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Zhang X, Liu Y. Computational Insights into the Catalysis of the pH Dependence of Bromite Decomposition Catalyzed by Chlorite Dismutase from Dechloromonas aromatica ( DaCld). Inorg Chem 2024; 63:6776-6786. [PMID: 38572830 DOI: 10.1021/acs.inorgchem.4c00126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
The heme-containing chlorite dismutases catalyze the rapid and efficient decomposition of chlorite (ClO2-) to yield Cl- and O2, and the catalytic efficiency of chlorite dismutase from Dechloromonas aromatica (DaCld) in catalyzing the decomposition of bromite (BrO2-) was dependent on pH, which was supposed to be caused by the conversion of active Cpd I to the inactive Cpd II by proton-coupled electron transfer (PCET) from the pocket Tyr118 to the propionate side chain of heme at high pH. However, the direct evidence of PCET and how the pH affects the efficiency of DaCld, as well as whether Cpd II is really inactive, are still poorly understood. Here, on the basis of the high-resolution crystal structures, the computational models in both acidic (pH 5.0) and alkaline (pH 9.0) environments were constructed, and a series of quantum mechanical/molecular mechanical calculations were performed. On the basis of our calculation results, the O-Br bond cleavage of BrO2- always follows the homolytic mode to generate Cpd II rather than Cpd I. It is different from the O-O cleavage of O2/H2O2 or peracetic acid catalyzed by the other heme-containing enzymes. Thus, in the subsequent O-O rebound reaction, it is the Fe(IV)═O in Cpd II that combines with the O-Br radical. Because the porphyrin ring in Cpd II does not bear an unpaired electron, the previously suggested PCET from Tyr118 to the propionate side chain of heme was not theoretically recognized in an alkaline environment. In addition, the O-O rebound step in an alkaline solution corresponds to an energy barrier that is larger than that in an acidic environment, which can well explain the pH dependence of the activity of DaCld. In addition, the protonation state of the propionic acid side chains of heme and the surrounding hydrogen bond networks were calculated to have a significant impact on the barriers of the O-O rebound step, which is mainly achieved by affecting the reactivity of the Fe(IV)═O group in Cpd II. In an acidic environment, the relatively weaker coordination of the O2 atom to Fe leads to its higher reactivity toward the O-O rebound reaction. These observations may provide useful information for understanding the catalysis of chlorite dismutases.
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Affiliation(s)
- Xianghui Zhang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
| | - Yongjun Liu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
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2
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González-Delgado JM, Thompson PM, Andrałojć W, Gdaniec Z, Ghiladi RA, Franzen S. Comparison of the Backbone Dynamics of Dehaloperoxidase-Hemoglobin Isoenzymes. J Phys Chem B 2024; 128:3383-3397. [PMID: 38563384 DOI: 10.1021/acs.jpcb.3c07176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Dehaloperoxidase (DHP) is a multifunctional hemeprotein with a functional switch generally regulated by the chemical class of the substrate. Its two isoforms, DHP-A and DHP-B, differ by only five amino acids and have an almost identical protein fold. However, the catalytic efficiency of DHP-B for oxidation by a peroxidase mechanism ranges from 2- to 6-fold greater than that of DHP-A depending on the conditions. X-ray crystallography has shown that many substrates and ligands have nearly identical binding in the two isoenzymes, suggesting that the difference in catalytic efficiency could be due to differences in the conformational dynamics. We compared the backbone dynamics of the DHP isoenzymes at pH 7 through heteronuclear relaxation dynamics at 11.75, 16.45, and 19.97 T in combination with four 300 ns MD simulations. While the overall dynamics of the isoenzymes are similar, there are specific local differences in functional regions of each protein. In DHP-A, Phe35 undergoes a slow chemical exchange between two conformational states likely coupled to a swinging motion of Tyr34. Moreover, Asn37 undergoes fast chemical exchange in DHP-A. Given that Phe35 and Asn37 are adjacent to Tyr34 and Tyr38, it is possible that their dynamics modulate the formation and migration of the active tyrosyl radicals in DHP-A at pH 7. Another significant difference is that both distal and proximal histidines have a 15-18% smaller S2 value in DHP-B, thus their greater flexibility could account for the higher catalytic activity. The distal histidine grants substrate access to the distal pocket. The greater flexibility of the proximal histidine could also accelerate H2O2 activation at the heme Fe by increased coupling of an amino acid charge relay to stabilize the ferryl Fe(IV) oxidation state in a Poulos-Kraut "push-pull"-type peroxidase mechanism.
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Affiliation(s)
| | - Peter M Thompson
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
- Molecular Education, Technology and Research Innovation Center (METRIC), North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Witold Andrałojć
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Zofia Gdaniec
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Reza A Ghiladi
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
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3
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Zhang X, Liu Y. Direct Electrophilic Attack of Compound I on the Indole Ring in the Peroxygenase Mechanism of Dehaloperoxidase DHP B in Degrading Haloindole: Electron Transfer Promotes the Reaction. Inorg Chem 2023; 62:13230-13240. [PMID: 37561650 DOI: 10.1021/acs.inorgchem.3c01425] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
The H2O2-dependent degradation of haloindole catalyzed by the dehaloperoxidase (DHP) from Amphitrite ornate has been reported to employ the peroxygenase mechanism, and the two oxidized products 5-halo-2-oxindole and 5-halo-3-oxindole have a similar amount. According to a previous experimental study, compound I (Cpd I) was suggested to be responsible for triggering the reaction, and the reaction may undergo three possible intermediates; however, the reaction details are still unclear. To clarify the reaction mechanism of DHP, the computational model was constructed on the basis of the high-resolution crystal structure, and a series of the quantum mechanical/molecular mechanical calculations were performed. Based on our calculation results, it is confirmed that the reaction starts from the direct electrophilic attack of Cpd I on the indole ring of the substrate, and the resulted intermediate contains both a carbocation and an oxygen anion, whereas the common hydrogen abstraction by Cpd I was calculated to correspond to a relatively higher barrier. In addition, a net electron transfer from the substrate to the iron center is observed during the attack of Cpd I on the indole ring; therefore, the carbocation/oxygen anion intermediate can easily undergo an intramolecular hydride transfer to form the product 5-halo-2-oxindole or isomerize to the epoxide intermediate which finally generates another product 5-halo-3-oxindole. It is the zwitterionic characteristic of the intermediate that makes the intermolecular hydride transfer quite easy, and it is the high electron affinity of the iron center that promotes the single-electron oxidation of the reaction intermediate. Our calculations well explain the formation of two oxidized products 5-halo-2-oxindole and 5-halo-3-oxindole.
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Affiliation(s)
- Xianghui Zhang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
| | - Yongjun Liu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
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4
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Yun D, de Serrano V, Ghiladi RA. Oxidation of bisphenol A (BPA) and related compounds by the multifunctional catalytic globin dehaloperoxidase. J Inorg Biochem 2023; 238:112020. [PMID: 36272837 DOI: 10.1016/j.jinorgbio.2022.112020] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/30/2022] [Accepted: 09/30/2022] [Indexed: 11/06/2022]
Abstract
Dehaloperoxidase (DHP) from the marine polychaete Amphitrite ornata is a multifunctional enzyme that possesses peroxidase, peroxygenase, oxidase and oxygenase activities. Herein, we investigated the reactivity of DHP B with bisphenol A (BPA) and related compounds (bisphenol E, bisphenol F, tetrachlorobisphenol A, 2,2'-biphenol, 3,3'-biphenol, 4,4'-biphenol, and 3,3'-dibromo-4,4'-biphenol). As a previously unknown substrate for DHP B, BPA (as a representative substrate) is an endocrine disruptor widely used in polycarbonate and epoxy resins, thus resulting in human exposure. Reactivity studies with these substrates were investigated using high performance liquid chromatography (HPLC), and their corresponding oxidation products were determined by mass spectrometry (GC-MS/ LC-MS). BPA undergoes oxidation in the presence of DHP B and hydrogen peroxide yielding two cleavage products (4-isopropenylphenol and 4-(2-hydroxypropan-2-yl)phenol), and oligomers with varying degrees of oxidation. 18O-labeling studies confirmed that the O-atom incorporated into the products was derived exclusively from water, consistent with substrate oxidation via a peroxidase-based mechanism. The X-ray crystal structures of DHP bound with bisphenol E (1.48 Å), bisphenol F (1.75 Å), 2,2'-biphenol (1.90 Å) and 3,3'-biphenol (1.30 Å) showed substrate binding sites are in the distal pocket of the heme cofactor, similar to other previously studied DHP substrates. Stopped-flow UV-visible spectroscopy was utilized to investigate the mechanistic details and enzyme oxidation states during substrate turnover, and a reaction mechanism is proposed. The data presented here strongly suggest that DHP B can catalyze the oxidation of bisphenols and biphenols, thus providing evidence of how infaunal invertebrates can contribute to the biotransformation of these marine pollutants.
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Affiliation(s)
- Dongju Yun
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, United States
| | - Vesna de Serrano
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, United States
| | - Reza A Ghiladi
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, United States.
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Malewschik T, Carey LM, de Serrano V, Ghiladi RA. Bridging the functional gap between reactivity and inhibition in dehaloperoxidase B from Amphitrite ornata: Mechanistic and structural studies with 2,4- and 2,6-dihalophenols. J Inorg Biochem 2022; 236:111944. [PMID: 35969974 DOI: 10.1016/j.jinorgbio.2022.111944] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 06/29/2022] [Accepted: 07/20/2022] [Indexed: 12/15/2022]
Abstract
The multifunctional catalytic globin dehaloperoxidase (DHP) from the marine worm Amphitrite ornata was shown to catalyze the H2O2-dependent oxidation of 2,4- and 2,6-dihalophenols (DXP; X = F, Cl, Br). Product identification by LC-MS revealed multiple monomeric products with varying degrees of oxidation and/or dehalogenation, as well as oligomers with n up to 6. Mechanistic and 18O-labeling studies demonstrated sequential dihalophenol oxidation via peroxidase and peroxygenase activities. Binding studies established that 2,4-DXP (X = Cl, Br) have the highest affinities of any known DHP substrate. X-ray crystallography identified different binding positions for 2,4- and 2,6-DXP substrates in the hydrophobic distal pocket of DHP. Correlation between the number of halogens and the substrate binding orientation revealed a halogen-dependent binding motif for mono- (4-halophenol), di- (2,4- and 2,6-dihalophenol) and trihalophenols (2,4,6-trihalopenol). Taken together, the findings here on dihalophenol reactivity with DHP advance our understanding of how these compounds bridge the inhibitory and oxidative functions of their mono- and trihalophenol counterparts, respectively, and provide further insight into the protein structure-function paradigm relevant to multifunctional catalytic globins in comparison to their monofunctional analogs.
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Affiliation(s)
- Talita Malewschik
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, United States
| | - Leiah M Carey
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, United States
| | - Vesna de Serrano
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, United States
| | - Reza A Ghiladi
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, United States.
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6
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Popescu C, Dinh T, Chen H, Miller D, Washburn A, McGuire A, Dumarieh R, D'Antonio J, Ghiladi RA. Mössbauer studies of the ferryl, ferrous and ferric states of dehaloperoxidase from A. ornata. J Inorg Biochem 2022; 234:111867. [DOI: 10.1016/j.jinorgbio.2022.111867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 04/13/2022] [Accepted: 05/17/2022] [Indexed: 10/18/2022]
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8
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Hu P, Sun Z, Shen Y, Pan Y. A Long-Term Stable Sensor Based on Fe@PCN-224 for Rapid and Quantitative Detection of H 2O 2 in Fishery Products. Foods 2021; 10:419. [PMID: 33672942 PMCID: PMC7918592 DOI: 10.3390/foods10020419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 02/10/2021] [Accepted: 02/10/2021] [Indexed: 11/16/2022] Open
Abstract
Hydrogen peroxide (H2O2) has been reported to be used for the illegal treatment of fishery products in order to obtain "fake" freshness. Residues of H2O2 in food may be of toxicology concern. In this study, a nonenzymatic sensor was developed based on Fe@PCN-224 metal-organic frameworks wrapped by Nafion to detect H2O2 concentration. The hybrid structure of Fe@PCN-224 was fabricated by incorporated free FeIII ions into the center of PCN-224, which was ultra-stable due to the strong interactions between Zr6 and the carboxyl group. Scanning electron spectroscopy images exhibited that Nafion sheets crossed together on the surface of Fe@PCN-224 nanoparticles to form a hierarchical and coherent structure for efficient electron transfer. Electrochemical investigations showed that the Fe@PCN-224/Nafion/GCE possessed good linearity from 2 to 13,000 μM (including four orders of magnitude), low detection limits (0.7 μM), high stability in continuous monitoring (current remained nearly stable over 2300 s) and in long-term measurement (current decreased 3.4% for 30 days). The prepared nanohybrid modified electrode was effectively applied to H2O2 detection in three different fishery products. The results were comparable to those measured using photometrical methods. The developed electrochemical method has a great potential in detecting the illegal management of fishery products with H2O2.
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Affiliation(s)
| | | | | | - Yiwen Pan
- Ocean College, Zhejiang University, Zhoushan 316021, China; (P.H.); (Z.S.); (Y.S.)
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9
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Malewschik T, de Serrano V, McGuire AH, Ghiladi RA. The multifunctional globin dehaloperoxidase strikes again: Simultaneous peroxidase and peroxygenase mechanisms in the oxidation of EPA pollutants. Arch Biochem Biophys 2019; 673:108079. [PMID: 31445024 DOI: 10.1016/j.abb.2019.108079] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 08/19/2019] [Accepted: 08/20/2019] [Indexed: 01/25/2023]
Abstract
The multifunctional catalytic hemoglobin dehaloperoxidase (DHP) from the terebellid polychaete Amphitrite ornata was found to catalyze the H2O2-dependent oxidation of EPA Priority Pollutants (4-Me-o-cresol, 4-Cl-m-cresol and pentachlorophenol) and EPA Toxic Substances Control Act compounds (o-, m-, p-cresol and 4-Cl-o-cresol). Biochemical assays (HPLC/LC-MS) indicated formation of multiple oxidation products, including the corresponding catechol, 2-methylbenzoquinone (2-MeBq), and oligomers with varying degrees of oxidation and/or dehalogenation. Using 4-Br-o-cresol as a representative substrate, labeling studies with 18O confirmed that the O-atom incorporated into the catechol was derived exclusively from H2O2, whereas the O-atom incorporated into 2-MeBq was from H2O, consistent with this single substrate being oxidized by both peroxygenase and peroxidase mechanisms, respectively. Stopped-flow UV-visible spectroscopic studies strongly implicate a role for Compound I in the peroxygenase mechanism leading to catechol formation, and for Compounds I and ES in the peroxidase mechanism that yields the 2-MeBq product. The X-ray crystal structures of DHP bound with 4-F-o-cresol (1.42 Å; PDB 6ONG), 4-Cl-o-cresol (1.50 Å; PDB 6ONK), 4-Br-o-cresol (1.70 Å; PDB 6ONX), 4-NO2-o-cresol (1.80 Å; PDB 6ONZ), o-cresol (1.60 Å; PDB 6OO1), p-cresol (2.10 Å; PDB 6OO6), 4-Me-o-cresol (1.35 Å; PDB 6ONR) and pentachlorophenol (1.80 Å; PDB 6OO8) revealed substrate binding sites in the distal pocket in close proximity to the heme cofactor, consistent with both oxidation mechanisms. The findings establish cresols as a new class of substrate for DHP, demonstrate that multiple oxidation mechanisms may exist for a given substrate, and provide further evidence that different substituents can serve as functional switches between the different activities performed by dehaloperoxidase. More broadly, the results demonstrate the complexities of marine pollution where both microbial and non-microbial systems may play significant roles in the biotransformations of EPA-classified pollutants, and further reinforces that heterocyclic compounds of anthropogenic origin should be considered as environmental stressors of infaunal organisms.
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Affiliation(s)
- Talita Malewschik
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695-8204, USA
| | - Vesna de Serrano
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695-8204, USA
| | - Ashlyn H McGuire
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695-8204, USA
| | - Reza A Ghiladi
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695-8204, USA.
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McGuire AH, Carey LM, de Serrano V, Dali S, Ghiladi RA. Peroxidase versus Peroxygenase Activity: Substrate Substituent Effects as Modulators of Enzyme Function in the Multifunctional Catalytic Globin Dehaloperoxidase. Biochemistry 2018; 57:4455-4468. [DOI: 10.1021/acs.biochem.8b00540] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Ashlyn H. McGuire
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Leiah M. Carey
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Vesna de Serrano
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Safaa Dali
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Reza A. Ghiladi
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
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Carey LM, Gavenko R, Svistunenko DA, Ghiladi RA. How nature tunes isoenzyme activity in the multifunctional catalytic globin dehaloperoxidase from Amphitrite ornata. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:230-241. [DOI: 10.1016/j.bbapap.2017.11.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 11/05/2017] [Accepted: 11/07/2017] [Indexed: 01/29/2023]
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12
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Selective tuning of activity in a multifunctional enzyme as revealed in the F21W mutant of dehaloperoxidase B from Amphitrite ornata. J Biol Inorg Chem 2017; 23:209-219. [DOI: 10.1007/s00775-017-1520-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 11/17/2017] [Indexed: 11/25/2022]
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13
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McCombs NL, D’Antonio J, Barrios DA, Carey LM, Ghiladi RA. Nonmicrobial Nitrophenol Degradation via Peroxygenase Activity of Dehaloperoxidase-Hemoglobin from Amphitrite ornata. Biochemistry 2016; 55:2465-78. [DOI: 10.1021/acs.biochem.6b00143] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nikolette L. McCombs
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, 27695-8204
| | - Jennifer D’Antonio
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, 27695-8204
| | - David A. Barrios
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, 27695-8204
| | - Leiah M. Carey
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, 27695-8204
| | - Reza A. Ghiladi
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, 27695-8204
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Davydov R, Im S, Shanmugam M, Gunderson WA, Pearl NM, Hoffman BM, Waskell L. Role of the Proximal Cysteine Hydrogen Bonding Interaction in Cytochrome P450 2B4 Studied by Cryoreduction, Electron Paramagnetic Resonance, and Electron-Nuclear Double Resonance Spectroscopy. Biochemistry 2016; 55:869-83. [PMID: 26750753 DOI: 10.1021/acs.biochem.5b00744] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Crystallographic studies have shown that the F429H mutation of cytochrome P450 2B4 introduces an H-bond between His429 and the proximal thiolate ligand, Cys436, without altering the protein fold but sharply decreases the enzymatic activity and stabilizes the oxyferrous P450 2B4 complex. To characterize the influence of this hydrogen bond on the states of the catalytic cycle, we have used radiolytic cryoreduction combined with electron paramagnetic resonance (EPR) and (electron-nuclear double resonance (ENDOR) spectroscopy to study and compare their characteristics for wild-type (WT) P450 2B4 and the F429H mutant. (i) The addition of an H-bond to the axial Cys436 thiolate significantly changes the EPR signals of both low-spin and high-spin heme-iron(III) and the hyperfine couplings of the heme-pyrrole (14)N but has relatively little effect on the (1)H ENDOR spectra of the water ligand in the six-coordinate low-spin ferriheme state. These changes indicate that the H-bond introduced between His and the proximal cysteine decreases the extent of S → Fe electron donation and weakens the Fe(III)-S bond. (ii) The added H-bond changes the primary product of cryoreduction of the Fe(II) enzyme, which is trapped in the conformation of the parent Fe(II) state. In the wild-type enzyme, the added electron localizes on the porphyrin, generating an S = (3)/2 state with the anion radical exchange-coupled to the Fe(II). In the mutant, it localizes on the iron, generating an S = (1)/2 Fe(I) state. (iii) The additional H-bond has little effect on g values and (1)H-(14)N hyperfine couplings of the cryogenerated, ferric hydroperoxo intermediate but noticeably slows its decay during cryoannealing. (iv) In both the WT and the mutant enzyme, this decay shows a significant solvent kinetic isotope effect, indicating that the decay reflects a proton-assisted conversion to Compound I (Cpd I). (v) We confirm that Cpd I formed during the annealing of the cryogenerated hydroperoxy intermediate and that it is the active hydroxylating species in both WT P450 2B4 and the F429H mutant. (vi) Our data also indicate that the added H-bond of the mutation diminishes the reactivity of Cpd I.
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Affiliation(s)
- Roman Davydov
- Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Sangchoul Im
- Department of Anesthesiology, University of Michigan, and VA Medical Center , 2215 Fuller Road, Ann Arbor, Michigan 48105, United States
| | - Muralidharan Shanmugam
- Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - William A Gunderson
- Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Naw May Pearl
- Department of Anesthesiology, University of Michigan, and VA Medical Center , 2215 Fuller Road, Ann Arbor, Michigan 48105, United States
| | - Brian M Hoffman
- Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Lucy Waskell
- Department of Anesthesiology, University of Michigan, and VA Medical Center , 2215 Fuller Road, Ann Arbor, Michigan 48105, United States
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Davydov R, Fleischhacker AS, Bagai I, Hoffman BM, Ragsdale SW. Comparison of the Mechanisms of Heme Hydroxylation by Heme Oxygenases-1 and -2: Kinetic and Cryoreduction Studies. Biochemistry 2015; 55:62-8. [PMID: 26652036 DOI: 10.1021/acs.biochem.5b00943] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The two isoforms of human heme oxygenase (HO1 and HO2) catalyze oxidative degradation of heme to biliverdin, Fe, and CO. Unlike HO1, HO2 contains two C-terminal heme regulatory motifs (HRMs) centered at Cys265 and Cys282 that act as redox switches and, in their reduced dithiolate state, bind heme (Fleischhacker et al., Biochemistry , 2015 , 54 , 2693 - 2708 ). Here, we describe cryoreduction/annealing and electron paramagnetic resonance spectroscopic experiments to study the structural features of the oxyheme moiety in HO2 and to elucidate the initial steps in heme degradation. We conclude that the same mechanism of heme hydroxylation to α-meso-hydroxyheme is employed by both isoforms and that the HRMs do not affect the physicochemical properties of the oxy-Fe(II) and HOO-Fe(III) states of HO2. However, the absorption spectrum of oxy-Fe(II)-HO2 is slightly blue-shifted relative to that of HO1. Furthermore, heme hydroxylation proceeds three times more slowly, and the oxy-Fe(II) state is 100-fold less stable in HO2 than in HO1. These distinctions are attributed to slight structural variances in the two proteins, including differences in equilibrium between open versus closed conformations. Kinetic studies revealed that heme oxygenation by HO2 occurs solely at the catalytic core in that a variant of HO2 lacking the C-terminal HRM domain exhibits the same specific activity as one containing both the catalytic core and HRM domain; furthermore, a truncated variant containing only the HRM region binds but cannot oxidize heme. In summary, HO1 and HO2 share similar catalytic mechanisms, and the HRMs do not play a direct role in the HO2 catalytic cycle.
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Affiliation(s)
- Roman Davydov
- Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Angela S Fleischhacker
- Department of Biological Chemistry, University of Michigan Medical School , Ann Arbor, Michigan 48109, United States
| | - Ireena Bagai
- Department of Biological Chemistry, University of Michigan Medical School , Ann Arbor, Michigan 48109, United States
| | - Brian M Hoffman
- Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Stephen W Ragsdale
- Department of Biological Chemistry, University of Michigan Medical School , Ann Arbor, Michigan 48109, United States
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Davydov R, Strushkevich N, Smil D, Yantsevich A, Gilep A, Usanov S, Hoffman BM. Evidence That Compound I Is the Active Species in Both the Hydroxylase and Lyase Steps by Which P450scc Converts Cholesterol to Pregnenolone: EPR/ENDOR/Cryoreduction/Annealing Studies. Biochemistry 2015; 54:7089-97. [PMID: 26603348 DOI: 10.1021/acs.biochem.5b00903] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cytochrome P450scc (CYP 11A1) catalyzes the conversion of cholesterol (Ch) to pregnenolone, the precursor to steroid hormones. This process proceeds via three sequential monooxygenation reactions: two hydroxylations of Ch first form 22(R)-hydroxycholesterol (HC) and then 20α,22(R)-dihydroxycholesterol (DHC); a lyase reaction then cleaves the C20-C22 bond to form pregnenolone. Recent cryoreduction/annealing studies that employed electron paramagnetic resonance (EPR)/electron nuclear double resonance (ENDOR) spectroscopy [Davydov, R., et al. (2012) J. Am. Chem. Soc. 134, 17149] showed that compound I (Cpd I) is the active intermediate in the first step, hydroxylation of Ch. Herein, we have employed EPR and ENDOR spectroscopy to characterize the intermediates in the second and third steps of the enzymatic process, as conducted by 77 K radiolytic one-electron cryoreduction and subsequent annealing of the ternary oxy-cytochrome P450scc complexes with HC and DHC. This procedure is validated by showing that the cryoreduced ternary complexes of oxy-cytochrome P450scc with HC and DHC are catalytically competent and during annealing generate DHC and pregnenolone, respectively. Cryoreduction of the oxy-P450scc-HC ternary complex trapped at 77K produces the superoxo-ferrous P450scc intermediate along with a minor fraction of ferric hydroperoxo intermediates. The superoxo-ferrous intermediate converts into a ferric-hydroperoxo species after annealing at 145 K. During subsequent annealing at 170-180 K, the ferric-hydroperoxo intermediate converts to the primary product complex with the large solvent kinetic isotope effect that indicates Cpd I is being formed, and (1)H ENDOR measurements of the primary product formed in D2O demonstrate that Cpd I is the active species. They show that the primary product contains Fe(III) coordinated to the 20-O(1)H of DHC with the (1)H derived from substrate, the signature of the Cpd I reaction. Hydroperoxo ferric intermediates are the primary species formed during cryoreduction of the oxy-P450scc-DHC ternary complex, and they decay at 185 K with a strong solvent kinetic isotope effect to form low-spin ferric P450scc. Together, these observations indicated that Cpd I also is the active intermediate in the C20,22 lyase final step. In combination with our previous results, this study thus indicates that Cpd I is the active species in each of the three sequential monooxygenation reactions by which P450scc catalytically converts Ch to pregnenolone.
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Affiliation(s)
- Roman Davydov
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Natallia Strushkevich
- Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus , Kuprevicha Street 5/2, Minsk 220141, Belarus
| | - David Smil
- Structural Genomics Consortium, University of Toronto , 101 College Street, Toronto, ON, Canada M5G 1L7
| | - Aliaksei Yantsevich
- Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus , Kuprevicha Street 5/2, Minsk 220141, Belarus
| | - Andrey Gilep
- Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus , Kuprevicha Street 5/2, Minsk 220141, Belarus
| | - Sergey Usanov
- Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus , Kuprevicha Street 5/2, Minsk 220141, Belarus
| | - Brian M Hoffman
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208-3113, United States
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17
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Zhao J, Lu C, Franzen S. Distinct Enzyme–Substrate Interactions Revealed by Two Dimensional Kinetic Comparison between Dehaloperoxidase-Hemoglobin and Horseradish Peroxidase. J Phys Chem B 2015; 119:12828-37. [DOI: 10.1021/acs.jpcb.5b07126] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jing Zhao
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Chang Lu
- Department
of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Stefan Franzen
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
- Department
of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China
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18
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Mak PJ, Thammawichai W, Wiedenhoeft D, Kincaid JR. Resonance Raman Spectroscopy Reveals pH-Dependent Active Site Structural Changes of Lactoperoxidase Compound 0 and Its Ferryl Heme O–O Bond Cleavage Products. J Am Chem Soc 2014; 137:349-61. [DOI: 10.1021/ja5107833] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Piotr J. Mak
- Department
of Chemistry, Marquette University, Milwaukee, Wisconsin 53233, United States
| | - Warut Thammawichai
- Department
of Chemistry, Marquette University, Milwaukee, Wisconsin 53233, United States
| | - Dennis Wiedenhoeft
- Department
of Chemistry, Marquette University, Milwaukee, Wisconsin 53233, United States
| | - James R. Kincaid
- Department
of Chemistry, Marquette University, Milwaukee, Wisconsin 53233, United States
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19
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Le P, Zhao J, Franzen S. Correlation of Heme Binding Affinity and Enzyme Kinetics of Dehaloperoxidase. Biochemistry 2014; 53:6863-77. [DOI: 10.1021/bi5005975] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Peter Le
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Jing Zhao
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
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20
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Sun S, Sono M, Du J, Dawson JH. Evidence of the Direct Involvement of the Substrate TCP Radical in Functional Switching from Oxyferrous O2 Carrier to Ferric Peroxidase in the Dual-Function Hemoglobin/Dehaloperoxidase from Amphitrite ornata. Biochemistry 2014; 53:4956-69. [DOI: 10.1021/bi5002757] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shengfang Sun
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Masanori Sono
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Jing Du
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - John H. Dawson
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
- School
of Medicine, University of South Carolina, Columbia, South Carolina 29208, United States
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21
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Davydov R, Laryukhin M, Ledbetter-Rogers A, Sono M, Dawson JH, Hoffman BM. Electron paramagnetic resonance and electron-nuclear double resonance studies of the reactions of cryogenerated hydroperoxoferric-hemoprotein intermediates. Biochemistry 2014; 53:4894-903. [PMID: 25046203 PMCID: PMC4144713 DOI: 10.1021/bi500296d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
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The fleeting ferric peroxo and hydroperoxo
intermediates of dioxygen
activation by hemoproteins can be readily trapped and characterized
during cryoradiolytic reduction of ferrous hemoprotein–O2 complexes at 77 K. Previous cryoannealing studies suggested
that the relaxation of cryogenerated hydroperoxoferric intermediates
of myoglobin (Mb), hemoglobin, and horseradish peroxidase (HRP), either
trapped directly at 77 K or generated by cryoannealing of a trapped
peroxo-ferric state, proceeds through dissociation of bound H2O2 and formation of the ferric heme without formation
of the ferryl porphyrin π-cation radical intermediate, compound
I (Cpd I). Herein we have reinvestigated the mechanism of decays of
the cryogenerated hydroperoxyferric intermediates of α- and
β-chains of human hemoglobin, HRP, and chloroperoxidase (CPO).
The latter two proteins are well-known to form spectroscopically detectable
quasistable Cpds I. Peroxoferric intermediates are trapped during
77 K cryoreduction of oxy Mb, α-chains, and β-chains of
human hemoglobin and CPO. They convert into hydroperoxoferric intermediates
during annealing at temperatures above 160 K. The hydroperoxoferric
intermediate of HRP is trapped directly at 77 K. All studied hydroperoxoferric
intermediates decay with measurable rates at temperatures above 170
K with appreciable solvent kinetic isotope effects. The hydroperoxoferric
intermediate of β-chains converts to the S =
3/2 Cpd I, which in turn decays to an electron paramagnetic resonance
(EPR)-silent product at temperature above 220 K. For all the other
hemoproteins studied, cryoannealing of the hydroperoxo intermediate
directly yields an EPR-silent majority product. In each case, a second
follow-up 77 K γ-irradiation of the annealed samples yields
low-spin EPR signals characteristic of cryoreduced ferrylheme (compound
II, Cpd II). This indicates that in general the hydroperoxoferric
intermediates relax to Cpd I during cryoanealing at low temperatures,
but when this state is not captured by reaction with a bound substrate,
it is reduced to Cpd II by redox-active products of radiolysis.
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Affiliation(s)
- Roman Davydov
- Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
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22
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Barrios DA, D'Antonio J, McCombs NL, Zhao J, Franzen S, Schmidt AC, Sombers LA, Ghiladi RA. Peroxygenase and oxidase activities of dehaloperoxidase-hemoglobin from Amphitrite ornata. J Am Chem Soc 2014; 136:7914-25. [PMID: 24791647 PMCID: PMC4063182 DOI: 10.1021/ja500293c] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
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The marine globin dehaloperoxidase-hemoglobin
(DHP) from Amphitrite ornata was found to catalyze
the H2O2-dependent oxidation of monohaloindoles,
a previously
unknown class of substrate for DHP. Using 5-Br-indole as a representative
substrate, the major monooxygenated products were found to be 5-Br-2-oxindole
and 5-Br-3-oxindolenine. Isotope labeling studies confirmed that the
oxygen atom incorporated was derived exclusively from H2O2, indicative of a previously unreported peroxygenase
activity for DHP. Peroxygenase activity could be initiated from either
the ferric or oxyferrous states with equivalent substrate conversion
and product distribution. It was found that 5-Br-3-oxindole, a precursor
of the product 5-Br-3-oxindolenine, readily reduced the ferric enzyme
to the oxyferrous state, demonstrating an unusual product-driven reduction
of the enzyme. As such, DHP returns to the globin-active oxyferrous
form after peroxygenase activity ceases. Reactivity with 5-Br-3-oxindole
in the absence of H2O2 also yielded 5,5′-Br2-indigo above the expected reaction stoichiometry under aerobic
conditions, and O2-concentration studies demonstrated dioxygen
consumption. Nonenzymatic and anaerobic controls both confirmed the
requirements for DHP and molecular oxygen in the catalytic generation
of 5,5′-Br2-indigo, and together suggest a newly
identified oxidase activity for DHP.
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Affiliation(s)
- David A Barrios
- Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States
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23
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Zhao J, Zhao J, Franzen S. The Regulatory Implications of Hydroquinone for the Multifunctional Enzyme Dehaloperoxidase-Hemoglobin from Amphitrite ornata. J Phys Chem B 2013; 117:14615-24. [DOI: 10.1021/jp407663n] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Jing Zhao
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Junjie Zhao
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
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24
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Dumarieh R, D'Antonio J, Deliz-Liang A, Smirnova T, Svistunenko DA, Ghiladi RA. Tyrosyl radicals in dehaloperoxidase: how nature deals with evolving an oxygen-binding globin to a biologically relevant peroxidase. J Biol Chem 2013; 288:33470-82. [PMID: 24100039 DOI: 10.1074/jbc.m113.496497] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dehaloperoxidase (DHP) from Amphitrite ornata, having been shown to catalyze the hydrogen peroxide-dependent oxidation of trihalophenols to dihaloquinones, is the first oxygen binding globin that possesses a biologically relevant peroxidase activity. The catalytically competent species in DHP appears to be Compound ES, a reactive intermediate that contains both a ferryl heme and a tyrosyl radical. By simulating the EPR spectra of DHP activated by H2O2, Thompson et al. (Thompson, M. K., Franzen, S., Ghiladi, R. A., Reeder, B. J., and Svistunenko, D. A. (2010) J. Am. Chem. Soc. 132, 17501-17510) proposed that two different radicals, depending on the pH, are formed, one located on either Tyr-34 or Tyr-28 and the other on Tyr-38. To provide additional support for these simulation-based assignments and to deduce the role(s) that tyrosyl radicals play in DHP, stopped-flow UV-visible and rapid-freeze-quench EPR spectroscopic methods were employed to study radical formation in DHP when three tyrosine residues, Tyr-28, Tyr-34, and Tyr-38, were replaced either individually or in combination with phenylalanines. The results indicate that radicals form on all three tyrosines in DHP. Evidence for the formation of DHP Compound I in several tyrosine mutants was obtained. Variants that formed Compound I showed an increase in the catalytic rate for substrate oxidation but also an increase in heme bleaching, suggesting that the tyrosines are necessary for protecting the enzyme from oxidizing itself. This protective role of tyrosines is likely an evolutionary adaptation allowing DHP to avoid self-inflicted damage in the oxidative environment.
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Affiliation(s)
- Rania Dumarieh
- From the Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204 and
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25
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The role of T56 in controlling the flexibility of the distal histidine in dehaloperoxidase-hemoglobin from Amphitrite ornata. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:2020-9. [DOI: 10.1016/j.bbapap.2013.06.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 06/07/2013] [Accepted: 06/10/2013] [Indexed: 11/23/2022]
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26
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Zhao J, Franzen S. Kinetic Study of the Inhibition Mechanism of Dehaloperoxidase-Hemoglobin A by 4-Bromophenol. J Phys Chem B 2013; 117:8301-9. [DOI: 10.1021/jp3116353] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jing Zhao
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United
States
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United
States
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27
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Collins DP, Isaac IS, Coulter ED, Hager PW, Ballou DP, Dawson JH. Reaction of ferric Caldariomyces fumago chloroperoxidase with meta-chloroperoxybenzoic acid: sequential formation of compound I, compound II and regeneration of the ferric state using one reactant. J PORPHYR PHTHALOCYA 2013. [DOI: 10.1142/s1088424612501234] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The mechanism of the reaction between ferric Caldariomyces fumago chloroperoxidase (CCPO) and meta-chloroperoxybenzoic acid (mCPBA) has been examined. It has previously been established that an Fe(IV) -oxo porphyrin radical species known as Compound I (Cpd I) is formed by two-electron oxidation of the native ferric enzyme by a variety of oxidants including organic peracids and hydroperoxides. Cpd I can return to the ferric state either by direct oxygen insertion into an organic substrate (e.g. a P450 oxygenase-like reaction), or by two consecutive one-electron additions, the first resulting in an intermediate Fe(IV) -oxo species known as Compound II (Cpd II). There has been much debate over the role of Cpd II and the details of its structure. In the present study, both CCPO Fe(IV) -oxo intermediates are formed, but unlike most CCPO reactions, Cpd I and Cpd II are formed using the same reactant, mCPBA. Thus, the peracid is used as an oxo donor to produce Cpd I and then as a reductant to reduce Cpd I to Cpd II, and finally, Cpd II to the ferric state. The observation of saturation kinetics with respect to mCPBA concentration for each step is consistent with the formation of CCPO-mCPBA complexes in each phase of the reaction. The original reaction mechanism for ferric CCPO with mCPBA was hypothesized to involve a scrambling mechanism with a unique Fe -OOO-C(O)R intermediate formed with no observed Cpd II intermediate. The data reported herein clearly demonstrate the formation of Cpd II in returning the oxidized enzyme back to its native ferric state.
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Affiliation(s)
- Daniel P. Collins
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA
| | - Issa S. Isaac
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA
| | - Eric D. Coulter
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA
| | - Paul W. Hager
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
| | - David P. Ballou
- Department of Biological Chemistry, Medical School, University of Michigan, Ann Arbor, MI 48109, USA
| | - John H. Dawson
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA
- School of Medicine, University of South Carolina, Columbia, SC 29208, USA
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28
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Davydov R, Dawson JH, Perera R, Hoffman BM. The use of deuterated camphor as a substrate in (1)H ENDOR studies of hydroxylation by cryoreduced oxy P450cam provides new evidence of the involvement of compound I. Biochemistry 2013; 52:667-71. [PMID: 23215047 DOI: 10.1021/bi301527c] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Electron paramagnetic resonance and (1)H electron nuclear double resonance (ENDOR) spectroscopies have been used to analyze intermediate states formed during the hydroxylation of (1R)-camphor (H(2)-camphor) and (1R)-5,5-dideuterocamphor (D(2)-camphor) as induced by cryoreduction (77 K) and annealing of the ternary ferrous cytochrome P450cam-O(2)-substrate complex. Hydroxylation of H(2)-camphor produced a primary product state in which 5-exo-hydroxycamphor is coordinated with Fe(III). ENDOR spectra contained signals derived from two protons [Fe(III)-bound C5-OH(exo) and C5-H(endo)] from camphor. When D(2)-camphor was hydroxylated under the same condition in H(2)O or D(2)O buffer, both ENDOR H(exo) and H(endo) signals are absent. For D(2)-camphor in H(2)O buffer, H/D exchange causes the C5-OH(exo) signal to reappear during relaxation upon annealing to 230 K; for H(2)-camphor in D(2)O, the magnitude of the C5-OH(exo) signal decreases via H/D exchange. These observations clearly show that Compound I is the reactive species in the hydroxylation of camphor in P450cam.
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Affiliation(s)
- Roman Davydov
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
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29
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Águila S, Vidal-Limón A, Alderete J, Sosa-Torres M, Vázquez-Duhalt R. Unusual activation during peroxidase reaction of a cytochrome c variant. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.molcatb.2012.09.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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30
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Sumithran S, Sono M, Raner GM, Dawson JH. Single turnover studies of oxidative halophenol dehalogenation by horseradish peroxidase reveal a mechanism involving two consecutive one electron steps: Toward a functional halophenol bioremediation catalyst. J Inorg Biochem 2012; 117:316-21. [DOI: 10.1016/j.jinorgbio.2012.09.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 09/18/2012] [Accepted: 09/18/2012] [Indexed: 10/27/2022]
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31
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Davydov R, Gilep AA, Strushkevich NV, Usanov SA, Hoffman BM. Compound I is the reactive intermediate in the first monooxygenation step during conversion of cholesterol to pregnenolone by cytochrome P450scc: EPR/ENDOR/cryoreduction/annealing studies. J Am Chem Soc 2012; 134:17149-56. [PMID: 23039857 DOI: 10.1021/ja3067226] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cytochrome P450scc (CYP11A1) catalyzes conversion of cholesterol (CH) to pregnenolone, the precursor to all steroid hormones. This process proceeds via three sequential monooxygenation reactions: two stereospecific hydroxylations with formation first of 22R-hydroxycholesterol (22-HC) and then 20α,22R-dihydroxycholesterol (20,22-DHC), followed by C20-C22 bond cleavage. Herein we have employed EPR and ENDOR spectroscopy to characterize the intermediates in the first hydroxylation step by 77 K radiolytic one-electron cryoreduction and subsequent annealing of the ternary oxy-cytochrome P450scc-cholesterol complex. This approach is fully validated by the demonstration that the cryoreduced ternary complex of oxy-P450scc-CH is catalytically competent and hydroxylates cholesterol to form 22-HC with no detectable formation of 20-HC, just as occurs under physiological conditions. Cryoreduction of the ternary complex trapped at 77 K produces predominantly the hydroperoxy-ferriheme P450scc intermediate, along with a minor fraction of peroxo-ferriheme intermediate that converts into a new hydroperoxo-ferriheme species at 145 K. This behavior reveals that the distal pocket of the parent oxy-P450scc-cholesterol complex exhibits an efficient proton delivery network, with an ordered water molecule H-bonded to the distal oxygen of the dioxygen ligand. During annealing of the hydroperoxy-ferric P450scc intermediates at 185 K, they convert to the primary product complex in which CH has been converted to 22-HC. In this process, the hydroperoxy-ferric intermediate decays with a large solvent kinetic isotope effect, as expected when proton delivery to the terminal O leads to formation of Compound I (Cpd I). (1)H ENDOR measurements of the primary product formed in deuterated solvent show that the heme Fe(III) is coordinated to the 22R-O(1)H of 22-HC, where the (1)H is derived from substrate and exchanges to D after annealing at higher temperatures. These observations establish that Cpd I is the agent that hydroxylates CH, rather than the hydroperoxy-ferric heme.
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Affiliation(s)
- Roman Davydov
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA
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32
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Zhao J, de Serrano V, Dumarieh R, Thompson M, Ghiladi RA, Franzen S. The Role of the Distal Histidine in H2O2 Activation and Heme Protection in both Peroxidase and Globin Functions. J Phys Chem B 2012; 116:12065-77. [DOI: 10.1021/jp300014b] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Junjie Zhao
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United
States
| | - Vesna de Serrano
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United
States
| | - Rania Dumarieh
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United
States
| | - Matt Thompson
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United
States
| | - Reza A. Ghiladi
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United
States
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United
States
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33
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Bernad S, Brunel A, Dorlet P, Sicard-Roselli C, Santolini J. A novel cryo-reduction method to investigate the molecular mechanism of nitric oxide synthases. J Phys Chem B 2012; 116:5595-603. [PMID: 22530945 DOI: 10.1021/jp300749b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nitric oxide synthases (NOSs) are hemoproteins responsible for the biosynthesis of NO in mammals. They catalyze two successive oxidation reactions. The mechanism of oxygen activation is based on the transfer of two electrons and two protons. Despite structural analogies with cytochromes P450, the molecular mechanism of NOS remains yet to be elucidated. Because of extremely high reaction rates, conventional kinetics methods failed to trap and characterize the major reaction intermediates. Cryo-reduction methods offer a possibility to circumvent this technological lock, by triggering oxygen activation at cryogenic temperatures by using water radiolysis. However, this method is not adapted to the NOS mechanism because of the high instability of the initial Fe(II)O2 complex (extremely fast autoxidation and/or reaction with the cofactor H4B). This imposed a protocol with a stable Fe(II)O2 complex (observed only for one NOS-like protein) and that excludes any redox role for H4B. A relevant approach to the NOS mechanism would use H4B to provide the (second) electron involved in oxygen activation; water radiolysis would thus provide the first electron (heme reduction). In this context, we report here an investigation of the first electron transfer by this alternative approach, i.e., the reduction of native NOS by water radiolysis. We combined EPR and resonance Raman spectroscopies to analyze NOS reduction for a combination of different substrates, cofactor, and oxygen concentrations, and for different NOS isoforms. Our results show that cryo-reduction of native NOS is achieved for all conditions that are relevant to the investigation of the NOS mechanism.
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Affiliation(s)
- Sophie Bernad
- Laboratoire de Chimie Physique, CNRS UMR 8000, Univ Paris-Sud, 91405 Orsay Cedex, France
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Franzen S, Thompson MK, Ghiladi RA. The dehaloperoxidase paradox. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:578-88. [DOI: 10.1016/j.bbapap.2011.12.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2011] [Revised: 12/20/2011] [Accepted: 12/23/2011] [Indexed: 12/01/2022]
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Study of the electrostatic effects of mutations on the surface of dehaloperoxidase-hemoglobin A. Biochem Biophys Res Commun 2012; 420:733-7. [DOI: 10.1016/j.bbrc.2012.03.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 03/12/2012] [Indexed: 11/17/2022]
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D'Antonio EL, D'Antonio J, de Serrano V, Gracz H, Thompson MK, Ghiladi RA, Bowden EF, Franzen S. Functional consequences of the creation of an Asp-His-Fe triad in a 3/3 globin. Biochemistry 2011; 50:9664-80. [PMID: 21950839 DOI: 10.1021/bi201368u] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The proximal side of dehaloperoxidase-hemoglobin A (DHP A) from Amphitrite ornata has been modified via site-directed mutagenesis of methionine 86 into aspartate (M86D) to introduce an Asp-His-Fe triad charge relay. X-ray crystallographic structure determination of the metcyano forms of M86D [Protein Data Bank (PDB) entry 3MYN ] and M86E (PDB entry 3MYM ) mutants reveal the structural origins of a stable catalytic triad in DHP A. A decrease in the rate of H(2)O(2) activation as well as a lowered reduction potential versus that of the wild-type enzyme was observed in M86D. One possible explanation for the significantly lower activity is an increased affinity for the distal histidine in binding to the heme Fe to form a bis-histidine adduct. Resonance Raman spectroscopy demonstrates a pH-dependent ligation by the distal histidine in M86D, which is indicative of an increased trans effect. At pH 5.0, the heme Fe is five-coordinate, and this structure resembles the wild-type DHP A resting state. However, at pH 7.0, the distal histidine appears to form a six-coordinate ferric bis-histidine (hemichrome) adduct. These observations can be explained by the effect of the increased positive charge on the heme Fe on the formation of a six-coordinate low-spin adduct, which inhibits the ligation and activation of H(2)O(2) as required for peroxidase activity. The results suggest that the proximal charge relay in peroxidases regulate the redox potential of the heme Fe but that the trans effect is a carefully balanced property that can both activate H(2)O(2) and attract ligation by the distal histidine. To understand the balance of forces that modulate peroxidase reactivity, we studied three M86 mutants, M86A, M86D, and M86E, by spectroelectrochemistry and nuclear magnetic resonance spectroscopy of (13)C- and (15)N-labeled cyanide adducts as probes of the redox potential and of the trans effect in the heme Fe, both of which can be correlated with the proximity of negative charge to the N(δ) hydrogen of the proximal histidine, consistent with an Asp-His-Fe charge relay observed in heme peroxidases.
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Affiliation(s)
- Edward L D'Antonio
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
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Miki Y, Calviño FR, Pogni R, Giansanti S, Ruiz-Dueñas FJ, Martínez MJ, Basosi R, Romero A, Martínez AT. Crystallographic, kinetic, and spectroscopic study of the first ligninolytic peroxidase presenting a catalytic tyrosine. J Biol Chem 2011; 286:15525-34. [PMID: 21367853 PMCID: PMC3083212 DOI: 10.1074/jbc.m111.220996] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Revised: 02/11/2011] [Indexed: 11/06/2022] Open
Abstract
Trametes cervina lignin peroxidase (LiP) is a unique enzyme lacking the catalytic tryptophan strictly conserved in all other LiPs and versatile peroxidases (more than 30 sequences available). Recombinant T. cervina LiP and site-directed variants were investigated by crystallographic, kinetic, and spectroscopic techniques. The crystal structure shows three substrate oxidation site candidates involving His-170, Asp-146, and Tyr-181. Steady-state kinetics for oxidation of veratryl alcohol (the typical LiP substrate) by variants at the above three residues reveals a crucial role of Tyr-181 in LiP activity. Moreover, assays with ferrocytochrome c show that its ability to oxidize large molecules (a requisite property for oxidation of the lignin polymer) originates in Tyr-181. This residue is also involved in the oxidation of 1,4-dimethoxybenzene, a reaction initiated by the one-electron abstraction with formation of substrate cation radical, as described for the well known Phanerochaete chrysosporium LiP. Detailed spectroscopic and kinetic investigations, including low temperature EPR, show that the porphyrin radical in the two-electron activated T. cervina LiP is unstable and rapidly receives one electron from Tyr-181, forming a catalytic protein radical, which is identified as an H-bonded neutral tyrosyl radical. The crystal structure reveals a partially exposed location of Tyr-181, compatible with its catalytic role, and several neighbor residues probably contributing to catalysis: (i) by enabling substrate recognition by aromatic interactions; (ii) by acting as proton acceptor/donor from Tyr-181 or H-bonding the radical form; and (iii) by providing the acidic environment that would facilitate oxidation. This is the first structure-function study of the only ligninolytic peroxidase described to date that has a catalytic tyrosine.
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Affiliation(s)
- Yuta Miki
- From the Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, E-28040 Madrid, Spain and
| | - Fabiola R. Calviño
- From the Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, E-28040 Madrid, Spain and
| | - Rebecca Pogni
- the Department of Chemistry, University of Siena, I-53100 Siena, Italy
| | | | - Francisco J. Ruiz-Dueñas
- From the Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, E-28040 Madrid, Spain and
| | - María Jesús Martínez
- From the Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, E-28040 Madrid, Spain and
| | - Riccardo Basosi
- the Department of Chemistry, University of Siena, I-53100 Siena, Italy
| | - Antonio Romero
- From the Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, E-28040 Madrid, Spain and
| | - Angel T. Martínez
- From the Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, E-28040 Madrid, Spain and
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Nicoletti FP, Thompson MK, Franzen S, Smulevich G. Degradation of sulfide by dehaloperoxidase-hemoglobin from Amphitrite ornata. J Biol Inorg Chem 2011; 16:611-9. [DOI: 10.1007/s00775-011-0762-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 01/26/2011] [Indexed: 10/18/2022]
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Active intermediates in heme monooxygenase reactions as revealed by cryoreduction/annealing, EPR/ENDOR studies. Arch Biochem Biophys 2010; 507:36-43. [PMID: 20854788 DOI: 10.1016/j.abb.2010.09.013] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 09/13/2010] [Accepted: 09/14/2010] [Indexed: 11/21/2022]
Abstract
This review describes the use of cryoreduction/annealing EPR/ENDOR techniques for determining the active oxidizing species in reactions catalyzed by heme monooxygenases. The three candidate heme states are: ferric peroxo, ferric hydroperoxo and compound I intermediates. The enzymes discussed include cytochromes P450, nitric oxide synthase and heme oxygenase.
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