1
|
Li RN, Chen SL. Mechanistic Insights into the N-Hydroxylations Catalyzed by the Binuclear Iron Domain of SznF Enzyme: Key Piece in the Synthesis of Streptozotocin. Chemistry 2024; 30:e202303845. [PMID: 38212866 DOI: 10.1002/chem.202303845] [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: 11/19/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 01/13/2024]
Abstract
SznF, a member of the emerging family of heme-oxygenase-like (HO-like) di-iron oxidases and oxygenases, employs two distinct domains to catalyze the conversion of Nω-methyl-L-arginine (L-NMA) into N-nitroso-containing product, which can subsequently be transformed into streptozotocin. Using unrestricted density functional theory (UDFT) with the hybrid functional B3LYP, we have mechanistically investigated the two sequential hydroxylations of L-NMA catalyzed by SznF's binuclear iron central domain. Mechanism B primarily involves the O-O bond dissociation, forming Fe(IV)=O, induced by the H+/e- introduction to the FeA side of μ-1,2-peroxo-Fe2(III/III), the substrate hydrogen abstraction by Fe(IV)=O, and the hydroxyl rebound to the substrate N radical. The stochastic addition of H+/e- to the FeB side (mechanism C) can transition to mechanism B, thereby preventing enzyme deactivation. Two other competing mechanisms, involving the direct O-O bond dissociation (mechanism A) and the addition of H2O as a co-substrate (mechanism D), have been ruled out.
Collapse
Affiliation(s)
- Rui-Ning Li
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Shi-Lu Chen
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| |
Collapse
|
2
|
Yang B, Song X, Wang B. DFT mechanistic study of biomimetic diiron complex catalyzed dehydrogenation: Unexpected Fe(III)Fe(III)-1,1-μ-hydroperoxy active species for hydride abstraction. J Inorg Biochem 2024; 251:112426. [PMID: 37980877 DOI: 10.1016/j.jinorgbio.2023.112426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/03/2023] [Accepted: 11/07/2023] [Indexed: 11/21/2023]
Abstract
The diiron active site is pivotal in catalyzing transformations in both biological and chemical systems. Recently, a range of biomimetic diiron catalysts have been synthesized, drawing inspiration from the active architecture of soluble methane monooxygenase (sMMO). These catalysts have been successfully deployed for the dehydrogenation of indolines, marking a significant advancement in the field. Using density functional theory (DFT) calculations, we have identified a novel mechanistic pathway that governs the dehydrogenation of indolines catalyzed by a biomimetic diiron complex. Specifically, this reaction is facilitated by the transfer of a hybrid atom from the C1 position of the substrate to the distal oxygen atom of the Fe(III)Fe(III)-1,1-μ-hydroperoxy active species. This transfer serves as the rate-limiting step for the heterolytic cleavage of the OO bond, ultimately generating the substrate cation. The mechanism we propose aligns well with mechanistic investigations incorporating both kinetic isotope effect (KIE) measurements and evaluations of stereochemical selectivity. This research contributes to the broader scientific understanding of catalysis involving biomimetic diiron complexes and offers valuable insights into the catalytic behaviors of non-heme diiron metalloenzymes.
Collapse
Affiliation(s)
- Boxuan Yang
- Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xitong Song
- Fujian Provincial Key Laboratory of Ecology-Toxicological Effects & Control for Emerging Contaminants, College of Environmental and Biological Engineering, Putian University, Putian 351100, China; Key Laboratory of Ecological Environment and Information Atlas, Fujian Provincial University (Putian University), Putian 351100, China
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| |
Collapse
|
3
|
Zhou TP, Deng WH, Wu Y, Liao RZ. QM/MM Calculations Suggested Concerted O‒O Bond Cleavage and Substrate Oxidation by Nonheme Diiron Toluene/o‐xylene Monooxygenase. Chem Asian J 2022; 17:e202200490. [DOI: 10.1002/asia.202200490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/01/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Tai-Ping Zhou
- Huazhong University of Science and Technology School of chemistry and chemical engineering CHINA
| | - Wen-Hao Deng
- Huazhong University of Science and Technology School of chemistry and chemical engineering CHINA
| | - Yuzhou Wu
- Huazhong University of Science and Technology School of chemistry and chemical engineering CHINA
| | - Rong-Zhen Liao
- Huazhong University of Science and technology College of Chemistry and Chemical Engeneering Luoyulu 1037 430074 Wuhan CHINA
| |
Collapse
|
4
|
Yeh CCG, Mokkawes T, Bradley J, Le Brun NE, de Visser S. Second coordination sphere effects on the mechanistic pathways for dioxygen activation by a ferritin: involvement of a Tyr radical and the identification of a cation binding site. Chembiochem 2022; 23:e202200257. [PMID: 35510795 PMCID: PMC9401865 DOI: 10.1002/cbic.202200257] [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: 05/04/2022] [Revised: 05/05/2022] [Indexed: 11/09/2022]
Abstract
Ferritins are ubiquitous diiron enzymes involved in iron(II) detoxification and oxidative stress responses and can act as metabolic iron stores. The overall reaction mechanisms of ferritin enzymes are still unclear, particularly concerning the role of the conserved, near catalytic center Tyr residue. Thus, we carried out a computational study of a ferritin using a large cluster model of well over 300 atoms including its first- and second-coordination sphere. The calculations reveal important insight into the structure and reactivity of ferritins. Specifically, the active site Tyr residue delivers a proton and electron in the catalytic cycle prior to iron(II) oxidation. In addition, the calculations highlight a likely cation binding site at Asp65, which through long-range electrostatic interactions, influences the electronic configuration and charge distributions of the metal center. The results are consistent with experimental observations but reveal novel detail of early mechanistic steps that lead to an unusual mixed-valent iron(III)-iron(II) center.
Collapse
Affiliation(s)
- Chieh-Chih George Yeh
- The University of Manchester, Department of Chemical Engineering, Oxford Road, Manchester, UNITED KINGDOM
| | - Thirakorn Mokkawes
- The University of Manchester, Department of Chemical Engineering, Manchester, UNITED KINGDOM
| | - Justin Bradley
- University of East Anglia, School of Chemistry, UNITED KINGDOM
| | - Nick E Le Brun
- University of East Anglia, School of Chemistry, UNITED KINGDOM
| | - Samuel de Visser
- The University of Manchester, Manchester Institute of Biotechnology, 131 Princess Street, M1 7DN, Manchester, UNITED KINGDOM
| |
Collapse
|
5
|
Tupec M, Culka M, Machara A, Macháček S, Bím D, Svatoš A, Rulíšek L, Pichová I. Understanding desaturation/hydroxylation activity of castor stearoyl Δ9-Desaturase through rational mutagenesis. Comput Struct Biotechnol J 2022; 20:1378-1388. [PMID: 35386101 PMCID: PMC8940945 DOI: 10.1016/j.csbj.2022.03.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 03/11/2022] [Accepted: 03/11/2022] [Indexed: 01/17/2023] Open
Abstract
Rationally designed mutations in the Δ9 desaturase promoted hydroxylation activity. Proton and electron transfer to the active site is crucial for the Δ9D to desaturate Detailed analysis of all enzymatic products of the Δ9D was carried out Insight into the chemo-, and stereoselectivity of non-heme diiron enzymes was obtained
A recently proposed reaction mechanism of soluble Δ9 desaturase (Δ9D) allowed us to identify auxiliary residues His203, Asp101, Thr206 and Cys222 localized near the di-iron active site that are supposedly involved in the proton transfer (PT) to and from the active site. The PT, along with the electron transfer (ET), seems to be crucial for efficient desaturation. Thus, perturbing the major PT chains is expected to impair the native reaction and (potentially) amplify minor reaction channels, such as the substrate hydroxylation. To verify this hypothesis, we mutated the four residues mentioned above into their counterparts present in a soluble methane monooxygenase (sMMO), and determined the reaction products of mutants. We found that the mutations significantly promote residual monohydroxylation activities on stearoyl-CoA, often at the expense of native desaturation activity. The favored hydroxylation positions are C9, followed by C10 and C11. Reactions with unsaturated substrate, oleoyl-CoA, yield erythro-9,10-diol, cis-9,10-epoxide and a mixture of allylic alcohols. Additionally, using 9- and 11-hydroxystearoyl-CoA, we showed that the desaturation reaction can proceed only with the hydroxyl group at position C11, whereas the hydroxylation reaction is possible in both cases, i.e. with hydroxyl at position C9 or C11. Despite the fact that the overall outcome of hydroxylation is rather modest and that it is mostly the desaturation/hydroxylation ratio that is affected, our results broaden understanding of the origin of chemo- and stereoselectivity of the Δ9D and provide further insight into the catalytic action of the NHFe2 enzymes.
Collapse
Affiliation(s)
- Michal Tupec
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 16610, Czech Republic
| | - Martin Culka
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 16610, Czech Republic
| | - Aleš Machara
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 16610, Czech Republic
| | - Stanislav Macháček
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 16610, Czech Republic
| | - Daniel Bím
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 16610, Czech Republic
| | - Aleš Svatoš
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 16610, Czech Republic
- Max-Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, Jena 07745, Germany
| | - Lubomír Rulíšek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 16610, Czech Republic
- Corresponding authors.
| | - Iva Pichová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 16610, Czech Republic
- Corresponding authors.
| |
Collapse
|
6
|
Bím D, Chalupský J, Culka M, Solomon EI, Rulíšek L, Srnec M. Proton-Electron Transfer to the Active Site Is Essential for the Reaction Mechanism of Soluble Δ 9-Desaturase. J Am Chem Soc 2020; 142:10412-10423. [PMID: 32406236 DOI: 10.1021/jacs.0c01786] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
A full understanding of the catalytic action of non-heme iron (NHFe) and non-heme diiron (NHFe2) enzymes is still beyond the grasp of contemporary computational and experimental techniques. Many of these enzymes exhibit fascinating chemo-, regio-, and stereoselectivity, in spite of employing highly reactive intermediates which are necessary for activations of most stable chemical bonds. Herein, we study in detail one intriguing representative of the NHFe2 family of enzymes: soluble Δ9 desaturase (Δ9D), which desaturates rather than performing the thermodynamically favorable hydroxylation of substrate. Its catalytic mechanism has been explored in great detail by using QM(DFT)/MM and multireference wave function methods. Starting from the spectroscopically observed 1,2-μ-peroxo diferric P intermediate, the proton-electron uptake by P is the favored mechanism for catalytic activation, since it allows a significant reduction of the barrier of the initial (and rate-determining) H-atom abstraction from the stearoyl substrate as compared to the "proton-only activated" pathway. Also, we ruled out that a Q-like intermediate (high-valent diamond-core bis-μ-oxo-[FeIV]2 unit) is involved in the reaction mechanism. Our mechanistic picture is consistent with the experimental data available for Δ9D and satisfies fairly stringent conditions required by Nature: the chemo-, stereo-, and regioselectivity of the desaturation of stearic acid. Finally, the mechanisms evaluated are placed into a broader context of NHFe2 chemistry, provided by an amino acid sequence analysis through the families of the NHFe2 enzymes. Our study thus represents an important contribution toward understanding the catalytic action of the NHFe2 enzymes and may inspire further work in NHFe(2) biomimetic chemistry.
Collapse
Affiliation(s)
- Daniel Bím
- J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, Prague 8 182 23, Czech Republic.,Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 166 10, Czech Republic
| | - Jakub Chalupský
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 166 10, Czech Republic
| | - Martin Culka
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 166 10, Czech Republic
| | - Edward I Solomon
- Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, California 94305-5080, United States
| | - Lubomír Rulíšek
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 166 10, Czech Republic
| | - Martin Srnec
- J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, Prague 8 182 23, Czech Republic
| |
Collapse
|
7
|
Wei WJ, Qian HX, Wang WJ, Liao RZ. Computational Understanding of the Selectivities in Metalloenzymes. Front Chem 2018; 6:638. [PMID: 30622942 PMCID: PMC6308299 DOI: 10.3389/fchem.2018.00638] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 12/07/2018] [Indexed: 01/26/2023] Open
Abstract
Metalloenzymes catalyze many different types of biological reactions with high efficiency and remarkable selectivity. The quantum chemical cluster approach and the combined quantum mechanics/molecular mechanics methods have proven very successful in the elucidation of the reaction mechanism and rationalization of selectivities in enzymes. In this review, recent progress in the computational understanding of various selectivities including chemoselectivity, regioselectivity, and stereoselectivity, in metalloenzymes, is discussed.
Collapse
Affiliation(s)
| | | | | | - Rong-Zhen Liao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, China
| |
Collapse
|
8
|
Wei W, Siegbahn PEM, Liao R. Mechanism of the Dinuclear Iron Enzymep‐Aminobenzoate N‐oxygenase from Density Functional Calculations. ChemCatChem 2018. [DOI: 10.1002/cctc.201801072] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Wen‐Jie Wei
- Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of Education Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica Hubei Key Laboratory of Materials Chemistry and Service Failure School of Chemistry and Chemical EngineeringHuazhong University of Science and Technology Wuhan 430074 P. R. China
| | - Per E. M. Siegbahn
- Department of Organic Chemistry, Arrhenius LaboratoryStockholm University Stockholm SE-10691 Sweden
| | - Rong‐Zhen Liao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of Education Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica Hubei Key Laboratory of Materials Chemistry and Service Failure School of Chemistry and Chemical EngineeringHuazhong University of Science and Technology Wuhan 430074 P. R. China
| |
Collapse
|
9
|
Roy L. Theoretical Insights into the Nature of Oxidant and Mechanism in the Regioselective Syn
-dihydroxylation of an Alkene with a Rieske oxygenase inspired Iron Catalyst. ChemCatChem 2018. [DOI: 10.1002/cctc.201800799] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Lisa Roy
- Surface Engineering and Tribology Division; CSIR Central Mechanical Engineering Research Institute; Mahatma Gandhi Avenue Durgapur 713209 India
| |
Collapse
|