1
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Khanppnavar B, Choo JPS, Hagedoorn PL, Smolentsev G, Štefanić S, Kumaran S, Tischler D, Winkler FK, Korkhov VM, Li Z, Kammerer RA, Li X. Structural basis of the Meinwald rearrangement catalysed by styrene oxide isomerase. Nat Chem 2024:10.1038/s41557-024-01523-y. [PMID: 38744914 DOI: 10.1038/s41557-024-01523-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 03/27/2024] [Indexed: 05/16/2024]
Abstract
Membrane-bound styrene oxide isomerase (SOI) catalyses the Meinwald rearrangement-a Lewis-acid-catalysed isomerization of an epoxide to a carbonyl compound-and has been used in single and cascade reactions. However, the structural information that explains its reaction mechanism has remained elusive. Here we determine cryo-electron microscopy (cryo-EM) structures of SOI bound to a single-domain antibody with and without the competitive inhibitor benzylamine, and elucidate the catalytic mechanism using electron paramagnetic resonance spectroscopy, functional assays, biophysical methods and docking experiments. We find ferric haem b bound at the subunit interface of the trimeric enzyme through H58, where Fe(III) acts as the Lewis acid by binding to the epoxide oxygen. Y103 and N64 and a hydrophobic pocket binding the oxygen of the epoxide and the aryl group, respectively, position substrates in a manner that explains the high regio-selectivity and stereo-specificity of SOI. Our findings can support extending the range of epoxide substrates and be used to potentially repurpose SOI for the catalysis of new-to-nature Fe-based chemical reactions.
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Affiliation(s)
- Basavraj Khanppnavar
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Joel P S Choo
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Singapore
| | - Peter-Leon Hagedoorn
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | | | - Saša Štefanić
- Nanobody Service Facility. AgroVet-Strickhof, University of Zurich, Lindau, Switzerland
| | | | - Dirk Tischler
- Microbial Biotechnology, Ruhr University Bochum, Bochum, Germany
| | | | - Volodymyr M Korkhov
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, Villigen, Switzerland.
- Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland.
| | - Zhi Li
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Singapore.
| | - Richard A Kammerer
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, Villigen, Switzerland.
| | - Xiaodan Li
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, Villigen, Switzerland.
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2
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Famulari A, Correddu D, Di Nardo G, Gilardi G, Mitrikas G, Chiesa M, García-Rubio I. Heme Spin Distribution in the Substrate-Free and Inhibited Novel CYP116B5hd: A Multifrequency Hyperfine Sublevel Correlation (HYSCORE) Study. Molecules 2024; 29:518. [PMID: 38276601 PMCID: PMC10819608 DOI: 10.3390/molecules29020518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 12/29/2023] [Accepted: 01/16/2024] [Indexed: 01/27/2024] Open
Abstract
The cytochrome P450 family consists of ubiquitous monooxygenases with the potential to perform a wide variety of catalytic applications. Among the members of this family, CYP116B5hd shows a very prominent resistance to peracid damage, a property that makes it a promising tool for fine chemical synthesis using the peroxide shunt. In this meticulous study, we use hyperfine spectroscopy with a multifrequency approach (X- and Q-band) to characterize in detail the electronic structure of the heme iron of CYP116B5hd in the resting state, which provides structural details about its active site. The hyperfine dipole-dipole interaction between the electron and proton nuclear spins allows for the locating of two different protons from the coordinated water and a beta proton from the cysteine axial ligand of heme iron with respect to the magnetic axes centered on the iron. Additionally, since new anti-cancer therapies target the inhibition of P450s, here we use the CYP116B5hd system-imidazole as a model for studying cytochrome P450 inhibition by an azo compound. The effects of the inhibition of protein by imidazole in the active-site geometry and electron spin distribution are presented. The binding of imidazole to CYP116B5hd results in an imidazole-nitrogen axial coordination and a low-spin heme FeIII. HYSCORE experiments were used to detect the hyperfine interactions. The combined interpretation of the gyromagnetic tensor and the hyperfine and quadrupole tensors of magnetic nuclei coupled to the iron electron spin allowed us to obtain a precise picture of the active-site geometry, including the orientation of the semi-occupied orbitals and magnetic axes, which coincide with the porphyrin N-Fe-N axes. The electronic structure of the iron does not seem to be affected by imidazole binding. Two different possible coordination geometries of the axial imidazole were observed. The angles between gx (coinciding with one of the N-Fe-N axes) and the projection of the imidazole plane on the heme were determined to be -60° and -25° for each of the two possibilities via measurement of the hyperfine structure of the axially coordinated 14N.
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Affiliation(s)
- Antonino Famulari
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain;
- Department of Chemistry, University of Turin, Via Giuria 9, 10125 Torino, Italy;
| | - Danilo Correddu
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Torino, Italy (G.D.N.); (G.G.)
| | - Giovanna Di Nardo
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Torino, Italy (G.D.N.); (G.G.)
| | - Gianfranco Gilardi
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Torino, Italy (G.D.N.); (G.G.)
| | - George Mitrikas
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 15341 Athens, Greece;
| | - Mario Chiesa
- Department of Chemistry, University of Turin, Via Giuria 9, 10125 Torino, Italy;
| | - Inés García-Rubio
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain;
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
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3
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Nolan K, Wang Y. Combined spectroscopic and structural approaches to explore the mechanism of histidine-ligated heme-dependent aromatic oxygenases. Methods Enzymol 2023; 685:405-432. [PMID: 37245909 PMCID: PMC11057917 DOI: 10.1016/bs.mie.2023.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The emergence of histidine-ligated heme-dependent aromatic oxygenases (HDAOs) has greatly enriched heme chemistry, and more studies are required to appreciate the diversity found in His-ligated heme proteins. This chapter describes recent methods in probing the HDAO mechanisms in detail, along with the discussion on how they can benefit structure-function studies of other heme systems. The experimental details are centered on studies of TyrHs, followed by explanation of how the results obtained would advance the understanding of the specific enzyme and also HDAOs. Spectroscopic methods, namely, electronic absorption and EPR spectroscopies, and X-ray crystallography are valuable techniques commonly used to characterize the properties of the heme center and the nature of heme-based intermediate. Herein, we show that the combination of these tools are extremely powerful, not only because one can acquire electronic, magnetic, and conformational information from different phases, but also because of the advantages brought by spectroscopic characterization on crystal samples.
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Affiliation(s)
- Katie Nolan
- Department of Chemistry, University of Georgia, Athens, GA, United States
| | - Yifan Wang
- Department of Chemistry, University of Georgia, Athens, GA, United States.
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4
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Park Y, Zhong H, Pabst TP, Kim J, Chirik PJ. Pentamethylcyclopentadienyl Metalloradical Iron Complexes Containing Redox Noninnocent α-Diimine-Type Ligands: Synthesis, Molecular, and Electronic Structures. Organometallics 2023. [DOI: 10.1021/acs.organomet.3c00027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/15/2023]
Affiliation(s)
- Yoonsu Park
- Department of Chemistry, Frick Laboratory, Princeton University, Princeton, New Jersey 08544, United States
| | - Hongyu Zhong
- Department of Chemistry, Frick Laboratory, Princeton University, Princeton, New Jersey 08544, United States
| | - Tyler P. Pabst
- Department of Chemistry, Frick Laboratory, Princeton University, Princeton, New Jersey 08544, United States
| | - Junho Kim
- Department of Chemistry, Frick Laboratory, Princeton University, Princeton, New Jersey 08544, United States
| | - Paul J. Chirik
- Department of Chemistry, Frick Laboratory, Princeton University, Princeton, New Jersey 08544, United States
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5
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Hagen WR. Low-frequency EPR of ferrimyoglobin fluoride and ferrimyoglobin cyanide: a case study on the applicability of broadband analysis to high-spin hemoproteins and to HALS hemoproteins. J Biol Inorg Chem 2022; 27:497-507. [PMID: 35802192 PMCID: PMC9399021 DOI: 10.1007/s00775-022-01948-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 06/04/2022] [Indexed: 11/29/2022]
Abstract
An EPR spectrometer has been developed that can be tuned to many frequencies in the range of ca 0.1–15 GHz. Applicability has been tested on ferrimyoglobin fluoride (MbF) and ferrimyoglobin cyanide (MbCN). MbF has a high-spin (S = 5/2) spectrum with 19F superhyperfine splitting that is only resolved in X-band along the heme normal. Low-frequency EPR also resolves the splitting in the heme plane. Measurement of linewidth as a function of frequency provides the basis for an analysis of inhomogeneous broadening in terms of g-strain, zero-field distribution, unresolved superhyperfine splittings and dipolar interaction. Rhombicity in the g tensor is found to be absent. MbCN (S = 1/2) has a highly anisotropic low spin (HALS) spectrum for which gx cannot be determined unequivocally in X-band. Low-frequency EPR allows for measurement of the complete spectrum and determination of the g-tensor.
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Affiliation(s)
- Wilfred R Hagen
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands.
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6
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CYP116B5hd, a self-sufficient P450 cytochrome: A dataset of its electronic and geometrical properties. Data Brief 2022; 42:108195. [PMID: 35572793 PMCID: PMC9097631 DOI: 10.1016/j.dib.2022.108195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/17/2022] [Accepted: 04/18/2022] [Indexed: 11/20/2022] Open
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7
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Lehnert N, Kim E, Dong HT, Harland JB, Hunt AP, Manickas EC, Oakley KM, Pham J, Reed GC, Alfaro VS. The Biologically Relevant Coordination Chemistry of Iron and Nitric Oxide: Electronic Structure and Reactivity. Chem Rev 2021; 121:14682-14905. [PMID: 34902255 DOI: 10.1021/acs.chemrev.1c00253] [Citation(s) in RCA: 92] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Nitric oxide (NO) is an important signaling molecule that is involved in a wide range of physiological and pathological events in biology. Metal coordination chemistry, especially with iron, is at the heart of many biological transformations involving NO. A series of heme proteins, nitric oxide synthases (NOS), soluble guanylate cyclase (sGC), and nitrophorins, are responsible for the biosynthesis, sensing, and transport of NO. Alternatively, NO can be generated from nitrite by heme- and copper-containing nitrite reductases (NIRs). The NO-bearing small molecules such as nitrosothiols and dinitrosyl iron complexes (DNICs) can serve as an alternative vehicle for NO storage and transport. Once NO is formed, the rich reaction chemistry of NO leads to a wide variety of biological activities including reduction of NO by heme or non-heme iron-containing NO reductases and protein post-translational modifications by DNICs. Much of our understanding of the reactivity of metal sites in biology with NO and the mechanisms of these transformations has come from the elucidation of the geometric and electronic structures and chemical reactivity of synthetic model systems, in synergy with biochemical and biophysical studies on the relevant proteins themselves. This review focuses on recent advancements from studies on proteins and model complexes that not only have improved our understanding of the biological roles of NO but also have provided foundations for biomedical research and for bio-inspired catalyst design in energy science.
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Affiliation(s)
- Nicolai Lehnert
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Eunsuk Kim
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Hai T Dong
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Jill B Harland
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Andrew P Hunt
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Elizabeth C Manickas
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Kady M Oakley
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - John Pham
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Garrett C Reed
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Victor Sosa Alfaro
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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8
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Serra I, Schmidt D, Pfanzagl V, Mlynek G, Hofbauer S, Djinović-Carugo K, Furtmüller PG, García-Rubio I, Van Doorslaer S, Obinger C. Impact of the dynamics of the catalytic arginine on nitrite and chlorite binding by dimeric chlorite dismutase. J Inorg Biochem 2021; 227:111689. [PMID: 34922158 DOI: 10.1016/j.jinorgbio.2021.111689] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/15/2021] [Accepted: 12/03/2021] [Indexed: 01/04/2023]
Abstract
Chlorite dismutases (Clds) are heme b containing oxidoreductases able to decompose chlorite to chloride and molecular oxygen. This work analyses the impact of the distal, flexible and catalytic arginine on the binding of anionic angulate ligands like nitrite and the substrate chlorite. Dimeric Cld from Cyanothece sp. PCC7425 was used as a model enzyme. We have investigated wild-type CCld having the distal catalytic R127 hydrogen-bonded to glutamine Q74 and variants with R127 (i) being arrested in a salt-bridge with a glutamate (Q74E), (ii) being fully flexible (Q74V) or (iii) substituted by either alanine (R127A) or lysine (R127K). We present the electronic and spectral signatures of the high-spin ferric proteins and the corresponding low-spin nitrite complexes elucidated by UV-visible, circular dichroism and electron paramagnetic resonance spectroscopies. Furthermore, we demonstrate the impact of the dynamics of R127 on the thermal stability of the respective nitrite adducts and present the X-ray crystal structures of the nitrite complexes of wild-type CCld and the variants Q74V, Q74E and R127A. In addition, the molecular dynamics (MD) and the binding modi of nitrite and chlorite to the ferric wild-type enzyme and the mutant proteins and the interaction of the oxoanions with R127 have been analysed by MD simulations. The findings are discussed with respect to the role(s) of R127 in ligand and chlorite binding and substrate degradation.
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Affiliation(s)
- Ilenia Serra
- BIMEF Laboratory, Department of Chemistry, University of Antwerp, Belgium
| | - Daniel Schmidt
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, A-1190 Vienna, Austria
| | - Vera Pfanzagl
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, A-1190 Vienna, Austria
| | - Georg Mlynek
- Core Facility Biomolecular & Cellular Analysis, University of Natural Resources and Life Sciences, Vienna, Muthgasse 11, A-1190 Vienna, Austria; Department of Structural and Computational Biology, Max Perutz Laboratories, A-1030, Vienna, Austria
| | - Stefan Hofbauer
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, A-1190 Vienna, Austria
| | - Kristina Djinović-Carugo
- Department of Structural and Computational Biology, Max Perutz Laboratories, A-1030, Vienna, Austria; Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 5, SI-1000 Ljubljana, Slovenia
| | - Paul G Furtmüller
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, A-1190 Vienna, Austria
| | - Inés García-Rubio
- Department of Condensed Matter Physics, Faculty of Sciences, University of Zaragoza, 50009 Zaragoza, Spain; Centro Universitario de la Defensa, 50090 Zaragoza, Spain
| | | | - Christian Obinger
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, A-1190 Vienna, Austria.
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9
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Caux C, Guigliarelli B, Vivès C, Biaso F, Horeau M, Hassoune H, Petit-Hartlein I, Juillan-Binard C, Torelli S, Fieschi F, Nivière V. Membrane-Bound Flavocytochrome MsrQ Is a Substrate of the Flavin Reductase Fre in Escherichia coli. ACS Chem Biol 2021; 16:2547-2559. [PMID: 34550690 DOI: 10.1021/acschembio.1c00613] [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
MsrPQ is a new type of methionine sulfoxide reductase (Msr) system found in bacteria. It is specifically involved in the repair of periplasmic methionine residues that are oxidized by hypochlorous acid. MsrP is a periplasmic molybdoenzyme that carries out the Msr activity, whereas MsrQ, an integral membrane-bound hemoprotein, acts as the physiological partner of MsrP to provide electrons for catalysis. Although MsrQ (YedZ) was associated since long with a protein superfamily named FRD (ferric reductase domain), including the eukaryotic NADPH oxidases and STEAP proteins, its biochemical properties are still sparsely documented. Here, we have investigated the cofactor content of the E. coli MsrQ and its mechanism of reduction by the flavin reductase Fre. We showed by electron paramagnetic resonance (EPR) spectroscopy that MsrQ contains a single highly anisotropic low-spin (HALS) b-type heme located on the periplasmic side of the membrane. We further demonstrated that MsrQ holds a flavin mononucleotide (FMN) cofactor that occupies the site where a second heme binds in other members of the FDR superfamily on the cytosolic side of the membrane. EPR spectroscopy indicates that the FMN cofactor can accommodate a radical semiquinone species. The cytosolic flavin reductase Fre was previously shown to reduce the MsrQ heme. Here, we demonstrated that Fre uses the FMN MsrQ cofactor as a substrate to catalyze the electron transfer from cytosolic NADH to the heme. Formation of a specific complex between MsrQ and Fre could favor this unprecedented mechanism, which most likely involves transfer of the reduced FMN cofactor from the Fre active site to MsrQ.
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Affiliation(s)
- Christelle Caux
- CNRS, CEA, IRIG-LCBM, Laboratoire de Chimie et Biologie des Métaux, Univ. Grenoble Alpes, Grenoble 38054, France
| | - Bruno Guigliarelli
- CNRS, BIP-UMR 7281 Laboratoire de Bioénergétique et Ingénierie des Protéines, Aix-Marseille Univ., Marseille 13402, France
| | - Corinne Vivès
- CNRS, CEA, Institut de Biologie Structurale, Univ. Grenoble Alpes, Grenoble 38044, France
| | - Frédéric Biaso
- CNRS, BIP-UMR 7281 Laboratoire de Bioénergétique et Ingénierie des Protéines, Aix-Marseille Univ., Marseille 13402, France
| | - Marius Horeau
- CNRS, CEA, IRIG-LCBM, Laboratoire de Chimie et Biologie des Métaux, Univ. Grenoble Alpes, Grenoble 38054, France
| | - Hawra Hassoune
- CNRS, CEA, IRIG-LCBM, Laboratoire de Chimie et Biologie des Métaux, Univ. Grenoble Alpes, Grenoble 38054, France
| | | | - Céline Juillan-Binard
- CNRS, CEA, Institut de Biologie Structurale, Univ. Grenoble Alpes, Grenoble 38044, France
| | - Stephane Torelli
- CNRS, CEA, IRIG-LCBM, Laboratoire de Chimie et Biologie des Métaux, Univ. Grenoble Alpes, Grenoble 38054, France
| | - Franck Fieschi
- CNRS, CEA, Institut de Biologie Structurale, Univ. Grenoble Alpes, Grenoble 38044, France
| | - Vincent Nivière
- CNRS, CEA, IRIG-LCBM, Laboratoire de Chimie et Biologie des Métaux, Univ. Grenoble Alpes, Grenoble 38054, France
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10
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Zhong F, Alden SL, Hughes RP, Pletneva EV. Comparing Properties of Common Bioinorganic Ligands with Switchable Variants of Cytochrome c. Inorg Chem 2021; 61:1207-1227. [PMID: 34699724 DOI: 10.1021/acs.inorgchem.1c02322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ligand substitution at the metal center is common in catalysis and signal transduction of metalloproteins. Understanding the effects of particular ligands, as well as the polypeptide surrounding, is critical for uncovering mechanisms of these biological processes and exploiting them in the design of bioinspired catalysts and molecular devices. A series of switchable K79G/M80X/F82C (X = Met, His, or Lys) variants of cytochrome (cyt) c was employed to directly compare the stability of differently ligated proteins and activation barriers for Met, His, and Lys replacement at the ferric heme iron. Studies of these variants and their nonswitchable counterparts K79G/M80X have revealed stability trends Met < Lys < His and Lys < His < Met for the protein FeIII-X and FeII-X species, respectively. The differences in the hydrogen-bonding interactions in folded proteins and in solvation of unbound X in the unfolded proteins explain these trends. Calculations of free energy of ligand dissociation in small heme model complexes reveal that the ease of the FeIII-X bond breaking increases in the series amine < imidazole < thioether, mirroring trends in hardness of these ligands. Experimental rate constants for X dissociation in differently ligated cyt c variants are consistent with this sequence, but the differences between Met and His dissociation rates are attenuated because the former process is limited by the heme crevice opening. Analyses of activation parameters and comparisons to those for the Lys-to-Met ligand switch in the alkaline transition suggest that ligand dissociation is entropically driven in all the variants and accompanied by Lys protonation at neutral pH. The described thiolate redox-linked switches have offered a wealth of new information about interactions of different protein-derived ligands with the heme iron in cyt c model proteins, and we anticipate that the strategy of employing these switches could benefit studies of other redox metalloproteins and model complexes.
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Affiliation(s)
- Fangfang Zhong
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Stephanie L Alden
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Russell P Hughes
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Ekaterina V Pletneva
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
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11
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Rivett ED, Heo L, Feig M, Hegg EL. Biosynthesis and trafficking of heme o and heme a: new structural insights and their implications for reaction mechanisms and prenylated heme transfer. Crit Rev Biochem Mol Biol 2021; 56:640-668. [PMID: 34428995 DOI: 10.1080/10409238.2021.1957668] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Aerobic respiration is a key energy-producing pathway in many prokaryotes and virtually all eukaryotes. The final step of aerobic respiration is most commonly catalyzed by heme-copper oxidases embedded in the cytoplasmic or mitochondrial membrane. The majority of these terminal oxidases contain a prenylated heme (typically heme a or occasionally heme o) in the active site. In addition, many heme-copper oxidases, including mitochondrial cytochrome c oxidases, possess a second heme a cofactor. Despite the critical role of heme a in the electron transport chain, the details of the mechanism by which heme b, the prototypical cellular heme, is converted to heme o and then to heme a remain poorly understood. Recent structural investigations, however, have helped clarify some elements of heme a biosynthesis. In this review, we discuss the insight gained from these advances. In particular, we present a new structural model of heme o synthase (HOS) based on distance restraints from inferred coevolutionary relationships and refined by molecular dynamics simulations that are in good agreement with the experimentally determined structures of HOS homologs. We also analyze the two structures of heme a synthase (HAS) that have recently been solved by other groups. For both HOS and HAS, we discuss the proposed catalytic mechanisms and highlight how new insights into the heme-binding site locations shed light on previously obtained biochemical data. Finally, we explore the implications of the new structural data in the broader context of heme trafficking in the heme a biosynthetic pathway and heme-copper oxidase assembly.
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Affiliation(s)
- Elise D Rivett
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Lim Heo
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Michael Feig
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Eric L Hegg
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
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12
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Hydrogen bonding rearrangement by a mitochondrial disease mutation in cytochrome bc 1 perturbs heme b H redox potential and spin state. Proc Natl Acad Sci U S A 2021; 118:2026169118. [PMID: 34389670 PMCID: PMC8379992 DOI: 10.1073/pnas.2026169118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
To perform their specific electron-transfer relay functions, hemes commonly adopt low spin states with fine-tuned redox potentials. Understanding molecular elements controlling these properties is crucial for the description of natural proteins and engineering redox-active systems. We describe unusual effects of mitochondrial disease-related mutation in cytochrome bc1, based on which we identify a dual role of hydrogen bonding to the propionate group of heme bH. We observe that stabilization of the hydrogen bond in mutant enhances the redox potential but destabilizes the low spin state of oxidized heme. This demonstrates a critical role of the hydrogen bonding, and heme-protein interactions in general, to secure a suitable redox potential and spin state, a notion that might be universal for other heme proteins. Hemes are common elements of biological redox cofactor chains involved in rapid electron transfer. While the redox properties of hemes and the stability of the spin state are recognized as key determinants of their function, understanding the molecular basis of control of these properties is challenging. Here, benefiting from the effects of one mitochondrial disease–related point mutation in cytochrome b, we identify a dual role of hydrogen bonding (H-bond) to the propionate group of heme bH of cytochrome bc1, a common component of energy-conserving systems. We found that replacing conserved glycine with serine in the vicinity of heme bH caused stabilization of this bond, which not only increased the redox potential of the heme but also induced structural and energetic changes in interactions between Fe ion and axial histidine ligands. The latter led to a reversible spin conversion of the oxidized Fe from 1/2 to 5/2, an effect that potentially reduces the electron transfer rate between the heme and its redox partners. We thus propose that H-bond to the propionate group and heme-protein packing contribute to the fine-tuning of the redox potential of heme and maintaining its proper spin state. A subtle balance is needed between these two contributions: While increasing the H-bond stability raises the heme potential, the extent of increase must be limited to maintain the low spin and diamagnetic form of heme. This principle might apply to other native heme proteins and can be exploited in engineering of artificial heme-containing protein maquettes.
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13
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Sosa Alfaro V, Campeciño J, Tracy M, Elliott SJ, Hegg EL, Lehnert N. Elucidating Electron Storage and Distribution within the Pentaheme Scaffold of Cytochrome c Nitrite Reductase (NrfA). Biochemistry 2021; 60:1853-1867. [PMID: 34061493 DOI: 10.1021/acs.biochem.0c00977] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cytochrome c nitrite reductases (CcNIR or NrfA) play important roles in the global nitrogen cycle by conserving the usable nitrogen in the soil. Here, the electron storage and distribution properties within the pentaheme scaffold of Geobacter lovleyi NrfA were investigated via electron paramagnetic resonance (EPR) spectroscopy coupled with chemical titration experiments. Initially, a chemical reduction method was established to sequentially add electrons to the fully oxidized protein, 1 equiv at a time. The step-by-step reduction of the hemes was then followed using ultraviolet-visible absorption and EPR spectroscopy. EPR spectral simulations were used to elucidate the sequence of heme reduction within the pentaheme scaffold of NrfA and identify the signals of all five hemes in the EPR spectra. Electrochemical experiments ascertain the reduction potentials for each heme, observed in a narrow range from +10 mV (heme 5) to -226 mV (heme 3) (vs the standard hydrogen electrode). On the basis of quantitative analysis and simulation of the EPR data, we demonstrate that hemes 4 and 5 are reduced first (before the active site heme 1) and serve the purpose of an electron storage unit within the protein. To probe the role of the central heme 3, an H108M NrfA variant was generated where the reduction potential of heme 3 is shifted positively (from -226 to +48 mV). The H108M mutation significantly impacts the distribution of electrons within the pentaheme scaffold and the reduction potentials of the hemes, reducing the catalytic activity of the enzyme to 1% compared to that of the wild type. We propose that this is due to heme 3's important role as an electron gateway in the wild-type enzyme.
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Affiliation(s)
- Victor Sosa Alfaro
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Julius Campeciño
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - Matthew Tracy
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Sean J Elliott
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Eric L Hegg
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - Nicolai Lehnert
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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14
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Dai J, Knott GJ, Fu W, Lin TW, Furst AL, Britt RD, Francis MB. Protein-Embedded Metalloporphyrin Arrays Templated by Circularly Permuted Tobacco Mosaic Virus Coat Proteins. ACS NANO 2021; 15:8110-8119. [PMID: 33285072 DOI: 10.1021/acsnano.0c07165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Bioenergetic processes in nature have relied on networks of cofactors for harvesting, storing, and transforming the energy from sunlight into chemical bonds. Models mimicking the structural arrangement and functional crosstalk of the cofactor arrays are important tools to understand the basic science of natural systems and to provide guidance for non-natural functional biomaterials. Here, we report an artificial multiheme system based on a circular permutant of the tobacco mosaic virus coat protein (cpTMV). The double disk assembly of cpTMV presents a gap region sandwiched by the two C2-symmetrically related disks. Non-native bis-his coordination sites formed by the mutation of the residues in this gap region were computationally screened and experimentally tested. A cpTMV mutant Q101H was identified to create a circular assembly of 17 protein-embedded hemes. Biophysical characterization using X-ray crystallography, cyclic voltammetry, and electron paramagnetic resonance (EPR) suggested both structural and functional similarity to natural multiheme cytochrome c proteins. This protein framework offers many further engineering opportunities for tuning the redox properties of the cofactors and incorporating non-native components bearing varied porphyrin structures and metal centers. Emulating the electron transfer pathways in nature using a tunable artificial system can contribute to the development of photocatalytic materials and bioelectronics.
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Affiliation(s)
- Jing Dai
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Gavin J Knott
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, United States
| | - Wen Fu
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
| | - Tiffany W Lin
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Late Stage Pharmaceutical Development, Genentech Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Ariel L Furst
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - R David Britt
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
| | - Matthew B Francis
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Materials Sciences Division and Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, United States
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15
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Zhao J, Qian F, Guo W, Li J, Lin Z. Linkage Isomers of 4-Methylimidazolate Mn(II) Porphyrinates: Hindered or Unhindered? Inorg Chem 2021; 60:7465-7474. [PMID: 33947188 DOI: 10.1021/acs.inorgchem.1c00755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Three different manganese(II) porphyrins have been exploited to react with 4-methylimidazolate (4-MeIm-), and the five-coordinate products are characterized by ultraviolet-visible, single-crystal X-ray, and electronic paramagnetic resonance spectroscopies. Interestingly, 4-MeIm- is found to bond to the metal center through either of the two N atoms (N1 or N3), which yielded two linkage isomers with either an unhindered or a hindered ligand conformation, respectively. Investigations revealed it is the large metal out-of-plane displacements (Δ24 and Δ4 ≥ 0.59 Å) that have rendered the equivalence of two isomers with a small energy difference (5.2-8.3 kJ/mol). The nonbonded intra- and intermolecular interactions thus become crucial factors in the balance of linkage isomerization. All of the products in both solution and solid states show the same characteristic resonances of high-spin Mn(II) (S = 5/2) with g⊥ ≈ 5.9 and g∥ ≈ 2.0 at 4 K, consistent with the weak effects of the axial ligand on core conformation and metal electronic configurations. Zero-field splitting parameters obtained through simulations are also reported.
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Affiliation(s)
- Jianping Zhao
- College of Materials Science and Optoelectronic Technology, CAS Center for Excellence in Topological Quantum Computation, and Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing 101408, China
| | - Fei Qian
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
| | - Wenping Guo
- National Energy Center for Coal to Liquids, Synfuels China Company, Ltd., Beijing 101400, China
| | - Jianfeng Li
- College of Materials Science and Optoelectronic Technology, CAS Center for Excellence in Topological Quantum Computation, and Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing 101408, China
| | - Zeyuan Lin
- The University of Chinese Academy of Sciences, Beijing 100049, China
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16
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Tarrago M, Römelt C, Nehrkorn J, Schnegg A, Neese F, Bill E, Ye S. Experimental and Theoretical Evidence for an Unusual Almost Triply Degenerate Electronic Ground State of Ferrous Tetraphenylporphyrin. Inorg Chem 2021; 60:4966-4985. [PMID: 33739093 DOI: 10.1021/acs.inorgchem.1c00031] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Iron porphyrins exhibit unrivalled catalytic activity for electrochemical CO2-to-CO conversion. Despite intensive experimental and computational studies in the last 4 decades, the exact nature of the prototypical square-planar [FeII(TPP)] complex (1; TPP2- = tetraphenylporphyrinate dianion) remained highly debated. Specifically, its intermediate-spin (S = 1) ground state was contradictorily assigned to either a nondegenerate 3A2g state with a (dxy)2(dz2)2(dxz,yz)2 configuration or a degenerate 3Egθ state with a (dxy)2(dxz,yz)3(dz2)1/(dz2)2(dxy)1(dxz,yz)3 configuration. To address this question, we present herein a comprehensive, spectroscopy-based theoretical and experimental electronic-structure investigation on complex 1. Highly correlated wave-function-based computations predicted that 3A2g and 3Egθ are well-isolated from other triplet states by ca. 4000 cm-1, whereas their splitting ΔA-E is on par with the effective spin-orbit coupling (SOC) constant of iron(II) (≈400 cm-1). Therfore, we invoked an effective Hamiltonian (EH) operating on the nine magnetic sublevels arising from SOC between the 3A2g and 3Egθ states. This approach enabled us to successfully simulate all spectroscopic data of 1 obtained by variable-temperature and variable-field magnetization, applied-field 57Fe Mössbauer, and terahertz electron paramagnetic resonance measurements. Remarkably, the EH contains only three adjustable parameters, namely, the energy gap without SOC, ΔA-E, an angle θ that describes the mixing of (dxy)2(dxz,yz)3(dz2)1 and (dz2)2(dxy)1(dxz,yz)3 configurations, and the ⟨rd-3⟩ expectation value of the iron d orbitals that is necessary to estimate the 57Fe magnetic hyperfine coupling tensor. The EH simulations revealed that the triplet ground state of 1 is genuinely multiconfigurational with substantial parentages of both 3A2g (<88%) and 3Eg (>12%), owing to their accidental near-triple degeneracy with ΔA-E = +950 cm-1. As a consequence of this peculiar electronic structure, 1 exhibits a huge effective magnetic moment (4.2 μB at 300 K), large temperature-independent paramagnetism, a large and positive axial zero-field splitting, strong easy-plane magnetization (g⊥ ≈ 3 and g∥ ≈ 1.7) and a large and positive internal field at the 57Fe nucleus aligned in the xy plane. Further in-depth analyses suggested that g⊥ ≫ g∥ is a general spectroscopic signature of near-triple orbital degeneracy with more than half-filled pseudodegenerate orbital sets. Implications of the unusual electronic structure of 1 for CO2 reduction are discussed.
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Affiliation(s)
- Maxime Tarrago
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | - Christina Römelt
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Joscha Nehrkorn
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Alexander Schnegg
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Shengfa Ye
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany.,State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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17
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Shumayrikh NM, Warren JJ, Bennet AJ, Sen D. A heme•DNAzyme activated by hydrogen peroxide catalytically oxidizes thioethers by direct oxygen atom transfer rather than by a Compound I-like intermediate. Nucleic Acids Res 2021; 49:1803-1815. [PMID: 33476369 PMCID: PMC7913675 DOI: 10.1093/nar/gkab007] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 12/31/2020] [Accepted: 01/04/2021] [Indexed: 12/21/2022] Open
Abstract
Hemin [Fe(III)-protoporphyrin IX] is known to bind tightly to single-stranded DNA and RNA molecules that fold into G-quadruplexes (GQ). Such complexes are strongly activated for oxidative catalysis. These heme•DNAzymes and ribozymes have found broad utility in bioanalytical and medicinal chemistry and have also been shown to occur within living cells. However, how a GQ is able to activate hemin is poorly understood. Herein, we report fast kinetic measurements (using stopped-flow UV-vis spectrophotometry) to identify the H2O2-generated activated heme species within a heme•DNAzyme that is active for the oxidation of a thioether substrate, dibenzothiophene (DBT). Singular value decomposition and global fitting analysis was used to analyze the kinetic data, with the results being consistent with the heme•DNAzyme's DBT oxidation being catalyzed by the initial Fe(III)heme-H2O2 complex. Such a complex has been predicted computationally to be a powerful oxidant for thioether substrates. In the heme•DNAzyme, the DNA GQ enhances both the kinetics of formation of the active intermediate as well as the oxidation step of DBT by the active intermediate. We show, using both stopped flow spectrophotometry and EPR measurements, that a classic Compound I is not observable during the catalytic cycle for thioether sulfoxidation.
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Affiliation(s)
- Nisreen M Shumayrikh
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Jeffrey J Warren
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Andrew J Bennet
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Dipankar Sen
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
- Department of Molecular Biology & Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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18
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Sarewicz M, Pintscher S, Pietras R, Borek A, Bujnowicz Ł, Hanke G, Cramer WA, Finazzi G, Osyczka A. Catalytic Reactions and Energy Conservation in the Cytochrome bc1 and b6f Complexes of Energy-Transducing Membranes. Chem Rev 2021; 121:2020-2108. [PMID: 33464892 PMCID: PMC7908018 DOI: 10.1021/acs.chemrev.0c00712] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Indexed: 12/16/2022]
Abstract
This review focuses on key components of respiratory and photosynthetic energy-transduction systems: the cytochrome bc1 and b6f (Cytbc1/b6f) membranous multisubunit homodimeric complexes. These remarkable molecular machines catalyze electron transfer from membranous quinones to water-soluble electron carriers (such as cytochromes c or plastocyanin), coupling electron flow to proton translocation across the energy-transducing membrane and contributing to the generation of a transmembrane electrochemical potential gradient, which powers cellular metabolism in the majority of living organisms. Cytsbc1/b6f share many similarities but also have significant differences. While decades of research have provided extensive knowledge on these enzymes, several important aspects of their molecular mechanisms remain to be elucidated. We summarize a broad range of structural, mechanistic, and physiological aspects required for function of Cytbc1/b6f, combining textbook fundamentals with new intriguing concepts that have emerged from more recent studies. The discussion covers but is not limited to (i) mechanisms of energy-conserving bifurcation of electron pathway and energy-wasting superoxide generation at the quinol oxidation site, (ii) the mechanism by which semiquinone is stabilized at the quinone reduction site, (iii) interactions with substrates and specific inhibitors, (iv) intermonomer electron transfer and the role of a dimeric complex, and (v) higher levels of organization and regulation that involve Cytsbc1/b6f. In addressing these topics, we point out existing uncertainties and controversies, which, as suggested, will drive further research in this field.
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Affiliation(s)
- Marcin Sarewicz
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Sebastian Pintscher
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Rafał Pietras
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Arkadiusz Borek
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Łukasz Bujnowicz
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Guy Hanke
- School
of Biological and Chemical Sciences, Queen
Mary University of London, London E1 4NS, U.K.
| | - William A. Cramer
- Department
of Biological Sciences, Purdue University, West Lafayette, Indiana 47907 United States
| | - Giovanni Finazzi
- Laboratoire
de Physiologie Cellulaire et Végétale, Université Grenoble Alpes, Centre National Recherche Scientifique,
Commissariat Energie Atomique et Energies Alternatives, Institut National
Recherche l’agriculture, l’alimentation et l’environnement, 38054 Grenoble Cedex 9, France
| | - Artur Osyczka
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
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19
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Shin I, Davis I, Nieves-Merced K, Wang Y, McHardy S, Liu A. A novel catalytic heme cofactor in SfmD with a single thioether bond and a bis-His ligand set revealed by a de novo crystal structural and spectroscopic study. Chem Sci 2021; 12:3984-3998. [PMID: 34163669 PMCID: PMC8179489 DOI: 10.1039/d0sc06369j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/21/2021] [Indexed: 12/13/2022] Open
Abstract
SfmD is a heme-dependent enzyme in the biosynthetic pathway of saframycin A. Here, we present a 1.78 Å resolution de novo crystal structure of SfmD, which unveils a novel heme cofactor attached to the protein with an unusual Hx n HxxxC motif (n ∼ 38). This heme cofactor is unique in two respects. It contains a single thioether bond in a cysteine-vinyl link with Cys317, and the ferric heme has two axial protein ligands, i.e., His274 and His313. We demonstrated that SfmD heme is catalytically active and can utilize dioxygen and ascorbate for a single-oxygen insertion into 3-methyl-l-tyrosine. Catalytic assays using ascorbate derivatives revealed the functional groups of ascorbate essential to its function as a cosubstrate. Abolishing the thioether linkage through mutation of Cys317 resulted in catalytically inactive SfmD variants. EPR and optical data revealed that the heme center undergoes a substantial conformational change with one axial histidine ligand dissociating from the iron ion in response to substrate 3-methyl-l-tyrosine binding or chemical reduction by a reducing agent, such as the cosubstrate ascorbate. The labile axial ligand was identified as His274 through redox-linked structural determinations. Together, identifying an unusual heme cofactor with a previously unknown heme-binding motif for a monooxygenase activity and the structural similarity of SfmD to the members of the heme-based tryptophan dioxygenase superfamily will broaden understanding of heme chemistry.
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Affiliation(s)
- Inchul Shin
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle Texas 78249 USA
| | - Ian Davis
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle Texas 78249 USA
| | - Karinel Nieves-Merced
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle Texas 78249 USA
- Center for Innovative Drug Discovery, The University of Texas at San Antonio One UTSA Circle Texas 78249 USA
| | - Yifan Wang
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle Texas 78249 USA
| | - Stanton McHardy
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle Texas 78249 USA
- Center for Innovative Drug Discovery, The University of Texas at San Antonio One UTSA Circle Texas 78249 USA
| | - Aimin Liu
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle Texas 78249 USA
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20
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Traore ES, Li J, Chiura T, Geng J, Sachla AJ, Yoshimoto F, Eichenbaum Z, Davis I, Mak PJ, Liu A. Heme Binding to HupZ with a C-Terminal Tag from Group A Streptococcus. Molecules 2021; 26:549. [PMID: 33494451 PMCID: PMC7865249 DOI: 10.3390/molecules26030549] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/14/2021] [Accepted: 01/16/2021] [Indexed: 12/23/2022] Open
Abstract
HupZ is an expected heme degrading enzyme in the heme acquisition and utilization pathway in Group A Streptococcus. The isolated HupZ protein containing a C-terminal V5-His6 tag exhibits a weak heme degradation activity. Here, we revisited and characterized the HupZ-V5-His6 protein via biochemical, mutagenesis, protein quaternary structure, UV-vis, EPR, and resonance Raman spectroscopies. The results show that the ferric heme-protein complex did not display an expected ferric EPR signal and that heme binding to HupZ triggered the formation of higher oligomeric states. We found that heme binding to HupZ was an O2-dependent process. The single histidine residue in the HupZ sequence, His111, did not bind to the ferric heme, nor was it involved with the weak heme-degradation activity. Our results do not favor the heme oxygenase assignment because of the slow binding of heme and the newly discovered association of the weak heme degradation activity with the His6-tag. Altogether, the data suggest that the protein binds heme by its His6-tag, resulting in a heme-induced higher-order oligomeric structure and heme stacking. This work emphasizes the importance of considering exogenous tags when interpreting experimental observations during the study of heme utilization proteins.
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Affiliation(s)
- Ephrahime S. Traore
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (E.S.T.); (J.L.); (F.Y.); (I.D.)
| | - Jiasong Li
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (E.S.T.); (J.L.); (F.Y.); (I.D.)
| | - Tapiwa Chiura
- Department of Chemistry, Saint Louis University, St. Louis, MO 63103, USA;
| | - Jiafeng Geng
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA;
| | - Ankita J. Sachla
- Department of Biology, Georgia State University, Atlanta, GA 30302, USA; (A.J.S.); (Z.E.)
| | - Francis Yoshimoto
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (E.S.T.); (J.L.); (F.Y.); (I.D.)
| | - Zehava Eichenbaum
- Department of Biology, Georgia State University, Atlanta, GA 30302, USA; (A.J.S.); (Z.E.)
| | - Ian Davis
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (E.S.T.); (J.L.); (F.Y.); (I.D.)
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA;
| | - Piotr J. Mak
- Department of Chemistry, Saint Louis University, St. Louis, MO 63103, USA;
| | - Aimin Liu
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (E.S.T.); (J.L.); (F.Y.); (I.D.)
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA;
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21
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Li Q, Ding W, Tu J, Chi C, Huang H, Ji X, Yao Z, Ma M, Ju J. Nonspecific Heme-Binding Cyclase, AbmU, Catalyzes [4 + 2] Cycloaddition during Neoabyssomicin Biosynthesis. ACS OMEGA 2020; 5:20548-20557. [PMID: 32832808 PMCID: PMC7439702 DOI: 10.1021/acsomega.0c02776] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 07/27/2020] [Indexed: 05/05/2023]
Abstract
Diels-Alder (DA) [4 + 2]-cycloaddition reactions rank among the most powerful transformations in synthetic organic chemistry; biosynthetic examples, however, are few and far between. We report here a heme-binding cyclase, AbmU, that catalyzes an essential [4 + 2] cycloaddition during neoabyssomicin scaffold assembly. In vivo genetic and in vitro biochemical analyses strongly suggest that AbmU catalyzes an intramolecular and stereoselective [4 + 2] cycloaddition to form a spirotetronate skeleton from an acyclic substrate featuring both a terminal 1,3-diene and an exo-methylene group. Biochemical assays and X-ray diffraction analyses reveal that AbmU binds nonspecifically to a heme b cofactor and that this association does not play a catalytic role in AbmU catalysis. A detailed study of the AbmU crystal structure reveals a unique mode of substrate binding and reaction catalysis; His160 forms a H-bond with the C-1 carbonyl O-atom of the acyclic substrate, and the imidazole of the same amino acid directs the tetronate moiety of acyclic substrate toward the terminal Δ10,11, Δ12,13-diene moiety, thereby facilitating intramolecular DA chemistry. Our findings expand upon what is known about mechanistic diversities available to biosynthetic [4 + 2] cyclases and help to lay the foundation for the use of AbmU in possible industrial applications.
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Affiliation(s)
- Qinglian Li
- CAS
Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong
Key Laboratory of Marine Materia
Medica, RNAM Center for Marine Microbiology, South China Sea Institute
of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
| | - Wenjuan Ding
- CAS
Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong
Key Laboratory of Marine Materia
Medica, RNAM Center for Marine Microbiology, South China Sea Institute
of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
- College
of Oceanology, University of Chinese Academy
of Sciences, 19 Yuquan
Road, Beijing 100049, China
| | - Jiajia Tu
- CAS
Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong
Key Laboratory of Marine Materia
Medica, RNAM Center for Marine Microbiology, South China Sea Institute
of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
| | - Changbiao Chi
- State
Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical
Sciences, Peking University, 38 Xueyuan Road, Haidian District, Beijing 100191, China
| | - Hongbo Huang
- CAS
Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong
Key Laboratory of Marine Materia
Medica, RNAM Center for Marine Microbiology, South China Sea Institute
of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
| | - Xiaoqi Ji
- CAS
Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong
Key Laboratory of Marine Materia
Medica, RNAM Center for Marine Microbiology, South China Sea Institute
of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
- College
of Oceanology, University of Chinese Academy
of Sciences, 19 Yuquan
Road, Beijing 100049, China
| | - Ziwei Yao
- CAS
Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong
Key Laboratory of Marine Materia
Medica, RNAM Center for Marine Microbiology, South China Sea Institute
of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
- College
of Oceanology, University of Chinese Academy
of Sciences, 19 Yuquan
Road, Beijing 100049, China
| | - Ming Ma
- State
Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical
Sciences, Peking University, 38 Xueyuan Road, Haidian District, Beijing 100191, China
| | - Jianhua Ju
- CAS
Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong
Key Laboratory of Marine Materia
Medica, RNAM Center for Marine Microbiology, South China Sea Institute
of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
- College
of Oceanology, University of Chinese Academy
of Sciences, 19 Yuquan
Road, Beijing 100049, China
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22
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Lohrey TD, Rao G, Small DW, Ouellette ET, Bergman RG, Britt RD, Arnold J. Electronic Structures of Rhenium(II) β-Diketiminates Probed by EPR Spectroscopy: Direct Comparison of an Acceptor-Free Complex to Its Dinitrogen, Isocyanide, and Carbon Monoxide Adducts. J Am Chem Soc 2020; 142:13805-13813. [PMID: 32786815 DOI: 10.1021/jacs.0c04719] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Electron paramagnetic resonance (EPR) studies of the rhenium(II) complex Re(η5-Cp)(BDI) (1; BDI = N,N'-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate) have revealed that this species reversibly binds N2 in solution: flash frozen toluene solutions of 1 disclose entirely different EPR spectra at 10 K when prepared under N2 versus Ar atmospheres. This observation was additionally verified by the synthesis of stable CO and 2,6-xylylisocyanide (XylNC) adducts of 1, which display EPR features akin to those observed in the putative N2 complex. While we found that 1 displays an extremely large gmax value of 3.99, the binding of an additional ligand leads to substantial decreases in this value, displaying gmax values of ca. 2.4. Following the generation of isotopically enriched 15N2 and 13CO adducts of 1, HYSCORE experiments allowed for the measurement of the corresponding hyperfine couplings associated with spin delocalization onto the electron-accepting ligands in these species, which proved to be small. A cumulative assessment of the EPR data, when combined with insights provided by near-infrared (NIR) spectroscopy and time-dependent density functional theory (TDDFT) calculations, indicated that while the binding of electron acceptors to 1 does lead to decreases in gmax in relative accord with the field strength (i.e., π-acidity) of the variable ligand, the magnitude of these decreases is primarily due to the changes in electronic structure at the Re center.
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Affiliation(s)
- Trevor D Lohrey
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Guodong Rao
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - David W Small
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Erik T Ouellette
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Robert G Bergman
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - R David Britt
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - John Arnold
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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23
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Tao L, Pattenaude SA, Joshi S, Begley TP, Rauchfuss TB, Britt RD. Radical SAM Enzyme HydE Generates Adenosylated Fe(I) Intermediates En Route to the [FeFe]-Hydrogenase Catalytic H-Cluster. J Am Chem Soc 2020; 142:10841-10848. [PMID: 32434327 PMCID: PMC7440672 DOI: 10.1021/jacs.0c03802] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The H-cluster of [FeFe]-hydrogenase consists of a [4Fe-4S]H-subcluster linked by a cysteinyl bridge to a unique organometallic [2Fe]H-subcluster assigned as the site of interconversion between protons and molecular hydrogen. This [2Fe]H-subcluster is assembled by a set of Fe-S maturase enzymes HydG, HydE and HydF. Here we show that the HydG product [FeII(Cys)(CO)2(CN)] synthon is the substrate of the radical SAM enzyme HydE, with the generated 5'-deoxyadenosyl radical attacking the cysteine S to form a C5'-S bond concomitant with reduction of the central low-spin Fe(II) to the Fe(I) oxidation state. This leads to the cleavage of the cysteine C3-S bond, producing a mononuclear [FeI(CO)2(CN)S] species that serves as the precursor to the dinuclear Fe(I)Fe(I) center of the [2Fe]H-subcluster. This work unveils the role played by HydE in the enzymatic assembly of the H-cluster and expands the scope of radical SAM enzyme chemistry.
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Affiliation(s)
- Lizhi Tao
- Department of Chemistry, University of California at Davis, Davis, California 95616, United States
| | - Scott A Pattenaude
- School of Chemical Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Sumedh Joshi
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Tadhg P Begley
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Thomas B Rauchfuss
- School of Chemical Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - R David Britt
- Department of Chemistry, University of California at Davis, Davis, California 95616, United States
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24
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Wolf MW, Rizzolo K, Elliott SJ, Lehnert N. Resonance Raman, Electron Paramagnetic Resonance, and Magnetic Circular Dichroism Spectroscopic Investigation of Diheme Cytochrome c Peroxidases from Nitrosomonas europaea and Shewanella oneidensis. Biochemistry 2018; 57:6416-6433. [PMID: 30335984 DOI: 10.1021/acs.biochem.8b00732] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cytochrome c peroxidases (bCcPs) are diheme enzymes required for the reduction of H2O2 to water in bacteria. There are two classes of bCcPs: one is active in the diferric form (constitutively active), and the other requires the reduction of the high-potential heme (H-heme) before catalysis commences (reductively activated) at the low-potential heme (L-heme). To improve our understanding of the mechanisms and heme electronic structures of these different bCcPs, a constitutively active bCcP from Nitrosomonas europaea ( NeCcP) and a reductively activated bCcP from Shewanella oneidensis ( SoCcP) were characterized in both the diferric and semireduced states by electron paramagnetic resonance (EPR), resonance Raman (rRaman), and magnetic circular dichroism (MCD) spectroscopy. In contrast to some previous crystallographic studies, EPR and rRaman spectra do not indicate the presence of significant amounts of a five-coordinate, high-spin ferric heme in NeCcP or SoCcP in either the diferric or semireduced state in solution. This observation points toward a mechanism of activation in which the active site L-heme is not in a static, five-coordinate state but where the activation is more subtle and likely involves formation of a six-coordinate hydroxo complex, which could then react with hydrogen peroxide in an acid-base-type reaction to create Compound 0, the ferric hydroperoxo complex. This mechanism lies in stark contrast to the diheme enzyme MauG that exhibits a static, five-coordinate open heme site at the peroxidatic heme and that forms a more stable FeIV═O intermediate.
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Affiliation(s)
- Matthew W Wolf
- Department of Chemistry and Department of Biophysics , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Kimberly Rizzolo
- Department of Chemistry , Boston University , 590 Commonwealth Avenue , Boston , Massachusetts 02215 , United States
| | - Sean J Elliott
- Department of Chemistry , Boston University , 590 Commonwealth Avenue , Boston , Massachusetts 02215 , United States
| | - Nicolai Lehnert
- Department of Chemistry and Department of Biophysics , University of Michigan , Ann Arbor , Michigan 48109 , United States
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25
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Influence of heme c attachment on heme conformation and potential. J Biol Inorg Chem 2018; 23:1073-1083. [PMID: 30143872 DOI: 10.1007/s00775-018-1603-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 08/16/2018] [Indexed: 10/28/2022]
Abstract
Heme c is characterized by its covalent attachment to a polypeptide. The attachment is typically to a CXXCH motif in which the two Cys form thioether bonds with the heme, "X" can be any amino acid other than Cys, and the His serves as a heme axial ligand. Some cytochromes c, however, contain heme attachment motifs with three or four intervening residues in a CX3CH or CX4CH motif. Here, the impacts of these variations in the heme attachment motif on heme ruffling and electronic structure are investigated by spectroscopically characterizing CX3CH and CX4CH variants of Hydrogenobacter thermophilus cytochrome c552. In addition, a novel CXCH variant is studied. 1H and 13C NMR, EPR, and resonance Raman spectra of the protein variants are analyzed to deduce the extent of ruffling using previously reported relationships between these spectral data and heme ruffling. In addition, the reduction potentials of these protein variants are measured using protein film voltammetry. The CXCH and CX4CH variants are found to have enhanced heme ruffling and lower reduction potentials. Implications of these results for the use of these noncanonical motifs in nature, and for the engineering of novel heme peptide structures, are discussed.
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26
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Nóbrega CS, Devreese B, Pauleta SR. YhjA - An Escherichia coli trihemic enzyme with quinol peroxidase activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:411-422. [PMID: 29550214 DOI: 10.1016/j.bbabio.2018.03.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 02/11/2018] [Accepted: 03/13/2018] [Indexed: 10/17/2022]
Abstract
The trihemic bacterial cytochrome c peroxidase from Escherichia coli, YhjA, is a membrane-anchored protein with a C-terminal domain homologous to the classical bacterial peroxidases and an additional N-terminal (NT) heme binding domain. Recombinant YhjA is a 50 kDa monomer in solution with three c-type hemes covalently bound. Here is reported the first biochemical and spectroscopic characterization of YhjA and of the NT domain demonstrating that NT heme is His63/Met125 coordinated. The reduction potentials of P (active site), NT and E hemes were established to be -170 mV, +133 mV and +210 mV, respectively, at pH 7.5. YhjA has quinol peroxidase activity in vitro with optimum activity at pH 7.0 and millimolar range KM values using hydroquinone and menadiol (a menaquinol analogue) as electron donors (KM = 0.6 ± 0.2 and 1.8 ± 0.5 mM H2O2, respectively), with similar turnover numbers (kcat = 19 ± 2 and 13 ± 2 s-1, respectively). YhjA does not require reductive activation for maximum activity, in opposition to classical bacterial peroxidases, as P heme is always high-spin 6-coordinated with a water-derived molecule as distal axial ligand but shares the need for the presence of calcium ions in the kinetic assays. Formation of a ferryl Fe(IV) = O species was observed upon incubation of fully oxidized YhjA with H2O2. The data reported improve our understanding of the biochemical properties and catalytic mechanism of YhjA, a three-heme peroxidase that uses the quinol pool to defend the cells against hydrogen peroxide during transient exposure to oxygenated environments.
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Affiliation(s)
- Cláudia S Nóbrega
- Microbial Stress Lab, UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal
| | - Bart Devreese
- Laboratory of Protein Biochemistry and Biomolecular Engineering, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium
| | - Sofia R Pauleta
- Microbial Stress Lab, UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal.
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27
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Ponomarenko N, Niklas J, Pokkuluri PR, Poluektov O, Tiede DM. Electron Paramagnetic Resonance Characterization of the Triheme Cytochrome from Geobacter sulfurreducens. Biochemistry 2018; 57:1722-1732. [DOI: 10.1021/acs.biochem.7b00917] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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28
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Prieto T, Santana V, Britto AMM, Araujo-Chaves JC, R Nascimento O, L Nantes-Cardoso I. Structure and Catalysis of Fe(III) and Cu(II) Microperoxidase-11 Interacting with the Positively Charged Interfaces of Lipids. Molecules 2017; 22:molecules22081212. [PMID: 28933729 PMCID: PMC6151982 DOI: 10.3390/molecules22081212] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 06/20/2017] [Accepted: 07/14/2017] [Indexed: 11/24/2022] Open
Abstract
Numerous applications have been described for microperoxidases (MPs) such as in photoreceptors, sensing, drugs, and hydrogen evolution. The last application was obtained by replacing Fe(III), the native central metal, by cobalt ion and inspired part of the present study. Here, the Fe(III) of MP-11 was replaced by Cu(II) that is also a stable redox state in aerated medium, and the structure and activity of both MPs were modulated by the interaction with the positively charged interfaces of lipids. Comparative spectroscopic characterization of Fe(III) and Cu(II)MP-11 in the studied media demonstrated the presence of high and low spin species with axial distortion. The association of the Fe(III)MP-11 with CTAB and Cu(II)MP-11 with DODAB affected the colloidal stability of the surfactants that was recovered by heating. This result is consistent with hydrophobic interactions of MPs with DODAB vesicles and CTAB micelles. The hydrophobic interactions decreased the heme accessibility to substrates and the Fe(III) MP-11catalytic efficiency. Cu(II)MP-11 challenged by peroxides exhibited a cyclic Cu(II)/Cu(I) interconversion mechanism that is suggestive of a mimetic Cu/ZnSOD (superoxide dismutase) activity against peroxides. Hydrogen peroxide-activated Cu(II)MP-11 converted Amplex Red® to dihydroresofurin. This study opens more possibilities for technological applications of MPs.
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Affiliation(s)
- Tatiana Prieto
- Universidade Federal do ABC, Santo André 09210-170, SP, Brazil.
| | - Vinicius Santana
- Universidade de São Paulo, Instituto de Física de São Carlos, São Carlos 13400-970, SP, Brazil.
| | | | | | - Otaciro R Nascimento
- Universidade de São Paulo, Instituto de Física de São Carlos, São Carlos 13400-970, SP, Brazil.
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29
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Van Doorslaer S. Understanding heme proteins with hyperfine spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 280:79-88. [PMID: 28579104 DOI: 10.1016/j.jmr.2017.01.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/10/2017] [Accepted: 01/11/2017] [Indexed: 06/07/2023]
Abstract
Heme proteins are versatile proteins that are involved in a large number of biological processes. Many spectroscopic methods are used to gain insight into the different mechanistic processes governing heme-protein functions. Since many (intermediate) states of heme proteins are paramagnetic, electron paramagnetic resonance (EPR) methods, such as hyperfine spectroscopy, offer unique tools for these investigations. This perspective gives an overview of the use of state-of-the-art hyperfine spectroscopy in heme research, focusing on the advantages, limits and challenges of the different techniques.
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Affiliation(s)
- Sabine Van Doorslaer
- BIMEF Laboratory, Department of Physics, University of Antwerp, B-2610 Antwerp, Belgium.
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30
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Solomon LA, Kronenberg JB, Fry HC. Control of Heme Coordination and Catalytic Activity by Conformational Changes in Peptide-Amphiphile Assemblies. J Am Chem Soc 2017; 139:8497-8507. [PMID: 28505436 DOI: 10.1021/jacs.7b01588] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Self-assembling peptide materials have gained significant attention, due to well-demonstrated applications, but they are functionally underutilized. To advance their utility, we use noncovalent interactions to incorporate the biological cofactor heme-B for catalysis. Heme-proteins achieve differing functions through structural and coordinative variations. Here, we replicate this phenomenon by highlighting changes in heme reactivity as a function of coordination, sequence, and morphology (micelles versus fibers) in a series of simple peptide amphiphiles with the sequence c16-xyL3K3-CO2H where c16 is a palmitoyl moiety and xy represents the heme binding region: AA, AH, HH, and MH. The morphology of this peptide series is characterized using transmission electron and atomic force microscopies as well as dynamic light scattering. Within this small library of peptide constructs, we show that three spectroscopically (UV/visible and electron paramagnetic resonance) distinct heme environments were generated: noncoordinated/embedded high-spin, five-coordinate high-spin, and six-coordinate low-spin. The resulting material's functional dependence on sequence and supramolecular morphology is highlighted 2-fold. First, the heme active site binds carbon monoxide in both micelles and fibers, demonstrating that the heme active site in both morphologies is accessible to small molecules for catalysis. Second, peroxidase activity was observed in heme-containing micelles yet was significantly reduced in heme-containing fibers. We briefly discuss the implications these findings have in the production of functional, self-assembling peptide materials.
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Affiliation(s)
- Lee A Solomon
- Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States
| | - Jacob B Kronenberg
- Illinois Math and Science Academy , 1500 West Sullivan Road, Aurora, Illinois 60506, United States
| | - H Christopher Fry
- Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States
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31
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Biochemical characterization of the bacterial peroxidase from the human pathogen Neisseria gonorrhoeae. J Inorg Biochem 2017; 171:108-119. [PMID: 28388513 DOI: 10.1016/j.jinorgbio.2017.03.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 02/21/2017] [Accepted: 03/19/2017] [Indexed: 10/19/2022]
Abstract
Neisseria gonorrhoeae is an obligate human pathogen that expresses an array of molecular systems to detoxify reactive oxygen species as defense mechanisms during colonization and infection. One of these is the bacterial peroxidase that reduces H2O2 to water in its periplasm. The soluble form of this enzyme was heterologously expressed in E. coli in the holo-form binding two c-types hemes, a high-potential E heme and a low-potential P heme, with redox potentials of (+310mV) and (-190mV/-300mV), respectively in the presence of calcium ions, at pH7.5. Visible and EPR spectroscopic analysis together with activity assays indicate the presence of a calcium dependent reductive activation mechanism in thgonorrhoeaeNeisseria gonorrhoeae bacterial peroxidase, in which P heme is bis-His coordinated low-spin in the fully oxidized state of the enzyme, and becomes penta-coordinated high-spin upon reduction of E heme in the presence of calcium ions. The activated enzyme has a high affinity for H2O2 (KM of 4±1μM), with maximum activity being attained at pH7.0 and 37°C, with the rate-limiting step in the catalytic cycle being the electron transfer between the two hemes. In this enzyme, dimer formation is not promoted at high ionic strength, thus differing from the classical bacterial peroxidases. These results contribute to the understanding of the involvement of Neisseria gonorrhoeae bacterial peroxidase has a first line defense mechanism against exogenously produced hydrogen peroxide in the host environment.
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32
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Sakurai N, Kataoka K, Sugaya N, Shimodaira T, Iwamoto M, Shoda M, Horiuchi H, Kiyono M, Ohta Y, Triwiyono B, Seo D, Sakurai T. Heterologous expression of Halomonas halodenitrificans nitric oxide reductase and its N-terminally truncated NorC subunit in Escherichia coli. J Inorg Biochem 2017; 169:61-67. [PMID: 28131879 DOI: 10.1016/j.jinorgbio.2017.01.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 12/30/2016] [Accepted: 01/20/2017] [Indexed: 11/29/2022]
Abstract
Halomonas halodenitrificans nitric oxide reductase (NOR) is the membrane-bound heterodimer complex of NorC, which contains a low-spin heme c center, and NorB, which contains a low-spin heme b center, a high-spin heme b3 center, and a non-heme FeB center. The soluble domain of NorC, NorC* (ΔMet1-Val37) was heterologously expressed in Escherichia coli using expression plasmids harboring the truncated norC gene deleted of its 84 5'-terminal nucleotides. Analogous scission of the N-terminal helix as the membrane anchor took place when the whole norC gene was used. NorC* exhibited spectra typical of a low-spin heme c. In addition, NorC* functioned as the acceptor of an electron from a cytochrome c isolated from the periplasm of H. halodenitrificans and small reducing reagents. The redox potential of NorC* shifted ca. 40mV in the negative direction from that of NorC. Unlike NorC, recombinant NorB was not heterologously expressed. However, recombinant NOR (rNOR) could be expressed in E. coli by using a plasmid harboring all genes in the nor operon, norCBQDX, from which the three hairpin loops (mRNA) were deleted, and by using the ccm genes for the maturation of C-type heme. rNOR exhibited the same spectroscopic properties and reactivity to NO and O2 as NOR, although its enzymatic activity toward NO was considerably decreased. These results on the expression of rNOR and NorC* will allow us to develop more profound studies on the properties of the four Fe centers and the reaction mechanism of NOR from this halophilic denitrifying bacterium.
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Affiliation(s)
- Nobuhiko Sakurai
- Division of Biological Science, Graduate School of Natural Sciences, Nagoya City University, Yamanohata 1, Mizuho, Nagoya 467-8501, Japan.
| | - Kunishige Kataoka
- Division of Material Science, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan
| | - Noriko Sugaya
- Division of Material Science, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan
| | - Takaki Shimodaira
- Division of Material Science, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan
| | - Mie Iwamoto
- Division of Material Science, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan
| | - Munehiro Shoda
- Division of Material Science, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan
| | - Hajime Horiuchi
- Division of Material Science, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan
| | - Miyuki Kiyono
- Division of Material Science, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan
| | - Yasuke Ohta
- Division of Biological Science, Graduate School of Natural Sciences, Nagoya City University, Yamanohata 1, Mizuho, Nagoya 467-8501, Japan
| | - Bambang Triwiyono
- Division of Biological Science, Graduate School of Natural Sciences, Nagoya City University, Yamanohata 1, Mizuho, Nagoya 467-8501, Japan
| | - Daisuke Seo
- Division of Material Science, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan
| | - Takeshi Sakurai
- Division of Material Science, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan
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33
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Christopher Fry H, Wood AR, Solomon LA. Supramolecular control of heme binding and electronic states in multi-heme peptide assemblies. Org Biomol Chem 2017; 15:6725-6730. [DOI: 10.1039/c7ob01081h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Three peptides that are compositionally identical but sequentially distinct have been designed to study the impact of morphology and hydrophobicity on heme coordination and function.
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Affiliation(s)
| | - Anna R. Wood
- Argonne National Laboratory
- Center for Nanoscale Materials
- Lemont
- USA
| | - Lee A. Solomon
- Argonne National Laboratory
- Center for Nanoscale Materials
- Lemont
- USA
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34
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Hu B, He M, Yao Z, Schulz CE, Li J. Unique Axial Imidazole Geometries of Fully Halogenated Iron(II) Porphyrin Complexes: Crystal Structures and Mössbauer Spectroscopic Studies. Inorg Chem 2016; 55:9632-9643. [DOI: 10.1021/acs.inorgchem.6b01364] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Bin Hu
- College
of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing 101408, China
| | - Mingrui He
- College
of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing 101408, China
| | - Zhen Yao
- College
of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing 101408, China
| | - Charles E. Schulz
- Department
of Physics, Knox College, Galesburg, Illinois 61401, United States
| | - Jianfeng Li
- College
of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing 101408, China
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35
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Bren KL. Going with the Electron Flow: Heme Electronic Structure and Electron Transfer in Cytochrome
c. Isr J Chem 2016. [DOI: 10.1002/ijch.201600021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Kara L. Bren
- Department of Chemistry University of Rochester Rochester NY 14627-0216 USA
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36
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He C, Ogata H, Lubitz W. Elucidation of the heme active site electronic structure affecting the unprecedented nitrite dismutase activity of the ferriheme b proteins, the nitrophorins. Chem Sci 2016; 7:5332-5340. [PMID: 30155185 PMCID: PMC6020753 DOI: 10.1039/c6sc01019a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 04/23/2016] [Indexed: 12/14/2022] Open
Abstract
Nitrophorins (NPs) catalyze the nitrite dismutation reaction that is unprecedented in ferriheme proteins. Despite progress in studying the reaction mechanism, fundamental issues regarding the correlation of the structural features with the nitrite dismutase activity of NPs remain elusive. On the other hand, it has been shown that the nitrite complexes of NPs are unique among those of the ferriheme proteins since some of their electron paramagnetic resonance (EPR) spectra show significant highly anisotropic low spin (HALS) signals with large gmax values over 3.2. The origin of HALS signals in ferriheme proteins or models is not well understood, especially in cases where axial ligands other than histidine are present. In this study several mutations were introduced in NP4. The related nitrite coordination and dismutation reaction were investigated. As a result, the EPR spectra of the NP-nitrite complexes were found to be tightly correlated with the extent of heme ruffling and protonation state of the proximal His ligand-dictated by an extended H-bonding network at the heme active site. Furthermore, it is established that the two factors are essential in determining the nitrite dismutase activity of NPs. These results may provide a valuable guide for identifying or designing novel heme proteins with similar activity.
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Affiliation(s)
- Chunmao He
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36 , D-45470 , Mülheim an der Ruhr , Germany . ;
| | - Hideaki Ogata
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36 , D-45470 , Mülheim an der Ruhr , Germany . ;
| | - Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36 , D-45470 , Mülheim an der Ruhr , Germany . ;
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37
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Ortiz de Orué Lucana D, Hickey N, Hensel M, Klare JP, Geremia S, Tiufiakova T, Torda AE. The Crystal Structure of the C-Terminal Domain of the Salmonella enterica PduO Protein: An Old Fold with a New Heme-Binding Mode. Front Microbiol 2016; 7:1010. [PMID: 27446048 PMCID: PMC4923194 DOI: 10.3389/fmicb.2016.01010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 06/14/2016] [Indexed: 02/05/2023] Open
Abstract
The two-domain protein PduO, involved in 1,2-propanediol utilization in the pathogenic Gram-negative bacterium Salmonella enterica is an ATP:Cob(I)alamin adenosyltransferase, but this is a function of the N-terminal domain alone. The role of its C-terminal domain (PduOC) is, however, unknown. In this study, comparative growth assays with a set of Salmonella mutant strains showed that this domain is necessary for effective in vivo catabolism of 1,2-propanediol. It was also shown that isolated, recombinantly-expressed PduOC binds heme in vivo. The structure of PduOC co-crystallized with heme was solved (1.9 Å resolution) showing an octameric assembly with four heme moieities. The four heme groups are highly solvent-exposed and the heme iron is hexa-coordinated with bis-His ligation by histidines from different monomers. Static light scattering confirmed the octameric assembly in solution, but a mutation of the heme-coordinating histidine caused dissociation into dimers. Isothermal titration calorimetry using the PduOC apoprotein showed strong heme binding (K d = 1.6 × 10(-7) M). Biochemical experiments showed that the absence of the C-terminal domain in PduO did not affect adenosyltransferase activity in vitro. The evidence suggests that PduOC:heme plays an important role in the set of cobalamin transformations required for effective catabolism of 1,2-propanediol. Salmonella PduO is one of the rare proteins which binds the redox-active metabolites heme and cobalamin, and the heme-binding mode of the C-terminal domain differs from that in other members of this protein family.
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Affiliation(s)
- Darío Ortiz de Orué Lucana
- Applied Genetics of Microorganisms, Department of Biology/Chemistry, University of OsnabrückOsnabrück, Germany
| | - Neal Hickey
- Centre of Excellence in Biocrystallography, Department of Chemical and Pharmaceutical Sciences, University of TriesteTrieste, Italy
| | - Michael Hensel
- Division of Microbiology, Department of Biology/Chemistry, University of OsnabrückOsnabrück, Germany
| | - Johann P. Klare
- Department of Physics, University of OsnabrückOsnabrück, Germany
| | - Silvano Geremia
- Centre of Excellence in Biocrystallography, Department of Chemical and Pharmaceutical Sciences, University of TriesteTrieste, Italy
| | | | - Andrew E. Torda
- Centre for Bioinformatics, University of HamburgHamburg, Germany
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38
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Reduction potential and heme-pocket polarity in low potential cytochrome b5 of Giardia intestinalis. J Inorg Biochem 2016; 158:110-114. [PMID: 27048807 DOI: 10.1016/j.jinorgbio.2016.02.021] [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: 09/11/2015] [Revised: 12/24/2015] [Accepted: 02/23/2016] [Indexed: 11/20/2022]
Abstract
Although it lacks mitochondria and the ability to synthesize heme, the protozoan parasite Giardia intestinalis encodes several heme proteins. This includes four members of the cytochrome b5 family, three of which are of similar size to mammalian cytochromes b5 but with reduction potentials that are 140 to 180mV lower. While no structures have yet been determined for any of these proteins, homology modeling points to an increase in heme pocket polarity as a reason for their low potentials. To test this we measured the reduction potentials of four mutants of Giardia cytochrome b5 isotype-I (gCYTB5-I) in which polar residues at two candidate positions (C84, Y51) in the heme pocket were changed to nonpolar ones (C84A, C84F; Y51L, Y51F). All mutants were expressed with comparable levels of heme incorporation and had UV-visible spectra consistent with low spin bis-histidyl coordination. These mutations increased the reduction potential by 18 to 57mV and highlight the influence of C84, which is a residue unique to gCYTB5-I and whose mutation to alanine caused the largest increase. The influence of these two residues plus that of Y61 reported previously accounts for much of the reduction potential difference between gCYTB5-I and microsomal cytochrome b5. A complementary triple mutant of the latter with the hydrophilic residues found in gCYTB5-I bound heme less effectively but nonetheless had a reduction potential that was 135mV lower than wild type.
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Swenson S, Cannon A, Harris NJ, Taylor NG, Fox JL, Khalimonchuk O. Analysis of Oligomerization Properties of Heme a Synthase Provides Insights into Its Function in Eukaryotes. J Biol Chem 2016; 291:10411-25. [PMID: 26940873 DOI: 10.1074/jbc.m115.707539] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Indexed: 11/06/2022] Open
Abstract
Heme a is an essential cofactor for function of cytochrome c oxidase in the mitochondrial electron transport chain. Several evolutionarily conserved enzymes have been implicated in the biosynthesis of heme a, including the heme a synthase Cox15. However, the structure of Cox15 is unknown, its enzymatic mechanism and the role of active site residues remain debated, and recent discoveries suggest additional chaperone-like roles for this enzyme. Here, we investigated Cox15 in the model eukaryote Saccharomyces cerevisiae via several approaches to examine its oligomeric states and determine the effects of active site and human pathogenic mutations. Our results indicate that Cox15 exhibits homotypic interactions, forming highly stable complexes dependent upon hydrophobic interactions. This multimerization is evolutionarily conserved and independent of heme levels and heme a synthase catalytic activity. Four conserved histidine residues are demonstrated to be critical for eukaryotic heme a synthase activity and cannot be substituted with other heme-ligating amino acids. The 20-residue linker region connecting the two conserved domains of Cox15 is also important; removal of this linker impairs both Cox15 multimerization and enzymatic activity. Mutations of COX15 causing single amino acid conversions associated with fatal infantile hypertrophic cardiomyopathy and the neurological disorder Leigh syndrome result in impaired stability (S344P) or catalytic function (R217W), and the latter mutation affects oligomeric properties of the enzyme. Structural modeling of Cox15 suggests these two mutations affect protein folding and heme binding, respectively. We conclude that Cox15 multimerization is important for heme a biosynthesis and/or transfer to maturing cytochrome c oxidase.
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Affiliation(s)
- Samantha Swenson
- From the Department of Biochemistry and Nebraska Redox Biology Center, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 and
| | - Andrew Cannon
- From the Department of Biochemistry and Nebraska Redox Biology Center, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 and
| | - Nicholas J Harris
- the Department of Chemistry and Biochemistry, College of Charleston, Charleston, South Carolina 29424
| | - Nicholas G Taylor
- the Department of Chemistry and Biochemistry, College of Charleston, Charleston, South Carolina 29424
| | - Jennifer L Fox
- the Department of Chemistry and Biochemistry, College of Charleston, Charleston, South Carolina 29424
| | - Oleh Khalimonchuk
- From the Department of Biochemistry and Nebraska Redox Biology Center, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 and
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40
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Pintscher S, Kuleta P, Cieluch E, Borek A, Sarewicz M, Osyczka A. Tuning of Hemes b Equilibrium Redox Potential Is Not Required for Cross-Membrane Electron Transfer. J Biol Chem 2016; 291:6872-81. [PMID: 26858251 PMCID: PMC4807273 DOI: 10.1074/jbc.m115.712307] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Indexed: 11/22/2022] Open
Abstract
In biological energy conversion, cross-membrane electron transfer often involves an assembly of two hemes b. The hemes display a large difference in redox midpoint potentials (ΔEm_b), which in several proteins is assumed to facilitate cross-membrane electron transfer and overcome a barrier of membrane potential. Here we challenge this assumption reporting on heme b ligand mutants of cytochrome bc1 in which, for the first time in transmembrane cytochrome, one natural histidine has been replaced by lysine without loss of the native low spin type of heme iron. With these mutants we show that ΔEm_b can be markedly increased, and the redox potential of one of the hemes can stay above the level of quinone pool, or ΔEm_b can be markedly decreased to the point that two hemes are almost isopotential, yet the enzyme retains catalytically competent electron transfer between quinone binding sites and remains functional in vivo. This reveals that cytochrome bc1 can accommodate large changes in ΔEm_b without hampering catalysis, as long as these changes do not impose overly endergonic steps on downhill electron transfer from substrate to product. We propose that hemes b in this cytochrome and in other membranous cytochromes b act as electronic connectors for the catalytic sites with no fine tuning in ΔEm_b required for efficient cross-membrane electron transfer. We link this concept with a natural flexibility in occurrence of several thermodynamic configurations of the direction of electron flow and the direction of the gradient of potential in relation to the vector of the electric membrane potential.
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Affiliation(s)
- Sebastian Pintscher
- From the Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Patryk Kuleta
- From the Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Ewelina Cieluch
- From the Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Arkadiusz Borek
- From the Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Marcin Sarewicz
- From the Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Artur Osyczka
- From the Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
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41
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Zhao Z, Wang D, Wang M, Sun X, Wang L, Huang X, Ma L, Li Z. Proximal environment controlling the reactivity between inorganic sulfide and heme-peptide model. RSC Adv 2016. [DOI: 10.1039/c6ra14100e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Synthesized deuterohemin-peptide, which is lack of the distal protein structure, is used as a heme model to investigate the effects of the proximal environment on the reactivity of inorganic sulfide to heme center.
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Affiliation(s)
- Zijian Zhao
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education
- College of Life Science
- Jilin University
- Changchun 130012
- PR China
| | - Dandan Wang
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education
- College of Life Science
- Jilin University
- Changchun 130012
- PR China
| | - Mingyang Wang
- National Engineering Laboratory for AIDS Vaccine
- Jilin University
- Changchun 130012
- PR China
| | - Xiaoli Sun
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- PR China
| | - Liping Wang
- National Engineering Laboratory for AIDS Vaccine
- Jilin University
- Changchun 130012
- PR China
| | - Xuri Huang
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- PR China
| | - Li Ma
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education
- College of Life Science
- Jilin University
- Changchun 130012
- PR China
| | - Zhengqiang Li
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education
- College of Life Science
- Jilin University
- Changchun 130012
- PR China
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42
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Low reduction potential cytochrome b5 isotypes of Giardia intestinalis. Exp Parasitol 2015; 157:197-201. [DOI: 10.1016/j.exppara.2015.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 07/10/2015] [Accepted: 08/16/2015] [Indexed: 11/22/2022]
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43
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Beltrán J, Kloss B, Hosler JP, Geng J, Liu A, Modi A, Dawson JH, Sono M, Shumskaya M, Ampomah-Dwamena C, Love JD, Wurtzel ET. Control of carotenoid biosynthesis through a heme-based cis-trans isomerase. Nat Chem Biol 2015; 11:598-605. [PMID: 26075523 PMCID: PMC4509827 DOI: 10.1038/nchembio.1840] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 05/13/2015] [Indexed: 01/27/2023]
Abstract
Plants synthesize carotenoids essential for plant development and survival. These metabolites also serve as essential nutrients for human health. The biosynthetic pathway leading to all plant carotenoids occurs in chloroplasts and other plastids and requires 15-cis-ζ-carotene isomerase (Z-ISO). It was not certain whether isomerization was achieved by Z-ISO alone or in combination with other enzymes. Here we show that Z-ISO is a bona fide enzyme and integral membrane protein. Z-ISO independently catalyzes the cis-to-trans isomerization of the 15–15′ C=C bond in 9,15,9′-cis-ζ-carotene to produce the substrate required by the following biosynthetic pathway enzyme. We discovered that isomerization depends upon a ferrous heme b cofactor that undergoes redox-regulated ligand-switching between the heme iron and alternate Z-ISO amino acid residues. Heme b-dependent isomerization of a large, hydrophobic compound in a membrane is unprecedented. As an isomerase, Z-ISO represents a new prototype for heme b proteins and potentially utilizes a novel chemical mechanism.
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Affiliation(s)
- Jesús Beltrán
- 1] Department of Biological Sciences, Lehman College, City University of New York (CUNY), Bronx, New York, USA. [2] Graduate School and University Center, CUNY, New York, New York, USA
| | - Brian Kloss
- New York Structural Biology Center, New York, New York, USA
| | - Jonathan P Hosler
- Department of Biochemistry, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Jiafeng Geng
- Department of Chemistry, Georgia State University, Atlanta, Georgia, USA
| | - Aimin Liu
- Department of Chemistry, Georgia State University, Atlanta, Georgia, USA
| | - Anuja Modi
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, USA
| | - John H Dawson
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, USA
| | - Masanori Sono
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, USA
| | - Maria Shumskaya
- Department of Biological Sciences, Lehman College, City University of New York (CUNY), Bronx, New York, USA
| | - Charles Ampomah-Dwamena
- Department of Biological Sciences, Lehman College, City University of New York (CUNY), Bronx, New York, USA
| | - James D Love
- New York Structural Biology Center, New York, New York, USA
| | - Eleanore T Wurtzel
- 1] Department of Biological Sciences, Lehman College, City University of New York (CUNY), Bronx, New York, USA. [2] Graduate School and University Center, CUNY, New York, New York, USA
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44
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Alonso PJ, Martínez JI. Magnetic properties of a Kramers doublet. An univocal bridge between experimental results and theoretical predictions. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 255:1-14. [PMID: 25879696 DOI: 10.1016/j.jmr.2015.03.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 03/14/2015] [Accepted: 03/16/2015] [Indexed: 06/04/2023]
Abstract
The magnetic response of a Kramers doublet is analyzed in a general case taking into account only the formal properties derived from time reversal operation. It leads to a definition of a matrix G (gyromagnetic matrix) whose expression depends on the chosen reference frame and on the Kramers conjugate basis used to describe the physical system. It is shown that there exists a reference frame and a suitable Kramers conjugate basis that gives a diagonal form for the G-matrix with all non-null elements having the same sign. A detailed procedure for obtaining this canonical expression of G is presented when the electronic structure of the KD is known regardless the level of the used theory. This procedure provides a univocal way to compare the theoretical predictions with the experimental results obtained from a complete set of magnetic experiments. In this way the problems arising from ambiguities in the g-tensor definition are overcome. This procedure is extended to find a spin-Hamiltonian suitable for describing the magnetic behavior of a pair of weakly coupled Kramers systems in the multispin scheme when the interaction between the two moieties as well as the individual Zeeman interaction are small enough as compared with ligand field splitting. Explicit relations between the physical interaction and the parameters of such a spin-Hamiltonian are also obtained.
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Affiliation(s)
- P J Alonso
- Instituto de Ciencia de Materiales de Aragón (Universidad de Zaragoza-Consejo Superior de Investigaciones Científicas), Facultad de Ciencias, Universidad de Zaragoza, C/ Pedro Cerbuna 12, 50009 Zaragoza, Spain.
| | - J I Martínez
- Instituto de Ciencia de Materiales de Aragón (Universidad de Zaragoza-Consejo Superior de Investigaciones Científicas), Facultad de Ciencias, Universidad de Zaragoza, C/ Pedro Cerbuna 12, 50009 Zaragoza, Spain
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45
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Mokry DZ, Nadia-Albete A, Johnson MK, Lukat-Rodgers GS, Rodgers KR, Lanzilotta WN. Spectroscopic evidence for a 5-coordinate oxygenic ligated high spin ferric heme moiety in the Neisseria meningitidis hemoglobin binding receptor. Biochim Biophys Acta Gen Subj 2014; 1840:3058-66. [PMID: 24968987 DOI: 10.1016/j.bbagen.2014.06.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 06/13/2014] [Accepted: 06/16/2014] [Indexed: 01/04/2023]
Abstract
BACKGROUND For many pathogenic microorganisms, iron acquisition represents a significant stress during the colonization of a mammalian host. Heme is the single most abundant source of soluble iron in this environment. While the importance of iron assimilation for nearly all organisms is clear, the mechanisms by which heme is acquired and utilized by many bacterial pathogens, even those most commonly found at sites of infection, remain poorly understood. METHODS An alternative protocol for the production and purification of the outer membrane hemoglobin receptor (HmbR) from the pathogen Neisseria meningitidis has facilitated a biophysical characterization of this outer membrane transporter by electronic absorption, circular dichroism, electron paramagnetic resonance, and resonance Raman techniques. RESULTS HmbR co-purifies with 5-coordinate high spin ferric heme bound. The heme binding site accommodates exogenous imidazole as a sixth ligand, which results in a 6-coordinate, low-spin ferric species. Both the 5- and 6-coordinate complexes are reduced by sodium hydrosulfite. Four HmbR variants with a modest decrease in binding efficiency for heme have been identified (H87C, H280A, Y282A, and Y456C). These findings are consistent with an emerging paradigm wherein the ferric iron center of bound heme is coordinated by a tyrosine ligand. CONCLUSION In summary, this study provides the first spectroscopic characterization for any heme or iron transporter in Neisseria meningitidis, and suggests a coordination environment heretofore unobserved in a TonB-dependent hemin transporter. GENERAL SIGNIFICANCE A detailed understanding of the nutrient acquisition pathways in common pathogens such as N. meningitidis provides a foundation for new antimicrobial strategies.
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Affiliation(s)
- David Z Mokry
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | | | - Michael K Johnson
- Department of Chemistry, University of Georgia, Athens, GA 30602, USA
| | - Gudrun S Lukat-Rodgers
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108-6050, USA
| | - Kenton R Rodgers
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108-6050, USA
| | - William N Lanzilotta
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, USA.
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46
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Affiliation(s)
- Russ Hille
- Department of Biochemistry, University of California, Riverside, Riverside, California 92521, United States
| | - James Hall
- Department of Biochemistry, University of California, Riverside, Riverside, California 92521, United States
| | - Partha Basu
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, United States
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47
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Davidson VL, Wilmot CM. Posttranslational biosynthesis of the protein-derived cofactor tryptophan tryptophylquinone. Annu Rev Biochem 2013; 82:531-50. [PMID: 23746262 DOI: 10.1146/annurev-biochem-051110-133601] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Methylamine dehydrogenase (MADH) catalyzes the oxidative deamination of methylamine to formaldehyde and ammonia. Tryptophan tryptophylquinone (TTQ) is the protein-derived cofactor of MADH required for this catalytic activity. TTQ is biosynthesized through the posttranslational modification of two tryptophan residues within MADH, during which the indole rings of two tryptophan side chains are cross-linked and two oxygen atoms are inserted into one of the indole rings. MauG is a c-type diheme enzyme that catalyzes the final three reactions in TTQ formation. In total, this is a six-electron oxidation process requiring three cycles of MauG-dependent two-electron oxidation events using either H2O2 or O2. The MauG redox form responsible for the catalytic activity is an unprecedented bis-Fe(IV) species. The amino acids of MADH that are modified are ≈ 40 Å from the site where MauG binds oxygen, and the reaction proceeds by a hole hopping electron transfer mechanism. This review addresses these highly unusual aspects of the long-range catalytic reaction mediated by MauG.
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Affiliation(s)
- Victor L Davidson
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32827, USA.
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48
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Kaur R, Bren KL. Redox state dependence of axial ligand dynamics in Nitrosomonas europaea cytochrome c552. J Phys Chem B 2013; 117:15720-8. [PMID: 23909651 DOI: 10.1021/jp4064577] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Analysis of NMR spectra reveals that the heme axial Met ligand orientation and dynamics in Nitrosomonas europaea cytochrome c552 (Ne cyt c) are dependent on the heme redox state. In the oxidized state, the heme axial Met is fluxional, interconverting between two conformers related to each other by inversion through the Met δS atom. In the reduced state, there is no evidence of fluxionality, with the Met occupying one conformation similar to that seen in the homologous Pseudomonas aeruginosa cytochrome c551. Comparison of the observed and calculated pseudocontact shifts for oxidized Ne cyt c using the reduced protein structure as a reference structure reveals a redox-dependent change in the structure of the loop bearing the axial Met (loop 3). Analysis of nuclear Overhauser effects (NOEs) and existing structural data provides further support for the redox state dependence of the loop 3 structure. Implications for electron transfer function are discussed.
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Affiliation(s)
- Ravinder Kaur
- Center for Infectious Disease and Immunology, Research Institute, Rochester General Hospital , Rochester, New York 14621, United States
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49
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Can M, Krucinska J, Zoppellaro G, Andersen NH, Wedekind JE, Hersleth HP, Andersson KK, Bren KL. Structural characterization of nitrosomonas europaea cytochrome c-552 variants with marked differences in electronic structure. Chembiochem 2013; 14:1828-38. [PMID: 23908017 DOI: 10.1002/cbic.201300118] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Indexed: 11/09/2022]
Abstract
Nitrosomonas europaea cytochrome c-552 (Ne c-552) variants with the same His/Met axial ligand set but with different EPR spectra have been characterized structurally, to aid understanding of how molecular structure determines heme electronic structure. Visible light absorption, Raman, and resonance Raman spectroscopy of the protein crystals was performed along with structure determination. The structures solved are those of Ne c-552, which displays a "HALS" (or highly anisotropic low-spin) EPR spectrum, and of the deletion mutant Ne N64Δ, which has a rhombic EPR spectrum. Two X-ray crystal structures of wild-type Ne c-552 are reported; one is of the protein isolated from N. europaea cells (Ne c-552n, 2.35 Å resolution), and the other is of recombinant protein expressed in Escherichia coli (Ne c-552r, 1.63 Å resolution). Ne N64Δ crystallized in two different space groups, and two structures are reported [monoclinic (2.1 Å resolution) and hexagonal (2.3 Å resolution)]. Comparison of the structures of the wild-type and mutant proteins reveals that heme ruffling is increased in the mutant; increased ruffling is predicted to yield a more rhombic EPR spectrum. The 2.35 Å Ne c-552n structure shows 18 molecules in the asymmetric unit; analysis of the structure is consistent with population of more than one axial Met configuration, as seen previously by NMR. Finally, the mutation was shown to yield a more hydrophobic heme pocket and to expel water molecules from near the axial Met. These structures reveal that heme pocket residue 64 plays multiple roles in regulating the axial ligand orientation and the interaction of water with the heme. These results support the hypothesis that more ruffled hemes lead to more rhombic EPR signals in cytochromes c with His/Met axial ligation.
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Affiliation(s)
- Mehmet Can
- Department of Chemistry, University of Rochester, Rochester, NY 14627 (USA)
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50
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Astashkin AV, Walker FA. Determination of the principal g-values of Type I or highly-anisotropic low spin (HALS) ferriheme centers in frozen solutions. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 231:15-21. [PMID: 23562666 PMCID: PMC3660502 DOI: 10.1016/j.jmr.2013.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 03/07/2013] [Accepted: 03/08/2013] [Indexed: 06/02/2023]
Abstract
Continuous wave (CW) electron paramagnetic resonance (EPR) spectroscopy of highly-anisotropic low spin (HALS) ferric heme centers in frozen solutions is not a very informative approach because usually only one feature is reliably observed in the spectra, that at the maximal principal g-value of, typically, 3.3-3.79. The other two EPR turning points are severely broadened by g-strain and are not easily observed in the first-derivative CW EPR spectra. In this work, we have explored the potential of alternative EPR techniques, the electron spin echo (ESE) field sweep and electron spin transient nutation (TN), for obtaining information about the g-tensors of such systems, using as an example a typical HALS ferric heme center, [Fe(III)((15)N-coproporphyrin)(CN)2]. The analysis of the experimental g-tensor of [Fe(III)((15)N-coproporphyrin)(CN)2](-) has shown that the widths of the underlying energy distributions for this HALS center are comparable to those found for the rhombic bis-imidazole complex. The greater effect on the g-value distributions for HALS centers is determined by near degeneracy of two of the three lower-energy d-orbitals, d(yz) and d(xz), which contain the unpaired electron.
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Affiliation(s)
- Andrei V Astashkin
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721-0041, USA.
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