1
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Babicz JT, Rogers MS, DeWeese DE, Sutherlin KD, Banerjee R, Böttger LH, Yoda Y, Nagasawa N, Saito M, Kitao S, Kurokuzu M, Kobayashi Y, Tamasaku K, Seto M, Lipscomb JD, Solomon EI. Nuclear Resonance Vibrational Spectroscopy Definition of Peroxy Intermediates in Catechol Dioxygenases: Factors that Determine Extra- versus Intradiol Cleavage. J Am Chem Soc 2023; 145:15230-15250. [PMID: 37414058 PMCID: PMC10804917 DOI: 10.1021/jacs.3c02242] [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: 07/08/2023]
Abstract
The extradiol dioxygenases (EDOs) and intradiol dioxygenases (IDOs) are nonheme iron enzymes that catalyze the oxidative aromatic ring cleavage of catechol substrates, playing an essential role in the carbon cycle. The EDOs and IDOs utilize very different FeII and FeIII active sites to catalyze the regiospecificity in their catechol ring cleavage products. The factors governing this difference in cleavage have remained undefined. The EDO homoprotocatechuate 2,3-dioxygenase (HPCD) and IDO protocatechuate 3,4-dioxygenase (PCD) provide an opportunity to understand this selectivity, as key O2 intermediates have been trapped for both enzymes. Nuclear resonance vibrational spectroscopy (in conjunction with density functional theory calculations) is used to define the geometric and electronic structures of these intermediates as FeII-alkylhydroperoxo (HPCD) and FeIII-alkylperoxo (PCD) species. Critically, in both intermediates, the initial peroxo bond orientation is directed toward extradiol product formation. Reaction coordinate calculations were thus performed to evaluate both the extra- and intradiol O-O cleavage for the simple organic alkylhydroperoxo and for the FeII and FeIII metal catalyzed reactions. These results show the FeII-alkylhydroperoxo (EDO) intermediate undergoes facile extradiol O-O bond homolysis due to its extra e-, while for the FeIII-alkylperoxo (IDO) intermediate the extradiol cleavage involves a large barrier and would yield the incorrect extradiol product. This prompted our evaluation of a viable mechanism to rearrange the FeIII-alkylperoxo IDO intermediate for intradiol cleavage, revealing a key role in the rebinding of the displaced Tyr447 ligand in this rearrangement, driven by the proton delivery necessary for O-O bond cleavage.
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Affiliation(s)
- Jeffrey T. Babicz
- Department of Chemistry, Stanford University, 380 Roth Way, Stanford, California 94305, United States
| | - Melanie S. Rogers
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55391, United States
| | - Dory E. DeWeese
- Department of Chemistry, Stanford University, 380 Roth Way, Stanford, California 94305, United States
| | - Kyle D. Sutherlin
- Department of Chemistry, Stanford University, 380 Roth Way, Stanford, California 94305, United States
| | - Rahul Banerjee
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55391, United States
| | - Lars H. Böttger
- Department of Chemistry, Stanford University, 380 Roth Way, Stanford, California 94305, United States
| | - Yoshitaka Yoda
- Japan Synchrotron Radiation Research Institute, Hyogo 679-5198, Japan
| | - Nobumoto Nagasawa
- Japan Synchrotron Radiation Research Institute, Hyogo 679-5198, Japan
| | - Makina Saito
- Department of Physics, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Shinji Kitao
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka 590-0494, Japan
| | - Masayuki Kurokuzu
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka 590-0494, Japan
| | - Yasuhiro Kobayashi
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka 590-0494, Japan
| | - Kenji Tamasaku
- RIKEN SPring-8 Center, RIKEN, Sayo, Hyogo 679-5148, Japan
| | - Makoto Seto
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka 590-0494, Japan
| | - John D. Lipscomb
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55391, United States
| | - Edward I. Solomon
- Department of Chemistry, Stanford University, 380 Roth Way, Stanford, California 94305, United States
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
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2
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Schober L, Dobiašová H, Jurkaš V, Parmeggiani F, Rudroff F, Winkler M. Enzymatic reactions towards aldehydes: An overview. FLAVOUR FRAG J 2023; 38:221-242. [PMID: 38505272 PMCID: PMC10947199 DOI: 10.1002/ffj.3739] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 03/01/2023] [Accepted: 03/06/2023] [Indexed: 03/21/2024]
Abstract
Many aldehydes are volatile compounds with distinct and characteristic olfactory properties. The aldehydic functional group is reactive and, as such, an invaluable chemical multi-tool to make all sorts of products. Owing to the reactivity, the selective synthesis of aldehydic is a challenging task. Nature has evolved a number of enzymatic reactions to produce aldehydes, and this review provides an overview of aldehyde-forming reactions in biological systems and beyond. Whereas some of these biotransformations are still in their infancy in terms of synthetic applicability, others are developed to an extent that allows their implementation as industrial biocatalysts.
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Affiliation(s)
- Lukas Schober
- Institute of Molecular BiotechnologyGraz University of TechnologyGrazAustria
| | - Hana Dobiašová
- Institute of Chemical and Environmental EngineeringSlovak University of TechnologyBratislavaSlovakia
| | - Valentina Jurkaš
- Institute of Molecular BiotechnologyGraz University of TechnologyGrazAustria
| | - Fabio Parmeggiani
- Dipartimento di Chimica, Materiali ed Ingegneria Chimica “Giulio Natta”Politecnico di MilanoMilanItaly
| | - Florian Rudroff
- Institute of Applied Synthetic ChemistryTU WienViennaAustria
| | - Margit Winkler
- Institute of Molecular BiotechnologyGraz University of TechnologyGrazAustria
- Area BiotransformationsAustrian Center of Industrial BiotechnologyGrazAustria
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3
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Abstract
Here, the choice of the first coordination shell of the metal center is analyzed from the perspective of charge maintenance in a binary enzyme-substrate complex and an O2-bound ternary complex in the nonheme iron oxygenases. Comparing homogentisate 1,2-dioxygenase and gentisate dioxygenase highlights the significance of charge maintenance after substrate binding as an important factor that drives the reaction coordinate. We then extend the charge analysis to several common types of nonheme iron oxygenases containing either a 2-His-1-carboxylate facial triad or a 3-His or 4-His ligand motif, including extradiol and intradiol ring-cleavage dioxygenases, thiol dioxygenases, α-ketoglutarate-dependent oxygenases, and carotenoid cleavage oxygenases. After forming the productive enzyme-substrate complex, the overall charge of the iron complex at the 0, +1, or +2 state is maintained in the remaining catalytic steps. Hence, maintaining a constant charge is crucial to promote the reaction of the iron center beginning from the formation of the Michaelis or ternary complex. The charge compensation to the iron ion is tuned not only by protein-derived carboxylate ligands but also by substrates. Overall, these analyses indicate that charge maintenance at the iron center is significant when all the necessary components form a productive complex. This charge maintenance concept may apply to most oxygen-activating metalloenzymes systems that do not draw electrons and protons step-by-step from a separate reactant, such as NADH, via a reductase. The charge maintenance perception may also be useful in proposing catalytic pathways or designing prototypical reactions using artificial or engineered enzymes for biotechnological applications.
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Affiliation(s)
- Ephrahime S. Traore
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Aimin Liu
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
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4
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Liu Y, Liu Y. Computational Study of Aromatic Hydroxylation Catalyzed by the Iron-Dependent Hydroxylase PqqB Involved in the Biosynthesis of Redox Cofactor Pyrroloquinoline Quinone. Inorg Chem 2022; 61:5943-5956. [PMID: 35362953 DOI: 10.1021/acs.inorgchem.2c00419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PqqB from Methylobacterium extorquens is a unique nonheme iron-dependent hydroxylase involved in the biosynthesis of redox cofactor pyrroloquinoline quinone (PQQ). A series of recent experiments have demonstrated that PqqB catalyzes the stepwise insertions of two oxygen atoms into the tyrosine ring of the diamino acid substrate, generating the quinone moiety of PQQ; however, the reaction details have not been elucidated yet. In this paper, on the basis of the crystal structures, the enzyme-substrate complex models were constructed, and the catalytic mechanism of PqqB was explored by performing a series of combined QM/MM calculations. Our results confirmed that the first hydroxylation is performed by the highly reactive FeIV-oxo species and follows the typical H-abstraction/hydroxyl rebound mechanism, which is similar to the common aliphatic hydroxylation catalyzed by the α-KG enzymes. Nevertheless, the second hydroxylation is achieved by the Fe-O2 species, and the reactant complex can be described as an intermediate radical-FeII-superoxide, that is, the dioxygen is activated by accepting an electron from the bidentate coordination intermediate. Since both the dioxygen and intermediate are activated by electron transfer, the distal oxygen of superoxide can directly attack the carbonyl carbon of substrate to form an alkylperoxo intermediate, then the O-O heterolysis occurs to afford the epoxide intermediate, which finally evolves into the product by rearrangement. It is the bidentate coordination of catechol moiety to iron that leads to the one-electron oxidation of the substrate by the dioxygen, which significantly activates the substrate and promotes the superoxide radical attack. During the catalysis, Asp90 and His240 in the second sphere play an important role by acting as acid-base catalysts to mediate the proton transfer and manipulate the suitable orientation of superoxide. These findings may provide useful information for understanding the unique reaction mechanism of PqqB that employs both the FeIV-oxo and FeII-superoxide to carry out the aromatic hydroxylation.
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Affiliation(s)
- Yaru Liu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
| | - Yongjun Liu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
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5
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Navas LE, Zahn M, Bajwa H, Grigg JC, Wolf ME, Chan ACK, Murphy MEP, McGeehan JE, Eltis LD. Characterization of a phylogenetically distinct extradiol dioxygenase involved in the bacterial catabolism of lignin-derived aromatic compounds. J Biol Chem 2022; 298:101871. [PMID: 35346686 PMCID: PMC9062432 DOI: 10.1016/j.jbc.2022.101871] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 03/21/2022] [Accepted: 03/24/2022] [Indexed: 10/28/2022] Open
Abstract
The actinobacterium Rhodococcus jostii RHA1 grows on a remarkable variety of aromatic compounds and has been studied for applications ranging from the degradation of polychlorinated biphenyls to the valorization of lignin, an underutilized component of biomass. In RHA1, the catabolism of two classes of lignin-derived compounds, alkylphenols and alkylguaiacols, involves a phylogenetically distinct extradiol dioxygenase, AphC, previously misannotated as BphC, an enzyme involved in biphenyl catabolism. To better understand the role of AphC in RHA1 catabolism, we first showed that purified AphC had highest apparent specificity for 4-propylcatechol (kcat/KM ∼106 M-1 s-1), and its apparent specificity for 4-alkylated substrates followed the trend for alkylguaiacols: propyl > ethyl > methyl > phenyl > unsubstituted. We also show AphC only poorly cleaved 3-phenylcatechol, the preferred substrate of BphC. Moreover, AphC and BphC cleaved 3-phenylcatechol and 4-phenylcatechol with different regiospecificities, likely due to the substrates' binding mode. A crystallographic structure of the AphC·4-ethylcatechol binary complex to 1.59 Å resolution revealed that the catechol is bound to the active site iron in a bidentate manner and that the substrate's alkyl side chain is accommodated by a hydrophobic pocket. Finally, we show RHA1 grows on a mixture of 4-ethylguaiacol and guaiacol, simultaneously catabolizing these substrates through meta-cleavage and ortho-cleavage pathways, respectively, suggesting that the specificity of AphC helps to prevent the routing of catechol through the Aph pathway. Overall, this study contributes to our understanding of the bacterial catabolism of aromatic compounds derived from lignin, and the determinants of specificity in extradiol dioxygenases.
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Affiliation(s)
- Laura E Navas
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, Canada
| | - Michael Zahn
- Centre for Enzyme Innovation, School of Biological Sciences, University of Portsmouth, Portsmouth, UK
| | - Harbir Bajwa
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, Canada
| | - Jason C Grigg
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, Canada
| | - Megan E Wolf
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, Canada
| | - Anson C K Chan
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, Canada
| | - Michael E P Murphy
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, Canada
| | - John E McGeehan
- Centre for Enzyme Innovation, School of Biological Sciences, University of Portsmouth, Portsmouth, UK
| | - Lindsay D Eltis
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, Canada.
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6
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Shapterhasmi T, Palani N, Velusamy M, Bhuvanesh NS, Sundaravel K, Easwaramoorthi S. Iron(III) Complexes of Pyrrolidine and Piperidine Appended Tridentate 3N Donor Ligands as Models for Catechol Dioxygenase Enzymes. Inorganica Chim Acta 2022. [DOI: 10.1016/j.ica.2022.120924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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7
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Goldberg AM, Robinson MK, Starr ES, Marasco RN, Alana AC, Cochrane CS, Klugh KL, Strzeminski DJ, Du M, Colabroy KL, Peterson LW. L-DOPA Dioxygenase Activity on 6-Substituted Dopamine Analogues. Biochemistry 2021; 60:2492-2507. [PMID: 34324302 DOI: 10.1021/acs.biochem.1c00310] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dioxygenase enzymes are essential protein catalysts for the breakdown of catecholic rings, structural components of plant woody tissue. This powerful chemistry is used in nature to make antibiotics and other bioactive materials or degrade plant material, but we have a limited understanding of the breadth and depth of substrate space for these potent catalysts. Here we report steady-state and pre-steady-state kinetic analysis of dopamine derivatives substituted at the 6-position as substrates of L-DOPA dioxygenase, and an analysis of that activity as a function of the electron-withdrawing nature of the substituent. Steady-state and pre-steady-state kinetic data demonstrate the dopamines are impaired in binding and catalysis with respect to the cosubstrate molecular oxygen, which likely afforded spectroscopic observation of an early reaction intermediate, the semiquinone of dopamine. The reaction pathway of dopamine in the pre-steady state is consistent with a nonproductive mode of binding of oxygen at the active site. Despite these limitations, L-DOPA dioxygenase is capable of binding all of the dopamine derivatives and catalyzing multiple turnovers of ring cleavage for dopamine, 6-bromodopamine, 6-carboxydopamine, and 6-cyanodopamine. 6-Nitrodopamine was a single-turnover substrate. The variety of substrates accepted by the enzyme is consistent with an interplay of factors, including the capacity of the active site to bind large, negatively charged groups at the 6-position and the overall oxidizability of each catecholamine, and is indicative of the utility of extradiol cleavage in semisynthetic and bioremediation applications.
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Affiliation(s)
- Alexander M Goldberg
- Department of Chemistry, Muhlenberg College, 2400 Chew Street, Allentown, Pennsylvania 18104, United States
| | - Miranda K Robinson
- Department of Chemistry, Muhlenberg College, 2400 Chew Street, Allentown, Pennsylvania 18104, United States
| | - Erykah S Starr
- Department of Chemistry, Rhodes College, 2000 North Parkway, Memphis, Tennessee 38112, United States
| | - Ryan N Marasco
- Department of Chemistry, Rhodes College, 2000 North Parkway, Memphis, Tennessee 38112, United States
| | - Alexa C Alana
- Department of Chemistry, Rhodes College, 2000 North Parkway, Memphis, Tennessee 38112, United States
| | - C Skyler Cochrane
- Department of Chemistry, Rhodes College, 2000 North Parkway, Memphis, Tennessee 38112, United States
| | - Kameron L Klugh
- Department of Chemistry, Rhodes College, 2000 North Parkway, Memphis, Tennessee 38112, United States
| | - David J Strzeminski
- Department of Chemistry, Muhlenberg College, 2400 Chew Street, Allentown, Pennsylvania 18104, United States
| | - Muxue Du
- Department of Chemistry, Muhlenberg College, 2400 Chew Street, Allentown, Pennsylvania 18104, United States
| | - Keri L Colabroy
- Department of Chemistry, Muhlenberg College, 2400 Chew Street, Allentown, Pennsylvania 18104, United States
| | - Larryn W Peterson
- Department of Chemistry, Rhodes College, 2000 North Parkway, Memphis, Tennessee 38112, United States
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8
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Wang Y, Liu KF, Yang Y, Davis I, Liu A. Observing 3-hydroxyanthranilate-3,4-dioxygenase in action through a crystalline lens. Proc Natl Acad Sci U S A 2020; 117:19720-19730. [PMID: 32732435 PMCID: PMC7443976 DOI: 10.1073/pnas.2005327117] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The synthesis of quinolinic acid from tryptophan is a critical step in the de novo biosynthesis of nicotinamide adenine dinucleotide (NAD+) in mammals. Herein, the nonheme iron-based 3-hydroxyanthranilate-3,4-dioxygenase responsible for quinolinic acid production was studied by performing time-resolved in crystallo reactions monitored by UV-vis microspectroscopy, electron paramagnetic resonance (EPR) spectroscopy, and X-ray crystallography. Seven catalytic intermediates were kinetically and structurally resolved in the crystalline state, and each accompanies protein conformational changes at the active site. Among them, a monooxygenated, seven-membered lactone intermediate as a monodentate ligand of the iron center at 1.59-Å resolution was captured, which presumably corresponds to a substrate-based radical species observed by EPR using a slurry of small-sized single crystals. Other structural snapshots determined at around 2.0-Å resolution include monodentate and subsequently bidentate coordinated substrate, superoxo, alkylperoxo, and two metal-bound enol tautomers of the unstable dioxygenase product. These results reveal a detailed stepwise O-atom transfer dioxygenase mechanism along with potential isomerization activity that fine-tunes product profiling and affects the production of quinolinic acid at a junction of the metabolic pathway.
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Affiliation(s)
- Yifan Wang
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249
| | - Kathy Fange Liu
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Yu Yang
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249
| | - Ian Davis
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249
| | - Aimin Liu
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249;
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9
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Colabroy KL, Horwitz AD, Basciano VR, Fu Y, Travitz KM, Robinson MK, Shimanski BA, Hoffmann TW. A New Way of Belonging: Active-Site Investigation of L-DOPA Dioxygenase, a VOC Family Enzyme from Lincomycin Biosynthesis. Biochemistry 2019; 58:4794-4798. [DOI: 10.1021/acs.biochem.9b00456] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Keri L. Colabroy
- Department of Chemistry, Muhlenberg College, Allentown, Pennsylvania 18104, United States
| | - Alyssa D. Horwitz
- Department of Chemistry, Muhlenberg College, Allentown, Pennsylvania 18104, United States
| | - Victoria R. Basciano
- Department of Chemistry, Muhlenberg College, Allentown, Pennsylvania 18104, United States
| | - Yizhi Fu
- Department of Chemistry, Muhlenberg College, Allentown, Pennsylvania 18104, United States
| | - Kelly M. Travitz
- Department of Chemistry, Muhlenberg College, Allentown, Pennsylvania 18104, United States
| | - Miranda K. Robinson
- Department of Chemistry, Muhlenberg College, Allentown, Pennsylvania 18104, United States
| | - Brittany A. Shimanski
- Department of Chemistry, Muhlenberg College, Allentown, Pennsylvania 18104, United States
| | - Thomas W. Hoffmann
- Department of Chemistry, Muhlenberg College, Allentown, Pennsylvania 18104, United States
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10
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Wang Y, Shin I, Fu Y, Colabroy KL, Liu A. Crystal Structures of L-DOPA Dioxygenase from Streptomyces sclerotialus. Biochemistry 2019; 58:5339-5350. [PMID: 31180203 DOI: 10.1021/acs.biochem.9b00396] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Extradiol dioxygenases are essential biocatalysts for breaking down catechols. The vicinal oxygen chelate (VOC) superfamily contains a large number of extradiol dioxygenases, most of which are found as part of catabolic pathways degrading a variety of natural and human-made aromatic rings. The l-3,4-dihydroxyphenylalanine (L-DOPA) extradiol dioxygenases compose a multitude of pathways that produce various antibacterial or antitumor natural products. The structural features of these dioxygenases are anticipated to be distinct from those of other VOC extradiol dioxygenases. Herein, we identified a new L-DOPA dioxygenase from the thermophilic bacterium Streptomyces sclerotialus (SsDDO) through a sequence and genome context analysis. The activity of SsDDO was kinetically characterized with L-DOPA using an ultraviolet-visible spectrophotometer and an oxygen electrode. The optimal temperature of the assay was 55 °C, at which the Km and kcat of SsDDO were 110 ± 10 μM and 2.0 ± 0.1 s-1, respectively. We determined the de novo crystal structures of SsDDO in the ligand-free form and as a substrate-bound complex, refined to 1.99 and 2.31 Å resolution, respectively. These structures reveal that SsDDO possesses a form IV arrangement of βαβββ modules, the first characterization of this assembly from among the VOC/type I extradiol dioxygenase protein family. Electron paramagnetic resonance spectra of Fe-NO adducts for the resting and substrate-bound enzyme were obtained. This work contributes to our understanding of a growing class of topologically distinct VOC dioxygenases, and the obtained structural features will improve our understanding of the extradiol cleavage reaction within the VOC superfamily.
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Affiliation(s)
- Yifan Wang
- Department of Chemistry , University of Texas at San Antonio , San Antonio , Texas 78249 , United States
| | - Inchul Shin
- Department of Chemistry , University of Texas at San Antonio , San Antonio , Texas 78249 , United States
| | - Yizhi Fu
- Department of Chemistry , Muhlenberg College , Allentown , Pennsylvania 18104 , United States
| | - Keri L Colabroy
- Department of Chemistry , Muhlenberg College , Allentown , Pennsylvania 18104 , United States
| | - Aimin Liu
- Department of Chemistry , University of Texas at San Antonio , San Antonio , Texas 78249 , United States
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11
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Burrows JE, Paulson MQ, Altman ER, Vukovic I, Machonkin TE. The role of halogen substituents and substrate pK a in defining the substrate specificity of 2,6-dichlorohydroquinone 1,2-dioxygenase (PcpA). J Biol Inorg Chem 2019; 24:575-589. [PMID: 31089822 DOI: 10.1007/s00775-019-01663-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 05/07/2019] [Indexed: 12/01/2022]
Abstract
2,6-Dichlorohydroquinone 1,2-dioxygenase (PcpA) is a non-heme Fe(II) enzyme that is specific for ortho-dihalohydroquinones. Here we deconvolute the role of halogen polarizability vs. substrate pKa in defining this specificity, and show how substrate binding compares to the structurally homologous catechol extradiol dioxygenases. The substrates 2,6-dichloro- and 2,6-dibromohydroquinone (polarizable halogens, pKa1 = 7.3), 2,6-difluorohydroquinone (nonpolarizable halogens, pKa1 = 7.5), and 2-chloro-6-methylhydroquinone (polarizable halogen, pKa1 = 9.0) were examined through spectrophotometric titrations and steady-state kinetics. The results show that binding of the substrates to the enzyme decreased [Formula: see text] by about 0.5, except for 2,6-difluorohydroquinone, which showed no change. Additionally, the Kd values of 2,6-dichloro- and 2,6-dibromohydroquinone are about equal to their respective [Formula: see text]. For comparison, with catechol 2,3-dioxygenase (XylE), the substrates 4-methyl- and 3-bromocatechol are bound to the enzyme exclusively in the monoanion form over a wide pH range, indicating a [Formula: see text] of at least - 2.9 and - 1.2, respectively. The steady-state kinetic studies showed that 2,6-difluorohydroquinone is a poor substrate, with [Formula: see text] approximately 40-fold lower and [Formula: see text] 20-fold higher than 2,6-dichlorohydroquinone, despite its similar pKa1. Likewise, the pH dependence of [Formula: see text] for 2-chloro-6-methylhydroquinone is nearly identical to that of 2,6-dichlorohydroquinone, despite its very different pKa1. These results show that (1) it is clearly the halogen polarizability and not the lower substrate pKa that determines the substrate specificity of PcpA, and (2) that PcpA, unlike the catechol extradiol dioxygenases, lacks an active site base that assists with substrate deprotonation, highlighting a key functional difference in what are otherwise similar active sites that defines their different reactivity.
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Affiliation(s)
- Julia E Burrows
- Department of Chemistry, Whitman College, 345 Boyer Ave, Walla Walla, WA, 99362, USA
| | - Monica Q Paulson
- Department of Chemistry, Whitman College, 345 Boyer Ave, Walla Walla, WA, 99362, USA
| | - Emma R Altman
- Department of Chemistry, Whitman College, 345 Boyer Ave, Walla Walla, WA, 99362, USA
| | - Ivana Vukovic
- Department of Chemistry, Whitman College, 345 Boyer Ave, Walla Walla, WA, 99362, USA
| | - Timothy E Machonkin
- Department of Chemistry, Whitman College, 345 Boyer Ave, Walla Walla, WA, 99362, USA.
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12
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Zhao Y, Du L, Li H, Xie W, Chen J. Is the Suzuki-Miyaura Cross-Coupling Reaction in the Presence of Pd Nanoparticles Heterogeneously or Homogeneously Catalyzed? An Interfacial Surface-Enhanced Raman Spectroscopy Study. J Phys Chem Lett 2019; 10:1286-1291. [PMID: 30830793 DOI: 10.1021/acs.jpclett.9b00351] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Pd-catalyzed Suzuki-Miyaura C-C cross-coupling is very central in chemistry. The question of whether the catalysis by using Pd nanoparticles (NPs) is heterogeneous (on the Pd surface) or homogeneous (by soluble Pd released from the NP surface) remains under fundamental physicochemical debate. This work reports on the in situ characterization of the Suzuki-Miyaura cross-coupling reactions by using surface-enhanced Raman spectroscopy. We find clear evidence of heterogeneous catalysis on the Pd surface. In contrast, the soluble Pd species leaching into the solution cannot catalyze the reaction, indicating a direct contact of the aryl halides with the metal surface is a prerequisite. Accordingly, the surface ligands and charge of the Pd NPs, which determine the molecule-metal contact, are very important in the couplings. By a simple exchange of the surface ligand or a surface modification of the support material, the catalytic activity of Pd NPs is improved due to the enhanced electric attraction between the metal and the reactant molecules.
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Affiliation(s)
- Yaran Zhao
- Key Lab of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Center, College of Chemistry , Nankai University , Weijin Road 94 , Tianjin 300071 , China
| | - Lili Du
- Key Lab of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Center, College of Chemistry , Nankai University , Weijin Road 94 , Tianjin 300071 , China
| | - Haixia Li
- Key Lab of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Center, College of Chemistry , Nankai University , Weijin Road 94 , Tianjin 300071 , China
| | - Wei Xie
- Key Lab of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Center, College of Chemistry , Nankai University , Weijin Road 94 , Tianjin 300071 , China
| | - Jun Chen
- Key Lab of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Center, College of Chemistry , Nankai University , Weijin Road 94 , Tianjin 300071 , China
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13
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Wang J, Chen J, Tang X, Li Y, Zhang R, Zhu L, Sun Y, Zhang Q, Wang W. Catalytic Mechanism for 2,3-Dihydroxybiphenyl Ring Cleavage by Nonheme Extradiol Dioxygenases BphC: Insights from QM/MM Analysis. J Phys Chem B 2019; 123:2244-2253. [DOI: 10.1021/acs.jpcb.8b11008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Junjie Wang
- Environment Research Institute, Shandong University, Qingdao 266237, P. R. China
| | - Jinfeng Chen
- Environment Research Institute, Shandong University, Qingdao 266237, P. R. China
| | - Xiaowen Tang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, P. R. China
| | - Yanwei Li
- Environment Research Institute, Shandong University, Qingdao 266237, P. R. China
| | - Ruiming Zhang
- Environment Research Institute, Shandong University, Qingdao 266237, P. R. China
| | - Ledong Zhu
- Environment Research Institute, Shandong University, Qingdao 266237, P. R. China
| | - Yanhui Sun
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, P. R. China
| | - Qingzhu Zhang
- Environment Research Institute, Shandong University, Qingdao 266237, P. R. China
| | - Wenxing Wang
- Environment Research Institute, Shandong University, Qingdao 266237, P. R. China
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14
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Li S, Lu J, Lai W. Mechanistic insights into ring cleavage of hydroquinone by PnpCD from quantum mechanical/molecular mechanical calculations. Org Biomol Chem 2019; 17:8194-8205. [DOI: 10.1039/c9ob01084j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
QM/MM calculations for ring cleavage of hydroquinone by PnpCD show that Asn258 loses coordination to the iron when the reaction begins. The first-sphere Glu262 can act as an acid–base catalyst to lower the rate-limiting barrier.
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Affiliation(s)
- Senzhi Li
- Department of Chemistry
- Renmin University of China
- Beijing
- China
| | - Jiarui Lu
- Department of Chemistry
- Renmin University of China
- Beijing
- China
| | - Wenzhen Lai
- Department of Chemistry
- Renmin University of China
- Beijing
- China
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15
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Sutherlin KD, Wasada-Tsutsui Y, Mbughuni MM, Rogers MS, Park K, Liu LV, Kwak Y, Srnec M, Böttger LH, Frenette M, Yoda Y, Kobayashi Y, Kurokuzu M, Saito M, Seto M, Hu M, Zhao J, Alp EE, Lipscomb JD, Solomon EI. Nuclear Resonance Vibrational Spectroscopy Definition of O 2 Intermediates in an Extradiol Dioxygenase: Correlation to Crystallography and Reactivity. J Am Chem Soc 2018; 140:16495-16513. [PMID: 30418018 DOI: 10.1021/jacs.8b06517] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The extradiol dioxygenases are a large subclass of mononuclear nonheme Fe enzymes that catalyze the oxidative cleavage of catechols distal to their OH groups. These enzymes are important in bioremediation, and there has been significant interest in understanding how they activate O2. The extradiol dioxygenase homoprotocatechuate 2,3-dioxygenase (HPCD) provides an opportunity to study this process, as two O2 intermediates have been trapped and crystallographically defined using the slow substrate 4-nitrocatechol (4NC): a side-on Fe-O2-4NC species and a Fe-O2-4NC peroxy bridged species. Also with 4NC, two solution intermediates have been trapped in the H200N variant, where H200 provides a second-sphere hydrogen bond in the wild-type enzyme. While the electronic structure of these solution intermediates has been defined previously as FeIII-superoxo-catecholate and FeIII-peroxy-semiquinone, their geometric structures are unknown. Nuclear resonance vibrational spectroscopy (NRVS) is an important tool for structural definition of nonheme Fe-O2 intermediates, as all normal modes with Fe displacement have intensity in the NRVS spectrum. In this study, NRVS is used to define the geometric structure of the H200N-4NC solution intermediates in HPCD as an end-on FeIII-superoxo-catecholate and an end-on FeIII-hydroperoxo-semiquinone. Parallel calculations are performed to define the electronic structures and protonation states of the crystallographically defined wild-type HPCD-4NC intermediates, where the side-on intermediate is found to be a FeIII-hydroperoxo-semiquinone. The assignment of this crystallographic intermediate is validated by correlation to the NRVS data through computational removal of H200. While the side-on hydroperoxo semiquinone intermediate is computationally found to be nonreactive in peroxide bridge formation, it is isoenergetic with a superoxo catecholate species that is competent in performing this reaction. This study provides insight into the relative reactivities of FeIII-superoxo and FeIII-hydroperoxo intermediates in nonheme Fe enzymes and into the role H200 plays in facilitating extradiol catalysis.
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Affiliation(s)
- Kyle D Sutherlin
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Yuko Wasada-Tsutsui
- Department of Life Science and Applied Chemistry, Graduate School of Engineering , Nagoya Institute of Technology , Gokiso-cho, Showa-ku, Nagoya 466-8555 , Japan
| | - Michael M Mbughuni
- Department of Biochemistry, Molecular Biology, & Biophysics , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Melanie S Rogers
- Department of Biochemistry, Molecular Biology, & Biophysics , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Kiyoung Park
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Lei V Liu
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Yeonju Kwak
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Martin Srnec
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Lars H Böttger
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Mathieu Frenette
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Yoshitaka Yoda
- Japan Synchrotron Radiation Research Institute , Hyogo 679-5198 , Japan
| | | | - Masayuki Kurokuzu
- Research Reactor Institute, Kyoto University , Osaka 590-0494 , Japan
| | - Makina Saito
- Research Reactor Institute, Kyoto University , Osaka 590-0494 , Japan
| | - Makoto Seto
- Research Reactor Institute, Kyoto University , Osaka 590-0494 , Japan
| | - Michael Hu
- Advanced Photon Source , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - Jiyong Zhao
- Advanced Photon Source , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - E Ercan Alp
- Advanced Photon Source , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - John D Lipscomb
- Department of Biochemistry, Molecular Biology, & Biophysics , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Edward I Solomon
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States.,SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
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16
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Suter D, van Summeren LTCG, Blacque O, Venkatesan K. Highly Stable and Strongly Emitting N-Heterocyclic Carbene Platinum(II) Biaryl Complexes. Inorg Chem 2018; 57:8160-8168. [DOI: 10.1021/acs.inorgchem.8b00564] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dominik Suter
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Luuk T. C. G. van Summeren
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
- Department of Molecular Materials, Radboud University, Nijmegen, 6525 AJ, Netherlands
| | - Olivier Blacque
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Koushik Venkatesan
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
- Department of Molecular Sciences, Macquarie University,
North Ryde, NSW 2109, Australia
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17
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Abstract
Crystallization has been a bottleneck in the X-ray crystallography of proteins. Although many techniques have been developed to overcome this obstacle, the impurities caused by chemical reactions during crystallization have not been sufficiently considered. Oxidation of proteins, which can lead to poor reproducibility of the crystallization, is a prominent example. Protein oxidization in the crystallization droplet causes inter-molecular disulfide bridge formation, formation of oxidation film, and precipitation of proteins. These changes by oxidation are typically irreversible. The best approach for preventing protein oxidization during crystallization is anaerobic crystallization. Here we review the anaerobic crystallization of proteins, which was originally developed to trap a reaction intermediate of the enzyme in the crystal. We also summarize representative anaerobic crystallizations from our laboratory and the general setup of anaerobic crystallization.
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Affiliation(s)
- Miki Senda
- Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Toshiya Senda
- Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan.
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18
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Kuatsjah E, Chen HM, Withers SG, Eltis LD. Characterization of an extradiol dioxygenase involved in the catabolism of lignin-derived biphenyl. FEBS Lett 2017; 591:1001-1009. [DOI: 10.1002/1873-3468.12611] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 02/22/2017] [Accepted: 02/23/2017] [Indexed: 11/10/2022]
Affiliation(s)
- Eugene Kuatsjah
- Genome Science and Technology Program; The University of British Columbia; Vancouver BC Canada
| | - Hong-Ming Chen
- Department of Chemistry; The University of British Columbia; Vancouver BC Canada
| | - Stephen G. Withers
- Genome Science and Technology Program; The University of British Columbia; Vancouver BC Canada
- Department of Chemistry; The University of British Columbia; Vancouver BC Canada
- Department of Biochemistry; Life Sciences Institute; The University of British Columbia; Vancouver BC Canada
| | - Lindsay D. Eltis
- Genome Science and Technology Program; The University of British Columbia; Vancouver BC Canada
- Department of Biochemistry; Life Sciences Institute; The University of British Columbia; Vancouver BC Canada
- Department of Microbiology and Immunology; Life Sciences Institute; The University of British Columbia; Vancouver BC Canada
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19
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Liu Y, Tu N, Xie W, Li Y. Theoretical investigation on proton transfer mechanism of extradiol dioxygenase. RSC Adv 2017. [DOI: 10.1039/c7ra08080h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The formation mechanism of alkyl(hydro)peroxo species is performed via two parallel pathways.
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Affiliation(s)
- Yang Liu
- State Key Laboratory of Pulp and Paper Engineering
- South China University of Technology
- Guangzhou 510640
- P. R. China
- Faculty of Environmental & Biological Engineering
| | - Ningyu Tu
- Faculty of Environmental & Biological Engineering
- Guangdong University of Petrochemical Technology
- Maoming 525000
- P. R. China
| | - Wenyu Xie
- Faculty of Environmental & Biological Engineering
- Guangdong University of Petrochemical Technology
- Maoming 525000
- P. R. China
| | - Youming Li
- State Key Laboratory of Pulp and Paper Engineering
- South China University of Technology
- Guangzhou 510640
- P. R. China
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20
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Abstract
The non-heme Fe enzymes are ubiquitous in nature and perform a wide range of functions involving O2 activation. These had been difficult to study relative to heme enzymes; however, spectroscopic methods that provide significant insight into the correlation of structure with function have now been developed. This Current Topics article summarizes both the molecular mechanism these enzymes use to control O2 activation in the presence of cosubstrates and the oxygen intermediates these reactions generate. Three types of O2 activation are observed. First, non-heme reactivity is shown to be different from heme chemistry where a low-spin FeIII-OOH non-heme intermediate directly reacts with substrate. Also, two subclasses of non-heme Fe enzymes generate high-spin FeIV═O intermediates that provide both σ and π frontier molecular orbitals that can control selectivity. Finally, for several subclasses of non-heme Fe enzymes, binding of the substrate to the FeII site leads to the one-electron reductive activation of O2 to an FeIII-superoxide capable of H atom abstraction and electrophilic attack.
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Affiliation(s)
- Edward I Solomon
- Department of Chemistry, Stanford University , Stanford, California 94305, United States.,SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Serra Goudarzi
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
| | - Kyle D Sutherlin
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
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21
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Meier KK, Rogers MS, Kovaleva EG, Lipscomb JD, Bominaar EL, Münck E. Enzyme Substrate Complex of the H200C Variant of Homoprotocatechuate 2,3-Dioxygenase: Mössbauer and Computational Studies. Inorg Chem 2016; 55:5862-70. [PMID: 27275865 PMCID: PMC4924929 DOI: 10.1021/acs.inorgchem.6b00148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The extradiol, aromatic ring-cleaving enzyme homoprotocatechuate 2,3-dioxygenase (HPCD) catalyzes a complex chain of reactions that involve second sphere residues of the active site. The importance of the second-sphere residue His200 was demonstrated in studies of HPCD variants, such as His200Cys (H200C), which revealed significant retardations of certain steps in the catalytic process as a result of the substitution, allowing novel reaction cycle intermediates to be trapped for spectroscopic characterization. As the H200C variant largely retains the wild-type active site structure and produces the correct ring-cleaved product, this variant presents a valuable target for mechanistic HPCD studies. Here, the high-spin Fe(II) states of resting H200C and the H200C-homoprotocatechuate enzyme-substrate (ES) complex have been characterized with Mössbauer spectroscopy to assess the electronic structures of the active site in these states. The analysis reveals a high-spin Fe(II) center in a low symmetry environment that is reflected in the values of the zero-field splitting (ZFS) (D ≈ - 8 cm(-1), E/D ≈ 1/3 in ES), as well as the relative orientations of the principal axes of the (57)Fe magnetic hyperfine (A) and electric field gradient (EFG) tensors relative to the ZFS tensor axes. A spin Hamiltonian analysis of the spectra for the ES complex indicates that the magnetization axis of the integer-spin S = 2 Fe(II) system is nearly parallel to the symmetry axis, z, of the doubly occupied dxy ground orbital deduced from the EFG and A-values, an observation, which cannot be rationalized by DFT assisted crystal-field theory. In contrast, ORCA/CASSCF calculations for the ZFS tensor in combination with DFT calculations for the EFG- and A-tensors describe the experimental data remarkably well.
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Affiliation(s)
- Katlyn K. Meier
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Melanie S. Rogers
- Department of Biochemistry, Molecular Biology and Biophysics and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Elena G. Kovaleva
- Stanford Synchrotron Radiation Lightsource, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - John D. Lipscomb
- Department of Biochemistry, Molecular Biology and Biophysics and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Emile L. Bominaar
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Eckard Münck
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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22
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Tearing down to build up: Metalloenzymes in the biosynthesis lincomycin, hormaomycin and the pyrrolo [1,4]benzodiazepines. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:724-737. [DOI: 10.1016/j.bbapap.2016.03.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 02/24/2016] [Accepted: 03/02/2016] [Indexed: 11/21/2022]
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23
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Qi Y, Lu J, Lai W. Insights into the Reaction Mechanism of Aromatic Ring Cleavage by Homogentisate Dioxygenase: A Quantum Mechanical/Molecular Mechanical Study. J Phys Chem B 2016; 120:4579-90. [PMID: 27119315 DOI: 10.1021/acs.jpcb.6b03006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To elucidate the reaction mechanism of the ring cleavage of homogentisate by homogentisate dioxygenase, quantum mechanical/molecular mechanical (QM/MM) calculations were carried out by using two systems in different protonation states of the substrate C2 hydroxyl group. When the substrate C2 hydroxyl group is ionized (the ionized pathway), the superoxo attack on the substrate is the rate-limiting step in the catalytic cycle, with a barrier of 15.9 kcal/mol. Glu396 was found to play an important role in stabilizing the bridge species and its O-O cleavage product by donating a proton via a hydrogen-bonded water molecule. When the substrate C2 hydroxyl group is not ionized (the nonionized pathway), the O-O bond cleavage of the bridge species is the rate-limiting step, with a barrier of 15.3 kcal/mol. The QM/MM-optimized geometries for the dioxygen and alkylperoxo complexes using the nonionized model (for the C2 hydroxyl group) are in agreement with the experimental crystal structures, suggesting that the C2 hydroxyl group is more likely to be nonionized.
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Affiliation(s)
- Yue Qi
- Department of Chemistry, Renmin University of China , Beijing, 100872, China
| | - Jiarui Lu
- Department of Chemistry, Renmin University of China , Beijing, 100872, China
| | - Wenzhen Lai
- Department of Chemistry, Renmin University of China , Beijing, 100872, China
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24
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Thermodynamics of substrate binding to the metal site in homoprotocatechuate 2,3-dioxygenase: Using ITC under anaerobic conditions to study enzyme–substrate interactions. Biochim Biophys Acta Gen Subj 2016; 1860:910-916. [DOI: 10.1016/j.bbagen.2015.07.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 07/17/2015] [Accepted: 07/24/2015] [Indexed: 11/24/2022]
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25
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Christian GJ, Neese F, Ye S. Unravelling the Molecular Origin of the Regiospecificity in Extradiol Catechol Dioxygenases. Inorg Chem 2016; 55:3853-64. [PMID: 27050565 DOI: 10.1021/acs.inorgchem.5b02978] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many factors have been suggested to control the selectivity for extradiol or intradiol cleavage in catechol dioxygenases. The varied selectivity of model complexes and the ability to force an extradiol enzyme to do intradiol cleavage indicate that the problem may be complex. In this paper we focus on the regiospecificity of the proximal extradiol dioxygenase, homoprotocatechuate 2,3-dioxygenase (HPCD), for which considerable advances have been made in our understanding of the mechanism from an experimental and computational standpoint. Two key steps in the reaction mechanism were investigated: (1) attack of the substrate by the superoxide moiety and (2) attack of the substrate by the oxyl radical generated by O-O bond cleavage. The selectivity at both steps was investigated through a systematic study of the role of the substrate and the first and second coordination spheres. For the isolated native substrate, intradiol cleavage is calculated to be both kinetically and thermodynamically favored, therefore nature must use the enzyme environment to reverse this preference. Two second sphere residues were found to play key roles in controlling the regiospecificity of the reaction: Tyr257 and His200. Tyr257 controls the selectivity by modulating the electronic structure of the substrate, while His200 controls selectivity through steric effects and by preventing alternative pathways to intradiol cleavage.
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Affiliation(s)
- Gemma J Christian
- Max-Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany.,Avondale College of Higher Education , Cooranbong, New South Wales 2265, Australia
| | - Frank Neese
- Max-Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Shengfa Ye
- Max-Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
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26
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Meier KK, Rogers MS, Kovaleva EG, Mbughuni MM, Bominaar EL, Lipscomb JD, Münck E. A Long-Lived Fe(III)-(Hydroperoxo) Intermediate in the Active H200C Variant of Homoprotocatechuate 2,3-Dioxygenase: Characterization by Mössbauer, Electron Paramagnetic Resonance, and Density Functional Theory Methods. Inorg Chem 2015; 54:10269-80. [PMID: 26485328 DOI: 10.1021/acs.inorgchem.5b01576] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The extradiol-cleaving dioxygenase homoprotocatechuate 2,3-dioxygenase (HPCD) binds substrate homoprotocatechuate (HPCA) and O2 sequentially in adjacent ligand sites of the active site Fe(II). Kinetic and spectroscopic studies of HPCD have elucidated catalytic roles of several active site residues, including the crucial acid-base chemistry of His200. In the present study, reaction of the His200Cys (H200C) variant with native substrate HPCA resulted in a decrease in both kcat and the rate constants for the activation steps following O2 binding by >400 fold. The reaction proceeds to form the correct extradiol product. This slow reaction allowed a long-lived (t1/2 = 1.5 min) intermediate, H200C-HPCAInt1 (Int1), to be trapped. Mössbauer and parallel mode electron paramagnetic resonance (EPR) studies show that Int1 contains an S1 = 5/2 Fe(III) center coupled to an SR = 1/2 radical to give a ground state with total spin S = 2 (J > 40 cm(-1)) in Hexch = JŜ1·ŜR. Density functional theory (DFT) property calculations for structural models suggest that Int1 is a (HPCA semiquinone(•))Fe(III)(OOH) complex, in which OOH is protonated at the distal O and the substrate hydroxyls are deprotonated. By combining Mössbauer and EPR data of Int1 with DFT calculations, the orientations of the principal axes of the (57)Fe electric field gradient and the zero-field splitting tensors (D = 1.6 cm(-1), E/D = 0.05) were determined. This information was used to predict hyperfine splittings from bound (17)OOH. DFT reactivity analysis suggests that Int1 can evolve from a ferromagnetically coupled Fe(III)-superoxo precursor by an inner-sphere proton-coupled-electron-transfer process. Our spectroscopic and DFT results suggest that a ferric hydroperoxo species is capable of extradiol catalysis.
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Affiliation(s)
- Katlyn K Meier
- Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Melanie S Rogers
- Department of Biochemistry, Molecular Biology and Biophysics and Center for Metals in Biocatalysis, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Elena G Kovaleva
- Stanford Synchrotron Radiation Lightsource, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Michael M Mbughuni
- Department of Biochemistry, Molecular Biology and Biophysics and Center for Metals in Biocatalysis, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Emile L Bominaar
- Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - John D Lipscomb
- Department of Biochemistry, Molecular Biology and Biophysics and Center for Metals in Biocatalysis, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Eckard Münck
- Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
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27
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Kovaleva EG, Rogers MS, Lipscomb JD. Structural Basis for Substrate and Oxygen Activation in Homoprotocatechuate 2,3-Dioxygenase: Roles of Conserved Active Site Histidine 200. Biochemistry 2015; 54:5329-39. [PMID: 26267790 DOI: 10.1021/acs.biochem.5b00709] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Kinetic and spectroscopic studies have shown that the conserved active site residue His200 of the extradiol ring-cleaving homoprotocatechuate 2,3-dioxygenase (FeHPCD) from Brevibacterium fuscum is critical for efficient catalysis. The roles played by this residue are probed here by analysis of the steady-state kinetics, pH dependence, and X-ray crystal structures of the FeHPCD position 200 variants His200Asn, His200Gln, and His200Glu alone and in complex with three catecholic substrates (homoprotocatechuate, 4-sulfonylcatechol, and 4-nitrocatechol) possessing substituents with different inductive capacity. Structures determined at 1.35-1.75 Å resolution show that there is essentially no change in overall active site architecture or substrate binding mode for these variants when compared to the structures of the wild-type enzyme and its analogous complexes. This shows that the maximal 50-fold decrease in kcat for ring cleavage, the dramatic changes in pH dependence, and the switch from ring cleavage to ring oxidation of 4-nitrocatechol by the FeHPCD variants can be attributed specifically to the properties of the altered second-sphere residue and the substrate. The results suggest that proton transfer is necessary for catalysis, and that it occurs most efficiently when the substrate provides the proton and His200 serves as a catalyst. However, in the absence of an available substrate proton, a defined proton-transfer pathway in the protein can be utilized. Changes in the steric bulk and charge of the residue at position 200 appear to be capable of altering the rate-limiting step in catalysis and, perhaps, the nature of the reactive species.
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Affiliation(s)
- Elena G Kovaleva
- Institute of Molecular and Cellular Biology, University of Leeds , Leeds LS2 9JT, U.K
| | - Melanie S Rogers
- Department of Biochemistry, Molecular Biology, and Biophysics and Center for Metals in Biocatalysis, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - John D Lipscomb
- Department of Biochemistry, Molecular Biology, and Biophysics and Center for Metals in Biocatalysis, University of Minnesota , Minneapolis, Minnesota 55455, United States
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28
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Eppinger E, Ferraroni M, Bürger S, Steimer L, Peng G, Briganti F, Stolz A. Function of different amino acid residues in the reaction mechanism of gentisate 1,2-dioxygenases deduced from the analysis of mutants of the salicylate 1,2-dioxygenase from Pseudaminobacter salicylatoxidans. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1425-37. [PMID: 26093111 DOI: 10.1016/j.bbapap.2015.06.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 05/28/2015] [Accepted: 06/15/2015] [Indexed: 11/24/2022]
Abstract
The genome of the α-proteobacterium Pseudaminobacter salicylatoxidans codes for a ferrous iron containing ring-fission dioxygenase which catalyzes the 1,2-cleavage of (substituted) salicylate(s), gentisate (2,5-dihydroxybenzoate), and 1-hydroxy-2-naphthoate. Sequence alignments suggested that the "salicylate 1,2-dioxygenase" (SDO) from this strain is homologous to gentisate 1,2-dioxygenases found in bacteria, archaea and fungi. In the present study the catalytic mechanism of the SDO and gentisate 1,2-dioxygenases in general was analyzed based on sequence alignments, mutational and previously performed crystallographic studies and mechanistic comparisons with "extradiol- dioxygenases" which cleave aromatic nuclei in the 2,3-position. Different highly conserved amino acid residues that were supposed to take part in binding and activation of the organic substrates were modified in the SDO by site-specific mutagenesis and the enzyme variants subsequently analyzed for the conversion of salicylate, gentisate and 1-hydroxy-2-naphthoate. The analysis of enzyme variants which carried exchanges in the positions Arg83, Trp104, Gly106, Gln108, Arg127, His162 and Asp174 demonstrated that Arg83 and Arg127 were indispensable for enzymatic activity. In contrast, residual activities were found for variants carrying mutations in the residues Trp104, Gly106, Gln108, His162, and Asp174 and some of these mutants still could oxidize gentisate, but lost the ability to convert salicylate. The results were used to suggest a general reaction mechanism for gentisate-1,2-dioxygenases and to assign to certain amino acid residues in the active site specific functions in the cleavage of (substituted) salicylate(s).
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Affiliation(s)
- Erik Eppinger
- Institut für Mikrobiologie, Universität Stuttgart, Stuttgart, Germany
| | - Marta Ferraroni
- Dipartimento di Chimica "Ugo Schiff", Università di Firenze, Sesto Fiorentin, Italy
| | - Sibylle Bürger
- Institut für Mikrobiologie, Universität Stuttgart, Stuttgart, Germany
| | - Lenz Steimer
- Institut für Mikrobiologie, Universität Stuttgart, Stuttgart, Germany
| | - Grace Peng
- Institut für Mikrobiologie, Universität Stuttgart, Stuttgart, Germany
| | - Fabrizio Briganti
- Dipartimento di Chimica "Ugo Schiff", Università di Firenze, Sesto Fiorentin, Italy
| | - Andreas Stolz
- Institut für Mikrobiologie, Universität Stuttgart, Stuttgart, Germany.
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Hernández-Ortega A, Quesne MG, Bui S, Heyes DJ, Steiner RA, Scrutton NS, de Visser SP. Catalytic Mechanism of Cofactor-Free Dioxygenases and How They Circumvent Spin-Forbidden Oxygenation of Their Substrates. J Am Chem Soc 2015; 137:7474-87. [DOI: 10.1021/jacs.5b03836] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Aitor Hernández-Ortega
- Manchester
Institute of Biotechnology and Faculty of Life Sciences, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Matthew G. Quesne
- Manchester
Institute of Biotechnology and School of Chemical Engineering and
Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Soi Bui
- Randall
Division of Cell and Molecular Biophysics, King’s College London, London SE1 1UL, United Kingdom
| | - Derren J. Heyes
- Manchester
Institute of Biotechnology and Faculty of Life Sciences, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Roberto A. Steiner
- Randall
Division of Cell and Molecular Biophysics, King’s College London, London SE1 1UL, United Kingdom
| | - Nigel S. Scrutton
- Manchester
Institute of Biotechnology and Faculty of Life Sciences, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Sam P. de Visser
- Manchester
Institute of Biotechnology and School of Chemical Engineering and
Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
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30
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Sugimoto K, Senda M, Kasai D, Fukuda M, Masai E, Senda T. Molecular mechanism of strict substrate specificity of an extradiol dioxygenase, DesB, derived from Sphingobium sp. SYK-6. PLoS One 2014; 9:e92249. [PMID: 24657997 PMCID: PMC3962378 DOI: 10.1371/journal.pone.0092249] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 02/20/2014] [Indexed: 11/18/2022] Open
Abstract
DesB, which is derived from Sphingobium sp. SYK-6, is a type II extradiol dioxygenase that catalyzes a ring opening reaction of gallate. While typical extradiol dioxygenases show broad substrate specificity, DesB has strict substrate specificity for gallate. The substrate specificity of DesB seems to be required for the efficient growth of S. sp. SYK-6 using lignin-derived aromatic compounds. Since direct coordination of hydroxyl groups of the substrate to the non-heme iron in the active site is a critical step for the catalytic reaction of the extradiol dioxygenases, the mechanism of the substrate recognition and coordination of DesB was analyzed by biochemical and crystallographic methods. Our study demonstrated that the direct coordination between the non-heme iron and hydroxyl groups of the substrate requires a large shift of the Fe (II) ion in the active site. Mutational analysis revealed that His124 and His192 in the active site are essential to the catalytic reaction of DesB. His124, which interacts with OH (4) of the bound gallate, seems to contribute to proper positioning of the substrate in the active site. His192, which is located close to OH (3) of the gallate, is likely to serve as the catalytic base. Glu377' interacts with OH (5) of the gallate and seems to play a critical role in the substrate specificity. Our biochemical and structural study showed the substrate recognition and catalytic mechanisms of DesB.
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Affiliation(s)
- Keisuke Sugimoto
- Department of Materials Chemistry, Asahikawa National College of Technology, Asahikawa, Hokkaido, Japan
| | - Miki Senda
- Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki, Japan
| | - Daisuke Kasai
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Masao Fukuda
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Eiji Masai
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Toshiya Senda
- Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki, Japan
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31
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Fielding AJ, Lipscomb JD, Que L. A two-electron-shell game: intermediates of the extradiol-cleaving catechol dioxygenases. J Biol Inorg Chem 2014; 19:491-504. [PMID: 24615282 DOI: 10.1007/s00775-014-1122-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 02/13/2014] [Indexed: 11/29/2022]
Abstract
Extradiol-cleaving catechol dioxygenases function by binding both the organic substrate and O2 at a divalent metal center in the active site. They have proven to be a particularly versatile group of enzymes with which to study the O2 activation process. Here, recent studies of homoprotocatechuate 2,3-dioxygenase are summarized, showing how nature can utilize the enzyme structure and the properties of the metal and the substrate to select among many possible chemical paths to achieve both specificity and efficiency. Possible intermediates in the mechanism have been trapped by swapping active-site metals, introducing active-site amino acid substituted variants, and using substrates with different electron-donating capacities. Although each of these intermediates could form part of a viable reaction pathway, kinetic measurements significantly limit the likely candidates. Structural, kinetic, spectroscopic, and computational analyses of the various intermediates shed light on how catalytic efficiency can be achieved.
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Affiliation(s)
- Andrew J Fielding
- Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA
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32
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Defining a kinetic mechanism for l-DOPA 2,3 dioxygenase, a single-domain type I extradiol dioxygenase from Streptomyces lincolnensis. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:607-14. [DOI: 10.1016/j.bbapap.2013.12.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 11/11/2013] [Accepted: 12/09/2013] [Indexed: 11/22/2022]
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Borowski T, Broclawik E. Bioinorganic Reaction Mechanisms – Quantum Chemistry Approach. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/978-3-642-28554-7_22] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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Hayden JA, Farquhar ER, Que L, Lipscomb JD, Hendrich MP. NO binding to Mn-substituted homoprotocatechuate 2,3-dioxygenase: relationship to O₂ reactivity. J Biol Inorg Chem 2013; 18:717-28. [PMID: 23824380 DOI: 10.1007/s00775-013-1016-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 06/15/2013] [Indexed: 10/26/2022]
Abstract
Iron(II)-containing homoprotocatechuate 2,3-dioxygenase (FeHPCD) activates O2 to catalyze the aromatic ring opening of homoprotocatechuate (HPCA). The enzyme requires Fe(II) for catalysis, but Mn(II) can be substituted (MnHPCD) with essentially no change in the steady-state kinetic parameters. Near simultaneous O2 and HPCA activation has been proposed to occur through transfer of an electron or electrons from HPCA to O2 through the divalent metal. In O2 reactions with MnHPCD-HPCA and the 4-nitrocatechol (4NC) complex of the His200Asn (H200N) variant of FeHPCD, this transfer has resulted in the detection of a transient M(III)-O2 (·-) species that is not observed during turnover of the wild-type FeHPCD. The factors governing formation of the M(III)-O2 (·-) species are explored here by EPR spectroscopy using MnHPCD and nitric oxide (NO) as an O2 surrogate. Both the HPCA and the dihydroxymandelic substrate complexes of MnHPCD bind NO, thus representing the first reported stable MnNO complexes of a nonheme enzyme. In contrast, the free enzyme, the MnHPCD-4NC complex, and the MnH200N and MnH200Q variants with or without HPCA bound do not bind NO. The MnHPCD-ligand complexes that bind NO are also active in normal O2-linked turnover, whereas the others are inactive. Past studies have shown that FeHPCD and the analogous variants and catecholic ligand complexes all bind NO, and are active in normal turnover. This contrasting behavior may stem from the ability of the enzyme to maintain the approximately 0.8-V difference in the solution redox potentials of Fe(II) and Mn(II). Owing to the higher potential of Mn, the formation of the NO adduct or the O2 adduct requires both strong charge donation from the bound catecholic ligand and additional stabilization by interaction with the active-site His200. The same nonoptimal electronic and structural forces that prevent NO and O2 binding in MnHPCD variants may lead to inefficient electron transfer from the catecholic substrate to the metal center in variants of FeHPCD during O2-linked turnover. Accordingly, past studies have shown that intermediate Fe(III) species are observed for these mutant enzymes.
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Affiliation(s)
- Joshua A Hayden
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave., Pittsburgh, PA, 15213, USA
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35
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Lehr J, Bennett J, Tropiano M, Sørensen TJ, Faulkner S, Beer PD, Davis JJ. Reversible recruitment and emission of DO3A-derived lanthanide complexes at ligating molecular films on gold. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:1475-1482. [PMID: 23320931 DOI: 10.1021/la3046725] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The recruitment of DO3A-derived lanthanide complexes by ligation to isophthalic acid and catechol-modified gold surfaces, and their resulting sensitization, is reported herein. Predictably pH-dependent surface recruitment is associated with the expected fingerprint europium and terbium emission characteristics. The intensity of the lanthanide luminescence scales exponentially with spacer length, indicating a strong quenching interaction between the lanthanide and the gold surface. The switchable catechol oxidation state provides a means of electrochemically triggering the release of prior ligated complexes.
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Affiliation(s)
- Joshua Lehr
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3TA, United Kingdom
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36
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Li DF, Zhang JY, Hou YJ, Liu L, Hu Y, Liu SJ, Wang DC, Liu W. Structures of aminophenol dioxygenase in complex with intermediate, product and inhibitor. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2012; 69:32-43. [PMID: 23275161 DOI: 10.1107/s0907444912042072] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 10/08/2012] [Indexed: 11/10/2022]
Abstract
Dioxygen activation by nonhaem Fe(II) enzymes containing the 2-His-1-carboxylate facial triad has been extensively studied in recent years. Here, crystal structures of 2-aminophenol 1,6-dioxygenase, an enzyme that represents a minor group of extradiol dioxygenases and that catalyses the ring opening of 2-aminophenol, in complex with the lactone intermediate (4Z,6Z)-3-iminooxepin-2(3H)-one and the product 2-aminomuconic 6-semialdehyde and in complex with the suicide inhibitor 4-nitrocatechol are reported. The Fe-ligand binding schemes observed in these structures revealed some common geometrical characteristics that are shared by the published structures of extradiol dioxygenases, suggesting that enzymes that catalyse the oxidation of noncatecholic compounds are very likely to utilize a similar strategy for dioxygen activation and the fission of aromatic rings as the canonical mechanism. The Fe-ligation arrangement, however, is strikingly enantiomeric to that of all other 2-His-1-carboxylate enzymes apart from protocatechuate 4,5-dioxygenase. This structural variance leads to the generation of an uncommon O(-)-Fe(2+)-O(-) species prior to O(2) binding, which probably forms the structural basis on which APD distinguishes its specific substrate and inhibitor, which share an analogous molecular structure.
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Affiliation(s)
- De Feng Li
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, People's Republic of China
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37
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Li DF, Zhang JY, Hou Y, Liu L, Liu SJ, Liu W. Crystallization and preliminary crystallographic analysis of 2-aminophenol 1,6-dioxygenase complexed with substrate and with an inhibitor. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:1337-40. [PMID: 23143244 PMCID: PMC3515376 DOI: 10.1107/s1744309112038705] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 09/10/2012] [Indexed: 11/10/2022]
Abstract
Dioxygen activation implemented by nonhaem Fe(II) enzymes containing the 2-His-1-carboxylate facial triad has been extensively studied in recent years. Extradiol dioxygenase is the archetypal member of this superfamily and catalyzes the oxygenolytic ring opening of catechol analogues. Here, the crystallization and preliminary X-ray analysis of 2-aminophenol 1,6-dioxygenase, an enzyme representing a minor subset of extradiol dioxygenases that catalyze the fission of 2-aminophenol rather than catecholic compounds, is reported. Crystals of the holoenzyme with FeII and of complexes with the substrate 2-aminophenol and the suicide inhibitor 4-nitrocatechol were grown using the cocrystallization method under the same conditions as used for the crystallization of the apoenzyme. The crystals belonged to space group C2 and diffracted to 2.3-2.7 Å resolution; the crystal that diffracted to the highest resolution had unit-cell parameters a=270.24, b=48.39, c=108.55 Å, β=109.57°. All X-ray data sets collected from diffraction-quality crystals were suitable for structure determination.
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Affiliation(s)
- De-Feng Li
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
| | - Jia-Yue Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
| | - Yanjie Hou
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
| | - Lei Liu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
| | - Shuang-Jiang Liu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
| | - Wei Liu
- Institute of Immunology, The Third Military Medical University, Chongqing 400038, People’s Republic of China
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38
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Mbughuni MM, Meier KK, Münck E, Lipscomb JD. Substrate-mediated oxygen activation by homoprotocatechuate 2,3-dioxygenase: intermediates formed by a tyrosine 257 variant. Biochemistry 2012; 51:8743-54. [PMID: 23066705 DOI: 10.1021/bi301114x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Homoprotocatechuate (HPCA; 3,4-dihydroxyphenylacetate or 4-carboxymethyl catechol) and O(2) bind in adjacent ligand sites of the active site Fe(II) of homoprotocatechuate 2,3-dioxygenase (FeHPCD). We have proposed that electron transfer from the chelated aromatic substrate through the Fe(II) to O(2) gives both substrates radical character. This would promote reaction between the substrates to form an alkylperoxo intermediate as the first step in aromatic ring cleavage. Several active site amino acids are thought to promote these reactions through acid/base chemistry, hydrogen bonding, and electrostatic interactions. Here the role of Tyr257 is explored by using the Tyr257Phe (Y257F) variant, which decreases k(cat) by about 75%. The crystal structure of the FeHPCD-HPCA complex has shown that Tyr257 hydrogen bonds to the deprotonated C2-hydroxyl of HPCA. Stopped-flow studies show that at least two reaction intermediates, termed Y257F(Int1)(HPCA) and Y257F(Int2)(HPCA), accumulate during the Y257F-HPCA + O(2) reaction prior to formation of the ring-cleaved product. Y257F(Int1)(HPCA) is colorless and is formed as O(2) binds reversibly to the HPCA−enzyme complex. Y257F(Int2)(HPCA) forms spontaneously from Y257F(Int1)(HPCA) and displays a chromophore at 425 nm (ε(425) = 10 500 M(−1) cm(−1)). Mössbauer spectra of the intermediates trapped by rapid freeze quench show that both intermediates contain Fe(II). The lack of a chromophore characteristic of a quinone or semiquinone form of HPCA, the presence of Fe(II), and the low O(2) affinity suggest that Y257F(Int1)(HPCA) is an HPCA-Fe(II)-O(2) complex with little electron delocalization onto the O(2). In contrast, the intense spectrum of Y257F(Int2)(HPCA) suggests the intermediate is most likely an HPCA quinone-Fe(II)-(hydro)peroxo species. Steady-state and transient kinetic analyses show that steps of the catalytic cycle are slowed by as much as 100-fold by the mutation. These effects can be rationalized by a failure of Y257F to facilitate the observed distortion of the bound HPCA that is proposed to promote transfer of one electron to O(2).
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Affiliation(s)
- Michael M Mbughuni
- Department of Biochemistry, Molecular Biology and Biophysics and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
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Baum AE, Park H, Wang D, Lindeman SV, Fiedler AT. Structural, spectroscopic, and electrochemical properties of nonheme Fe(II)-hydroquinonate complexes: synthetic models of hydroquinone dioxygenases. Dalton Trans 2012; 41:12244-53. [PMID: 22930005 PMCID: PMC3891569 DOI: 10.1039/c2dt31504a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using the tris(3,5-diphenylpyrazol-1-yl)borate ((Ph2)Tp) supporting ligand, a series of mono- and dinuclear ferrous complexes containing hydroquinonate (HQate) ligands have been prepared and structurally characterized with X-ray crystallography. The monoiron(II) complexes serve as faithful mimics of the substrate-bound form of hydroquinone dioxygenases (HQDOs) - a family of nonheme Fe enzymes that catalyze the oxidative cleavage of 1,4-dihydroxybenzene units. Reflecting the variety of HQDO substrates, the synthetic complexes feature both mono- and bidentate HQate ligands. The bidentate HQates cleanly provide five-coordinate, high-spin Fe(II) complexes with the general formula [Fe((Ph2)Tp)(HL(X))] (1X), where HL(X) is a HQate(1-) ligand substituted at the 2-position with a benzimidazolyl (1A), acetyl (1B and 1C), or methoxy (1D) group. In contrast, the monodentate ligand 2,6-dimethylhydroquinone (H(2)L(F)) exhibited a greater tendency to bridge between two Fe(II) centers, resulting in formation of [Fe(2)((Ph2)Tp)(2)(μ-L(F))(MeCN)]·[2F(MeCN)]. However, addition of one equivalent of "free" pyrazole ((Ph2)pz) ligand provided the mononuclear complex, [Fe((Ph2)Tp)(HL(F))((Ph2)pz)]·[1F((Ph2)pz)], which is stabilized by an intramolecular hydrogen bond between the HL(F) and (Ph2)pz donors. Complex 1F((Ph2)pz) represents the first crystallographically-characterized example of a monoiron complex bound to an untethered HQate ligand. The geometric and electronic structures of the Fe/HQate complexes were further probed with spectroscopic (UV-vis absorption, (1)H NMR) and electrochemical methods. Cyclic voltammograms of complexes in the 1X series revealed an Fe-based oxidation between 0 and -300 mV (vs. Fc(+/0)), in addition to irreversible oxidation(s) of the HQate ligand at higher potentials. The one-electron oxidized species (1X(OX)) were examined with UV-vis absorption and electron paramagnetic resonance (EPR) spectroscopies.
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Affiliation(s)
- Amanda E. Baum
- Department of Chemistry, Marquette University, Milwaukee, WI 53201-1881
| | - Heaweon Park
- Department of Chemistry, Marquette University, Milwaukee, WI 53201-1881
| | - Denan Wang
- Department of Chemistry, Marquette University, Milwaukee, WI 53201-1881
| | | | - Adam T. Fiedler
- Department of Chemistry, Marquette University, Milwaukee, WI 53201-1881
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40
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Henderson KL, Le VH, Lewis EA, Emerson JP. Exploring substrate binding in homoprotocatechuate 2,3-dioxygenase using isothermal titration calorimetry. J Biol Inorg Chem 2012; 17:991-4. [PMID: 22915062 DOI: 10.1007/s00775-012-0929-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Accepted: 07/31/2012] [Indexed: 11/30/2022]
Abstract
Homoprotocatechuate 2,3-dioxygenase (HPCD) is a member of the extradiol dioxygenase family of non-heme iron enzymes. These enzymes catalyze the ring-cleavage step in the aromatic degradation pathway commonly found in soil bacteria. In this study, isothermal titration calorimetry (ITC) is used to measure the equilibrium constant (K = 1.1 ± 0.6 × 10(6)) and enthalpy change (ΔH = -17.0 ± 1.7 kcal/mol) associated with homoprotocatechuate binding to HPCD. The ITC data are consistent with the release of approximately 2.6 protons upon binding of the substrate to HPCD. These results raise new questions regarding the relationships between substrate, protein, and the oxygen activation mechanism for this class of non-heme metalloenzymes.
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Affiliation(s)
- Kate L Henderson
- Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA
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41
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Alkene cleavage catalysed by heme and nonheme enzymes: reaction mechanisms and biocatalytic applications. Bioinorg Chem Appl 2012; 2012:626909. [PMID: 22811656 PMCID: PMC3395118 DOI: 10.1155/2012/626909] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2012] [Accepted: 05/13/2012] [Indexed: 11/17/2022] Open
Abstract
The oxidative cleavage of alkenes is classically performed by chemical methods, although they display several drawbacks. Ozonolysis requires harsh conditions (−78°C, for a safe process) and reducing reagents in a molar amount, whereas the use of poisonous heavy metals such as Cr, Os, or Ru as catalysts is additionally plagued by low yield and selectivity. Conversely, heme and nonheme enzymes can catalyse the oxidative alkene cleavage at ambient temperature and atmospheric pressure in an aqueous buffer, showing excellent chemo- and regioselectivities in certain cases. This paper focuses on the alkene cleavage catalysed by iron cofactor-dependent enzymes encompassing the reaction mechanisms (in case where it is known) and the application of these enzymes in biocatalysis.
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42
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Abstract
Ring-cleaving dioxygenases catalyze key reactions in the aerobic microbial degradation of aromatic compounds. Many pathways converge to catecholic intermediates, which are subject to ortho or meta cleavage by intradiol or extradiol dioxygenases, respectively. However, a number of degradation pathways proceed via noncatecholic hydroxy-substituted aromatic carboxylic acids like gentisate, salicylate, 1-hydroxy-2-naphthoate, or aminohydroxybenzoates. The ring-cleaving dioxygenases active toward these compounds belong to the cupin superfamily, which is characterized by a six-stranded β-barrel fold and conserved amino acid motifs that provide the 3His or 2- or 3His-1Glu ligand environment of a divalent metal ion. Most cupin-type ring cleavage dioxygenases use an Fe(II) center for catalysis, and the proposed mechanism is very similar to that of the canonical (type I) extradiol dioxygenases. The metal ion is presumed to act as an electron conduit for single electron transfer from the metal-bound substrate anion to O(2), resulting in activation of both substrates to radical species. The family of cupin-type dioxygenases also involves quercetinase (flavonol 2,4-dioxygenase), which opens up two C-C bonds of the heterocyclic ring of quercetin, a wide-spread plant flavonol. Remarkably, bacterial quercetinases are capable of using different divalent metal ions for catalysis, suggesting that the redox properties of the metal are relatively unimportant for the catalytic reaction. The major role of the active-site metal ion could be to correctly position the substrate and to stabilize transition states and intermediates rather than to mediate electron transfer. The tentative hypothesis that quercetinase catalysis involves direct electron transfer from metal-bound flavonolate to O(2) is supported by model chemistry.
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43
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Christian GJ, Ye S, Neese F. Oxygen activation in extradiol catecholate dioxygenases – a density functional study. Chem Sci 2012. [DOI: 10.1039/c2sc00754a] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Fielding AJ, Lipscomb JD, Que L. Characterization of an O2 adduct of an active cobalt-substituted extradiol-cleaving catechol dioxygenase. J Am Chem Soc 2011; 134:796-9. [PMID: 22175783 DOI: 10.1021/ja2095365] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The first example of an O(2) adduct of an active Co-substituted oxygenase has been observed in the extradiol ring cleavage of the electron-poor substrate 4-nitrocatechol (4NC) by Co(II)-homoprotocatechuate 2,3-dioxygenase (Co-HPCD). Upon O(2) binding to the high-spin Co(II) (S = (3)/(2)) enzyme-substrate complex, an S = (1)/(2) EPR signal exhibiting (59)Co hyperfine splitting (A = 24 G) typical of a low-spin Co(III)-superoxide complex was observed. Both the formation and decay of the new intermediate are very slow in comparison to the analogous steps for turnover of 4NC by native high-spin Fe(II)-HPCD, which is likely to remain high-spin upon O(2) binding. A similar but effectively stable S = (1)/(2) intermediate was formed by the inactive [H200N-Co-HPCD(4NC)] variant. The observations presented shed light on the key roles played by the substrate, the second-sphere His200 residue, and the spin state of the metal center in facilitating O(2) binding and activation.
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Affiliation(s)
- Andrew J Fielding
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Visvaganesan K, Ramachitra S, Palaniandavar M. Functional models for enzyme–substrate adducts of catechol dioxygenase enzymes: The Lewis basicity of facially coordinating tridentate phenolate ligands tunes the rate of dioxygenation and product selectivity. Inorganica Chim Acta 2011. [DOI: 10.1016/j.ica.2011.08.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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He P, Moran GR. Structural and mechanistic comparisons of the metal-binding members of the vicinal oxygen chelate (VOC) superfamily. J Inorg Biochem 2011; 105:1259-72. [DOI: 10.1016/j.jinorgbio.2011.06.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 06/21/2011] [Accepted: 06/24/2011] [Indexed: 11/30/2022]
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PALANIANDAVAR MALLAYAN, VISVAGANESAN KUSALENDIRAN. Mononuclear non-heme iron(III) complexes of linear and tripodal tridentate ligands as functional models for catechol dioxygenases: Effect of N-alkyl substitution on regioselectivity and reaction rate. J CHEM SCI 2011. [DOI: 10.1007/s12039-011-0110-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Synthesis, anticancer activity, and iron affinity of the Actinoplanes metabolite 7,8-dihydroxy-1-methylnaphtho[2,3-c]furan-4,9-dione. Bioorg Med Chem 2011; 19:1264-7. [DOI: 10.1016/j.bmc.2010.12.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Revised: 12/01/2010] [Accepted: 12/04/2010] [Indexed: 11/21/2022]
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Fielding AJ, Kovaleva EG, Farquhar ER, Lipscomb JD, Que L. A hyperactive cobalt-substituted extradiol-cleaving catechol dioxygenase. J Biol Inorg Chem 2011; 16:341-55. [PMID: 21153851 PMCID: PMC3192431 DOI: 10.1007/s00775-010-0732-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 10/27/2010] [Indexed: 11/27/2022]
Abstract
Homoprotocatechuate 2,3-dioxygenase from Brevibacterium fuscum (HPCD) has an Fe(II) center in its active site that can be replaced with Mn(II) or Co(II). Whereas Mn-HPCD exhibits steady-state kinetic parameters comparable to those of Fe-HPCD, Co-HPCD behaves somewhat differently, exhibiting significantly higher [Formula: see text] and k (cat). The high activity of Co-HPCD is surprising, given that cobalt has the highest standard M(III/II) redox potential of the three metals. Comparison of the X-ray crystal structures of the resting and substrate-bound forms of Fe-HPCD, Mn-HPCD, and Co-HPCD shows that metal substitution has no effect on the local ligand environment, the conformational integrity of the active site, or the overall protein structure, suggesting that the protein structure does not differentially tune the potential of the metal center. Analysis of the steady-state kinetics of Co-HPCD suggests that the Co(II) center alters the relative rate constants for the interconversion of intermediates in the catalytic cycle but still allows the dioxygenase reaction to proceed efficiently. When compared with the kinetic data for Fe-HPCD and Mn-HPCD, these results show that dioxygenase catalysis can proceed at high rates over a wide range of metal redox potentials. This is consistent with the proposed mechanism in which the metal mediates electron transfer between the catechol substrate and O(2) to form the postulated [M(II)(semiquinone)superoxo] reactive species. These kinetic differences and the spectroscopic properties of Co-HPCD provide new tools with which to explore the unique O(2) activation mechanism associated with the extradiol dioxygenase family.
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Affiliation(s)
- Andrew J Fielding
- Department of Chemistry, Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant Street, Minneapolis, MN 55455, USA
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Shashilov VA, Lednev IK. Advanced statistical and numerical methods for spectroscopic characterization of protein structural evolution. Chem Rev 2011; 110:5692-713. [PMID: 20593900 DOI: 10.1021/cr900152h] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Victor A Shashilov
- Aegis Analytical Corporation, 1380 Forest Park Circle, Suite 200, Lafayette, Colorado 80026, USA
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