1
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Johnson KL, Graves AB, Eckhert K, Liptak MD. Second-sphere tuning of analogues for the ferric-hydroperoxoheme form of Mycobacterium tuberculosis MhuD. J Inorg Biochem 2023; 246:112300. [PMID: 37364353 PMCID: PMC10332388 DOI: 10.1016/j.jinorgbio.2023.112300] [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: 04/03/2023] [Revised: 06/15/2023] [Accepted: 06/17/2023] [Indexed: 06/28/2023]
Abstract
Mycobacterium tuberculosis MhuD catalyzes the oxygenation of heme to mycobilin; experimental data presented here elucidates the novel hydroxylation reaction catalyzed by this enzyme. Analogues for the critical ferric-hydroperoxoheme (MhuD-heme-OOH) intermediate of this enzyme were characterized using UV/Vis absorption (Abs), circular dichroism (CD), and magnetic CD (MCD) spectroscopies. In order to extract electronic transition energies from these spectroscopic data, a novel global fitting model was developed for analysis of UV/Vis Abs, CD, and MCD data. A variant of MhuD was prepared, N7S, which weakens the affinity of heme-bound enzyme for a hydroperoxo analogue, azide, without significantly altering the protein secondary structure. Global fitting of spectroscopic data acquired in this study revealed that the second-sphere N7S substitution perturbs the electronic structure of two analogues for MhuD-heme-OOH: azide-inhibited MhuD (MhuD-heme-N3) and cyanide-inhibited MhuD (MhuD-heme-CN). The ground state electronic structures of MhuD-heme-N3 and MhuD-heme-CN were assessed using variable-temperature, variable-field MCD. Altogether, these data strongly suggest that there is a hydrogen bond between the Asn7 side-chain and the terminal oxygen of the hydroperoxo ligand in MhuD-heme-OOH. As discussed herein, this finding supports a novel hydroxylation reaction mechanism where the Asn7 side-chain guides a transient hydroxyl radical derived from homolysis of the OO bond in MhuD-heme-OOH to the β- or δ-meso carbon of the porphyrin ligand yielding β- or δ-meso-hydroxyheme, respectively.
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Affiliation(s)
- Kayla L Johnson
- Department of Chemistry, University of Vermont, 82 University Place, Burlington, VT 05405, United States of America
| | - Amanda B Graves
- Department of Chemistry, University of Vermont, 82 University Place, Burlington, VT 05405, United States of America
| | - Kaitlyn Eckhert
- Department of Chemistry, University of Vermont, 82 University Place, Burlington, VT 05405, United States of America
| | - Matthew D Liptak
- Department of Chemistry, University of Vermont, 82 University Place, Burlington, VT 05405, United States of America.
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2
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Bollmeyer MM, Coleman RE, Majer SH, Ferrao SD, Lancaster KM. Cytochrome P460 Cofactor Maturation Proceeds via Peroxide-Dependent Post-translational Modification. J Am Chem Soc 2023; 145:14404-14416. [PMID: 37338957 PMCID: PMC10431212 DOI: 10.1021/jacs.3c03608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2023]
Abstract
Cytochrome P460s are heme enzymes that oxidize hydroxylamine to nitrous oxide. They bear specialized "heme P460" cofactors that are cross-linked to their host polypeptides by a post-translationally modified lysine residue. Wild-type N. europaea cytochrome P460 may be isolated as a cross-link-deficient proenzyme following anaerobic overexpression in E. coli. When treated with peroxide, this proenzyme undergoes maturation to active enzyme with spectroscopic and catalytic properties that match wild-type cyt P460. This maturation reactivity requires no chaperones─it is intrinsic to the protein. This behavior extends to the broader cytochrome c'β superfamily. Accumulated data reveal key contributions from the secondary coordination sphere that enable selective, complete maturation. Spectroscopic data support the intermediacy of a ferryl species along the maturation pathway.
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Affiliation(s)
- Melissa M. Bollmeyer
- Department of Chemistry and Chemical Biology Cornell University, Baker Laboratory, 162 Sciences Drive, Ithaca, NY 14853, USA
| | - Rachael E. Coleman
- Department of Chemistry and Chemical Biology Cornell University, Baker Laboratory, 162 Sciences Drive, Ithaca, NY 14853, USA
| | - Sean H. Majer
- Department of Chemistry and Chemical Biology Cornell University, Baker Laboratory, 162 Sciences Drive, Ithaca, NY 14853, USA
| | - Silas D. Ferrao
- Department of Chemistry and Chemical Biology Cornell University, Baker Laboratory, 162 Sciences Drive, Ithaca, NY 14853, USA
| | - Kyle M. Lancaster
- Department of Chemistry and Chemical Biology Cornell University, Baker Laboratory, 162 Sciences Drive, Ithaca, NY 14853, USA
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3
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Wang M, Wang Y, Wang M, Liu M, Cheng A. Heme acquisition and tolerance in Gram-positive model bacteria: An orchestrated balance. Heliyon 2023; 9:e18233. [PMID: 37501967 PMCID: PMC10368836 DOI: 10.1016/j.heliyon.2023.e18233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 06/26/2023] [Accepted: 07/12/2023] [Indexed: 07/29/2023] Open
Abstract
As a nutrient, heme is important for various cellular processes of organism. Bacteria can obtain heme via heme biosynthesis or/and uptake of exogenous heme from the host. On the other side, absorption of excess heme is cytotoxic to bacteria. Thus, bacteria have developed systems to relieve heme toxicity and contribute to the maintenance of heme homeostasis. In the past decades, the mechanisms underlying heme acquisition and tolerance have been well studied in Gram-positive model bacteria, such as Staphylococcus, Streptococcus and other Gram-positive bacteria. Here, we review the elaborate mechanisms by which these bacteria acquire heme and resist heme toxicity. Since both the heme utilization system and the heme tolerance system contribute to bacterial virulence, this review is not only helpful for a comprehensive understanding of the heme homeostasis mechanism in Gram-positive bacteria but also provides a theoretical basis for the development of antimicrobial agents.
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Affiliation(s)
- Mengying Wang
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People's Republic of China, Chengdu 611130, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu 611130, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
| | - Yuwei Wang
- Mianyang Academy of Agricultural Sciences, Institute of Livestock Research, Mianyang 621023, China
| | - Mingshu Wang
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People's Republic of China, Chengdu 611130, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu 611130, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
| | - Mafeng Liu
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People's Republic of China, Chengdu 611130, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu 611130, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
| | - Anchun Cheng
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People's Republic of China, Chengdu 611130, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu 611130, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
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4
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Yan Y, Wu J, Hu G, Gao C, Guo L, Chen X, Liu L, Song W. Current state and future perspectives of cytochrome P450 enzymes for C–H and C=C oxygenation. Synth Syst Biotechnol 2022; 7:887-899. [PMID: 35601824 PMCID: PMC9112060 DOI: 10.1016/j.synbio.2022.04.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/24/2022] [Accepted: 04/26/2022] [Indexed: 01/11/2023] Open
Abstract
Cytochrome P450 enzymes (CYPs) catalyze a series of C–H and C=C oxygenation reactions, including hydroxylation, epoxidation, and ketonization. They are attractive biocatalysts because of their ability to selectively introduce oxygen into inert molecules under mild conditions. This review provides a comprehensive overview of the C–H and C=C oxygenation reactions catalyzed by CYPs and the various strategies for achieving higher selectivity and enzymatic activity. Furthermore, we discuss the application of C–H and C=C oxygenation catalyzed by CYPs to obtain the desired chemicals or pharmaceutical intermediates in practical production. The rapid development of protein engineering for CYPs provides excellent biocatalysts for selective C–H and C=C oxygenation reactions, thereby promoting the development of environmentally friendly and sustainable production processes.
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Affiliation(s)
- Yu Yan
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, China
| | - Jing Wu
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, China
| | - Guipeng Hu
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, China
| | - Cong Gao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China
| | - Liang Guo
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China
| | - Xiulai Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China
| | - Liming Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China
| | - Wei Song
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, China
- Corresponding author.
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5
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Theoretical (DFT) study on the hydroxylation mechanism of Sn(IV)porphyrin: How does Sn(IV)porphyrin inhibit heme oxygenase catalysis function. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.132097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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6
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Schuelke-Sanchez AE, Cornetta AR, Kocian TA, Conger MA, Liptak MD. Ruffling is essential for Staphylococcus aureus IsdG-catalyzed degradation of heme to staphylobilin. J Inorg Biochem 2022; 230:111775. [PMID: 35247855 PMCID: PMC8930504 DOI: 10.1016/j.jinorgbio.2022.111775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/31/2022] [Accepted: 02/21/2022] [Indexed: 10/19/2022]
Abstract
Non-canonical heme oxygenases are enzymes that degrade heme to non-biliverdin products within bacterial heme iron acquisition pathways. These enzymes all contain a conserved second-sphere Trp residue that is essential for enzymatic turnover. Here, UV/Vis absorption (Abs) and circular dichroism (CD) spectroscopies were employed to show that the W67F variant of IsdG perturbs the heme substrate conformation. In general, a dynamic equilibrium between "planar" and "ruffled" substrate conformations exists within non-canonical heme oxygenases, and that the second-sphere Trp favors population of the "ruffled" substrate conformation. 1H nuclear magnetic resonance and magnetic CD spectroscopies were used to characterize the electronic structures of IsdG and IsdI variants with different substrate conformational distributions. These data revealed that the "ruffled" substrate conformation promotes partial porphyrin-to‑iron electron transfer, which makes the meso carbons of the porphyrin ring susceptible to radical attack. Finally, UV/Vis Abs spectroscopy was utilized to quantify the enzymatic rates, and electrospray ionization mass spectrometry was used to identify the product distributions, for variants of IsdG with altered substrate conformational distributions. In general, the rate of heme oxygenation by non-canonical heme oxygenases depends upon the population of the "ruffled" substrate conformation. Also, the production of staphylobilin or mycobilin by these enzymes is correlated with the population of the "ruffled" substrate conformation, since variants that favor population of the "planar" substrate conformation yield significant amounts of biliverdin. These data can be understood within the framework of a concerted rearrangement mechanism for the monooxygenation of heme to meso-hydroxyheme by non-canonical heme oxygenases.
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7
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Structure-function characterization of the mono- and diheme forms of MhuD, a noncanonical heme oxygenase from Mycobacterium tuberculosis. J Biol Chem 2021; 298:101475. [PMID: 34883099 PMCID: PMC8801480 DOI: 10.1016/j.jbc.2021.101475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/30/2021] [Accepted: 12/01/2021] [Indexed: 11/29/2022] Open
Abstract
MhuD is a noncanonical heme oxygenase (HO) from Mycobacterium tuberculosis (Mtb) that catalyzes unique heme degradation chemistry distinct from canonical HOs, generating mycobilin products without releasing carbon monoxide. Its crucial role in the Mtb heme uptake pathway has identified MhuD as an auspicious drug target. MhuD is capable of binding either one or two hemes within a single active site, but only the monoheme form was previously reported to be enzymatically active. Here we employed resonance Raman (rR) spectroscopy to examine several factors proposed to impact the reactivity of mono- and diheme MhuD, including heme ruffling, heme pocket hydrophobicity, and amino acid–heme interactions. We determined that the distal heme in the diheme MhuD active site has negligible effects on both the planarity of the His-coordinated heme macrocycle and the strength of the Fe-NHis linkage relative to the monoheme form. Our rR studies using isotopically labeled hemes unveiled unexpected biomolecular dynamics for the process of heme binding that converts MhuD from mono- to diheme form, where the second incoming heme replaces the first as the His75-coordinated heme. Ferrous CO-ligated diheme MhuD was found to exhibit multiple Fe-C-O conformers, one of which contains catalytically predisposed H-bonding interactions with the distal Asn7 residue identical to those in the monoheme form, implying that it is also enzymatically active. This was substantiated by activity assays and MS product analysis that confirmed the diheme form also degrades heme to mycobilins, redefining MhuD’s functional paradigm and further expanding our understanding of its role in Mtb physiology.
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8
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Chiura T, Mak PJ. Investigation of Cyanide Ligand as an Active Site Probe of Human Heme Oxygenase. Inorg Chem 2021; 60:4633-4645. [PMID: 33754715 DOI: 10.1021/acs.inorgchem.0c03611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Human heme oxygenase (hHO-1) is a physiologically important enzyme responsible for free heme catabolism. The enzyme's high regiospecificity is controlled by the distal site hydrogen bond network that involves water molecules and the D140 amino acid residue. In this work, we probe the active site environment of the wild-type (WT) hHO-1 and its D140 mutants using resonance Raman (rR) spectroscopy. Cyanide ligands are more stable than dioxygen adducts and are an effective probe of active site environment of heme proteins. The inherently linear geometry of the Fe-C-N fragment can be altered by the steric, electrostatic, and H-bonding interactions imposed by the amino acid residues present in the heme distal site, resulting in a tilted or bent configuration. The WT hHO-1 and its D140A, D140N, and D140E mutants were studied in the presence of natural abundance CN- and its isotopic analogues (13CN-, C15N-, and 13C15N-). Deconvolution of spectral data revealed that the ν(Fe-CN) stretching and δ(Fe-CN) bending modes are present at 454 and 376 cm-1, respectively. The rR spectral patterns of the CN- adducts of WT revealed that the Fe-C-N fragment adopts a tilted conformation, with a larger bending contribution for the D140A, D140N, and D140E mutants. These studies suggest that the FeCN fragment in hHO-1 is tilted more strongly toward the porphyrin macrocycle compared to other histidine-ligated proteins, reflecting the propensity of the exogenous hHO-l ligands to position toward the α-meso-carbon, which is crucial for the HO reactivity and essential for regioselectivity.
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Affiliation(s)
- Tapiwa Chiura
- Chemistry Department, Saint Louis University, Saint Louis, Missouri 63103, United States
| | - Piotr J Mak
- Chemistry Department, Saint Louis University, Saint Louis, Missouri 63103, United States
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9
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Yuan C, Zhang Y, Tan H, Li X, Chen G, Jia Z. ONIOM investigations of the heme degradation mechanism by MhuD: the critical function of heme ruffling. Phys Chem Chem Phys 2020; 22:8817-8826. [DOI: 10.1039/c9cp05868k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A unique ruffling conformation of hydroxyheme in MhuD inhibits its “on-site” monooxygenation but induces “remote-site” dioxygenation.
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Affiliation(s)
- Chang Yuan
- College of Chemistry
- Key Laboratories of Theoretical and Computational Photochemistry
- Ministry of Education
- Beijing Normal University
- Beijing
| | - Ying Zhang
- College of Chemistry
- Key Laboratories of Theoretical and Computational Photochemistry
- Ministry of Education
- Beijing Normal University
- Beijing
| | - Hongwei Tan
- College of Chemistry
- Key Laboratories of Theoretical and Computational Photochemistry
- Ministry of Education
- Beijing Normal University
- Beijing
| | - Xichen Li
- College of Chemistry
- Key Laboratories of Theoretical and Computational Photochemistry
- Ministry of Education
- Beijing Normal University
- Beijing
| | - Guangju Chen
- College of Chemistry
- Key Laboratories of Theoretical and Computational Photochemistry
- Ministry of Education
- Beijing Normal University
- Beijing
| | - Zongchao Jia
- Department of Biomedical and Molecular Sciences
- Queen's University
- Kingston
- Ontario
- Canada
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10
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Zhang Y, Wang J, Yuan C, Liu W, Tan H, Li X, Chen G. Ruffling drives coproheme decarboxylation by facilitating PCET: a theoretical investigation of ChdC. Phys Chem Chem Phys 2020; 22:16117-16124. [DOI: 10.1039/d0cp02690e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Coproheme decarboxylase (ChdC) is an essential enzyme in the coproporphyrin-dependent heme synthesis pathway, which catalyzes oxidative decarboxylation of coproheme at the positions p2 and p4 to generate heme b under the action of hydrogen peroxide.
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Affiliation(s)
- Ying Zhang
- Key Laboratory of Theoretical and Computational Photochemistry
- College of Chemistry
- Beijing Normal University
- Beijing 100875
- China
| | - Junkai Wang
- Key Laboratory of Theoretical and Computational Photochemistry
- College of Chemistry
- Beijing Normal University
- Beijing 100875
- China
| | - Chang Yuan
- Key Laboratory of Theoretical and Computational Photochemistry
- College of Chemistry
- Beijing Normal University
- Beijing 100875
- China
| | - Wei Liu
- Key Laboratory of Theoretical and Computational Photochemistry
- College of Chemistry
- Beijing Normal University
- Beijing 100875
- China
| | - Hongwei Tan
- Key Laboratory of Theoretical and Computational Photochemistry
- College of Chemistry
- Beijing Normal University
- Beijing 100875
- China
| | - Xichen Li
- Key Laboratory of Theoretical and Computational Photochemistry
- College of Chemistry
- Beijing Normal University
- Beijing 100875
- China
| | - Guangju Chen
- Key Laboratory of Theoretical and Computational Photochemistry
- College of Chemistry
- Beijing Normal University
- Beijing 100875
- China
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11
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Adam SM, Wijeratne GB, Rogler PJ, Diaz DE, Quist DA, Liu JJ, Karlin KD. Synthetic Fe/Cu Complexes: Toward Understanding Heme-Copper Oxidase Structure and Function. Chem Rev 2018; 118:10840-11022. [PMID: 30372042 PMCID: PMC6360144 DOI: 10.1021/acs.chemrev.8b00074] [Citation(s) in RCA: 145] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Heme-copper oxidases (HCOs) are terminal enzymes on the mitochondrial or bacterial respiratory electron transport chain, which utilize a unique heterobinuclear active site to catalyze the 4H+/4e- reduction of dioxygen to water. This process involves a proton-coupled electron transfer (PCET) from a tyrosine (phenolic) residue and additional redox events coupled to transmembrane proton pumping and ATP synthesis. Given that HCOs are large, complex, membrane-bound enzymes, bioinspired synthetic model chemistry is a promising approach to better understand heme-Cu-mediated dioxygen reduction, including the details of proton and electron movements. This review encompasses important aspects of heme-O2 and copper-O2 (bio)chemistries as they relate to the design and interpretation of small molecule model systems and provides perspectives from fundamental coordination chemistry, which can be applied to the understanding of HCO activity. We focus on recent advancements from studies of heme-Cu models, evaluating experimental and computational results, which highlight important fundamental structure-function relationships. Finally, we provide an outlook for future potential contributions from synthetic inorganic chemistry and discuss their implications with relevance to biological O2-reduction.
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Affiliation(s)
- Suzanne M. Adam
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Gayan B. Wijeratne
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Patrick J. Rogler
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Daniel E. Diaz
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - David A. Quist
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Jeffrey J. Liu
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Kenneth D. Karlin
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
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12
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Gheidi M, Safari N, Zahedi M. Density functional theory studies on the conversion of hydroxyheme to iron-verdoheme in the presence of dioxygen. Dalton Trans 2018; 46:2146-2158. [PMID: 28120965 DOI: 10.1039/c6dt04250c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Detailed insight into the second step of heme degradation by heme oxygenase, oxophlorin to verdoheme and biliverdin, is presented. Density functional theory methods are reported for the conversion of oxophlorin to verdoheme. Since it is currently unclear whether dioxygen binding to iron oxophlorin is followed by a reduction or not, in this work we have focused on the difference in reactivity between [(Im)(O2˙)FeIII(PO˙)] (PO˙ is the oxophlorin dianion radical) and [(Im)(O2˙)FeIII(PO)]- (PO is the oxophlorin trianion). Thus, we have shown that in [(Im)(O2˙)FeIII(PO˙)] and [(Im)(O2˙)FeIII(PO)]-, the mechanisms are stepwise with an initial C-O bond activation to form a ring-structure where the oxophlorin is distorted from planarity. This is followed by homolytic dioxygen bond breaking that directly leads to iron-oxo verdoheme products. The [(Im)(O2˙)FeIII(PO˙)] mechanism proceeds via two-state-reactivity patterns on the adjacent doublet and quartet spin state surfaces, whereas the [(Im)(O2˙)FeIII(PO)]- route shows single-state-reactivity on a triplet spin state surface. In both, the rate determining step is the C-O bond activation, with substantially lower barriers on the [(Im)(O2˙)FeIII(PO˙)] surface of 12.15 kcal mol-1 in the gas phase compared to 22.55 kcal mol-1 for the intermediate-spin of [(Im)(O2˙)FeIII(PO)]-. The complete active space self-consistent-field wave functions with second-order multi-reference perturbation theory were also studied. Finally, the effects of the solvent and the medium on the reaction barriers were tested and shown to be considerable.
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Affiliation(s)
- Mahin Gheidi
- Department of Chemistry, Faculty of Sciences, Shahid Beheshti University, G. C., Evin, 19839-63113, Tehran, Iran.
| | - Nasser Safari
- Department of Chemistry, Faculty of Sciences, Shahid Beheshti University, G. C., Evin, 19839-63113, Tehran, Iran.
| | - Mansour Zahedi
- Department of Chemistry, Faculty of Sciences, Shahid Beheshti University, G. C., Evin, 19839-63113, Tehran, Iran.
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13
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Conger MA, Pokhrel D, Liptak MD. Tight binding of heme to Staphylococcus aureus IsdG and IsdI precludes design of a competitive inhibitor. Metallomics 2018; 9:556-563. [PMID: 28401968 DOI: 10.1039/c7mt00035a] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The micromolar equilibrium constants for heme dissociation from IsdG and IsdI reported in the literature call into question whether these enzymes are actually members of the iron-regulated surface determinant system of Staphylococcus aureus, which harvests heme iron from a host during infection. In order to address this question, the heme dissociation constants for IsdG and IsdI were reevaluated using three approaches. The heme dissociation equilibrium constants were measured using a UV/Vis absorption-detected assay analyzed with an assumption-free model, and using a newly developed fluorescence-detected assay. The heme dissociation rate constants were estimated using apomyoglobin competition assays. Analyses of the UV/Vis absorption data revealed a critical flaw in the previous measurements; heme is 99.9% protein-bound at the micromolar concentrations needed for UV/Vis absorption spectroscopy, which renders accurate equilibrium constant measurement nearly impossible. However, fluorescence can be measured for more dilute samples, and analyses of these data resulted in dissociation equilibrium constants of 1.4 ± 0.6 nM and 12.9 ± 1.3 nM for IsdG and IsdI, respectively. Analyses of the kinetic data obtained from apomyoglobin competition assays estimated heme dissociation rate constants of 0.022 ± 0.002 s-1 for IsdG and 0.092 ± 0.008 s-1 for IsdI. Based upon these data, and what is known regarding the post-translational regulation of IsdG and IsdI, it is proposed that only IsdG is a member of the heme iron acquisition pathway and IsdI regulates heme homeostasis. Furthermore, the nanomolar dissociation constants mean that heme is bound tightly by IsdG and indicates that competitive inhibition of this protein will be difficult. Instead, uncompetitive inhibition based upon a detailed understanding of enzyme mechanism is a more promising antibiotic development strategy.
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Affiliation(s)
- Matthew A Conger
- Department of Chemistry, University of Vermont, Burlington, Vermont 05405, USA.
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14
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Alavi FS, Gheidi M, Zahedi M, Safari N, Ryde U. A novel mechanism of heme degradation to biliverdin studied by QM/MM and QM calculations. Dalton Trans 2018; 47:8283-8291. [DOI: 10.1039/c8dt00064f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Heme degradation by heme oxygenase enzymes is important for maintaining iron homeostasis and prevention of oxidative stress.
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Affiliation(s)
- Fatemeh Sadat Alavi
- Department of Chemistry
- Faculty of Sciences
- Shahid Beheshti University
- Tehran
- Iran
| | - Mahin Gheidi
- Department of Chemistry
- Faculty of Sciences
- Shahid Beheshti University
- Tehran
- Iran
| | - Mansour Zahedi
- Department of Chemistry
- Faculty of Sciences
- Shahid Beheshti University
- Tehran
- Iran
| | - Nasser Safari
- Department of Chemistry
- Faculty of Sciences
- Shahid Beheshti University
- Tehran
- Iran
| | - Ulf Ryde
- Department of Theoretical Chemistry
- Lund University
- Chemical Centre
- SE-221 00 Lund
- Sweden
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15
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Lee MJY, Wang Y, Jiang Y, Li X, Ma J, Tan H, Turner-Wood K, Rahman MN, Chen G, Jia Z. Function Coupling Mechanism of PhuS and HemO in Heme Degradation. Sci Rep 2017; 7:11273. [PMID: 28900278 PMCID: PMC5596023 DOI: 10.1038/s41598-017-11907-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 08/31/2017] [Indexed: 12/24/2022] Open
Abstract
Most bacteria possess only one heme-degrading enzyme for obtaining iron, however few bacteria such as Pseudomonas aeruginosa express two, namely PhuS and HemO. While HemO is a well-known heme oxygenase, previously we discovered that PhuS also possesses heme degradation activity and generates verdoheme, an intermediate of heme breakdown. To understand the coexistence of these two enzymes, using the DFT calculation we reveal that PhuS effectively enhances heme degradation through its participation in heme hydroxylation, the rate limiting reaction. Heme is converted to verdoheme in this reaction and the energy barrier for PhuS is substantially lower than for HemO. Thus, HemO is mainly involved in the ring opening reaction which converts verdoheme to biliverdin and free iron. Our kinetics experiments show that, in the presence of both PhuS and HemO, complete degradation of heme to biliverdin is enhanced. We further show that PhuS is more active than HemO using heme as a substrate and generates more CO. Combined experimental and theoretical results directly identify function coupling of this two-enzyme system, resulting in more efficient heme breakdown and utilization.
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Affiliation(s)
- Michael J Y Lee
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Ye Wang
- College of Chemistry, Beijing Normal University, 100875, Beijing, China
| | - Yafei Jiang
- College of Chemistry, Beijing Normal University, 100875, Beijing, China
| | - Xichen Li
- College of Chemistry, Beijing Normal University, 100875, Beijing, China
| | - Jianqiu Ma
- College of Chemistry, Beijing Normal University, 100875, Beijing, China
| | - Hongwei Tan
- College of Chemistry, Beijing Normal University, 100875, Beijing, China.
| | - Keegan Turner-Wood
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Mona N Rahman
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Guangju Chen
- College of Chemistry, Beijing Normal University, 100875, Beijing, China
| | - Zongchao Jia
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada. .,College of Chemistry, Beijing Normal University, 100875, Beijing, China.
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16
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Zhao C, Chen H. Mechanism of Organophosphonate Catabolism by Diiron Oxygenase PhnZ: A Third Iron-Mediated O–O Activation Scenario in Nature. ACS Catal 2017. [DOI: 10.1021/acscatal.7b00578] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chongyang Zhao
- Beijing
National Laboratory for Molecular Sciences (BNLMS), Key Laboratory
of Photochemistry, CAS Research/Education Center for Excellence in
Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Hui Chen
- Beijing
National Laboratory for Molecular Sciences (BNLMS), Key Laboratory
of Photochemistry, CAS Research/Education Center for Excellence in
Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
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17
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Dojun N, Sekine Y, Ishimori K, Uchida T. Iron chelators inhibit the heme-degradation reaction by HutZ from Vibrio cholerae. Dalton Trans 2017; 46:5147-5150. [DOI: 10.1039/c7dt00121e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The heme-degradation reaction by HutZ fromVibrio choleraeis inhibited by the iron chelators.
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Affiliation(s)
- Nobuhiko Dojun
- Graduate School of Chemical Sciences and Engineering
- Hokkaido University
- Sapporo 060-8628
- Japan
| | - Yukari Sekine
- Graduate School of Chemical Sciences and Engineering
- Hokkaido University
- Sapporo 060-8628
- Japan
| | - Koichiro Ishimori
- Graduate School of Chemical Sciences and Engineering
- Hokkaido University
- Sapporo 060-8628
- Japan
- Department of Chemistry
| | - Takeshi Uchida
- Graduate School of Chemical Sciences and Engineering
- Hokkaido University
- Sapporo 060-8628
- Japan
- Department of Chemistry
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18
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Sigala PA, Morante K, Tsumoto K, Caaveiro JMM, Goldberg DE. In-Cell Enzymology To Probe His-Heme Ligation in Heme Oxygenase Catalysis. Biochemistry 2016; 55:4836-49. [PMID: 27490825 DOI: 10.1021/acs.biochem.6b00562] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Heme oxygenase (HO) is a ubiquitous enzyme with key roles in inflammation, cell signaling, heme disposal, and iron acquisition. HO catalyzes the oxidative conversion of heme to biliverdin (BV) using a conserved histidine to coordinate the iron atom of bound heme. This His-heme interaction has been regarded as being essential for enzyme activity, because His-to-Ala mutants fail to convert heme to biliverdin in vitro. We probed a panel of proximal His mutants of cyanobacterial, human, and plant HO enzymes using a live-cell activity assay based on heterologous co-expression in Escherichia coli of each HO mutant and a fluorescent biliverdin biosensor. In contrast to in vitro studies with purified proteins, we observed that multiple HO mutants retained significant activity within the intracellular environment of bacteria. X-ray crystallographic structures of human HO1 H25R with bound heme and additional functional studies suggest that HO mutant activity inside these cells does not involve heme ligation by a proximal amino acid. Our study reveals unexpected plasticity in the active site binding interactions with heme that can support HO activity within cells, suggests important contributions by the surrounding active site environment to HO catalysis, and can guide efforts to understand the evolution and divergence of HO function.
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Affiliation(s)
- Paul A Sigala
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine , St. Louis, Missouri 63110, United States
| | - Koldo Morante
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo , Bunkyo-ku, Tokyo 113-8654, Japan
| | - Kouhei Tsumoto
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo , Bunkyo-ku, Tokyo 113-8654, Japan.,Medical Proteomics Laboratory, Institute of Medical Science, The University of Tokyo , Minato-ku, Tokyo 108-8639, Japan
| | - Jose M M Caaveiro
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo , Bunkyo-ku, Tokyo 113-8654, Japan
| | - Daniel E Goldberg
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine , St. Louis, Missouri 63110, United States
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19
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Ramanan R, Dubey KD, Wang B, Mandal D, Shaik S. Emergence of Function in P450-Proteins: A Combined Quantum Mechanical/Molecular Mechanical and Molecular Dynamics Study of the Reactive Species in the H2O2-Dependent Cytochrome P450SPα and Its Regio- and Enantioselective Hydroxylation of Fatty Acids. J Am Chem Soc 2016; 138:6786-97. [DOI: 10.1021/jacs.6b01716] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Rajeev Ramanan
- Institute of Chemistry and
the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Kshatresh Dutta Dubey
- Institute of Chemistry and
the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Binju Wang
- Institute of Chemistry and
the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Debasish Mandal
- Institute of Chemistry and
the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Sason Shaik
- Institute of Chemistry and
the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
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20
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Graves AB, Graves MT, Liptak MD. Measurement of Heme Ruffling Changes in MhuD Using UV–vis Spectroscopy. J Phys Chem B 2016; 120:3844-53. [DOI: 10.1021/acs.jpcb.6b01497] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Amanda B. Graves
- Department of Chemistry, University of Vermont, Burlington, Vermont 05405, United States
| | - Max T. Graves
- Department of Chemistry, University of Vermont, Burlington, Vermont 05405, United States
| | - Matthew D. Liptak
- Department of Chemistry, University of Vermont, Burlington, Vermont 05405, United States
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21
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Graves AB, Horak EH, Liptak MD. Dynamic ruffling distortion of the heme substrate in non-canonical heme oxygenase enzymes. Dalton Trans 2016; 45:10058-67. [DOI: 10.1039/c6dt00702c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A double-well exists along the ruffling coordinate of cyanide-inhibited ferric heme, which explains the observation of “nested” VTVH MCD saturation magnetization curves.
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Affiliation(s)
| | - Erik H. Horak
- Department of Chemistry
- University of Vermont
- Burlington
- USA
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22
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Hydrogen bond donation to the heme distal ligand of Staphylococcus aureus IsdG tunes the electronic structure. J Biol Inorg Chem 2015; 20:757-70. [DOI: 10.1007/s00775-015-1263-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 04/13/2015] [Indexed: 10/23/2022]
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23
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Takayama SIJ, Loutet SA, Mauk AG, Murphy MEP. A Ferric-Peroxo Intermediate in the Oxidation of Heme by IsdI. Biochemistry 2015; 54:2613-21. [PMID: 25853501 DOI: 10.1021/acs.biochem.5b00239] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The canonical heme oxygenases (HOs) catalyze heme oxidation via a heme-bound hydroperoxo intermediate that is stabilized by a water cluster at the active site of the enzyme. In contrast, the hydrophobic active site of IsdI, a heme-degrading enzyme from Staphylococcus aureus, lacks a water cluster and is expected to oxidize heme by an alternative mechanism. Reaction of the IsdI-heme complex with either H2O2 or m-chloroperoxybenzoic acid fails to produce a specific oxidized heme iron intermediate, suggesting that ferric-hydroperoxo or ferryl derivatives of IsdI are not involved in the catalytic mechanism of this enzyme. IsdI lacks a proton-donating group in the distal heme pocket, so the possible involvement of a ferric-peroxo intermediate has been evaluated. Density functional theory (DFT) calculations indicate that heme oxidation involving a ferric-peroxo intermediate is energetically accessible, whereas the energy barrier for a reaction involving a ferric-hydroperoxo intermediate is too great in the absence of a proton donor. We propose that IsdI catalyzes heme oxidation through nucleophilic attack by the heme-bound peroxo species. This proposal is consistent with our previous demonstration by nuclear magnetic resonance spectroscopy that heme ruffling increases the susceptibility of the meso-carbon of heme to nucleophilic attack.
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Affiliation(s)
- Shin-Ichi J Takayama
- †Department of Microbiology and Immunology, ‡Department of Biochemistry and Molecular Biology, and §UBC Centre for Blood Research, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Slade A Loutet
- †Department of Microbiology and Immunology, ‡Department of Biochemistry and Molecular Biology, and §UBC Centre for Blood Research, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - A Grant Mauk
- †Department of Microbiology and Immunology, ‡Department of Biochemistry and Molecular Biology, and §UBC Centre for Blood Research, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Michael E P Murphy
- †Department of Microbiology and Immunology, ‡Department of Biochemistry and Molecular Biology, and §UBC Centre for Blood Research, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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24
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Schatzschneider U. Novel lead structures and activation mechanisms for CO-releasing molecules (CORMs). Br J Pharmacol 2015; 172:1638-50. [PMID: 24628281 PMCID: PMC4369270 DOI: 10.1111/bph.12688] [Citation(s) in RCA: 194] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 02/28/2014] [Accepted: 03/06/2014] [Indexed: 12/11/2022] Open
Abstract
Carbon monoxide (CO) is an endogenous small signalling molecule in the human body, produced by the action of haem oxygenase on haem. Since it is very difficult to apply safely as a gas, solid storage and delivery forms for CO are now explored. Most of these CO-releasing molecules (CORMs) are based on the inactivation of the CO by coordinating it to a transition metal centre in a prodrug approach. After a brief look at the potential cellular target structures of CO, an overview of the design principles and activation mechanisms for CO release from a metal coordination sphere is given. Endogenous and exogenous triggers discussed include ligand exchange reactions with medium, enzymatically-induced CO release and photoactivated liberation of CO. Furthermore, the attachment of CORMs to hard and soft nanomaterials to confer additional target specificity to such systems is critically assessed. A survey of analytical methods for the study of the stoichiometry and kinetics of CO release, as well as the tracking of CO in living systems by using fluorescent probes, concludes this review. CORMs are very valuable tools for studying CO bioactivity and might lead to new drug candidates; however, in the design of future generations of CORMs, particular attention has to be paid to their drug-likeness and the tuning of the peripheral 'drug sphere' for specific biomedical applications. Further progress in this field will thus critically depend on a close interaction between synthetic chemists and researchers exploring the physiological effects and therapeutic applications of CO.
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Affiliation(s)
- U Schatzschneider
- Institut für Anorganische Chemie, Julius-Maximilians-Universität WürzburgWürzburg, Germany
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25
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Wilks A, Ikeda-Saito M. Heme utilization by pathogenic bacteria: not all pathways lead to biliverdin. Acc Chem Res 2014; 47:2291-8. [PMID: 24873177 PMCID: PMC4139177 DOI: 10.1021/ar500028n] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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The eukaryotic heme oxygenases (HOs) (E.C. 1.14.99.3) convert heme
to biliverdin, iron, and carbon monoxide (CO) in three successive
oxygenation steps. Pathogenic bacteria require iron for survival and
infection. Extracellular heme uptake from the host plays a critical
role in iron acquisition and virulence. In the past decade, several
HOs required for the release of iron from extracellular heme have
been identified in pathogenic bacteria, including Corynebacterium
diphtheriae, Neisseriae meningitides, and Pseudomonas aeruginosa. The
bacterial enzymes were shown to be structurally and mechanistically
similar to those of the canonical eukaryotic HO enzymes. However,
the recent discovery of the structurally and mechanistically distinct
noncanonical heme oxygenases of Staphylococcus aureus and Mycobacterium tuberculosis has
expanded the reaction manifold of heme degradation. The distinct ferredoxin-like
structural fold and extreme heme ruffling are proposed to give rise
to the alternate heme degradation products in the S.
aureus and M. tuberculosis enzymes. In addition, several “heme-degrading factors”
with no structural homology to either class of HOs have recently been
reported. The identification of these “heme-degrading proteins”
has largely been determined on the basis of in vitro heme degradation
assays. Many of these proteins were reported to produce biliverdin,
although no extensive characterization of the products was performed.
Prior to the characterization of the canonical HO enzymes, the nonenzymatic
degradation of heme and heme proteins in the presence of a reductant
such as ascorbate or hydrazine, a reaction termed “coupled
oxidation”, served as a model for biological heme degradation.
However, it was recognized that there were important mechanistic differences
between the so-called coupled oxidation of heme proteins and enzymatic
heme oxygenation. In the coupled oxidation reaction, the final product,
verdoheme, can readily be converted to biliverdin under hydrolytic
conditions. The differences between heme oxygenation by the canonical
and noncanonical HOs and coupled oxidation will be discussed in the
context of the stabilization of the reactive FeIII–OOH
intermediate and regioselective heme hydroxylation. Thus, in the determination
of heme oxygenase activity in vitro, it is important to ensure that
the reaction proceeds through successive oxygenation steps. We further
suggest that when bacterial heme degradation is being characterized,
a systems biology approach combining genetics, mechanistic enzymology,
and metabolite profiling should be undertaken.
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Affiliation(s)
- Angela Wilks
- Department
of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland 21201-1140, United States
| | - Masao Ikeda-Saito
- Institute
of Multidisciplinary Research for Advanced Materials, Tohoku University Katahira, Aoba, Sendai 980-8577, Japan
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26
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Graves AB, Morse RP, Chao A, Iniguez A, Goulding CW, Liptak MD. Crystallographic and spectroscopic insights into heme degradation by Mycobacterium tuberculosis MhuD. Inorg Chem 2014; 53:5931-40. [PMID: 24901029 PMCID: PMC4060609 DOI: 10.1021/ic500033b] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mycobacterium heme utilization degrader (MhuD) is a heme-degrading protein from Mycobacterium tuberculosis responsible for extracting the essential nutrient iron from host-derived heme. MhuD has been previously shown to produce unique organic products compared to those of canonical heme oxygenases (HOs) as well as those of the IsdG/I heme-degrading enzymes from Staphylococcus aureus. Here, we report the X-ray crystal structure of cyanide-inhibited MhuD (MhuD-heme-CN) as well as detailed (1)H nuclear magnetic resonance (NMR), UV/vis absorption, and magnetic circular dichroism (MCD) spectroscopic characterization of this species. There is no evidence for an ordered network of water molecules on the distal side of the heme substrate in the X-ray crystal structure, as was previously reported for canonical HOs. The degree of heme ruffling in the crystal structure of MhuD is greater than that observed for HO and less than that observed for IsdI. As a consequence, the Fe 3dxz-, 3dyz-, and 3dxy-based MOs are very close in energy, and the room-temperature (1)H NMR spectrum of MhuD-heme-CN is consistent with population of both a (2)Eg electronic state with a (dxy)(2)(dxz,dyz)(3) electron configuration, similar to the ground state of canonical HOs, and a (2)B2g state with a (dxz,dyz)(4)(dxy)(1) electron configuration, similar to the ground state of cyanide-inhibited IsdI. Variable temperature, variable field MCD saturation magnetization data establishes that MhuD-heme-CN has a (2)B2g electronic ground state with a low-lying (2)Eg excited state. Our crystallographic and spectroscopic data suggest that there are both structural and electronic contributions to the α-meso regioselectivity of MhuD-catalyzed heme cleavage. The structural distortion of the heme substrate observed in the X-ray crystal structure of MhuD-heme-CN is likely to favor cleavage at the α- and γ-meso carbons, whereas the spin density distribution may favor selective oxygenation of the α-meso carbon.
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Affiliation(s)
- Amanda B Graves
- Department of Chemistry, University of Vermont , Burlington, Vermont 05405, United States
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27
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Ueda T, Kitagishi H, Kano K. Intramolecular Direct Oxygen Transfer from Oxoferryl Porphyrin to a Sulfide Bond. Inorg Chem 2013; 53:543-51. [DOI: 10.1021/ic4026393] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Takunori Ueda
- Department of Molecular Chemistry and Biochemistry, Doshisha University, Kyotanabe, Kyoto 610-0321, Japan
| | - Hiroaki Kitagishi
- Department of Molecular Chemistry and Biochemistry, Doshisha University, Kyotanabe, Kyoto 610-0321, Japan
| | - Koji Kano
- Department of Molecular Chemistry and Biochemistry, Doshisha University, Kyotanabe, Kyoto 610-0321, Japan
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28
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Wilks A, Heinzl G. Heme oxygenation and the widening paradigm of heme degradation. Arch Biochem Biophys 2013; 544:87-95. [PMID: 24161941 DOI: 10.1016/j.abb.2013.10.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 10/09/2013] [Accepted: 10/15/2013] [Indexed: 12/11/2022]
Abstract
Heme degradation through the action of heme oxygenase (HO) is unusual in that it utilizes heme as both a substrate and cofactor for its own degradation. HO catalyzes the oxygen-dependent degradation of heme to biliverdin with the release of CO and "free" iron. The characterization of HO enzymes from humans to bacteria reveals a similar overall structural fold that contributes to the unique reaction manifold. The heme oxygenases share a similar heme-dependent activation of O2 to the ferric hydroperoxide as that of the cytochrome P450s and peroxidases. However, whereas the P450s promote cleavage of the ferric hydroperoxide OO bond to the oxoferryl species the HOs stabilize the ferric hydroperoxide promoting hydroxylation at the heme edge. The alternate reaction pathway in HO is achieved through the conformational flexibility and extensive hydrogen bond network within the heme binding site priming the heme for hydroxylation. Until recently it was believed that all heme degrading enzymes converted heme to biliverdin and iron, with the release of carbon monoxide (CO). However, the recent discovery of the bacterial IsdG-like heme degrading proteins of Staphylococcus aureus, Bacillus anthracis and Mycobacterium tuberculosis has expanded the reaction manifold of heme oxidation. Characterization of the heme degradation products in the IsdG-like reaction suggests a mechanism distinct from the classical HOs. In the following review we will discuss the structure-function of the canonical HOs as it relates to the emerging alternate reaction manifold of the IsdG-like proteins.
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Affiliation(s)
- Angela Wilks
- Department of Pharmaceutical Sciences, University of Maryland, Baltimore, MD 21201-1180, USA.
| | - Geoffrey Heinzl
- Department of Pharmaceutical Sciences, University of Maryland, Baltimore, MD 21201-1180, USA
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29
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Garcia-Bosch I, Sharma SK, Karlin KD. A selective stepwise heme oxygenase model system: an iron(IV)-oxo porphyrin π-cation radical leads to a verdoheme-type compound via an isoporphyrin intermediate. J Am Chem Soc 2013; 135:16248-51. [PMID: 24147457 DOI: 10.1021/ja405739m] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The selective oxidation of the α-position of two heme-Fe(III) tetraarylporphryinate complexes occurs when water(hydroxide) attacks their oxidized Cmpd I-type equivalents, high-valent Fe(IV)═O π-cation radical species ((P(+•))Fe(IV)═O). Stepwise intermediate formation occurs, as detected by UV-vis spectroscopic monitoring or mass spectrometric interrogation, being iron(III) isoporphyrins, iron(III) benzoyl-biliverdins, and the final verdoheme-like products. Heme oxygenase (HO) enzymes could proceed through heterolytic cleavage of an iron(III)-hydroperoxo intermediate to form a transient Cmpd I-type species.
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Affiliation(s)
- Isaac Garcia-Bosch
- Department of Chemistry, The Johns Hopkins University , Baltimore, Maryland 21218, United States
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30
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Du L, Gao J, Liu Y, Liu C. Water-Dependent Reaction Pathways: An Essential Factor for the Catalysis in HEPD Enzyme. J Phys Chem B 2012; 116:11837-44. [DOI: 10.1021/jp305454m] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Likai Du
- Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, Institute of Theoretical Chemistry, School of Chemistry & Chemical Engineering, Shandong University, Jinan, 250100, P. R. China
| | - Jun Gao
- Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, Institute of Theoretical Chemistry, School of Chemistry & Chemical Engineering, Shandong University, Jinan, 250100, P. R. China
- Key Laboratory of Theoretical and Computational Chemistry in Universities of Shandong (Shandong University), Jinan, 250100, P. R. China
| | - Yongjun Liu
- Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, Institute of Theoretical Chemistry, School of Chemistry & Chemical Engineering, Shandong University, Jinan, 250100, P. R. China
- Key Laboratory of Theoretical and Computational Chemistry in Universities of Shandong (Shandong University), Jinan, 250100, P. R. China
| | - Chengbu Liu
- Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, Institute of Theoretical Chemistry, School of Chemistry & Chemical Engineering, Shandong University, Jinan, 250100, P. R. China
- Key Laboratory of Theoretical and Computational Chemistry in Universities of Shandong (Shandong University), Jinan, 250100, P. R. China
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31
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Liao RZ, Thiel W. Why Is the Oxidation State of Iron Crucial for the Activity of Heme-Dependent Aldoxime Dehydratase? A QM/MM Study. J Phys Chem B 2012; 116:9396-408. [DOI: 10.1021/jp305510c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Rong-Zhen Liao
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470, Mülheim an der Ruhr, Germany
| | - Walter Thiel
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470, Mülheim an der Ruhr, Germany
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32
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Sicking W, Somnitz H, Schmuck C. DFT Calculations Suggest a New Type of Self-Protection and Self-Inhibition Mechanism in the Mammalian Heme Enzyme Myeloperoxidase: Nucleophilic Addition of a Functional Water rather than One-Electron Reduction. Chemistry 2012; 18:10937-48. [DOI: 10.1002/chem.201103477] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Revised: 05/14/2012] [Indexed: 11/09/2022]
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33
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Kamachi T, Nishimi T, Yoshizawa K. A new understanding on how heme metabolism occurs in heme oxygenase: water-assisted oxo mechanism. Dalton Trans 2012; 41:11642-50. [PMID: 22825429 DOI: 10.1039/c2dt30777d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Heme metabolism by heme oxygenase (HO) is investigated with quantum mechanical/molecular mechanical (QM/MM) calculations. A mechanism assisted by water is proposed: (1) an iron-oxo species and a water molecule are generated by the heterolytic cleavage of the O-O bond of an iron-hydroperoxo species in a similar way to P450-mediated reactions, (2) a hydrogen atom abstraction by the iron-oxo species from the generated water molecule and the C-O bond formation between the water molecule and the α-meso carbon take place simultaneously. The water molecule is hydrogen-bonded to the oxo ligand and to the water cluster in the active site of HO. The water cluster can control the position of the generated water molecule to ensure the regioselective oxidation of heme at the α-meso position, at the same time, can facilitate the oxidation by stabilizing a positive charge on the water molecule in the transition state. A key difference between HO and P450 is observed in the structure of the active site; Thr252 in P450 blocks the access of the water molecule to the α-meso position, and can thus suppress the undesired heme oxidation for P450.
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Affiliation(s)
- Takashi Kamachi
- Institute for Materials Chemistry and Engineering and International Research Center for Molecular Systems, Kyushu University, Fukuoka 819-0395, Japan
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Chen T, Zou Y, Yu C, Zhou X, Li Y. Heteronuclear Cu(II)–Mn(II)–Cu(II) Complex Constructed from Metallo-Ligand Through Carboxylate Oxygens: Coexistence of Water Hexamers. J Inorg Organomet Polym Mater 2012. [DOI: 10.1007/s10904-012-9703-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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35
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Crystallographic studies of heme oxygenase complexed with an unstable reaction intermediate, verdoheme. J Inorg Biochem 2012; 113:102-9. [PMID: 22673156 DOI: 10.1016/j.jinorgbio.2012.04.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 04/05/2012] [Accepted: 04/11/2012] [Indexed: 11/20/2022]
Abstract
This article discusses the accuracy of X-ray structural studies of heme oxygenase (HO) in complex with an unstable intermediate, verdoheme. Heme degradation by HO proceeds through three successive steps of O(2) activation. The mechanism of the third step, the ring opening of verdoheme, has been the least understood. Recent structural studies of the verdoheme-HO complex provide detailed information concerning this mechanism. Due to X-ray-induced photoreduction and the instability of verdoheme, it has been difficult to obtain an accurate structure for the ferrous verdoheme-HO complex. Therefore, accurate structural studies, including analysis of the electronic state of the verdoheme-HO complex, are needed to elucidate the proper reaction mechanism.
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Usharani D, Zazza C, Lai W, Chourasia M, Waskell L, Shaik S. A single-site mutation (F429H) converts the enzyme CYP 2B4 into a heme oxygenase: a QM/MM study. J Am Chem Soc 2012; 134:4053-6. [PMID: 22356576 DOI: 10.1021/ja211905e] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The intriguing deactivation of the cytochrome P450 (CYP) 2B4 enzyme induced by mutation of a single residue, Phe429 to His, is explored by quantum mechanical/molecular mechanical calculations of the O-OH bond activation of the (Fe(3+)OOH)(-) intermediate. It is found that the F429H mutant of CYP 2B4 undergoes homolytic instead of heterolytic O-OH bond cleavage. Thus, the mutant acquires the following characteristics of a heme oxygenase enzyme: (a) donation by His429 of an additional NH---S H-bond to the cysteine ligand combined with the presence of the substrate retards the heterolytic cleavage and gives rise to homolytic O-OH cleavage, and (b) the Thr302/water cluster orients nascent OH(•) and ensures efficient meso hydroxylation.
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Affiliation(s)
- Dandamudi Usharani
- Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
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Electronic properties of the highly ruffled heme bound to the heme degrading enzyme IsdI. Proc Natl Acad Sci U S A 2011; 108:13071-6. [PMID: 21788475 DOI: 10.1073/pnas.1101459108] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
IsdI, a heme-degrading protein from Staphylococcus aureus, binds heme in a manner that distorts the normally planar heme prosthetic group to an extent greater than that observed so far for any other heme-binding protein. To understand better the relationship between this distinct structural characteristic and the functional properties of IsdI, spectroscopic, electrochemical, and crystallographic results are reported that provide evidence that this heme ruffling is essential to the catalytic activity of the protein and eliminates the need for the water cluster in the distal heme pocket that is essential for the activity of classical heme oxygenases. The lack of heme orientational disorder in (1)H-NMR spectra of the protein argues that the catalytic formation of β- and δ-biliverdin in nearly equal yield results from the ability of the protein to attack opposite sides of the heme ring rather than from binding of the heme substrate in two alternative orientations.
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Chen H, Lai W, Shaik S. Multireference and multiconfiguration ab initio methods in heme-related systems: what have we learned so far? J Phys Chem B 2011; 115:1727-42. [PMID: 21344948 DOI: 10.1021/jp110016u] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
This work reviews the recent applications of ab initio multireference/multiconfiguration (MR/MC) electronic structure methods to heme-related systems, involving tetra-, penta-, and hexa-coordinate species, as well as the high-valent iron-oxo species. The current accuracy of these methods in the various systems is discussed, with special attention to potential sources of systematic errors. Thus, the review summarizes and tries to rationalize the key elements of MR/MC calculations, namely, the choice of the employed active space, especially the so-called double-shell effect that has already been recognized to be important in transition-metal-containing systems, and the impact of these elements on the spin-state energetics of heme species, as well as on the bonding mechanism of small molecules to the heme. It is shown that expansion of the MC wave function into one based on localized orbitals provides a compact and insightful view on some otherwise complex electronic structures. The effects of protein environment on the MR/MC results are summarized for the few available quantum mechanical/molecular mechanical (QM/MM) studies. Comparisons with corresponding DFT results are also made wherever available. Potential future directions are proposed.
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Affiliation(s)
- Hui Chen
- Institute of Chemistry, Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel.
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Lai W, Chen H, Matsui T, Omori K, Unno M, Ikeda-Saito M, Shaik S. Enzymatic Ring-Opening Mechanism of Verdoheme by the Heme Oxygenase: A Combined X-ray Crystallography and QM/MM Study. J Am Chem Soc 2010; 132:12960-70. [DOI: 10.1021/ja104674q] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Wenzhen Lai
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, 980-8577, Japan
| | - Hui Chen
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, 980-8577, Japan
| | - Toshitaka Matsui
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, 980-8577, Japan
| | - Kohei Omori
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, 980-8577, Japan
| | - Masaki Unno
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, 980-8577, Japan
| | - Masao Ikeda-Saito
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, 980-8577, Japan
| | - Sason Shaik
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, 980-8577, Japan
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40
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Chung LW, Li X, Sugimoto H, Shiro Y, Morokuma K. ONIOM Study on a Missing Piece in Our Understanding of Heme Chemistry: Bacterial Tryptophan 2,3-Dioxygenase with Dual Oxidants. J Am Chem Soc 2010; 132:11993-2005. [DOI: 10.1021/ja103530v] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Lung Wa Chung
- Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan, and Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, Hyogo 679-5148, Japan
| | - Xin Li
- Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan, and Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, Hyogo 679-5148, Japan
| | - Hiroshi Sugimoto
- Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan, and Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, Hyogo 679-5148, Japan
| | - Yoshitsugu Shiro
- Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan, and Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, Hyogo 679-5148, Japan
| | - Keiji Morokuma
- Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan, and Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, Hyogo 679-5148, Japan
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41
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Matsui T, Iwasaki M, Sugiyama R, Unno M, Ikeda-Saito M. Dioxygen activation for the self-degradation of heme: reaction mechanism and regulation of heme oxygenase. Inorg Chem 2010; 49:3602-9. [PMID: 20380462 DOI: 10.1021/ic901869t] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Heme oxygenase (HO) catalyzes the regiospecific conversion of heme to biliverdin, CO, and free iron through three successive oxygenation reactions. HO catalysis is unique in that all three O(2) activations are performed by the substrate itself. This Forum Article overviews our current understanding on the structural and biochemical properties of HO catalysis, especially its first and third oxygenation steps. The HO first step, regiospecific hydroxylation of the porphyrin alpha-meso-carbon atom, is of particular interest because of its sharp contrast to O(2) activation by cytochrome P450. HO was proposed to utilize the FeOOH species but not conventional ferryl hemes as a reactive intermediate for self-hydroxylation. We have succeeded in preparing and characterizing the FeOOH species of HO at low temperature, and our analyses of its reaction, together with mutational and crystallographic studies, reveal that protonation of FeOOH by a distal water molecule is critical in promoting the unique self-hydroxylation. The second oxygenation is a rapid, spontaneous autooxidation of the reactive alpha-meso-hydroxyheme in which the HO enzyme does not play a critical role. Further O(2) activation by verdoheme cleaves its porphyrin macrocycle to form biliverdin and free ferrous iron. This third step has been considered to be a major rate-determining step of HO catalysis to regulate the enzyme activity. Our reaction analysis strongly supports the FeOOH verdoheme as the key intermediate of the ring-opening reaction. This mechanism is very similar to that of the first meso-hydroxylation, and the distal water is suggested to enhance the third step as expected from the similarity. The HO mechanistic studies highlight the catalytic importance of the distal hydrogen-bonding network, and this manuscript also involves our attempts to develop HO inhibitors targeting the unique distal structure.
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Affiliation(s)
- Toshitaka Matsui
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Aoba, Sendai 980-8577, Japan.
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42
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Coupling and uncoupling mechanisms in the methoxythreonine mutant of cytochrome P450cam: a quantum mechanical/molecular mechanical study. J Biol Inorg Chem 2010; 15:361-72. [PMID: 20225401 PMCID: PMC2830628 DOI: 10.1007/s00775-009-0608-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The Thr252 residue plays a vital role in the catalytic cycle of cytochrome P450cam during the formation of the active species (Compound I) from its precursor (Compound 0). We investigate the effect of replacing Thr252 by methoxythreonine (MeO-Thr) on this protonation reaction (coupling) and on the competing formation of the ferric resting state and H2O2 (uncoupling) by combined quantum mechanical/molecular mechanical (QM/MM) methods. For each reaction, two possible mechanisms are studied, and for each of these the residues Asp251 and Glu366 are considered as proton sources. The computed QM/MM barriers indicate that uncoupling is unfavorable in the case of the Thr252MeO-Thr mutant, whereas there are two energetically feasible proton transfer pathways for coupling. The corresponding rate-limiting barriers for the formation of Compound I are higher in the mutant than in the wild-type enzyme. These findings are consistent with the experimental observations that the Thr252MeO-Thr mutant forms the alcohol product exclusively (via Compound I), but at lower reaction rates compared with the wild-type enzyme.
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43
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Effect of the axial ligands on the structure and reactivity of tin verdoheme in the ring opening process. Inorganica Chim Acta 2010. [DOI: 10.1016/j.ica.2009.12.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Affiliation(s)
- Ulrich Schatzschneider
- Lehrstuhl für Anorganische Chemie I – Bioanorganische Chemie and Research Department Interfacial Systems Chemistry (RD IFSC), Ruhr‐Universität Bochum NC 3/74, Universitätsstr. 150, 44801 Bochum, Germany, Fax: +49‐234‐32‐14378
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45
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Yeung CS, Ng PL, Guan X, Phillips DL. Water-Assisted Dehalogenation of Thionyl Chloride in the Presence of Water Molecules. J Phys Chem A 2010; 114:4123-30. [DOI: 10.1021/jp9106926] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chi Shun Yeung
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, People's Repubic of China
| | - Ping Leung Ng
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, People's Repubic of China
| | - Xiangguo Guan
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, People's Repubic of China
| | - David Lee Phillips
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, People's Repubic of China
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46
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Matsui T, Unno M, Ikeda-Saito M. Heme oxygenase reveals its strategy for catalyzing three successive oxygenation reactions. Acc Chem Res 2010; 43:240-7. [PMID: 19827796 DOI: 10.1021/ar9001685] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Heme oxygenase (HO) is an enzyme that catalyzes the regiospecific conversion of heme to biliverdin IXalpha, CO, and free iron. In mammals, HO has a variety of physiological functions, including heme catabolism, iron homeostasis, antioxidant defense, cellular signaling, and O(2) sensing. The enzyme is also found in plants (producing light-harvesting pigments) and in some pathogenic bacteria, where it acquires iron from the host heme. The HO-catalyzed heme conversion proceeds through three successive oxygenations, a process that has attracted considerable attention because of its reaction mechanism and physiological importance. The HO reaction is unique in that all three O(2) activations are affected by the substrate itself. The first step is the regiospecific self-hydroxylation of the porphyrin alpha-meso carbon atom. The resulting alpha-meso-hydroxyheme reacts in the second step with another O(2) to yield verdoheme and CO. The third O(2) activation, by verdoheme, cleaves its porphyrin macrocycle to release biliverdin and free ferrous iron. In this Account, we provide an overview of our current understanding of the structural and biochemical properties of the complex self-oxidation reactions in HO catalysis. The first meso-hydroxylation is of particular interest because of its distinct contrast with O(2) activation by cytochrome P450. Although most heme enzymes oxidize exogenous substrates by high-valent oxo intermediates, HO was proposed to utilize the Fe-OOH intermediate for the self-hydroxylation. We have succeeded in preparing and characterizing the Fe-OOH species of HO at low temperature, and an analysis of its reaction, together with mutational and crystallographic studies, reveals that protonation of Fe-OOH by a distal water molecule is critical in promoting the unique self-hydroxylation. The second oxygenation is a rapid, spontaneous auto-oxidation of the reactive alpha-meso-hydroxyheme; its mechanism remains elusive, but the HO enzyme has been shown not to play a critical role in it. Until recently, the means of the third O(2) activation had remained unclear as well, but we have recently untangled its mechanistic outline. Reaction analysis of the verdoheme-HO complex strongly suggests the Fe-OOH species as a key intermediate of the ring-opening reaction. This mechanism is very similar to that of the first meso-hydroxylation, including the critical roles of the distal water molecule. A comprehensive study of the three oxygenations of HO highlights the rational design of the enzyme architecture and its catalytic mechanism. Elucidation of the last oxygenation step has enabled a kinetic analysis of the rate-determining step, making it possible to discuss the HO reaction mechanism in relation to its physiological functions.
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Affiliation(s)
- Toshitaka Matsui
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Aoba, Sendai 980-8577, Japan
| | - Masaki Unno
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Aoba, Sendai 980-8577, Japan
| | - Masao Ikeda-Saito
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Aoba, Sendai 980-8577, Japan
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47
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Peng D, Ogura H, Zhu W, Ma LH, Evans JP, Ortiz de Montellano PR, La Mar GN. Coupling of the distal hydrogen bond network to the exogenous ligand in substrate-bound, resting state human heme oxygenase. Biochemistry 2009; 48:11231-42. [PMID: 19842713 DOI: 10.1021/bi901216s] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mammalian heme oxygenase (HO) possesses catalytically implicated distal ordered water molecules within an extended H-bond network, with one of the ordered water molecules (#1) providing a bridge between the iron-coordinated ligand and the catalytically critical Asp140, that, in turn, serves as an acceptor for the Tyr58 OH H-bond. The degree of H-bonding by the ligated water molecule and the coupling of this water molecule to the H-bond network are of current interest and are herein investigated by (1)H NMR. Two-dimensional NMR allowed sufficient assignments to provide both the H-bond strength and hyperfine shifts, the latter of which were used to quantify the magnetic anisotropy in both the ferric high-spin aquo and low-spin hydroxo complexes. The anisotropy in the aquo complex indicates that the H-bond donation to water #1 is marginally stronger than in a bacterial HO, while the anisotropy for the hydroxo complex reveals a conventional (d(xz), d(yz))(1) ground state indicative of only moderate to weak H-bond acceptance by the ligated hydroxide. Mapping out the changes of the H-bond strengths in the network during the ligated water --> hydroxide conversion by correcting for the effects of magnetic anisotropy reveals a very substantial change in H-bond strength for Tyr58 OH and lesser effects on nearby H-bonds. The effect of pH on the H-bonding network in human HO is much larger and transmitted much further from the iron than in a pathogenic bacterial HO. The implications for the HO mechanism of the H-bond of Tyr58 to Asp140 are discussed.
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Affiliation(s)
- Dungeng Peng
- Department of Chemistry, University of California, Davis, California 95616, USA
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Cramer CJ, Truhlar DG. Density functional theory for transition metals and transition metal chemistry. Phys Chem Chem Phys 2009; 11:10757-816. [PMID: 19924312 DOI: 10.1039/b907148b] [Citation(s) in RCA: 1079] [Impact Index Per Article: 71.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We introduce density functional theory and review recent progress in its application to transition metal chemistry. Topics covered include local, meta, hybrid, hybrid meta, and range-separated functionals, band theory, software, validation tests, and applications to spin states, magnetic exchange coupling, spectra, structure, reactivity, and catalysis, including molecules, clusters, nanoparticles, surfaces, and solids.
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Affiliation(s)
- Christopher J Cramer
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455-0431, USA.
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49
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Kwasnieski O, Verdier L, Malacria M, Derat E. Fixation of the two Tabun isomers in acetylcholinesterase: a QM/MM study. J Phys Chem B 2009; 113:10001-7. [PMID: 19569635 DOI: 10.1021/jp903843s] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Dysfunction of acetylcholinesterase (AChE) due to inhibition by organophosphorus (OP) compounds is a major threat since AChE is a key enzyme in neurotransmission. To more rigorously design reactivation agents, it is of prime importance to understand the mechanism of inhibition of AChE by OP compounds. Tabun is one of the more potent nerve agents. It is produced as a mixture of two enantiomers, one of them (the levorotatory isomer) being 6.3 times more potent. Could it be that the inhibition mechanism is different for the two enantiomers? To address this critical issue, we used a hybrid quantum mechanics/molecular mechanics (QM/MM) methodology. Calculations were performed using BP86 functional and TZVP basis set. Single points were also done with B3LYP and PBE0 functionals. We studied the four possible attacks of tabun on the oxygen of Ser203 using two crystallographic structures (PDB codes 2C0P and 3DL7): (S) tabun with the cyano group syn to the oxygen of Ser203 and (R) tabun with the cyano group anti, corresponding to the experimental X-ray structure; (S) tabun with the cyano group anti to the oxygen of Ser203 and (R) tabun with the cyano group syn, leading to a different isomer than was experimentally seen. We found that the most active enantiomer is (S) tabun with the cyano group syn to the oxygen of Ser203. Thus it seems that the cyano group does not leave anti to the oxygen of Ser203 due to repulsive polar interactions between cyanide and aromatic residues in the active site.
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Affiliation(s)
- Ophélie Kwasnieski
- Institut de chimie moléculaire, UMR CNRS 7201, UPMC University Paris 06, C. 229, 4 place Jussieu, 75005 Paris, France
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50
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Bhate MP, Woodard JC, Mehta MA. Solvation and Hydrogen Bonding in Alanine- and Glycine-Containing Dipeptides Probed Using Solution- and Solid-State NMR Spectroscopy. J Am Chem Soc 2009; 131:9579-89. [DOI: 10.1021/ja902917s] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Manasi P. Bhate
- Department of Chemistry and Biochemistry, Oberlin College, Oberlin, Ohio 44074
| | - Jaie C. Woodard
- Department of Chemistry and Biochemistry, Oberlin College, Oberlin, Ohio 44074
| | - Manish A. Mehta
- Department of Chemistry and Biochemistry, Oberlin College, Oberlin, Ohio 44074
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