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DeWeese DE, Everett MP, Babicz JT, Daruwalla A, Solomon EI, Kiser PD. Spectroscopy and crystallography define carotenoid oxygenases as a new subclass of mononuclear non-heme Fe II enzymes. J Biol Chem 2025; 301:108444. [PMID: 40147775 PMCID: PMC12051055 DOI: 10.1016/j.jbc.2025.108444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2025] [Revised: 03/14/2025] [Accepted: 03/20/2025] [Indexed: 03/29/2025] Open
Abstract
Carotenoid cleavage dioxygenases (CCDs) are non-heme FeII enzymes that catalyze the oxidative cleavage of alkene bonds in carotenoids, stilbenoids, and related compounds. How these enzymes control the reaction of dioxygen (O2) with their alkene substrates is unclear. Here, we apply spectroscopy in conjunction with X-ray crystallography to define the iron coordination geometry of a model CCD, CAO1 (Neurospora crassa carotenoid oxygenase 1), in its resting state and following substrate binding and coordination sphere substitutions. Resting CAO1 exhibits a five-coordinate (5C), square pyramidal FeII center that undergoes steric distortion toward a trigonal bipyramidal geometry in the presence of piceatannol. Titrations with the O2-analog, nitric oxide, show a >100-fold increase in iron-nitric oxide affinity upon substrate binding, defining a crucial role for the substrate in activating the FeII site for O2 reactivity. The importance of the 5C FeII structure for reactivity was probed through mutagenesis of the second-sphere Thr151 residue of CAO1, which occludes ligand binding at the sixth coordination position. A T151G substitution resulted in the conversion of the iron center to a six-coordinate state and a 135-fold reduction in apparent catalytic efficiency toward piceatannol compared with the wildtype enzyme. Substrate complexation resulted in partial six-coordinate to 5C conversion, indicating solvent dissociation from the iron center. Additional substitutions at this site demonstrated a general functional importance of the occluding residue within the CCD superfamily. Taken together, these data suggest an ordered mechanism of CCD catalysis occurring via substrate-promoted solvent replacement by O2. CCDs thus represent a new class of mononuclear non-heme FeII enzymes.
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Affiliation(s)
- Dory E DeWeese
- Department of Chemistry, Stanford University, Stanford, California, USA
| | - Michael P Everett
- Department of Physiology & Biophysics, University of California, Irvine School of Medicine, Irvine, California, USA
| | - Jeffrey T Babicz
- Department of Chemistry, Stanford University, Stanford, California, USA; SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California, USA
| | - Anahita Daruwalla
- Department of Physiology & Biophysics, University of California, Irvine School of Medicine, Irvine, California, USA
| | - Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, California, USA; SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California, USA.
| | - Philip D Kiser
- Department of Physiology & Biophysics, University of California, Irvine School of Medicine, Irvine, California, USA; Research Service, VA Long Beach Healthcare System, Long Beach, California, USA.
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2
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Yadav S, Lyons RS, Readi-Brown Z, Siegler MA, Goldberg DP. Influence of the second coordination sphere on O 2 activation by a nonheme iron(II) thiolate complex. J Inorg Biochem 2025; 264:112776. [PMID: 39644805 DOI: 10.1016/j.jinorgbio.2024.112776] [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: 08/01/2024] [Revised: 11/05/2024] [Accepted: 11/14/2024] [Indexed: 12/09/2024]
Abstract
The synthesis and characterization of a new ligand, 1-(bis(pyridin-2-ylmethyl) amino)-2-methylpropane-2-thiolate (BPAMe2S-) and its nonheme iron complex, FeII(BPAMe2S)Br (1), is reported. Reaction of 1 with O2 at -20 °C generates a high-spin iron(III)-hydroxide complex, [FeIII(OH)(BPAMe2S)(Br)] (2), that was characterized by UV-vis, 57Fe Mössbauer, and electron paramagnetic resonance (EPR) spectroscopies, and electrospray ionization mass spectrometry (ESI-MS). Density functional theory (DFT) calculations were employed to support the spectroscopic assignments. In a previous report (J. Am. Chem. Soc.2024, 146, 7915-7921), the related iron(II) complex, FeII(BNPAMe2S)Br (BNPAMe2S- = (bis((6-(neopentylamino)pyridinyl) methyl)amino)-2-methylpropane-2-thiolate) was reported and shown to react with O2 at low temperature to give a rare iron(III)-superoxide intermediate, which then converts to an S‑oxygenated sulfinate as seen for the nonheme iron thiol dioxygenases. This complex includes two hydrogen bonding neopentylamino groups in the second coordination sphere. Complex 1 does not include these H-bonding groups, and its reactivity with O2 does not yield a stabilized Fe/O2 intermediate or S‑oxygenated products, although the data suggest an inner-sphere mechanism and formation of an iron‑oxygen species that is capable of abstracting hydrogen atoms from solvent or weak CH bond substrates. This study indicates that the H-bond donors are critical for stabilizing the FeIII(O2-•) intermediate with the BNPAMe2S- ligand, which in turn leads to S‑oxygenation, as opposed to H-atom abstraction, following O2 activation by the nonheme iron center.
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Affiliation(s)
- Sudha Yadav
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, United States
| | - Robert S Lyons
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, United States
| | - Zoe Readi-Brown
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, United States
| | - Maxime A Siegler
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, United States
| | - David P Goldberg
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, United States.
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3
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Rudenko TS, Trubitsina LI, Terentyev VV, Trubitsin IV, Borshchevskiy VI, Tishchenko SV, Gabdulkhakov AG, Leontievsky AA, Grabovich MY. Mechanism of Intracellular Elemental Sulfur Oxidation in Beggiatoa leptomitoformis, Where Persulfide Dioxygenase Plays a Key Role. Int J Mol Sci 2024; 25:10962. [PMID: 39456744 PMCID: PMC11507549 DOI: 10.3390/ijms252010962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2024] [Revised: 10/08/2024] [Accepted: 10/09/2024] [Indexed: 10/28/2024] Open
Abstract
Representatives of the colorless sulfur bacteria of the genus Beggiatoa use reduced sulfur compounds in the processes of lithotrophic growth, which is accompanied by the storage of intracellular sulfur. However, it is still unknown how the transformation of intracellular sulfur occurs in Beggiatoa representatives. Annotation of the genome of Beggiatoa leptomitoformis D-402 did not identify any genes for the oxidation or reduction of elemental sulfur. By searching BLASTP, two putative persulfide dioxygenase (PDO) homologs were found in the genome of B. leptomitoformis. In some heterotrophic prokaryotes, PDO is involved in the oxidation of sulfane sulfur. According to HPLC-MS/MS, the revealed protein was reliably detected in a culture sample grown only in the presence of endogenous sulfur and CO2. The recombinant protein from B. leptomitoformis was active in the presence of glutathione persulfide. The crystal structure of recombinant PDO exhibited consistency with known structures of type I PDO. Thus, it was shown that B. leptomitoformis uses PDO to oxidize endogenous sulfur. Additionally, on the basis of HPLC-MS/MS, RT-qPCR, and the study of PDO reaction products, we predicted the interrelation of PDO and Sox-system function in the oxidation of endogenous sulfur in B. leptomitoformis and the connection of this process with energy metabolism.
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Affiliation(s)
- Tatyana S. Rudenko
- Department of Biochemistry and Cell Physiology, Voronezh State University, 394018 Voronezh, Russia
| | - Liubov I. Trubitsina
- Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms of the Russian Academy of Sciences, 142290 Pushchino, Russia
| | - Vasily V. Terentyev
- Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, Institute of Basic Biological Problems, 142290 Pushchino, Russia
| | - Ivan V. Trubitsin
- Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms of the Russian Academy of Sciences, 142290 Pushchino, Russia
| | - Valentin I. Borshchevskiy
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
| | | | - Azat G. Gabdulkhakov
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Russia
| | - Alexey A. Leontievsky
- Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms of the Russian Academy of Sciences, 142290 Pushchino, Russia
| | - Margarita Yu. Grabovich
- Department of Biochemistry and Cell Physiology, Voronezh State University, 394018 Voronezh, Russia
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4
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She X, Xu J, Zhang H, Yu C, Rao Z, Zhang J, Zhan W, Hu F, Song D, Li H, Luo X, Wang G, Hu J, Lai S. ETHE1 dampens colorectal cancer angiogenesis by promoting TC45 Dephosphorylation of STAT3 to inhibit VEGF-A expression. Cell Death Dis 2024; 15:631. [PMID: 39198402 PMCID: PMC11358511 DOI: 10.1038/s41419-024-07021-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 08/16/2024] [Accepted: 08/20/2024] [Indexed: 09/01/2024]
Abstract
Angiogenesis is critical for colorectal cancer (CRC) progression, but its mechanisms remain unclear. Here, we reveal that ethylmalonic encephalopathy protein 1 (ETHE1), an essential enzyme in hydrogen sulfide catabolism, inhibits VEGF-A expression and tumor angiogenesis in vitro and in vivo. Moreover, we find that this biological function of ETHE1 depends on the STAT3/VEGF-A pathway. Further investigation demonstrates that ETHE1 promotes the interaction between T cell protein tyrosine phosphatase (TC45) and STAT3, resulting in decreased STAT3 phosphorylation and inhibition of the STAT3 signaling pathway. In clinical samples, we find that ETHE1 is downregulated in CRC and positively correlates with survival outcomes of CRC patients. Meanwhile, the negative correlation of ETHE1 and VEGF-A expression is verified in CRC specimens, and the patients with low ETHE1 and high VEGF-A expression exhibits poorer prognosis. Collectively, our study identifies ETHE1 as a novel regulator of tumor angiogenesis, implying its potential as a prognostic biomarker and promising antiangiogenic target for CRC patients.
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Affiliation(s)
- Xiaowei She
- GI Cancer Research Institute, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Jialu Xu
- Department of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Haokun Zhang
- GI Cancer Research Institute, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Chengxin Yu
- GI Cancer Research Institute, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Zejun Rao
- GI Cancer Research Institute, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Jiakun Zhang
- GI Cancer Research Institute, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Wenli Zhan
- GI Cancer Research Institute, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Fuqing Hu
- GI Cancer Research Institute, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Da Song
- GI Cancer Research Institute, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Haijie Li
- GI Cancer Research Institute, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Xuelai Luo
- GI Cancer Research Institute, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Guihua Wang
- GI Cancer Research Institute, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
- Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Disease, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Junbo Hu
- GI Cancer Research Institute, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Senyan Lai
- GI Cancer Research Institute, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China.
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5
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Li K, Zakharov LN, Pluth MD. Synthesis, Characterization, and Reactivity of a Synthetic End-On Cobalt(II) Alkyl Persulfide Complex as a Model Platform for Thiolate Persulfidation. J Am Chem Soc 2024; 146:21999-22007. [PMID: 39044627 DOI: 10.1021/jacs.4c07276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
Persulfides (RSS-) are ubiquitous source of sulfides (S2-) in biology, and interactions between RSS- and bioinorganic metal centers play critical roles in biological hydrogen sulfide (H2S) biogenesis, signaling, and catabolism. Here, we report the use of contact-ion stabilized [Na(15-crown-5)][tBuSS] (1) as a simple synthon to access rare metal alkyl persulfide complexes and to investigate the reactivity of RSS- with transition metal centers to provide insights into metal thiolate persulfidation, including the fundamental difference between alkyl persulfides and alkyl thiolates. Reaction of 1 with [CoII(TPA)(OTf)]+ afforded the η1-alkyl persulfide complex [CoII(TPA)(SStBu)]+ (2), which was characterized by X-ray crystallography, UV-vis spectroscopy, and Raman spectroscopy. RSS- coordination to the Lewis acidic Co2+ center provided additional stability to the S-S bond, as evidenced by a significant increase in the Raman stretching frequency for 2 (vS-S = 522 cm-1, ΔvS-S = 66 cm-1). The effect of persulfidation on metal center redox potentials was further elucidated using cyclic voltammetry, in which the Co2+ → Co3+ oxidation potential of 2 (Ep,a = +89 mV vs SCE) is lowered by nearly 700 mV when compared to the corresponding thiolate complex [CoII(TPA)(StBu)]+ (3) (Ep,a = +818 mV vs SCE), despite persulfidation being generally seen as an oxidative post-translational modification. The reactivity of 2 toward reducing agents including PPh3, BH4-, and biologically relevant thiol reductant DTT led to different S2- output pathways, including formation of a dinuclear 2Co-2SH complex [CoII2(TPA)2(μ2-SH)2]2+(4).
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Affiliation(s)
- Keyan Li
- Department of Chemistry and Biochemistry, Materials Science Institute, Knight Campus for Accelerating Scientific Impact, and Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403-1253, United States
| | - Lev N Zakharov
- Department of Chemistry and Biochemistry, Materials Science Institute, Knight Campus for Accelerating Scientific Impact, and Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403-1253, United States
| | - Michael D Pluth
- Department of Chemistry and Biochemistry, Materials Science Institute, Knight Campus for Accelerating Scientific Impact, and Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403-1253, United States
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6
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Solomon EI, Gipson RR. Spectroscopic definition of ferrous active sites in non-heme iron enzymes. Methods Enzymol 2024; 703:29-49. [PMID: 39261000 PMCID: PMC11391101 DOI: 10.1016/bs.mie.2024.05.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2024]
Abstract
Non-heme iron enzymes play key roles in antibiotic, neurotransmitter, and natural product biosynthesis, DNA repair, hypoxia regulation, and disease states. These enzymes had been refractory to traditional bioinorganic spectroscopic methods. Thus, we developed variable-temperature variable-field magnetic circular dichroism (VTVH MCD) spectroscopy to experimentally define the excited and ground ligand field states of non-heme ferrous enzymes (Solomon et al., 1995). This method provides detailed geometric and electronic structure insight and thus enables a molecular level understanding of catalytic mechanisms. Application of this method across the five classes of non-heme ferrous enzymes has defined that a general mechanistic strategy is utilized where O2 activation is controlled to occur only in the presence of all cosubstrates.
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Affiliation(s)
- Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, CA, United States; Stanford Synchrotron Radiation Lightsource, SLAC National Acceleration Laboratory, Stanford University, Menlo Park, CA, United States.
| | - Robert R Gipson
- Department of Chemistry, Stanford University, Stanford, CA, United States
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7
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Liu Y, Shao K, Yang W, Shen Q, Lu M, Shao Z, Chu S, Wang Y, Wang X, Chen X, Bai J, Wu X. Phosphorylated FOXQ1, a novel substrate of JNK1, inhibits sorafenib-induced ferroptosis by activating ETHE1 in hepatocellular carcinoma. Cell Death Dis 2024; 15:395. [PMID: 38839744 PMCID: PMC11153576 DOI: 10.1038/s41419-024-06789-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 05/27/2024] [Accepted: 05/29/2024] [Indexed: 06/07/2024]
Abstract
Hepatocellular carcinoma (HCC) is a highly heterogeneous and malignant cancer with poor overall survival. The application of sorafenib is a major breakthrough in the treatment of HCC. In our study, FOXQ1 was significantly overexpressed in sorafenib-resistant HCC cells and suppressed sorafenib-induced ferroptosis. We found that phosphorylation of FOXQ1 at serine 248 is critical for the suppression of sorafenib-induced ferroptosis. Furthermore, as the upstream phosphorylation kinase of FOXQ1, JNK1, which is activated by sorafenib, can directly phosphorylate the serine 248 site of FOXQ1. Then, the phosphorylated FOXQ1 got a high affinity for the promoter of ETHE1 and activates its transcription. Further flow cytometry results showed that ETHE1 reduced intracellular lipid peroxidation and iron levels. Collectively, our study implicated the JNK1-FOXQ1-ETHE1 axis in HCC ferroptosis induced by sorafenib, providing mechanistic insight into sensitivity to sorafenib therapy of HCC.
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Affiliation(s)
- Yiwei Liu
- Hepatobiliary Center, The First Affiliated Hospital of Nanjing Medical University; Key Laboratory of Liver Transplantation, Chinese Academy of Medical Sciences; NHC Key Laboratory of Living Donor Liver Transplantation (Nanjing Medical University), Nanjing, Jiangsu Province, China
| | - Ke Shao
- Hepatobiliary Center, The First Affiliated Hospital of Nanjing Medical University; Key Laboratory of Liver Transplantation, Chinese Academy of Medical Sciences; NHC Key Laboratory of Living Donor Liver Transplantation (Nanjing Medical University), Nanjing, Jiangsu Province, China
- Department of General Surgery, The People's Hospital of Rugao, Affiliated Rugao Hospital of Nantong University, Nantong, Jiangsu Province, China
| | - Wendong Yang
- Cancer Institute, Xuzhou Medical University, Xuzhou, Jiangsu Province, China
| | - Qi Shen
- Cancer Institute, Xuzhou Medical University, Xuzhou, Jiangsu Province, China
| | - Mengru Lu
- Cancer Institute, Xuzhou Medical University, Xuzhou, Jiangsu Province, China
| | - Zhiying Shao
- Cancer Institute, Xuzhou Medical University, Xuzhou, Jiangsu Province, China
| | - Sufang Chu
- Cancer Institute, Xuzhou Medical University, Xuzhou, Jiangsu Province, China
| | - Yuming Wang
- Hepatobiliary Center, The First Affiliated Hospital of Nanjing Medical University; Key Laboratory of Liver Transplantation, Chinese Academy of Medical Sciences; NHC Key Laboratory of Living Donor Liver Transplantation (Nanjing Medical University), Nanjing, Jiangsu Province, China
| | - Xuehao Wang
- Hepatobiliary Center, The First Affiliated Hospital of Nanjing Medical University; Key Laboratory of Liver Transplantation, Chinese Academy of Medical Sciences; NHC Key Laboratory of Living Donor Liver Transplantation (Nanjing Medical University), Nanjing, Jiangsu Province, China.
| | - Xiaofeng Chen
- Department of Oncology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China.
| | - Jin Bai
- Cancer Institute, Xuzhou Medical University, Xuzhou, Jiangsu Province, China.
- Center of Clinical Oncology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, China.
| | - Xiaofeng Wu
- Hepatobiliary Center, The First Affiliated Hospital of Nanjing Medical University; Key Laboratory of Liver Transplantation, Chinese Academy of Medical Sciences; NHC Key Laboratory of Living Donor Liver Transplantation (Nanjing Medical University), Nanjing, Jiangsu Province, China.
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8
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Yang SY, Liao L, Hu SY, Deng L, Andriani L, Zhang TM, Zhang YL, Ma XY, Zhang FL, Liu YY, Li DQ. ETHE1 Accelerates Triple-Negative Breast Cancer Metastasis by Activating GCN2/eIF2α/ATF4 Signaling. Int J Mol Sci 2023; 24:14566. [PMID: 37834012 PMCID: PMC10572406 DOI: 10.3390/ijms241914566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 09/10/2023] [Accepted: 09/12/2023] [Indexed: 10/15/2023] Open
Abstract
Triple-negative breast cancer (TNBC) is the most fatal subtype of breast cancer; however, effective treatment strategies for TNBC are lacking. Therefore, it is important to explore the mechanism of TNBC metastasis and identify its therapeutic targets. Dysregulation of ETHE1 leads to ethylmalonic encephalopathy in humans; however, the role of ETHE1 in TNBC remains elusive. Stable cell lines with ETHE1 overexpression or knockdown were constructed to explore the biological functions of ETHE1 during TNBC progression in vitro and in vivo. Mass spectrometry was used to analyze the molecular mechanism through which ETHE1 functions in TNBC progression. ETHE1 had no impact on TNBC cell proliferation and xenograft tumor growth but promoted TNBC cell migration and invasion in vitro and lung metastasis in vivo. The effect of ETHE1 on TNBC cell migratory potential was independent of its enzymatic activity. Mechanistic investigations revealed that ETHE1 interacted with eIF2α and enhanced its phosphorylation by promoting the interaction between eIF2α and GCN2. Phosphorylated eIF2α in turn upregulated the expression of ATF4, a transcriptional activator of genes involved in cell migration and tumor metastasis. Notably, inhibition of eIF2α phosphorylation through ISRIB or ATF4 knockdown partially abolished the tumor-promoting effect of ETHE1 overexpression. ETHE1 has a functional and mechanistic role in TNBC metastasis and offers a new therapeutic strategy for targeting ETHE1-propelled TNBC using ISRIB.
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Affiliation(s)
- Shao-Ying Yang
- Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China; (S.-Y.Y.); (L.L.); (S.-Y.H.); (L.D.); (T.-M.Z.)
- Cancer Institute, Shanghai Medical College, Fudan University, Shanghai 200032, China; (Y.-L.Z.); (F.-L.Z.)
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Li Liao
- Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China; (S.-Y.Y.); (L.L.); (S.-Y.H.); (L.D.); (T.-M.Z.)
- Cancer Institute, Shanghai Medical College, Fudan University, Shanghai 200032, China; (Y.-L.Z.); (F.-L.Z.)
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Shu-Yuan Hu
- Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China; (S.-Y.Y.); (L.L.); (S.-Y.H.); (L.D.); (T.-M.Z.)
| | - Ling Deng
- Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China; (S.-Y.Y.); (L.L.); (S.-Y.H.); (L.D.); (T.-M.Z.)
| | - Lisa Andriani
- Department of Breast Surgery, Shanghai Medical College, Fudan University, Shanghai 200032, China; (L.A.); (X.-Y.M.)
| | - Tai-Mei Zhang
- Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China; (S.-Y.Y.); (L.L.); (S.-Y.H.); (L.D.); (T.-M.Z.)
| | - Yin-Ling Zhang
- Cancer Institute, Shanghai Medical College, Fudan University, Shanghai 200032, China; (Y.-L.Z.); (F.-L.Z.)
| | - Xiao-Yan Ma
- Department of Breast Surgery, Shanghai Medical College, Fudan University, Shanghai 200032, China; (L.A.); (X.-Y.M.)
| | - Fang-Lin Zhang
- Cancer Institute, Shanghai Medical College, Fudan University, Shanghai 200032, China; (Y.-L.Z.); (F.-L.Z.)
| | - Ying-Ying Liu
- Department of Breast Surgery, Shanghai Medical College, Fudan University, Shanghai 200032, China; (L.A.); (X.-Y.M.)
| | - Da-Qiang Li
- Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China; (S.-Y.Y.); (L.L.); (S.-Y.H.); (L.D.); (T.-M.Z.)
- Cancer Institute, Shanghai Medical College, Fudan University, Shanghai 200032, China; (Y.-L.Z.); (F.-L.Z.)
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
- Department of Breast Surgery, Shanghai Medical College, Fudan University, Shanghai 200032, China; (L.A.); (X.-Y.M.)
- Shanghai Key Laboratory of Breast Cancer, Shanghai Medical College, Fudan University, Shanghai 200032, China
- Shanghai Key Laboratory of Radiation Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
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9
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Dedushko MA, Greiner MB, Downing AN, Coggins M, Kovacs JA. Electronic Structure and Reactivity of Dioxygen-Derived Aliphatic Thiolate-Ligated Fe-Peroxo and Fe(IV) Oxo Compounds. J Am Chem Soc 2022; 144:8515-8528. [PMID: 35522532 DOI: 10.1021/jacs.1c07656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Herein, we examine the electronic and geometric structural properties of O2-derived aliphatic thiolate-ligated Fe-peroxo, Fe-hydroxo, and Fe(IV) oxo compounds. The latter cleaves strong C-H bonds (96 kcal mol-1) on par with the valine C-H bond cleaved by isopencillin N synthase (IPNS). Stopped-flow kinetics studies indicate that the barrier to O2 binding to [FeII(SMe2N4(tren))]+ (3) is extremely low (Ea = 36(2) kJ mol-1), as theoretically predicted for IPNS. Dioxygen binding to 3 is shown to be reversible, and a superoxo intermediate, [FeIII(SMe2N4(tren))(O2)]+ (6), forms in the first 25 ms of the reaction at -40 °C prior to the rate-determining (Ea = 46(2) kJ mol-1) formation of peroxo-bridged [(SMe2N4(tren))Fe(III)]2(μ-O2)2+ (7). A log(kobs) vs log([Fe]) plot for the formation of 7 is consistent with the second-order dependence on iron, and H2O2 assays are consistent with a 2:1 ratio of Fe/H2O2. Peroxo 7 is shown to convert to ferric-hydroxo [FeIII(SMe2N(tren))(OH)]+ (9, g⊥ = 2.24, g∥ = 1.96), the identity of which was determined via its independent synthesis. Rates of the conversion 7 → 9 are shown to be dependent on the X-H bond strength of the H-atom donor, with a kH/kD = 4 when CD3OD is used in place of CH3OH as a solvent. A crystallographically characterized cis thiolate-ligated high-valent iron oxo, [FeIV(O)(SMe2N4(tren))]+ (11), is shown to form en route to hydroxo 9. Electronic structure calculations were shown to be consistent with 11 being an S = 1 Fe(IV)═O with an unusually high νFe-O stretching frequency at 918 cm-1 in line with the extremely short Fe-O bond (1.603(7) Å).
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Affiliation(s)
- Maksym A Dedushko
- Department of Chemistry, University of Washington, Campus Box 351700, Seattle, Washington 98195-1700, United States
| | - Maria B Greiner
- Department of Chemistry, University of Washington, Campus Box 351700, Seattle, Washington 98195-1700, United States
| | - Alexandra N Downing
- Department of Chemistry, University of Washington, Campus Box 351700, Seattle, Washington 98195-1700, United States
| | - Michael Coggins
- Department of Chemistry, University of Washington, Campus Box 351700, Seattle, Washington 98195-1700, United States
| | - Julie A Kovacs
- Department of Chemistry, University of Washington, Campus Box 351700, Seattle, Washington 98195-1700, United States
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10
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Liu SF, Zhao YN, Jia CW, Ma TY, Cai SD, Gao F. Spontaneous dissection of proximal left main coronary artery in a healthy adolescent presenting with syncope: A case report. World J Clin Cases 2022; 10:2341-2350. [PMID: 35321168 PMCID: PMC8895162 DOI: 10.12998/wjcc.v10.i7.2341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 11/29/2021] [Accepted: 01/20/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Spontaneous coronary artery dissection (SCAD) is a frequent cause of acute coronary syndrome in young to middle-aged women with few or no traditional cardiovascular risk factors. Chest pain is the most frequently described presenting symptom, but syncope is extremely rare. Herein, we report on a 16-year-old girl who presented with an episode of syncope occurring during a race. Despite significantly elevated troponin level, the diagnosis of the left main coronary artery SCAD with cardiogenic shock was delayed.
CASE SUMMARY A 16-year-old girl presented with an episode of syncope. Myocardial injury markers were positive. Echocardiography showed a mildly reduced left ventricular ejection fraction (50%). Although initially stable, she later experienced recurrent chest pain accompanying precordial ST segment elevation with dynamic changes and developed cardiogenic shock, necessitating emergent revascularization. Coronary angiography demonstrated almost total occlusion at the ostium and proximal segment of the left main trunk coronary artery (LMT). Intravascular ultrasound confirmed a false lumen with prominent dissection in the LMT. Percutaneous coronary intervention assisted by intra-aortic balloon pump was conducted in the LMT. A 3.5 mm × 24 mm everolimus-eluting stent was deployed to the focal lesions of the LMT. A postprocedural electrocardiogram showed alleviation of the precordial ST-segment elevation. The diagnosis of SCAD was confirmed. Transthoracic echocardiography showed an improved left ventricular ejection fraction (57%). The patient was asymptomatic during the 24-mo. follow-up period.
CONCLUSION SCAD should always be considered in the differential diagnosis of acute coronary syndrome presentations in low-risk patients, regardless of age.
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Affiliation(s)
- Sui-Feng Liu
- Department of Cardiology, Zhongshan Hospital, Xiamen University, Xiamen 361000, Fujian Province, China
| | - Ya-Nan Zhao
- Department of Cardiology, Zhongshan Hospital, Xiamen University, Xiamen 361000, Fujian Province, China
| | - Chun-Wen Jia
- Department of Cardiology, Zhongshan Hospital, Xiamen University, Xiamen 361000, Fujian Province, China
| | - Tian-Yi Ma
- Department of Cardiology, Zhongshan Hospital, Xiamen University, Xiamen 361000, Fujian Province, China
| | - Shi-Da Cai
- Department of Cardiology, Zhongshan Hospital, Xiamen University, Xiamen 361000, Fujian Province, China
| | - Feng Gao
- Department of Cardiology, Zhongshan Hospital, Xiamen University, Xiamen 361000, Fujian Province, China
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11
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Solomon EI, DeWeese DE, Babicz JT. Mechanisms of O 2 Activation by Mononuclear Non-Heme Iron Enzymes. Biochemistry 2021; 60:3497-3506. [PMID: 34266238 PMCID: PMC8768060 DOI: 10.1021/acs.biochem.1c00370] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Two major subclasses of mononuclear non-heme ferrous enzymes use two electron-donating organic cofactors (α-ketoglutarate or pterin) to activate O2 to form FeIV═O intermediates that further react with their substrates through hydrogen atom abstraction or electrophilic aromatic substitution. New spectroscopic methodologies have been developed, enabling the study of the active sites in these enzymes and their oxygen intermediates. Coupled to electronic structure calculations, the results of these spectroscopies provide fundamental insight into mechanism. This Perspective summarizes the results of these studies in elucidating the mechanism of dioxygen activation to form the FeIV═O intermediate and the geometric and electronic structure of this intermediate that enables its high reactivity and selectivity in product formation.
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Affiliation(s)
- Edward I. Solomon
- Department of Chemistry, Stanford University, 333 Campus Dr. Stanford, CA, 94305, United States,SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA, 94025, United States
| | - Dory E. DeWeese
- Department of Chemistry, Stanford University, 333 Campus Dr. Stanford, CA, 94305, United States
| | - Jeffrey T. Babicz
- Department of Chemistry, Stanford University, 333 Campus Dr. Stanford, CA, 94305, United States
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12
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A redox cycle with complex II prioritizes sulfide quinone oxidoreductase-dependent H 2S oxidation. J Biol Chem 2021; 298:101435. [PMID: 34808207 PMCID: PMC8683732 DOI: 10.1016/j.jbc.2021.101435] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/16/2021] [Accepted: 11/16/2021] [Indexed: 12/14/2022] Open
Abstract
The dual roles of H2S as an endogenously synthesized respiratory substrate and as a toxin raise questions as to how it is cleared when the electron transport chain is inhibited. Sulfide quinone oxidoreductase (SQOR) catalyzes the first step in the mitochondrial H2S oxidation pathway, using CoQ as an electron acceptor, and connects to the electron transport chain at the level of complex III. We have discovered that at high H2S concentrations, which are known to inhibit complex IV, a new redox cycle is established between SQOR and complex II, operating in reverse. Under these conditions, the purine nucleotide cycle and the malate aspartate shuttle furnish fumarate, which supports complex II reversal and leads to succinate accumulation. Complex II knockdown in colonocytes decreases the efficiency of H2S clearance while targeted knockout of complex II in intestinal epithelial cells significantly decreases the levels of thiosulfate, a biomarker of H2S oxidation, to approximately one-third of the values seen in serum and urine samples from control mice. These data establish the physiological relevance of this newly discovered redox circuitry between SQOR and complex II for prioritizing H2S oxidation and reveal the quantitatively significant contribution of intestinal epithelial cells to systemic H2S metabolism.
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13
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Ekanayake DM, Pham D, Probst AL, Miller JR, Popescu CV, Fiedler AT. Electronic structures and spectroscopic signatures of diiron intermediates generated by O 2 activation of nonheme iron(II)-thiolate complexes. Dalton Trans 2021; 50:14432-14443. [PMID: 34570147 PMCID: PMC8721859 DOI: 10.1039/d1dt02286e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The activation of O2 at thiolate-ligated iron(II) sites is essential to the function of numerous metalloenzymes and synthetic catalysts. Iron-thiolate bonds in the active sites of nonheme iron enzymes arise from either coordination of an endogenous cysteinate residue or binding of a deprotonated thiol-containing substrate. Examples of the latter include sulfoxide synthases, such as EgtB and OvoA, that utilize O2 to catalyze tandem S-C bond formation and S-oxygenation steps in thiohistidine biosyntheses. We recently reported the preparation of two mononuclear nonheme iron-thiolate complexes (1 and 2) that serve as structural active-site models of substrate-bound EgtB and OvoA (Dalton Trans. 2020, 49, 17745-17757). These models feature monodentate thiolate ligands and tripodal N4 ligands with mixed pyridyl/imidazolyl donors. Here, we describe the reactivity of 1 and 2 with O2 at low temperatures to give metastable intermediates (3 and 4, respectively). Characterization with multiple spectroscopic techniques (UV-vis absorption, NMR, variable-field and -temperature Mössbauer, and resonance Raman) revealed that these intermediates are thiolate-ligated iron(III) dimers with a bridging oxo ligand derived from the four-electron reduction of O2. Structural models of 3 and 4 consistent with the experimental data were generated via density functional theory (DFT) calculations. The combined experimental and computational results illuminate the geometric and electronic origins of the unique spectral features of diiron(III)-μ-oxo complexes with thiolate ligands, and the spectroscopic signatures of 3 and 4 are compared to those of closely-related diiron(III)-μ-peroxo species. Collectively, these results will assist in the identification of intermediates that appear on the O2 reaction landscapes of iron-thiolate species in both biological and synthetic environments.
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Affiliation(s)
| | - Dao Pham
- Department of Chemistry, The College of Arts and Sciences, University of St. Thomas, St. Paul, Minnesota 55105, USA.
| | - Andrew L Probst
- Department of Chemistry, The College of Arts and Sciences, University of St. Thomas, St. Paul, Minnesota 55105, USA.
| | - Joshua R Miller
- Department of Chemistry, University of Wisconsin - Madison, Madison, Wisconsin 53706, USA
| | - Codrina V Popescu
- Department of Chemistry, The College of Arts and Sciences, University of St. Thomas, St. Paul, Minnesota 55105, USA.
| | - Adam T Fiedler
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53233, USA.
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14
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Yeh CCG, Pierides C, Jameson GNL, de Visser SP. Structure and Functional Differences of Cysteine and 3-Mercaptopropionate Dioxygenases: A Computational Study. Chemistry 2021; 27:13793-13806. [PMID: 34310770 DOI: 10.1002/chem.202101878] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Indexed: 11/09/2022]
Abstract
Thiol dioxygenases are important enzymes for human health; they are involved in the detoxification and catabolism of toxic thiol-containing natural products such as cysteine. As such, these enzymes have relevance to the development of Alzheimer's and Parkinson's diseases in the brain. Recent crystal structure coordinates of cysteine and 3-mercaptopropionate dioxygenase (CDO and MDO) showed major differences in the second-coordination spheres of the two enzymes. To understand the difference in activity between these two analogous enzymes, we created large, active-site cluster models. We show that CDO and MDO have different iron(III)-superoxo-bound structures due to differences in ligand coordination. Furthermore, our studies show that the differences in the second-coordination sphere and particularly the position of a positively charged Arg residue results in changes in substrate positioning, mobility and enzymatic turnover. Furthermore, the substrate scope of MDO is explored with cysteinate and 2-mercaptosuccinic acid and their reactivity is predicted.
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Affiliation(s)
- C-C George Yeh
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.,Department of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Christos Pierides
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.,Department of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Guy N L Jameson
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Parkville, Vic, 3010, Australia
| | - Sam P de Visser
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.,Department of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
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15
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Gordon JB, McGale JP, Siegler MA, Goldberg DP. Proton-Coupled Electron-Transfer Reactivity Controls Iron versus Sulfur Oxidation in Nonheme Iron-Thiolate Complexes. Inorg Chem 2021; 60:6255-6265. [PMID: 33872005 DOI: 10.1021/acs.inorgchem.0c03779] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reaction of the five-coordinate FeII(N4S) complexes, [FeII(iPr3TACN)(abtX)](OTf) (abt = aminobenzenethiolate, X = H, CF3), with a one-electron oxidant and an appropriate base leads to net H atom loss, generating new FeIII(iminobenzenethiolate) complexes that were characterized by single-crystal X-ray diffraction (XRD), as well as UV-vis, EPR, and Mössbauer spectroscopies. The spectroscopic data indicate that the iminobenzenethiolate complexes have S = 3/2 ground states. In the absence of a base, oxidation of the FeII(abt) complexes leads to disulfide formation instead of oxidation at the metal center. Bracketing studies with separated proton-coupled electron-transfer (PCET) reagents show that the FeII(aminobenzenethiolate) and FeIII(iminobenzenethiolate) forms are readily interconvertible by H+/e- transfer and provide a measure of the bond dissociation free energy (BDFE) for the coordinated N-H bond between 64 and 69 kcal mol-1. This work shows that coordination to the iron center causes a dramatic weakening of the N-H bond and that Fe- versus S-oxidation in a nonheme iron complex can be controlled by the protonation state of an ancillary amino donor.
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Affiliation(s)
- Jesse B Gordon
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Jeremy P McGale
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Maxime A Siegler
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - David P Goldberg
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
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16
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Sherbow TJ, Zakharov LN, Johnson DW, Pluth MD. Hydrosulfide Oxidation at a Molybdenum Tetrasulfido Complex. Inorg Chem 2020; 59:15574-15578. [DOI: 10.1021/acs.inorgchem.0c02622] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Tobias J. Sherbow
- Department of Chemistry and Biochemistry, Materials Science Institute, Knight Campus for Accelerating Scientific Impact, and Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403-1253, United States
| | - Lev N. Zakharov
- Department of Chemistry and Biochemistry, Materials Science Institute, Knight Campus for Accelerating Scientific Impact, and Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403-1253, United States
| | - Darren W. Johnson
- Department of Chemistry and Biochemistry, Materials Science Institute, Knight Campus for Accelerating Scientific Impact, and Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403-1253, United States
| | - Michael D. Pluth
- Department of Chemistry and Biochemistry, Materials Science Institute, Knight Campus for Accelerating Scientific Impact, and Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403-1253, United States
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17
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Stipanuk MH. Metabolism of Sulfur-Containing Amino Acids: How the Body Copes with Excess Methionine, Cysteine, and Sulfide. J Nutr 2020; 150:2494S-2505S. [PMID: 33000151 DOI: 10.1093/jn/nxaa094] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 02/28/2020] [Accepted: 03/16/2020] [Indexed: 02/06/2023] Open
Abstract
Metabolism of excess methionine (Met) to homocysteine (Hcy) by transmethylation is facilitated by the expression of methionine adenosyltransferase (MAT) I/III and glycine N-methyltransferase (GNMT) in liver, and a lack of either enzyme results in hypermethioninemia despite normal concentrations of MATII and methyltransferases other than GNMT. The further metabolism of Hcy by the transsulfuration pathway is facilitated by activation of cystathionine β-synthase (CBS) by S-adenosylmethionine (SAM) as well as the relatively high KM of CBS for Hcy. Transmethylation plus transsulfuration effects catabolism of the Met molecule along with transfer of the sulfur atom of Met to serine to synthesize cysteine (Cys). Oxidation and excretion of Met sulfur depend upon Cys catabolism and sulfur oxidation pathways. Excess Cys is oxidized by cysteine dioxygenase 1 (CDO1) and further metabolized to taurine or sulfate. Some Cys is normally metabolized by desulfhydration pathways, and the hydrogen sulfide (H2S) produced is further oxidized to sulfate. If Cys or Hcy concentrations are elevated, Cys or Hcy desulfhydration can result in excess H2S and thiosulfate production. Excess Cys or Met may also promote their limited metabolism by transamination pathways.
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Affiliation(s)
- Martha H Stipanuk
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
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18
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The catalytic mechanism of sulfoxide synthases. Curr Opin Chem Biol 2020; 59:111-118. [PMID: 32726707 DOI: 10.1016/j.cbpa.2020.06.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/09/2020] [Accepted: 06/17/2020] [Indexed: 02/06/2023]
Abstract
Sulfoxide synthases are non-heme iron enzymes that catalyze oxidative carbonsulfur bond formation in the biosynthesis of thiohistidines such as ergothioneine and ovothiol. The catalytic mechanism of these enzymes has been studied by protein crystallography, steady-state kinetics, non-natural amino acid incorporation and computational modeling. This review discusses the current status of this research and also highlights similarities between the CS bond forming activity of sulfoxide synthases with that of synthetic coordination compounds.
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19
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Persulfides, at the crossroads between hydrogen sulfide and thiols. Essays Biochem 2020; 64:155-168. [DOI: 10.1042/ebc20190049] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 01/13/2020] [Accepted: 01/15/2020] [Indexed: 12/14/2022]
Abstract
AbstractPersulfides (RSSH/RSS−) can be formed in protein and non-protein thiols (RSH) through several different pathways, some of which are dependent on hydrogen sulfide (H2S/HS−). In addition to their roles in biosynthetic processes, persulfides are possible transducers of physiological effects of H2S through the modification of critical cysteines. Persulfides have a very rich biological chemistry that is currently under investigation. They are more nucleophilic and acidic than thiols and, unlike thiols, they can also be electrophilic. They are especially good one-electron reductants. Methods to detect their formation are under continuous development. In this minireview we describe the pathways of formation of persulfides, their biochemical properties and the techniques available for their detection, and we discuss the possible implications of their formation in biological systems.
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20
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Solomon EI, Iyer SR. Geometric and Electronic Structural Contributions to Fe/O 2 Reactivity. ACTA ACUST UNITED AC 2019; 73:3-14. [PMID: 32391114 DOI: 10.4019/bjscc.73.3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
While two classes of non-heme iron enzymes use ferric centers to activate singlet organic substrates for the spin forbidden reaction with 3O2, most classes use high spin ferrous sites to activate dioxygen. These FeII active sites do not exhibit intense absorption bands and have an integer spin ground state thus are mostly EPR inactive. We have developed new spectroscopic methodologies that provide geometric and electronic structural insight into the ferrous centers and their interactions with cosubstrates for dioxygen activation and into the nature of the intermediates generated in these reactions. First, we present our variable-temperature variable-field magnetic circular dichroism (VTVH MCD) methodology to experimentally define the geometric and electronic structure of the high spin ferrous active site. Then, we focus on using Nuclear Resonance Vibrational Spectroscopy (NRVS, performed at SPring-8) to define geometric structure and VTVH MCD to define the electronic structure of the FeIII-OOH and FeIV=O intermediates generated in O2 activation and the spin state dependence of their frontier molecular orbitals (FMOs) in controlling reactivity. Experimentally validated reaction coordinates are derived for the anticancer drug bleomycin in its cleavage of DNA and for an alpha- ketoglutarate dependent dioxygenase in its selective halogenation over the thermodynamically favored hydroxylation of substrate.
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21
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Gordon JB, Vilbert AC, Siegler MA, Lancaster KM, Moënne-Loccoz P, Goldberg DP. A Nonheme Thiolate-Ligated Cobalt Superoxo Complex: Synthesis and Spectroscopic Characterization, Computational Studies, and Hydrogen Atom Abstraction Reactivity. J Am Chem Soc 2019; 141:3641-3653. [PMID: 30776222 DOI: 10.1021/jacs.8b13134] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The synthesis and characterization of a Co(II) dithiolato complex Co(Me3TACN)(S2SiMe2) (1) are reported. Reaction of 1 with O2 generates a rare thiolate-ligated cobalt-superoxo species Co(O2)(Me3TACN)(S2SiMe2) (2) that was characterized spectroscopically and structurally by resonance Raman, EPR, and X-ray absorption spectroscopies as well as density functional theory. Metal-superoxo species are proposed to S-oxygenate metal-bound thiolate donors in nonheme thiol dioxygenases, but 2 does not lead to S-oxygenation of the intramolecular thiolate donors and does not react with exogenous sulfur donors. However, complex 2 is capable of oxidizing the O-H bonds of 2,2,6,6-tetramethylpiperidin-1-ol derivatives via H atom abstraction. Complementary proton-coupled electron-transfer reactivity is seen for 2 with separated proton/reductant pairs. The reactivity studies indicate that 2 can abstract H atoms from weak X-H bonds with bond dissociation free energy (BDFE) ≤ 70 kcal mol-1. DFT calculations predict that the putative Co(OOH) product has an O-H BDFE = 67 kcal mol-1, which matches the observed pattern of reactivity seen for 2. These data provide new information regarding the selectivity of S-oxygenation versus H atom abstraction in thiolate-ligated nonheme metalloenzymes that react with O2.
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Affiliation(s)
- Jesse B Gordon
- Department of Chemistry , The Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
| | - Avery C Vilbert
- Department of Chemistry and Chemical Biology, Baker Laboratory , Cornell University , Ithaca , New York 14853 , United States
| | - Maxime A Siegler
- Department of Chemistry , The Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
| | - Kyle M Lancaster
- Department of Chemistry and Chemical Biology, Baker Laboratory , Cornell University , Ithaca , New York 14853 , United States
| | - Pierre Moënne-Loccoz
- Department of Biochemistry & Molecular Biology , Oregon Health & Science University , Portland , Oregon 97239-3098 , United States
| | - David P Goldberg
- Department of Chemistry , The Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
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