1
|
Sutradhar S, Rahaman R, Bhattacharya S, Paul S, Paine TK. Oxygenolytic cleavage of 1,2-diols with dioxygen by a mononuclear nonheme iron complex: Mimicking the reaction of myo-inositol oxygenase. J Inorg Biochem 2024; 257:112611. [PMID: 38788359 DOI: 10.1016/j.jinorgbio.2024.112611] [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: 02/14/2024] [Revised: 05/08/2024] [Accepted: 05/09/2024] [Indexed: 05/26/2024]
Abstract
A mononuclear iron(II) complex, [(TpPh2)FeII(OTf)(CH3CN)] (1) (TpPh2 = hydrotris(3,5-diphenylpyrazol-1-yl)borate, OTf = triflate) has been isolated and its efficiency toward the aliphatic CC bond cleavage reaction of 1,2-diols with dioxygen has been investigated. Separate reactions between 1 and different 1,2-diolates form the corresponding iron(II)-diolate complexes in solution. While the iron(II) complex of the tetradentate TPA (tris(2-pyridylmethyl)amine) ligand is not efficient in affecting the CC cleavage of 1,2-diol with dioxygen, complex 1 displays catalytic activity to afford carboxylic acid and aldehyde. Isotope labeling studies with 18O2 reveal that one oxygen atom from dioxygen is incorporated into the carboxylic acid product. The oxygenative CC cleavage reactions occur on the 1,2-diols containing at least one α-H atom. The kinetic isotope effect value of 5.7 supports the abstraction of an α-H by an iron(III)-superoxo species to propagate the CC cleavage reactions. The oxidative cleavage of 1,2-diolates by the iron(II) complex mimics the reaction catalyzed by the nonheme diiron enzyme, myo-inositol oxygenase.
Collapse
Affiliation(s)
- Subhankar Sutradhar
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A&2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Rubina Rahaman
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A&2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India; Department of Chemistry, Krishnagar Government College, Krishnagar, West Bengal 741101, India
| | - Shrabanti Bhattacharya
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A&2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Satadal Paul
- Department of Chemistry, Bangabasi Morning College, 19 Rajkumar Chakraborty Sarani, Kolkata 700009, India
| | - Tapan Kanti Paine
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A&2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India.
| |
Collapse
|
2
|
Liu J, Wu P, Yan S, Li Y, Cao Z, Wang B. Spin-Regulated Inner-Sphere Electron Transfer Enables Efficient O—O Bond Activation in Nonheme Diiron Monooxygenase MIOX. ACS Catal 2021. [DOI: 10.1021/acscatal.1c00898] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Jia Liu
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| | - Peng Wu
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| | - Shengheng Yan
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| | - Yuanyuan Li
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, China
| | - Zexing Cao
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| | - Binju Wang
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| |
Collapse
|
3
|
Chen LZ, Huang SL, Hou J, Guo XP, Wang FS, Sheng JZ. Cell-based and cell-free biocatalysis for the production of D-glucaric acid. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:203. [PMID: 33303009 PMCID: PMC7731778 DOI: 10.1186/s13068-020-01847-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 12/02/2020] [Indexed: 05/17/2023]
Abstract
D-Glucaric acid (GA) is a value-added chemical produced from biomass, and has potential applications as a versatile platform chemical, food additive, metal sequestering agent, and therapeutic agent. Marketed GA is currently produced chemically, but increasing demand is driving the search for eco-friendlier and more efficient production approaches. Cell-based production of GA represents an alternative strategy for GA production. A series of synthetic pathways for GA have been ported into Escherichia coli, Saccharomyces cerevisiae and Pichia pastoris, respectively, and these engineered cells show the ability to synthesize GA de novo. Optimization of the GA metabolic pathways in host cells has leapt forward, and the titer and yield have increased rapidly. Meanwhile, cell-free multi-enzyme catalysis, in which the desired pathway is constructed in vitro from enzymes and cofactors involved in GA biosynthesis, has also realized efficient GA bioconversion. This review presents an overview of studies of the development of cell-based GA production, followed by a brief discussion of potential applications of biosensors that respond to GA in these biosynthesis routes.
Collapse
Affiliation(s)
- Lu-Zhou Chen
- Key Laboratory of Chemical Biology of Natural Products (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China
| | - Si-Ling Huang
- Bloomage BioTechnology Corp., Ltd., Jinan, 250010, China
| | - Jin Hou
- The State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Xue-Ping Guo
- Bloomage BioTechnology Corp., Ltd., Jinan, 250010, China
| | - Feng-Shan Wang
- Key Laboratory of Chemical Biology of Natural Products (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China
- National Glycoengineering Research Center, Shandong University, Jinan, 250012, China
| | - Ju-Zheng Sheng
- Key Laboratory of Chemical Biology of Natural Products (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China.
- National Glycoengineering Research Center, Shandong University, Jinan, 250012, China.
| |
Collapse
|
4
|
Zheng S, Wei P, Huang L, Cai J, Xu Z. Efficient expression of myo-inositol oxygenase in Escherichia coli and application for conversion of myo-inositol to glucuronic acid. Food Sci Biotechnol 2014. [DOI: 10.1007/s10068-014-0061-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
5
|
Majumdar A, Apfel UP, Jiang Y, Moënne-Loccoz P, Lippard SJ. Versatile reactivity of a solvent-coordinated diiron(II) compound: synthesis and dioxygen reactivity of a mixed-valent Fe(II)Fe(III) species. Inorg Chem 2014; 53:167-81. [PMID: 24359397 PMCID: PMC3915513 DOI: 10.1021/ic4019585] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A new, DMF-coordinated, preorganized diiron compound [Fe2(N-Et-HPTB)(DMF)4](BF4)3 (1) was synthesized, avoiding the formation of [Fe(N-Et-HPTB)](BF4)2 (10) and [Fe2(N-Et-HPTB)(μ-MeCONH)](BF4)2 (11), where N-Et-HPTB is the anion of N,N,N',N'-tetrakis[2-(1-ethylbenzimidazolyl)]-2-hydroxy-1,3-diaminopropane. Compound 1 is a versatile reactant from which nine new compounds have been generated. Transformations include solvent exchange to yield [Fe2(N-Et-HPTB)(MeCN)4](BF4)3 (2), substitution to afford [Fe2(N-Et-HPTB)(μ-RCOO)](BF4)2 (3, R = Ph; 4, RCOO = 4-methyl-2,6-diphenyl benzoate]), one-electron oxidation by (Cp2Fe)(BF4) to yield a Robin-Day class II mixed-valent diiron(II,III) compound, [Fe2(N-Et-HPTB)(μ-PhCOO)(DMF)2](BF4)3 (5), two-electron oxidation with tris(4-bromophenyl)aminium hexachloroantimonate to generate [Fe2(N-Et-HPTB)Cl3(DMF)](BF4)2 (6), reaction with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl to form [Fe5(N-Et-HPTB)2(μ-OH)4(μ-O)(DMF)2](BF4)4 (7), and reaction with dioxygen to yield an unstable peroxo compound that decomposes at room temperature to generate [Fe4(N-Et-HPTB)2(μ-O)3(H2O)2](BF4)·8DMF (8) and [Fe4(N-Et-HPTB)2(μ-O)4](BF4)2 (9). Compound 5 loses its bridging benzoate ligand upon further oxidation to form [Fe2(N-Et-HPTB)(OH)2(DMF)2](BF4)3 (12). Reaction of the diiron(II,III) compound 5 with dioxygen was studied in detail by spectroscopic methods. All compounds (1-12) were characterized by single-crystal X-ray structure determinations. Selected compounds and reaction intermediates were further examined by a combination of elemental analysis, electronic absorption spectroscopy, Mössbauer spectroscopy, EPR spectroscopy, resonance Raman spectroscopy, and cyclic voltammetry.
Collapse
Affiliation(s)
- Amit Majumdar
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Ulf-Peter Apfel
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Yunbo Jiang
- Division of Environmental and Biomolecular Systems, Institute of Environmental Health, Oregon Health and Science University, Portland, Oregon 97239
| | - Pierre Moënne-Loccoz
- Division of Environmental and Biomolecular Systems, Institute of Environmental Health, Oregon Health and Science University, Portland, Oregon 97239
| | - Stephen J. Lippard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| |
Collapse
|
6
|
Organophosphonate-degrading PhnZ reveals an emerging family of HD domain mixed-valent diiron oxygenases. Proc Natl Acad Sci U S A 2013; 110:18874-9. [PMID: 24198335 DOI: 10.1073/pnas.1315927110] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The founding members of the HD-domain protein superfamily are phosphohydrolases, and newly discovered members are generally annotated as such. However, myo-inositol oxygenase (MIOX) exemplifies a second, very different function that has evolved within the common scaffold of this superfamily. A recently discovered HD protein, PhnZ, catalyzes conversion of 2-amino-1-hydroxyethylphosphonate to glycine and phosphate, culminating a bacterial pathway for the utilization of environmentally abundant 2-aminoethylphosphonate. Using Mössbauer and EPR spectroscopies, X-ray crystallography, and activity measurements, we show here that, like MIOX, PhnZ employs a mixed-valent Fe(II)/Fe(III) cofactor for the O2-dependent oxidative cleavage of its substrate. Phylogenetic analysis suggests that many more HD proteins may catalyze yet-unknown oxygenation reactions using this hitherto exceptional Fe(II)/Fe(III) cofactor. The results demonstrate that the catalytic repertoire of the HD superfamily extends well beyond phosphohydrolysis and suggest that the mechanism used by MIOX and PhnZ may be a common strategy for oxidative C-X bond cleavage.
Collapse
|
7
|
Snyder RA, Bell CB, Diao Y, Krebs C, Bollinger JM, Solomon EI. Circular dichroism, magnetic circular dichroism, and variable temperature variable field magnetic circular dichroism studies of biferrous and mixed-valent myo-inositol oxygenase: insights into substrate activation of O2 reactivity. J Am Chem Soc 2013; 135:15851-63. [PMID: 24066857 DOI: 10.1021/ja406635k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
myo-Inositol oxygenase (MIOX) catalyzes the 4e(-) oxidation of myo-inositol (MI) to D-glucuronate using a substrate activated Fe(II)Fe(III) site. The biferrous and Fe(II)Fe(III) forms of MIOX were studied with circular dichroism (CD), magnetic circular dichroism (MCD), and variable temperature variable field (VTVH) MCD spectroscopies. The MCD spectrum of biferrous MIOX shows two ligand field (LF) transitions near 10000 cm(-1), split by ~2000 cm(-1), characteristic of six coordinate (6C) Fe(II) sites, indicating that the modest reactivity of the biferrous form toward O2 can be attributed to the saturated coordination of both irons. Upon oxidation to the Fe(II)Fe(III) state, MIOX shows two LF transitions in the ~10000 cm(-1) region, again implying a coordinatively saturated Fe(II) site. Upon MI binding, these split in energy to 5200 and 11200 cm(-1), showing that MI binding causes the Fe(II) to become coordinatively unsaturated. VTVH MCD magnetization curves of unbound and MI-bound Fe(II)Fe(III) forms show that upon substrate binding, the isotherms become more nested, requiring that the exchange coupling and ferrous zero-field splitting (ZFS) both decrease in magnitude. These results imply that MI binds to the ferric site, weakening the Fe(III)-μ-OH bond and strengthening the Fe(II)-μ-OH bond. This perturbation results in the release of a coordinated water from the Fe(II) that enables its O2 activation.
Collapse
Affiliation(s)
- Rae Ana Snyder
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
| | | | | | | | | | | |
Collapse
|
8
|
Alford SR, Rangarajan P, Williams P, Gillaspy GE. myo-Inositol Oxygenase is Required for Responses to Low Energy Conditions in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2012; 3:69. [PMID: 22639659 PMCID: PMC3355591 DOI: 10.3389/fpls.2012.00069] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 03/22/2012] [Indexed: 05/03/2023]
Abstract
myo-Inositol is a precursor for cell wall components, is used as a backbone of myo-inositol trisphosphate (Ins(1,4,5)P(3)) and phosphatidylinositol phosphate signaling molecules, and is debated about whether it is also a precursor in an alternate ascorbic acid synthesis pathway. Plants control inositol homeostasis by regulation of key enzymes involved in myo-inositol synthesis and catabolism. Recent transcriptional profiling data indicate up-regulation of the myo-inositol oxygenase (MIOX) genes under conditions in which energy or nutrients are limited. To test whether the MIOX genes are required for responses to low energy, we first examined MIOX2 and MIOX4 gene expression regulation by energy/nutrient conditions. We found that both MIOX2 and MIOX4 expression are suppressed by exogenous glucose addition in the shoot, but not in the root. Both genes were abundantly expressed during low energy/nutrient conditions. Loss-of-function mutants in MIOX genes contain alterations in myo-inositol levels and growth changes in the root. Miox2 mutants can be complemented with a MIOX2:green fluorescent protein fusion. Further we show here that MIOX2 is a cytoplasmic protein, while MIOX4 is present mostly in the cytoplasm, but also occasionally in the nucleus. Together, these data suggest that MIOX catabolism in the shoot may influence root growth responses during low energy/nutrient conditions.
Collapse
Affiliation(s)
| | | | - Phoebe Williams
- Department of Biochemistry, Virginia TechBlacksburg, VA, USA
| | - Glenda E. Gillaspy
- Department of Biochemistry, Virginia TechBlacksburg, VA, USA
- *Correspondence: Glenda E. Gillaspy, Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA. e-mail:
| |
Collapse
|
9
|
Endres S, Tenhaken R. Down-regulation of the myo-inositol oxygenase gene family has no effect on cell wall composition in Arabidopsis. PLANTA 2011; 234:157-69. [PMID: 21394467 PMCID: PMC3123461 DOI: 10.1007/s00425-011-1394-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Accepted: 02/24/2011] [Indexed: 05/19/2023]
Abstract
The enzyme myo-inositol oxygenase (MIOX; E.C. 1.13.99.1) catalyzes the ring-opening four-electron oxidation of myo-inositol into glucuronic acid, which is subsequently activated to UDP-glucuronic acid (UDP-GlcA) and serves as a precursor for plant cell wall polysaccharides. Starting from single T-DNA insertion lines in different MIOX-genes a quadruple knockdown (miox1/2/4/5-mutant) was obtained by crossing, which exhibits greater than 90% down-regulation of all four functional MIOX genes. Miox1/2/4/5-mutant shows no visible phenotype and produces viable pollen. The alternative pathway to UDP-glucuronic acid via UDP-glucose is upregulated in the miox1/2/4/5-mutant as a compensatory mechanism. Miox1/2/4/5-mutant is impaired in the utilization of myo-inositol for seedling growth. The incorporation of myo-inositol derived sugars into cell walls is strongly (>90%) inhibited. Instead, myo-inositol and metabolites produced from myo-inositol such as galactinol accumulate in the miox1/2/4/5-mutant. The increase in galactinol and raffinose family oligosaccharides does not enhance stress tolerance. The ascorbic acid levels are the same in mutant and wild type plants.
Collapse
Affiliation(s)
- Stefanie Endres
- Department of Cell Biology, Plant Physiology, University of Salzburg, Hellbrunnerstr. 34, 5020 Salzburg, Austria
| | - Raimund Tenhaken
- Department of Cell Biology, Plant Physiology, University of Salzburg, Hellbrunnerstr. 34, 5020 Salzburg, Austria
| |
Collapse
|
10
|
van der Donk WA, Krebs C, Bollinger JM. Substrate activation by iron superoxo intermediates. Curr Opin Struct Biol 2010; 20:673-83. [PMID: 20951572 PMCID: PMC3030196 DOI: 10.1016/j.sbi.2010.08.005] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 08/21/2010] [Indexed: 11/17/2022]
Abstract
A growing number of non-heme-iron oxygenases and oxidases catalyze reactions for which the well-established mechanistic paradigm involving a single C-H-bond-cleaving intermediate of the Fe(IV)-oxo (ferryl) type [1(•)] is insufficient to explain the chemistry. It is becoming clear that, in several of these cases, Fe(III)-superoxide complexes formed by simple addition of O(2) to the reduced [Fe(II)] cofactor initiate substrate oxidation by abstracting hydrogen [2,3(•)]. This substrate-oxidizing entry route into high-valent-iron intermediates makes possible an array of complex and elegant oxidation reactions without the consumption of valuable reducing equivalents. Examples of this novel mechanistic strategy are discussed with the goal of bringing forth unifying principles.
Collapse
Affiliation(s)
- Wilfred A. van der Donk
- Department of Chemistry and Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave, Urbana, Illinois 61801, USA,
| | - Carsten Krebs
- Department of Chemistry and Department of Biochemistry and Molecular Biology, Penn State University, 332 Chemistry Building, University Park, PA, 16802, USA,
| | - J. Martin Bollinger
- Department of Chemistry and Department of Biochemistry and Molecular Biology, Penn State University, 336 Chemistry Building, University Park, PA, 16802, USA,
| |
Collapse
|
11
|
Hirao H, Morokuma K. Insights into the (superoxo)Fe(III)Fe(III) intermediate and reaction mechanism of myo-inositol oxygenase: DFT and ONIOM(DFT:MM) study. J Am Chem Soc 2010; 131:17206-14. [PMID: 19929019 DOI: 10.1021/ja905296w] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The (superoxo)Fe(III)Fe(III) reactive species and the catalytic reaction mechanism of a diiron enzyme, myo-inositol oxygenase (MIOX), were theoretically investigated by means of density functional theory (DFT) and ONIOM quantum mechanical/molecular mechanical (QM/MM) approaches. The ground state of the (superoxo)Fe(III)Fe(III) intermediate was shown to have a side-on coordination geometry and an S = 1/2 spin state, wherein the two iron sites are antiferromagnetically coupled while the superoxide site and the nearest iron are ferromagnetically coupled. A full reaction pathway leading to a D-glucuronate product from myo-inositol was proposed based on ONIOM computational results. Two major roles of the enzyme surrounding during the catalytic reaction were identified. One is to facilitate the initial H-abstraction step, and the other is to restrict the movement of the substrate via H-bonding interactions in order to avoid unwanted side reactions. In our proposed mechanism, O-O bond cleavage has the highest barrier, thus constituting the rate-limiting step of the reaction. The unique role of the bridging hydroxide ligand as a catalytic base was also identified.
Collapse
Affiliation(s)
- Hajime Hirao
- Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
| | | |
Collapse
|
12
|
Bollinger JM, Diao Y, Matthews ML, Xing G, Krebs C. myo-Inositol oxygenase: a radical new pathway for O(2) and C-H activation at a nonheme diiron cluster. Dalton Trans 2009:905-14. [PMID: 19173070 PMCID: PMC2788986 DOI: 10.1039/b811885j] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The enzyme myo-inositol oxygenase (MIOX) catalyzes conversion of myo-inositol (cyclohexan-1,2,3,5/4,6-hexa-ol or MI) to d-glucuronate (DG), initiating the only known pathway in humans for catabolism of the carbon skeleton of cell-signaling inositol (poly)phosphates and phosphoinositides. Recent kinetic, spectroscopic and crystallographic studies have shown that the enzyme activates its substrates, MI and O(2), at a carboxylate-bridged nonheme diiron(ii/iii) cluster, making it the first of many known nonheme diiron oxygenases to employ the mixed-valent form of its cofactor. Evidence suggests that: (1) the Fe(iii) site coordinates MI via its C1 and C6 hydroxyl groups; (2) the Fe(ii) site reversibly coordinates O(2) to produce a superoxo-diiron(iii/iii) intermediate; and (3) the pendant oxygen atom of the superoxide ligand abstracts hydrogen from C1 to initiate the unique C-C-bond-cleaving, four-electron oxidation reaction. This review recounts the studies leading to the recognition of the novel cofactor requirement and catalytic mechanism of MIOX and forecasts how remaining gaps in our understanding might be filled by additional experiments.
Collapse
Affiliation(s)
- J. Martin Bollinger
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Yinghui Diao
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Megan L. Matthews
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Gang Xing
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Carsten Krebs
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| |
Collapse
|
13
|
Kim SH, Xing G, Bollinger JM, Krebs C, Hoffman BM. Demonstration by 2H ENDOR spectroscopy that myo-inositol binds via an alkoxide bridge to the mixed-valent diiron center of myo-inositol oxygenase. J Am Chem Soc 2007; 128:10374-5. [PMID: 16895396 DOI: 10.1021/ja063602c] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
myo-Inositol oxygenase (MIOX) is a non-heme diiron oxygenase that cleaves cyclohexane-(1,2,3,5/4,6-hexa)-ol (myo-inositol, MI) to d-glucuronate. Here, we use 2H ENDOR spectroscopy to demonstrate that MI binds to the diiron(II/III) cofactor of MIOX via an alkoxide bridge, most likely involving O1. Analysis shows that MI adopts a symmetrical geometry in which the O-C-2H plane of the bridge is approximately orthogonal to the Fe-O-Fe plane.
Collapse
Affiliation(s)
- Sun Hee Kim
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA
| | | | | | | | | |
Collapse
|
14
|
Brown PM, Caradoc-Davies TT, Dickson JMJ, Cooper GJS, Loomes KM, Baker EN. Crystal structure of a substrate complex of myo-inositol oxygenase, a di-iron oxygenase with a key role in inositol metabolism. Proc Natl Acad Sci U S A 2006; 103:15032-7. [PMID: 17012379 PMCID: PMC1622774 DOI: 10.1073/pnas.0605143103] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Indexed: 11/18/2022] Open
Abstract
Altered metabolism of the inositol sugars myo-inositol (MI) and d-chiro-inositol is implicated in diabetic complications. In animals, catabolism of MI and D-chiro-inositol depends on the enzyme MI oxygenase (MIOX), which catalyzes the first committed step of the glucuronate-xylulose pathway, and is found almost exclusively in the kidneys. The crystal structure of MIOX, in complex with MI, has been determined by multiwavelength anomalous diffraction methods and refined at 2.0-A resolution (R=0.206, Rfree=0.253). The structure reveals a monomeric, single-domain protein with a mostly helical fold that is distantly related to the diverse HD domain superfamily. Five helices form the structural core and provide six ligands (four His and two Asp) for the di-iron center, in which the two iron atoms are bridged by a putative hydroxide ion and one of the Asp ligands, Asp-124. A key loop forms a lid over the MI substrate, which is coordinated in bidentate mode to one iron atom. It is proposed that this mode of iron coordination, and interaction with a key Lys residue, activate MI for bond cleavage. The structure also reveals the basis of substrate specificity and suggests routes for the development of specific MIOX inhibitors.
Collapse
Affiliation(s)
- Peter M. Brown
- *Maurice Wilkins Centre for Molecular Biodiscovery
- School of Biological Sciences, and
| | - Tom T. Caradoc-Davies
- *Maurice Wilkins Centre for Molecular Biodiscovery
- School of Biological Sciences, and
| | - James M. J. Dickson
- *Maurice Wilkins Centre for Molecular Biodiscovery
- School of Biological Sciences, and
| | - Garth J. S. Cooper
- *Maurice Wilkins Centre for Molecular Biodiscovery
- School of Biological Sciences, and
| | - Kerry M. Loomes
- *Maurice Wilkins Centre for Molecular Biodiscovery
- School of Biological Sciences, and
| | - Edward N. Baker
- *Maurice Wilkins Centre for Molecular Biodiscovery
- School of Biological Sciences, and
- Department of Chemistry, University of Auckland, Auckland 1142, New Zealand
| |
Collapse
|
15
|
Xing G, Diao Y, Hoffart LM, Barr EW, Prabhu KS, Arner RJ, Reddy CC, Krebs C, Bollinger JM. Evidence for C-H cleavage by an iron-superoxide complex in the glycol cleavage reaction catalyzed by myo-inositol oxygenase. Proc Natl Acad Sci U S A 2006; 103:6130-5. [PMID: 16606846 PMCID: PMC1458843 DOI: 10.1073/pnas.0508473103] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
myo-Inositol oxygenase (MIOX) activates O2 at a mixed-valent nonheme diiron(II/III) cluster to effect oxidation of its cyclohexan-(1,2,3,4,5,6-hexa)-ol substrate [myo-inositol (MI)] by four electrons to d-glucuronate. Abstraction of hydrogen from C1 by a formally (superoxo)diiron(III/III) intermediate was previously proposed. Use of deuterium-labeled substrate, 1,2,3,4,5,6-[2H]6-MI (D6-MI), has now permitted initial characterization of the C-H-cleaving intermediate. The MIOX.1,2,3,4,5,6-[2H]6-MI complex reacts rapidly and reversibly with O2 to form an intermediate, G, with a g = (2.05, 1.98, 1.90) EPR signal. The rhombic g-tensor and observed hyperfine coupling to 57Fe are rationalized in terms of a (superoxo)diiron(III/III) structure with coordination of the superoxide to a single iron. G decays to H, the intermediate previously detected in the reaction with unlabeled substrate. This step is associated with a kinetic isotope effect of > or =5, showing that the superoxide-level complex does indeed cleave a C-H(D) bond of MI.
Collapse
Affiliation(s)
- Gang Xing
- *Departments of Biochemistry and Molecular Biology
| | - Yinghui Diao
- *Departments of Biochemistry and Molecular Biology
| | | | - Eric W. Barr
- *Departments of Biochemistry and Molecular Biology
| | | | | | | | - Carsten Krebs
- *Departments of Biochemistry and Molecular Biology
- Chemistry, Pennsylvania State University, University Park, PA 16802
- To whom correspondence may be addressed. E-mail:
or
| | - J. Martin Bollinger
- *Departments of Biochemistry and Molecular Biology
- Chemistry, Pennsylvania State University, University Park, PA 16802
- To whom correspondence may be addressed. E-mail:
or
| |
Collapse
|
16
|
Arner RJ, Prabhu KS, Reddy CC. Molecular cloning, expression, and characterization of myo-inositol oxygenase from mouse, rat, and human kidney. Biochem Biophys Res Commun 2004; 324:1386-92. [PMID: 15504367 DOI: 10.1016/j.bbrc.2004.09.209] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2004] [Indexed: 11/29/2022]
Abstract
myo-Inositol oxygenase (MIOX) is a non-heme iron enzyme, which catalyzes the conversion of myo-inositol to d-glucuronic acid, the first committed step in myo-inositol catabolism. Full-length cDNAs of 858bp each coding for 33kDa protein were cloned from kidney cDNA libraries of mouse, rat, and human. The individual clones were expressed in Escherichia coli and recombinant MIOX proteins were purified to electrophoretic homogeneity. A hydrophobic interaction chromatography step yielded multiple conformers, with mouse and human MIOX showing three peaks and rat enzyme revealing two peaks. Individual MIOX peaks exhibited distinct V(max) and K(m) values. Interestingly, upon storage, the 33kDa protein was degraded to a approximately 30kDa truncated protein in each species, and formed small amounts of dimers of identical subunits. While MIOX is a highly conserved enzyme in all mammalian species, the labile nature and tendency to degrade in solution may be the source of significant differences in size previously reported in the literature. Regardless of the source, our results strongly dispel previous conflicting literature reports on the size of the protein and confirm that MIOX is a 33kDa protein.
Collapse
Affiliation(s)
- Ryan J Arner
- Department of Veterinary Science, Center for Molecular Toxicology and Carcinogensis, 115 Henning Building, The Pennsylvania State University, University Park, PA 16802, USA
| | | | | |
Collapse
|
17
|
Arner RJ, Prabhu KS, Thompson JT, Hildenbrandt GR, Liken AD, Reddy CC. myo-Inositol oxygenase: molecular cloning and expression of a unique enzyme that oxidizes myo-inositol and D-chiro-inositol. Biochem J 2001; 360:313-20. [PMID: 11716759 PMCID: PMC1222231 DOI: 10.1042/0264-6021:3600313] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
myo-Inositol oxygenase (MIOX) catalyses the first committed step in the only pathway of myo-inositol catabolism, which occurs predominantly in the kidney. The enzyme is a non-haem-iron enzyme that catalyses the ring cleavage of myo-inositol with the incorporation of a single atom of oxygen. A full-length cDNA was isolated from a pig kidney library with an open reading frame of 849 bp and a corresponding protein subunit molecular mass of 32.7 kDa. The cDNA was expressed in a bacterial pET expression system and an active recombinant MIOX was purified from bacterial lysates to electrophoretic homogeneity. The purified enzyme displayed the same catalytic properties as the native enzyme with K(m) and k(cat) values of 5.9 mM and 11 min(-1) respectively. The pI was estimated to be 4.5. Preincubation with 1 mM Fe(2+) and 2 mM cysteine was essential for the enzyme's activity. D-chiro-Inositol, a myo-inositol isomer, is a substrate for the recombinant MIOX with an estimated K(m) of 33.5 mM. Both myo-inositol and D-chiro-inositol have been implicated in the pathogenesis of diabetes. Thus an understanding of the regulation of MIOX expression clearly represents a potential window on the aetiology of diabetes as well as on the control of various intracellular phosphoinositides and key signalling pathways.
Collapse
Affiliation(s)
- R J Arner
- Department of Veterinary Science and Center for Molecular Toxicology and Carcinogenesis, 115 Henning Building, The Pennsylvania State University, University Park, PA 16802, USA
| | | | | | | | | | | |
Collapse
|
18
|
Koller F, Koller E. myo-inositol oxygenase from rat kidneys. Substrate-dependent oligomerization. EUROPEAN JOURNAL OF BIOCHEMISTRY 1990; 193:421-7. [PMID: 2226462 DOI: 10.1111/j.1432-1033.1990.tb19355.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
myo-Inositol from rat kidneys, an oligomeric protein with apparent molecular mass of about 270 kDa can be dissociated under mild conditions to structured 16.8-kDa monomers. This dissociation can be reversed at high protein concentrations at room temperature. The corresponding apparent dimerization constant K2app = 1.38 x 10(5) M-1, the corresponding rate constant k2 = 350 s-1.M-1, and the apparent constant for the association of dimers, K4app = 2.7 x 10(6) M-1. Reassociation is significantly enhanced in the presence of the substrate and iron(II) (K2app = 9.8 x 10(5) M-1; K4app = 3.75 x 10(6) M-1, k2 = 1750 s-1.M-1, at 20 mM myo-inositol and 0.5 mM FeSO4). Under these conditions almost 100% of the original enzymatic activity was reconstituted. Monomers, with or without bound ligands, lack catalytic activity, whereas the dimer is likely to be the elementary active enzyme-building unit. The effects of myo-inositol on the dimerization lead to the conclusion that this step is both mediated and facilitated by the substrate.
Collapse
Affiliation(s)
- F Koller
- Institut für Allgemeine Biochemie, University of Vienna, Austria
| | | |
Collapse
|
19
|
Naber NI, Hamilton GA. Concerning the mechanism for transfer of D-glucuronate from myo-inositol oxygenase to D-glucuronate reductase. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 911:365-8. [PMID: 3814609 DOI: 10.1016/0167-4838(87)90078-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The D-glucuronate product of myo-inositol oxygenase (EC 1.13.99.1) is efficiently reduced by NADPH in the presence of either purified D-glucuronate reductase (EC 1.1.1.19), or reductase that is part of a protein aggregate that also contains the oxygenase. This occurs despite the fact that the maximum concentration of D-glucuronate that could be formed by the oxygenase under the conditions used for the coupled enzyme experiments is 7 microM, and 10 microM externally supplied D-glucuronate (Km = 7.6 mM) does not support any detectable NADPH oxidation under the reaction conditions. The most likely explanation for the results is that the uncyclized aldehyde form of D-glucuronate is the product of the oxygenase reaction, and that it diffuses into solution and is captured by the reductase before it cyclizes to the more stable but less reactive hemiacetal form.
Collapse
|
20
|
Naber NI, Swan JS, Hamilton GA. L-myo-inosose-1 as a probable intermediate in the reaction catalyzed by myo-inositol oxygenase. Biochemistry 1986; 25:7201-7. [PMID: 3801412 DOI: 10.1021/bi00370a065] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In previous investigations, it was necessary to have Fe(II) and cysteine present in order to assay the catalytic activity of purified hog kidney myo-inositol oxygenase. In the present study it was found that, if this purified nonheme iron enzyme is slowly frozen in solution with glutathione and stored at -20 degrees C, it is fully active in the absence of activators if catalase is present to remove adventitious H2O2. With this simpler assay system it was possible to clarify the effects of several variables on the enzymic reaction. Thus, the maximum velocity is pH-dependent with a maximum around pH 9.5, but the apparent Km for myo-inositol (air atmosphere) remains constant at 5.0 mM throughout a broad pH range. The enzyme is quite specific for its substrate myo-inositol, is very sensitive to oxidants and reductants, but is not affected by a variety of complexing agents, nucleotides, sulfhydryl reagents, etc. In other experiments it was found that L-myo-inosose-1, a potential intermediate in the enzymic reaction, is a potent competitive inhibitor (Ki = 62 microM), while other inososes and a solution thought to contain D-glucodialdehyde, another potential intermediate, are weak inhibitors. Also, both a kinetic deuterium isotope effect (kH/kD = 2.1) and a tritium isotope effect (kH/kT = 7.5) are observed for the enzymic reaction when [1-2H]- and [1-3H]-myo-inositol are used as reactants. These latter results are considered strong evidence that the oxygenase reaction proceeds by a pathway involving L-myo-inosose-1 as an intermediate rather than by an alternative pathway that would have D-glucodialdehyde as the intermediate.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
|
21
|
Parthasarathy R, Eisenberg F. The inositol phospholipids: a stereochemical view of biological activity. Biochem J 1986; 235:313-22. [PMID: 3017301 PMCID: PMC1146689 DOI: 10.1042/bj2350313] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
22
|
Koller F, Koller E. Affinity chromatography of myo-inositol oxygenase from rat kidney by means of an insoluble D-galacto-hexodialdose derivative. J Chromatogr A 1984; 283:191-7. [PMID: 6707116 DOI: 10.1016/s0021-9673(00)96254-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Following partial acid hydrolysis, Sepharose 6B-CL was treated with galactose oxidase, leading to an insoluble matrix containing 3-O-substituted D-galacto-hexodialdose. The latter substance strongly binds to myo-inositol oxygenase from rat kidneys, obviously because of its structural relationship to a reaction intermediate. Free apo-monomers, reconstituted iron(II)-containing monomers and fully active reassociated tetramers of the enzyme all interact with the affinity matrix, the degree of affinity increasing in this order. Thermodynamic analysis led to the conclusion that the ligand coordinates directly to the protein-bound iron ions, but this attachment is strengthened by interactions within and between the protein moiety of the oligomeric enzyme. These interactions seem to be essentially hydrophobic.
Collapse
|
23
|
Reddy C, Pierzchala P, Hamilton G. myo-Inositol oxygenase from hog kidney. II. Catalytic properties of the homogeneous enzyme. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)68874-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
24
|
Reddy CC, Hamilton GA. Activation of homogeneous preparations of hog kidney myo-inositol oxygenase by quinolinic acid and ferrous ions. Biochem Biophys Res Commun 1981; 100:1389-95. [PMID: 6456001 DOI: 10.1016/0006-291x(81)91978-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
|