1
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Srour B, Gervason S, Hoock MH, Monfort B, Want K, Larkem D, Trabelsi N, Landrot G, Zitolo A, Fonda E, Etienne E, Gerbaud G, Müller CS, Oltmanns J, Gordon JB, Yadav V, Kleczewska M, Jelen M, Toledano MB, Dutkiewicz R, Goldberg DP, Schünemann V, Guigliarelli B, Burlat B, Sizun C, D'Autréaux B. Iron Insertion at the Assembly Site of the ISCU Scaffold Protein Is a Conserved Process Initiating Fe-S Cluster Biosynthesis. J Am Chem Soc 2022; 144:17496-17515. [PMID: 36121382 PMCID: PMC10163866 DOI: 10.1021/jacs.2c06338] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Iron-sulfur (Fe-S) clusters are prosthetic groups of proteins biosynthesized on scaffold proteins by highly conserved multi-protein machineries. Biosynthesis of Fe-S clusters into the ISCU scaffold protein is initiated by ferrous iron insertion, followed by sulfur acquisition, via a still elusive mechanism. Notably, whether iron initially binds to the ISCU cysteine-rich assembly site or to a cysteine-less auxiliary site via N/O ligands remains unclear. We show here by SEC, circular dichroism (CD), and Mössbauer spectroscopies that iron binds to the assembly site of the monomeric form of prokaryotic and eukaryotic ISCU proteins via either one or two cysteines, referred to the 1-Cys and 2-Cys forms, respectively. The latter predominated at pH 8.0 and correlated with the Fe-S cluster assembly activity, whereas the former increased at a more acidic pH, together with free iron, suggesting that it constitutes an intermediate of the iron insertion process. Iron not binding to the assembly site was non-specifically bound to the aggregated ISCU, ruling out the existence of a structurally defined auxiliary site in ISCU. Characterization of the 2-Cys form by site-directed mutagenesis, CD, NMR, X-ray absorption, Mössbauer, and electron paramagnetic resonance spectroscopies showed that the iron center is coordinated by four strictly conserved amino acids of the assembly site, Cys35, Asp37, Cys61, and His103, in a tetrahedral geometry. The sulfur receptor Cys104 was at a very close distance and apparently bound to the iron center when His103 was missing, which may enable iron-dependent sulfur acquisition. Altogether, these data provide the structural basis to elucidate the Fe-S cluster assembly process and establish that the initiation of Fe-S cluster biosynthesis by insertion of a ferrous iron in the assembly site of ISCU is a conserved mechanism.
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Affiliation(s)
- Batoul Srour
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Sylvain Gervason
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Maren Hellen Hoock
- Fachbereich Physik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 56, 67663 Kaiserslautern, Germany
| | - Beata Monfort
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Kristian Want
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Djabir Larkem
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Nadine Trabelsi
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Gautier Landrot
- Synchrotron SOLEIL, L'Orme des Merisiers, BP48 Saint Aubin 91192 Gif-Sur-Yvette, France
| | - Andrea Zitolo
- Synchrotron SOLEIL, L'Orme des Merisiers, BP48 Saint Aubin 91192 Gif-Sur-Yvette, France
| | - Emiliano Fonda
- Synchrotron SOLEIL, L'Orme des Merisiers, BP48 Saint Aubin 91192 Gif-Sur-Yvette, France
| | - Emilien Etienne
- Aix Marseille Univ, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines (BIP), 31 Chemin Joseph Aiguier, 13402 Marseille, France
| | - Guillaume Gerbaud
- Aix Marseille Univ, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines (BIP), 31 Chemin Joseph Aiguier, 13402 Marseille, France
| | - Christina Sophia Müller
- Fachbereich Physik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 56, 67663 Kaiserslautern, Germany
| | - Jonathan Oltmanns
- Fachbereich Physik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 56, 67663 Kaiserslautern, Germany
| | - Jesse B Gordon
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Vishal Yadav
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Malgorzata Kleczewska
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
| | - Marcin Jelen
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
| | - Michel B Toledano
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Rafal Dutkiewicz
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
| | - David P Goldberg
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Volker Schünemann
- Fachbereich Physik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 56, 67663 Kaiserslautern, Germany
| | - Bruno Guigliarelli
- Aix Marseille Univ, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines (BIP), 31 Chemin Joseph Aiguier, 13402 Marseille, France
| | - Bénédicte Burlat
- Aix Marseille Univ, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines (BIP), 31 Chemin Joseph Aiguier, 13402 Marseille, France
| | - Christina Sizun
- Institut de Chimie des Substances Naturelles, CNRS, Université Paris Saclay, Avenue de La Terrasse, 91190 Gif-sur-Yvette, France
| | - Benoit D'Autréaux
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
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2
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Van Stappen C, Deng Y, Liu Y, Heidari H, Wang JX, Zhou Y, Ledray AP, Lu Y. Designing Artificial Metalloenzymes by Tuning of the Environment beyond the Primary Coordination Sphere. Chem Rev 2022; 122:11974-12045. [PMID: 35816578 DOI: 10.1021/acs.chemrev.2c00106] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Metalloenzymes catalyze a variety of reactions using a limited number of natural amino acids and metallocofactors. Therefore, the environment beyond the primary coordination sphere must play an important role in both conferring and tuning their phenomenal catalytic properties, enabling active sites with otherwise similar primary coordination environments to perform a diverse array of biological functions. However, since the interactions beyond the primary coordination sphere are numerous and weak, it has been difficult to pinpoint structural features responsible for the tuning of activities of native enzymes. Designing artificial metalloenzymes (ArMs) offers an excellent basis to elucidate the roles of these interactions and to further develop practical biological catalysts. In this review, we highlight how the secondary coordination spheres of ArMs influence metal binding and catalysis, with particular focus on the use of native protein scaffolds as templates for the design of ArMs by either rational design aided by computational modeling, directed evolution, or a combination of both approaches. In describing successes in designing heme, nonheme Fe, and Cu metalloenzymes, heteronuclear metalloenzymes containing heme, and those ArMs containing other metal centers (including those with non-native metal ions and metallocofactors), we have summarized insights gained on how careful controls of the interactions in the secondary coordination sphere, including hydrophobic and hydrogen bonding interactions, allow the generation and tuning of these respective systems to approach, rival, and, in a few cases, exceed those of native enzymes. We have also provided an outlook on the remaining challenges in the field and future directions that will allow for a deeper understanding of the secondary coordination sphere a deeper understanding of the secondary coordintion sphere to be gained, and in turn to guide the design of a broader and more efficient variety of ArMs.
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Affiliation(s)
- Casey Van Stappen
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Austin, Texas 78712, United States
| | - Yunling Deng
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Austin, Texas 78712, United States
| | - Yiwei Liu
- Department of Chemistry, University of Illinois, Urbana-Champaign, 505 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Hirbod Heidari
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Austin, Texas 78712, United States
| | - Jing-Xiang Wang
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Austin, Texas 78712, United States
| | - Yu Zhou
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Austin, Texas 78712, United States
| | - Aaron P Ledray
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Austin, Texas 78712, United States
| | - Yi Lu
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Austin, Texas 78712, United States.,Department of Chemistry, University of Illinois, Urbana-Champaign, 505 South Mathews Avenue, Urbana, Illinois 61801, United States
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3
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The Role of Metal Ions in the Electron Transport through Azurin-Based Junctions. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11093732] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We studied the coherent electron transport through metal–protein–metal junctions based on a blue copper azurin, in which the copper ion was replaced by three different metal ions (Co, Ni and Zn). Our results show that neither the protein structure nor the transmission at the Fermi level change significantly upon metal replacement. The discrepancy with previous experimental observations suggests that the transport mechanism taking place in these types of junctions is probably not fully coherent.
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Tian S, Fan R, Albert T, Khade RL, Dai H, Harnden KA, Hosseinzadeh P, Liu J, Nilges MJ, Zhang Y, Moënne-Loccoz P, Guo Y, Lu Y. Stepwise nitrosylation of the nonheme iron site in an engineered azurin and a molecular basis for nitric oxide signaling mediated by nonheme iron proteins. Chem Sci 2021; 12:6569-6579. [PMID: 34040732 PMCID: PMC8132939 DOI: 10.1039/d1sc00364j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Mononitrosyl and dinitrosyl iron species, such as {FeNO}7, {FeNO}8 and {Fe(NO)2}9, have been proposed to play pivotal roles in the nitrosylation processes of nonheme iron centers in biological systems. Despite their importance, it has been difficult to capture and characterize them in the same scaffold of either native enzymes or their synthetic analogs due to the distinct structural requirements of the three species, using redox reagents compatible with biomolecules under physiological conditions. Here, we report the realization of stepwise nitrosylation of a mononuclear nonheme iron site in an engineered azurin under such conditions. Through tuning the number of nitric oxide equivalents and reaction time, controlled formation of {FeNO}7 and {Fe(NO)2}9 species was achieved, and the elusive {FeNO}8 species was inferred by EPR spectroscopy and observed by Mössbauer spectroscopy, with complemental evidence for the conversion of {FeNO}7 to {Fe(NO)2}9 species by UV-Vis, resonance Raman and FT-IR spectroscopies. The entire pathway of the nitrosylation process, Fe(ii) → {FeNO}7 → {FeNO}8 → {Fe(NO)2}9, has been elucidated within the same protein scaffold based on spectroscopic characterization and DFT calculations. These results not only enhance the understanding of the dinitrosyl iron complex formation process, but also shed light on the physiological roles of nitric oxide signaling mediated by nonheme iron proteins. Stepwise nitrosylation from Fe(ii) to {FeNO}7, {FeNO}8 and then to {Fe(NO)2}9 is reported for the first time in the same protein scaffold, providing deeper understanding of the detailed mechanism of dinitrosyl iron complex formation.![]()
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Affiliation(s)
- Shiliang Tian
- Department of Chemistry, Department of Biochemistry, School of Chemical Sciences Electron Paramagnetic Resonance Lab, University of Illinois at Urbana-Champaign 600 South Mathews Avenue Urbana IL USA +1-217-333-2619
| | - Ruixi Fan
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA USA +1-412-268-1061 +1-412-268-1704
| | - Therese Albert
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University 3181 S.W. Sam Jackson Park Road Portland OR USA +1-503-346-3429
| | - Rahul L Khade
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology 1 Castle Point Terrace Hoboken NJ USA +1-201-216-8240 +1-201-216-5513
| | - Huiguang Dai
- Department of Chemistry, Department of Biochemistry, School of Chemical Sciences Electron Paramagnetic Resonance Lab, University of Illinois at Urbana-Champaign 600 South Mathews Avenue Urbana IL USA +1-217-333-2619
| | - Kevin A Harnden
- Department of Chemistry, Department of Biochemistry, School of Chemical Sciences Electron Paramagnetic Resonance Lab, University of Illinois at Urbana-Champaign 600 South Mathews Avenue Urbana IL USA +1-217-333-2619
| | - Parisa Hosseinzadeh
- Department of Chemistry, Department of Biochemistry, School of Chemical Sciences Electron Paramagnetic Resonance Lab, University of Illinois at Urbana-Champaign 600 South Mathews Avenue Urbana IL USA +1-217-333-2619
| | - Jing Liu
- Department of Chemistry, Department of Biochemistry, School of Chemical Sciences Electron Paramagnetic Resonance Lab, University of Illinois at Urbana-Champaign 600 South Mathews Avenue Urbana IL USA +1-217-333-2619
| | - Mark J Nilges
- Department of Chemistry, Department of Biochemistry, School of Chemical Sciences Electron Paramagnetic Resonance Lab, University of Illinois at Urbana-Champaign 600 South Mathews Avenue Urbana IL USA +1-217-333-2619
| | - Yong Zhang
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology 1 Castle Point Terrace Hoboken NJ USA +1-201-216-8240 +1-201-216-5513
| | - Pierre Moënne-Loccoz
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University 3181 S.W. Sam Jackson Park Road Portland OR USA +1-503-346-3429
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA USA +1-412-268-1061 +1-412-268-1704
| | - Yi Lu
- Department of Chemistry, Department of Biochemistry, School of Chemical Sciences Electron Paramagnetic Resonance Lab, University of Illinois at Urbana-Champaign 600 South Mathews Avenue Urbana IL USA +1-217-333-2619
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5
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DiPrimio DJ, Holland PL. Repurposing metalloproteins as mimics of natural metalloenzymes for small-molecule activation. J Inorg Biochem 2021; 219:111430. [PMID: 33873051 DOI: 10.1016/j.jinorgbio.2021.111430] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 03/11/2021] [Accepted: 03/15/2021] [Indexed: 12/12/2022]
Abstract
Artificial metalloenzymes (ArMs) consist of an unnatural metal or cofactor embedded in a protein scaffold, and are an excellent platform for applying the concepts of protein engineering to catalysis. In this Focused Review, we describe the application of ArMs as simple, tunable artificial models of the active sites of complex natural metalloenzymes for small-molecule activation. In this sense, ArMs expand the strategies of synthetic model chemistry to protein-based supporting ligands with potential for participation from the second coordination sphere. We focus specifically on ArMs that are structural, spectroscopic, and functional models of enzymes for activation of small molecules like CO, CO2, O2, N2, and NO, as well as production/consumption of H2. These ArMs give insight into the identities and roles of metalloenzyme structural features within and near the cofactor. We give examples of ArM work relevant to hydrogenases, acetyl-coenzyme A synthase, superoxide dismutase, heme oxygenases, nitric oxide reductase, methyl-coenzyme M reductase, copper-O2 enzymes, and nitrogenases.
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Affiliation(s)
- Daniel J DiPrimio
- Department of Chemistry, Yale University, New Haven, CT, 06520, United States
| | - Patrick L Holland
- Department of Chemistry, Yale University, New Haven, CT, 06520, United States.
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6
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Miller KR, Paretsky JD, Follmer AH, Heinisch T, Mittra K, Gul S, Kim IS, Fuller FD, Batyuk A, Sutherlin KD, Brewster AS, Bhowmick A, Sauter NK, Kern J, Yano J, Green MT, Ward TR, Borovik AS. Artificial Iron Proteins: Modeling the Active Sites in Non-Heme Dioxygenases. Inorg Chem 2020; 59:6000-6009. [PMID: 32309932 PMCID: PMC7219546 DOI: 10.1021/acs.inorgchem.9b03791] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An important class of non-heme dioxygenases contains a conserved Fe binding site that consists of a 2-His-1-carboxylate facial triad. Results from structural biology show that, in the resting state, these proteins are six-coordinate with aqua ligands occupying the remaining three coordination sites. We have utilized biotin-streptavidin (Sav) technology to design new artificial Fe proteins (ArMs) that have many of the same structural features found within active sites of these non-heme dioxygenases. An Sav variant was isolated that contains the S112E mutation, which installed a carboxylate side chain in the appropriate position to bind to a synthetic FeII complex confined within Sav. Structural studies using X-ray diffraction (XRD) methods revealed a facial triad binding site that is composed of two N donors from the biotinylated ligand and the monodentate coordination of the carboxylate from S112E. Two aqua ligands complete the primary coordination sphere of the FeII center with both involved in hydrogen bond networks within Sav. The corresponding FeIII protein was also prepared and structurally characterized to show a six-coordinate complex with two exogenous acetato ligands. The FeIII protein was further shown to bind an exogenous azido ligand through replacement of one acetato ligand. Spectroscopic studies of the ArMs in solution support the results found by XRD.
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Affiliation(s)
- Kelsey R. Miller
- Department of Chemistry, 1102 Natural Science II, University of California, Irvine, CA 9269
| | - Jonathan D. Paretsky
- Department of Chemistry, 1102 Natural Science II, University of California, Irvine, CA 9269
| | - Alec H. Follmer
- Department of Chemistry, 1102 Natural Science II, University of California, Irvine, CA 9269
| | - Tillmann Heinisch
- Department of Chemistry, University of Basel, PO Box 3350, Mattenstrasse 24a, BPR 1096, CH-4002 Basel, Switzerland
| | - Kaustuv Mittra
- Department of Molecular Biosciences and Biochemistry, University of California, Irvine, CA 92697
| | - Sheraz Gul
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - In-Sik Kim
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Franklin D. Fuller
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025 USA
| | - Alexander Batyuk
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025 USA
| | - Kyle D. Sutherlin
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Aaron S. Brewster
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Asmit Bhowmick
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Nicholas K. Sauter
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jan Kern
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Junko Yano
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Michael T. Green
- Department of Chemistry, 1102 Natural Science II, University of California, Irvine, CA 9269
- Department of Molecular Biosciences and Biochemistry, University of California, Irvine, CA 92697
| | - Thomas R. Ward
- Department of Chemistry, University of Basel, PO Box 3350, Mattenstrasse 24a, BPR 1096, CH-4002 Basel, Switzerland
| | - A. S. Borovik
- Department of Chemistry, 1102 Natural Science II, University of California, Irvine, CA 9269
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7
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Gervason S, Larkem D, Mansour AB, Botzanowski T, Müller CS, Pecqueur L, Le Pavec G, Delaunay-Moisan A, Brun O, Agramunt J, Grandas A, Fontecave M, Schünemann V, Cianférani S, Sizun C, Tolédano MB, D'Autréaux B. Physiologically relevant reconstitution of iron-sulfur cluster biosynthesis uncovers persulfide-processing functions of ferredoxin-2 and frataxin. Nat Commun 2019; 10:3566. [PMID: 31395877 PMCID: PMC6687725 DOI: 10.1038/s41467-019-11470-9] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 07/04/2019] [Indexed: 12/16/2022] Open
Abstract
Iron-sulfur (Fe-S) clusters are essential protein cofactors whose biosynthetic defects lead to severe diseases among which is Friedreich's ataxia caused by impaired expression of frataxin (FXN). Fe-S clusters are biosynthesized on the scaffold protein ISCU, with cysteine desulfurase NFS1 providing sulfur as persulfide and ferredoxin FDX2 supplying electrons, in a process stimulated by FXN but not clearly understood. Here, we report the breakdown of this process, made possible by removing a zinc ion in ISCU that hinders iron insertion and promotes non-physiological Fe-S cluster synthesis from free sulfide in vitro. By binding zinc-free ISCU, iron drives persulfide uptake from NFS1 and allows persulfide reduction into sulfide by FDX2, thereby coordinating sulfide production with its availability to generate Fe-S clusters. FXN stimulates the whole process by accelerating persulfide transfer. We propose that this reconstitution recapitulates physiological conditions which provides a model for Fe-S cluster biosynthesis, clarifies the roles of FDX2 and FXN and may help develop Friedreich's ataxia therapies.
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Affiliation(s)
- Sylvain Gervason
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Djabir Larkem
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Amir Ben Mansour
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Thomas Botzanowski
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, CNRS, IPHC UMR 7178, 67000, Strasbourg, France
| | - Christina S Müller
- Fachbreich Physik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 56, 67663, Kaiserslautern, Germany
| | - Ludovic Pecqueur
- Laboratoire de Chimie des Processus Biologiques, Collège de France, Sorbonne Université, CNRS UMR 8229, PSL Research University, 11 place Marcelin Berthelot, 75005, Paris, France
| | - Gwenaelle Le Pavec
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Agnès Delaunay-Moisan
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Omar Brun
- Departament de Química Orgànica i IBUB, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, E-08028, Barcelona, Spain
| | - Jordi Agramunt
- Departament de Química Orgànica i IBUB, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, E-08028, Barcelona, Spain
| | - Anna Grandas
- Departament de Química Orgànica i IBUB, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, E-08028, Barcelona, Spain
| | - Marc Fontecave
- Laboratoire de Chimie des Processus Biologiques, Collège de France, Sorbonne Université, CNRS UMR 8229, PSL Research University, 11 place Marcelin Berthelot, 75005, Paris, France
| | - Volker Schünemann
- Fachbreich Physik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 56, 67663, Kaiserslautern, Germany
| | - Sarah Cianférani
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, CNRS, IPHC UMR 7178, 67000, Strasbourg, France
| | - Christina Sizun
- Institut de Chimie des Substances Naturelles, CNRS, Université Paris Saclay, 91190, Gif-sur-Yvette, France
| | - Michel B Tolédano
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Benoit D'Autréaux
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France.
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8
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Rittle J, Field MJ, Green MT, Tezcan FA. An efficient, step-economical strategy for the design of functional metalloproteins. Nat Chem 2019; 11:434-441. [PMID: 30778140 PMCID: PMC6483823 DOI: 10.1038/s41557-019-0218-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 01/11/2019] [Indexed: 01/31/2023]
Abstract
The bottom-up design and construction of functional metalloproteins remains a formidable task in biomolecular design. Although numerous strategies have been used to create new metalloproteins, pre-existing knowledge of the tertiary and quaternary protein structure is often required to generate suitable platforms for robust metal coordination and activity. Here we report an alternative and easily implemented approach (metal active sites by covalent tethering or MASCoT) in which folded protein building blocks are linked by a single disulfide bond to create diverse metal coordination environments within evolutionarily naive protein-protein interfaces. Metalloproteins generated using this strategy uniformly bind a wide array of first-row transition metal ions (MnII, FeII, CoII, NiII, CuII, ZnII and vanadyl) with physiologically relevant thermodynamic affinities (dissociation constants ranging from 700 nM for MnII to 50 fM for CuII). MASCoT readily affords coordinatively unsaturated metal centres-including a penta-His-coordinated non-haem Fe site-and well-defined binding pockets that can accommodate modifications and enable coordination of exogenous ligands such as nitric oxide to the interfacial metal centre.
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Affiliation(s)
- Jonathan Rittle
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Mackenzie J Field
- Department of Chemistry, University of California, Irvine, Irvine, CA, USA
| | - Michael T Green
- Department of Chemistry, University of California, Irvine, Irvine, CA, USA
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, USA
| | - F Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA.
- Materials Science and Engineering, University of California, San Diego, La Jolla, CA, USA.
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9
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Mirts EN, Bhagi-Damodaran A, Lu Y. Understanding and Modulating Metalloenzymes with Unnatural Amino Acids, Non-Native Metal Ions, and Non-Native Metallocofactors. Acc Chem Res 2019; 52:935-944. [PMID: 30912643 DOI: 10.1021/acs.accounts.9b00011] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Metalloproteins set the gold standard for performing important functions, including catalyzing demanding reactions under mild conditions. Designing artificial metalloenzymes (ArMs) to catalyze abiological reactions has been a major endeavor for many years, but most ArM activities are far below those of native enzymes, making them unsuitable for most pratical applications. A critical step to advance the field is to fundamentally understand what it takes to not only confer but also fine-tune ArM activities so they match those of native enzymes. Indeed, only once we can freely modulate ArM activity to rival (or surpass!) natural enzymes can the potential of ArMs be fully realized. A key to unlocking ArM potential is the observation that one metal primary coordination sphere can display a range of functions and levels of activity, leading to the realization that secondary coordination sphere (SCS) interactions are critically important. However, SCS interactions are numerous, long-range, and weak, making them very difficult to reproduce in ArMs. Furthermore, natural enzymes are tied to a small set of biologically available functional moieties from canonical amino acids and physiologically available metal ions and metallocofactors, severely limiting the chemical space available to probe and tune ArMs. In this Account, we summarize the use of unnatural amino acids (UAAs) and non-native metal ions and metallocofactors by our group and our collaborators to probe and modulate ArM functions. We incorporated isostructural UAAs in a type 1 copper (T1Cu) protein azurin to provide conclusive evidence that axial ligand hydrophobicity is a major determinant of T1Cu redunction potential ( E°'). Closely related work from other groups are also discussed. We also probed the role of protein backbone interactions that cannot be altered by standard mutagenesis by replacing the peptide bond with an ester linkage. We used insight gained from these studies to tune the E°' of azurin across the entire physiological range, the broadest range ever achieved in a single metalloprotein. Introducing UAA analogues of Tyr into ArM models of heme-copper oxidase (HCO) revealed a linear relationship between p Ka, E°', and activity. We also substituted non-native hemes and non-native metal ions for their native equivalents in these models to resolve several issues that were intractable in native HCOs and the closely related nitric oxide reductases, such as their roles in modulating substrate affinity, electron transfer rate, and activity. We incorporated abiological cofactors such as ferrocene and Mn(salen) into azurin and myoglobin, respectively, to stabilize these inorganic and organometallic compounds in water, confer abiological functions, tune their E°' and activity through SCS interactions, and show that the approach to metallocofactor anchoring and orientation can tune enantioselectivity and alter function. Replacing Cu in azurin with non-native Fe or Ni can impart novel activities, such as superoxide reduction and C-C bond formation. While progress was made, we have identified only a small fraction of the interactions that can be generally applied to ArMs to fine-tune their functions. Because SCS interactions are subtle and heavily interconnected, it has been difficult to characterize their effects quantitatively. It is vital to develop spectroscopic and computational techniques to detect and quantify their effects in both resting states and catalytic intermediates.
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Affiliation(s)
- Evan N. Mirts
- Department of Chemistry and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Ambika Bhagi-Damodaran
- Department of Chemistry and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Yi Lu
- Department of Chemistry and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
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10
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Bhagi-Damodaran A, Lu Y. The Periodic Table's Impact on Bioinorganic Chemistry and Biology's Selective Use of Metal Ions. STRUCTURE AND BONDING 2019; 182:153-173. [PMID: 36567794 PMCID: PMC9788643 DOI: 10.1007/430_2019_45] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Despite the availability of a vast variety of metal ions in the periodic table, biology uses only a selective few metal ions. Most of the redox active metals used belong to the first row of transition metals in the periodic table and include Fe, Co, Ni, Mn and Cu. On the other hand, Ca, Zn and Mg are the most commonly used redox inactive metals in biology. In this chapter, we discuss the periodic table's impact on bio-inorganic chemistry, by exploring reasons behind this selective choice of metals biology. A special focus is placed on the chemical and functional reasons why one metal ion is preferred over another one. We discuss the implications of metal choice in various biological processes including catalysis, electron transfer, redox sensing and signaling. We find that bioavailability of metal ions along with their redox potentials, coordination flexibility, valency and ligand affinity determine the specificity of metals for biological processes. Understanding the implications underlying the selective choice of metals of the periodic table in these biological processes can help design more efficient catalysts, more precise biosensors and more effective drugs.
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Affiliation(s)
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
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11
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Nóbrega CS, Pauleta SR. Interaction between Neisseria gonorrhoeae bacterial peroxidase and its electron donor, the lipid-modified azurin. FEBS Lett 2018; 592:1473-1483. [PMID: 29665008 DOI: 10.1002/1873-3468.13053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 11/05/2022]
Abstract
The Neisseria gonorrhoeae bacterial cytochrome c peroxidase plays a key role in detoxifying the cells from H2 O2 by reducing it to water using the lipid-modified azurin, LAz, a small type 1 copper protein, as electron donor. Here, the interaction between these two proteins was characterized by steady-state kinetics, two-dimensional NMR and molecular docking simulations. LAz is an efficient electron donor capable of activating this enzyme. This electron transfer complex is weak with a hydrophobic character, with LAz binding close to the electron transferring heme of the enzyme. The high catalytic rate (39 ± 0.03 s-1 ) is explained by the LAz pre-orientation, due to a positive dipole moment, and by the fast-dynamic ensemble of orientations, suggested by the small chemical shifts.
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Affiliation(s)
- Cláudia S Nóbrega
- Microbial Stress Lab, UCIBIO, REQUIMTE, Department of Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Sofia R Pauleta
- Microbial Stress Lab, UCIBIO, REQUIMTE, Department of Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
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12
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Schneider CR, Shafaat HS. An internal electron reservoir enhances catalytic CO2 reduction by a semisynthetic enzyme. Chem Commun (Camb) 2018; 52:9889-92. [PMID: 27406946 DOI: 10.1039/c6cc03901d] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The development of an artificial metalloenzyme for CO2 reduction is described. The small-molecule catalyst [Ni(II)(cyclam)](2+) has been incorporated within azurin. Selectivity for CO generation over H(+) reduction is enhanced within the protein environment, while the azurin active site metal impacts the electrochemical overpotential and photocatalytic activity. The enhanced catalysis observed for copper azurin suggests an important role for intramolecular electron transfer, analogous to native CO2 reducing enzymes.
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Affiliation(s)
- Camille R Schneider
- Department of Chemistry and Biochemistry and Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.
| | - Hannah S Shafaat
- Department of Chemistry and Biochemistry and Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.
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13
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Gong M, Cao Z, Liu W, Nichols EM, Smith PT, Derrick JS, Liu YS, Liu J, Wen X, Chang CJ. Supramolecular Porphyrin Cages Assembled at Molecular-Materials Interfaces for Electrocatalytic CO Reduction. ACS CENTRAL SCIENCE 2017; 3:1032-1040. [PMID: 28979945 PMCID: PMC5620982 DOI: 10.1021/acscentsci.7b00316] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Indexed: 05/19/2023]
Abstract
Conversion of carbon monoxide (CO), a major one-carbon product of carbon dioxide (CO2) reduction, into value-added multicarbon species is a challenge to addressing global energy demands and climate change. Here we report a modular synthetic approach for aqueous electrochemical CO reduction to carbon-carbon coupled products via self-assembly of supramolecular cages at molecular-materials interfaces. Heterobimetallic cavities formed by face-to-face coordination of thiol-terminated metalloporphyrins to copper electrodes through varying organic struts convert CO to C2 products with high faradaic efficiency (FE = 83% total with 57% to ethanol) and current density (1.34 mA/cm2) at a potential of -0.40 V vs RHE. The cage-functionalized electrodes offer an order of magnitude improvement in both selectivity and activity for electrocatalytic carbon fixation compared to parent copper surfaces or copper functionalized with porphyrins in an edge-on orientation.
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Affiliation(s)
- Ming Gong
- Department
of Chemistry, Department of Molecular and Cell Biology, and Howard Hughes
Medical Institute, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division and The Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Zhi Cao
- Department
of Chemistry, Department of Molecular and Cell Biology, and Howard Hughes
Medical Institute, University of California, Berkeley, California 94720, United States
| | - Wei Liu
- Department
of Chemistry, Department of Molecular and Cell Biology, and Howard Hughes
Medical Institute, University of California, Berkeley, California 94720, United States
| | - Eva M. Nichols
- Department
of Chemistry, Department of Molecular and Cell Biology, and Howard Hughes
Medical Institute, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division and The Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Peter T. Smith
- Department
of Chemistry, Department of Molecular and Cell Biology, and Howard Hughes
Medical Institute, University of California, Berkeley, California 94720, United States
| | - Jeffrey S. Derrick
- Department
of Chemistry, Department of Molecular and Cell Biology, and Howard Hughes
Medical Institute, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division and The Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Yi-Sheng Liu
- Chemical Sciences Division and The Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Jinjia Liu
- Institute
of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, Shanxi 030001, China
| | - Xiaodong Wen
- Institute
of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, Shanxi 030001, China
- Synfuels
China, Beijing, 100195, China
| | - Christopher J. Chang
- Department
of Chemistry, Department of Molecular and Cell Biology, and Howard Hughes
Medical Institute, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division and The Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- E-mail:
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14
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Manesis AC, O'Connor MJ, Schneider CR, Shafaat HS. Multielectron Chemistry within a Model Nickel Metalloprotein: Mechanistic Implications for Acetyl-CoA Synthase. J Am Chem Soc 2017; 139:10328-10338. [PMID: 28675928 DOI: 10.1021/jacs.7b03892] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The acetyl coenzyme A synthase (ACS) enzyme plays a central role in the metabolism of anaerobic bacteria and archaea, catalyzing the reversible synthesis of acetyl-CoA from CO and a methyl group through a series of nickel-based organometallic intermediates. Owing to the extreme complexity of the native enzyme systems, the mechanism by which this catalysis occurs remains poorly understood. In this work, we have developed a protein-based model for the NiP center of acetyl coenzyme A synthase using a nickel-substituted azurin protein (NiAz). NiAz is the first model nickel protein system capable of accessing three (NiI/NiII/NiIII) distinct oxidation states within a physiological potential range in aqueous solution, a critical feature for achieving organometallic ACS activity, and binds CO and -CH3 groups with biologically relevant affinity. Characterization of the NiI-CO species through spectroscopic and computational techniques reveals fundamentally similar features between the model NiAz system and the native ACS enzyme, highlighting the potential for related reactivity in this model protein. This work provides insight into the enzymatic process, with implications toward engineering biological catalysts for organometallic processes.
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Affiliation(s)
- Anastasia C Manesis
- The Ohio State University , 100 West 18th Avenue, Newman & Wolfrom Laboratory of Chemistry, Columbus, Ohio 43210, United States
| | - Matthew J O'Connor
- The Ohio State University , 100 West 18th Avenue, Newman & Wolfrom Laboratory of Chemistry, Columbus, Ohio 43210, United States
| | - Camille R Schneider
- The Ohio State University , 100 West 18th Avenue, Newman & Wolfrom Laboratory of Chemistry, Columbus, Ohio 43210, United States
| | - Hannah S Shafaat
- The Ohio State University , 100 West 18th Avenue, Newman & Wolfrom Laboratory of Chemistry, Columbus, Ohio 43210, United States
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15
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McWilliams SF, Brennan-Wydra E, MacLeod KC, Holland PL. Density Functional Calculations for Prediction of 57Fe Mössbauer Isomer Shifts and Quadrupole Splittings in β-Diketiminate Complexes. ACS OMEGA 2017; 2:2594-2606. [PMID: 28691111 PMCID: PMC5494642 DOI: 10.1021/acsomega.7b00595] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 05/24/2017] [Indexed: 05/09/2023]
Abstract
The relative ease of Mössbauer spectroscopy and of density functional theory (DFT) calculations encourages the use of Mössbauer parameters as a validation method for calculations, and the use of calculations as a double check on crystallographic structures. A number of studies have proposed correlations between the computationally determined electron density at the iron nucleus and the observed isomer shift, but deviations from these correlations in low-valent iron β-diketiminate complexes encouraged us to determine a new correlation for these compounds. The use of B3LYP/def2-TZVP in the ORCA platform provides an excellent balance of accuracy and speed. We provide here not only this new correlation and a clear guide to its use but also a systematic analysis of the limitations of this approach. We also highlight the impact of crystallographic inaccuracies, DFT model truncation, and spin states, with intent to assist experimentalists to use Mössbauer spectroscopy and calculations together.
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Affiliation(s)
- Sean F McWilliams
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Emma Brennan-Wydra
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - K Cory MacLeod
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Patrick L Holland
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
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16
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Proteome scale identification, classification and structural analysis of iron-binding proteins in bread wheat. J Inorg Biochem 2017; 170:63-74. [DOI: 10.1016/j.jinorgbio.2017.02.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 01/23/2017] [Accepted: 02/10/2017] [Indexed: 12/26/2022]
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17
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18
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Steiner RA, Dzul SP, Stemmler TL, Harrop TC. Synthesis and Speciation-Dependent Properties of a Multimetallic Model Complex of NiSOD That Exhibits Unique Hydrogen-Bonding. Inorg Chem 2017; 56:2849-2862. [PMID: 28212040 DOI: 10.1021/acs.inorgchem.6b02997] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The complex Na3[{NiII(nmp)}3S3BTAalk)] (1) (nmp2- = deprotonated form of N-(2-mercaptoethyl)picolinamide; H3S3BTAalk = N1,N3,N5-tris(2-mercaptoethyl)benzene-1,3,5-tricarboxamide, where H = dissociable protons), supported by the thiolate-benzenetricarboxamide scaffold (S3BTAalk), has been synthesized as a trimetallic model of nickel-containing superoxide dismutase (NiSOD). X-ray absorption spectroscopy (XAS) and 1H NMR measurements on 1 indicate that the NiII centers are square-planar with N2S2 coordination, and Ni-N and Ni-S distances of 1.95 and 2.16 Å, respectively. Additional evidence from IR indicates the presence of H-bonds in 1 from the approximately -200 cm-1 shift in νNH from free ligand. The presence of H-bonds allows for speciation that is temperature-, concentration-, and solvent-dependent. In unbuffered water and at low temperature, a dimeric complex (1A; λ = 410 nm) that aggregates through intermolecular NH···O═C bonds of BTA units is observed. Dissolution of 1 in pH 7.4 buffer or in unbuffered water at temperatures above 50 °C results in monomeric complex (1M; λ = 367 nm) linked through intramolecular NH···S bonds. DFT computations indicate a low energy barrier between 1A and 1M with nearly identical frontier MOs and Ni-ligand metrics. Notably, 1A and 1M exhibit remarkable stability in protic solvents such as MeOH and H2O, in stark contrast to monometallic [NiII(nmp)(SR)]- complexes. The reactivity of 1 with excess O2, H2O2, and O2•- is species-dependent. IR and UV-vis reveal that 1A in MeOH reacts with excess O2 to yield an S-bound sulfinate, but does not react with O2•-. In contrast, 1M is stable to O2 in pH 7.4 buffer, but reacts with O2•- to yield a putative [NiII(nmp)(O2)]- complex from release of the BTA-thiolate based on EPR.
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Affiliation(s)
- Ramsey A Steiner
- Department of Chemistry and Center for Metalloenzyme Studies, The University of Georgia , 140 Cedar St, Athens, Georgia 30602, United States
| | - Stephen P Dzul
- Departments of Pharmaceutical Sciences, and Biochemistry and Molecular Biology, Wayne State University , Detroit, Michigan 48201, United States
| | - Timothy L Stemmler
- Departments of Pharmaceutical Sciences, and Biochemistry and Molecular Biology, Wayne State University , Detroit, Michigan 48201, United States
| | - Todd C Harrop
- Department of Chemistry and Center for Metalloenzyme Studies, The University of Georgia , 140 Cedar St, Athens, Georgia 30602, United States
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19
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Meier KK, Rogers MS, Kovaleva EG, Lipscomb JD, Bominaar EL, Münck E. Enzyme Substrate Complex of the H200C Variant of Homoprotocatechuate 2,3-Dioxygenase: Mössbauer and Computational Studies. Inorg Chem 2016; 55:5862-70. [PMID: 27275865 PMCID: PMC4924929 DOI: 10.1021/acs.inorgchem.6b00148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The extradiol, aromatic ring-cleaving enzyme homoprotocatechuate 2,3-dioxygenase (HPCD) catalyzes a complex chain of reactions that involve second sphere residues of the active site. The importance of the second-sphere residue His200 was demonstrated in studies of HPCD variants, such as His200Cys (H200C), which revealed significant retardations of certain steps in the catalytic process as a result of the substitution, allowing novel reaction cycle intermediates to be trapped for spectroscopic characterization. As the H200C variant largely retains the wild-type active site structure and produces the correct ring-cleaved product, this variant presents a valuable target for mechanistic HPCD studies. Here, the high-spin Fe(II) states of resting H200C and the H200C-homoprotocatechuate enzyme-substrate (ES) complex have been characterized with Mössbauer spectroscopy to assess the electronic structures of the active site in these states. The analysis reveals a high-spin Fe(II) center in a low symmetry environment that is reflected in the values of the zero-field splitting (ZFS) (D ≈ - 8 cm(-1), E/D ≈ 1/3 in ES), as well as the relative orientations of the principal axes of the (57)Fe magnetic hyperfine (A) and electric field gradient (EFG) tensors relative to the ZFS tensor axes. A spin Hamiltonian analysis of the spectra for the ES complex indicates that the magnetization axis of the integer-spin S = 2 Fe(II) system is nearly parallel to the symmetry axis, z, of the doubly occupied dxy ground orbital deduced from the EFG and A-values, an observation, which cannot be rationalized by DFT assisted crystal-field theory. In contrast, ORCA/CASSCF calculations for the ZFS tensor in combination with DFT calculations for the EFG- and A-tensors describe the experimental data remarkably well.
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Affiliation(s)
- Katlyn K. Meier
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Melanie S. Rogers
- Department of Biochemistry, Molecular Biology and Biophysics and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Elena G. Kovaleva
- Stanford Synchrotron Radiation Lightsource, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - John D. Lipscomb
- Department of Biochemistry, Molecular Biology and Biophysics and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Emile L. Bominaar
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Eckard Münck
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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20
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Nóbrega CS, Saraiva IH, Carreira C, Devreese B, Matzapetakis M, Pauleta SR. The solution structure of the soluble form of the lipid-modified azurin from Neisseria gonorrhoeae , the electron donor of cytochrome c peroxidase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:169-176. [DOI: 10.1016/j.bbabio.2015.11.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 10/25/2015] [Accepted: 11/13/2015] [Indexed: 12/26/2022]
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21
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22
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Flores M, Olson TL, Wang D, Edwardraja S, Shinde S, Williams JC, Ghirlanda G, Allen JP. Copper Environment in Artificial Metalloproteins Probed by Electron Paramagnetic Resonance Spectroscopy. J Phys Chem B 2015. [DOI: 10.1021/acs.jpcb.5b04172] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Marco Flores
- Department
of Chemistry and
Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Tien L. Olson
- Department
of Chemistry and
Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Dong Wang
- Department
of Chemistry and
Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Selvakumar Edwardraja
- Department
of Chemistry and
Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Sandip Shinde
- Department
of Chemistry and
Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - JoAnn C. Williams
- Department
of Chemistry and
Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Giovanna Ghirlanda
- Department
of Chemistry and
Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - James P. Allen
- Department
of Chemistry and
Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
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23
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Manesis AC, Shafaat HS. Electrochemical, Spectroscopic, and Density Functional Theory Characterization of Redox Activity in Nickel-Substituted Azurin: A Model for Acetyl-CoA Synthase. Inorg Chem 2015; 54:7959-67. [PMID: 26234790 DOI: 10.1021/acs.inorgchem.5b01103] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Nickel-containing enzymes are key players in global hydrogen, carbon dioxide, and methane cycles. Many of these enzymes rely on Ni(I) oxidation states in critical catalytic intermediates. However, due to the highly reactive nature of these species, their isolation within metalloenzymes has often proved elusive. In this report, we describe and characterize a model biological Ni(I) species that has been generated within the electron transfer protein, azurin. Replacement of the native copper cofactor with nickel is shown to preserve the redox activity of the protein. The Ni(II/I) couple is observed at -590 mV versus NHE, with an interfacial electron transfer rate of 70 s(-1). Chemical reduction of Ni(II)Az generates a stable species with strong absorption features at 350 nm and a highly anisotropic, axial EPR signal with principal g-values of 2.56 and 2.10. Density functional theory calculations provide insight into the electronic and geometric structure of the Ni(I) species, suggesting a trigonal planar coordination environment. The predicted spectroscopic features of this low-coordinate nickel site are in good agreement with the experimental data. Molecular orbital analysis suggests potential for both metal-centered and ligand-centered reactivity, highlighting the covalency of the metal-thiolate bond. Characterization of a stable Ni(I) species within a model protein has implications for understanding the mechanisms of complex enzymes, including acetyl coenzyme A synthase, and developing scaffolds for unique reactivity.
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24
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Pordea A. Metal-binding promiscuity in artificial metalloenzyme design. Curr Opin Chem Biol 2015; 25:124-32. [PMID: 25603469 DOI: 10.1016/j.cbpa.2014.12.035] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 12/16/2014] [Accepted: 12/18/2014] [Indexed: 01/16/2023]
Abstract
This review presents recent examples of metal-binding promiscuity in protein scaffolds and highlights the effect of metal variation on catalytic functionality. Naturally evolved binding sites, as well as unnatural amino acids and cofactors can bind a diverse range of metals, including non-biological transition elements. Computational screening and rational design have been successfully used to create promiscuous binding-sites. Incorporation of non-native metals into proteins expands the catalytic range of transformations catalysed by enzymes and enhances their potential for application in chemicals synthesis.
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Affiliation(s)
- Anca Pordea
- Department of Chemical and Environmental Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.
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25
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Liu J, Meier KK, Tian S, Zhang JL, Guo H, Schulz CE, Robinson H, Nilges MJ, Münck E, Lu Y. Redesigning the blue copper azurin into a redox-active mononuclear nonheme iron protein: preparation and study of Fe(II)-M121E azurin. J Am Chem Soc 2014; 136:12337-44. [PMID: 25082811 DOI: 10.1021/ja505410u] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Much progress has been made in designing heme and dinuclear nonheme iron enzymes. In contrast, engineering mononuclear nonheme iron enzymes is lagging, even though these enzymes belong to a large class that catalyzes quite diverse reactions. Herein we report spectroscopic and X-ray crystallographic studies of Fe(II)-M121E azurin (Az), by replacing the axial Met121 and Cu(II) in wild-type azurin (wtAz) with Glu and Fe(II), respectively. In contrast to the redox inactive Fe(II)-wtAz, the Fe(II)-M121EAz mutant can be readily oxidized by Na2IrCl6, and interestingly, the protein exhibits superoxide scavenging activity. Mössbauer and EPR spectroscopies, along with X-ray structural comparisons, revealed similarities and differences between Fe(II)-M121EAz, Fe(II)-wtAz, and superoxide reductase (SOR) and allowed design of the second generation mutant, Fe(II)-M121EM44KAz, that exhibits increased superoxide scavenging activity by 2 orders of magnitude. This finding demonstrates the importance of noncovalent secondary coordination sphere interactions in fine-tuning enzymatic activity.
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Affiliation(s)
- Jing Liu
- Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
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26
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Weber K, Erdem ÖF, Bill E, Weyhermüller T, Lubitz W. Modeling the Active Site of [NiFe] Hydrogenases and the [NiFeu] Subsite of the C-Cluster of Carbon Monoxide Dehydrogenases: Low-Spin Iron(II) Versus High-Spin Iron(II). Inorg Chem 2014; 53:6329-37. [DOI: 10.1021/ic500910z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Katharina Weber
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Özlen F. Erdem
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Eckhard Bill
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Thomas Weyhermüller
- 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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27
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Tobin PH, Wilson CJ. Examining Photoinduced Energy Transfer in Pseudomonas aeruginosa Azurin. J Am Chem Soc 2014; 136:1793-802. [DOI: 10.1021/ja412308r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Peter H. Tobin
- Department
of Chemical and Environmental Engineering, ‡Department of Biomedical
Engineering, and §Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8286, United States
| | - Corey J. Wilson
- Department
of Chemical and Environmental Engineering, ‡Department of Biomedical
Engineering, and §Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8286, United States
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28
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Davydov RM, McLaughlin MP, Bill E, Hoffman BM, Holland PL. Generation of high-spin iron(I) in a protein environment using cryoreduction. Inorg Chem 2013; 52:7323-5. [PMID: 24004284 DOI: 10.1021/ic4011339] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
High-spin Fe(1+) sites are potentially important in iron-sulfur proteins but are rare in synthetic compounds and unknown in metalloproteins. Here, we demonstrate a spectroscopically characterized example of high-spin non-heme Fe(1+) in a protein environment. Cryoreduction of Fe(2+)-substituted azurin at 77 K with (60)Co γ radiation generates a new species with a S = (3)/2 (high-spin) Fe(1+) center having D > 0 and E/D ~ 0.25. This transient species is stable in a glycerol-water glass only up to ~170 K. A combination of electron paramagnetic resonance and Mössbauer spectroscopies provides a powerful means of identifying a transient high-spin Fe(1+) site in a protein scaffold.
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Affiliation(s)
- Roman M Davydov
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
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