/chem.201501850] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Indexed: 11/07/2022]
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