1
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Ríos P, See MS, Gonzalez O, Handford RC, Nicolay A, Rao G, Britt RD, Bediako DK, Tilley TD. Iron homo- and heterobimetallic complexes supported by a symmetrical dinucleating ligand. Chem Commun (Camb) 2024; 60:8912-8915. [PMID: 39091216 DOI: 10.1039/d4cc02155j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
The selective synthesis of biomimetic Fe/Mn complexes able to mimic the geometry and catalytic activity of enzymes possessing this cofactor is still a challenge. Herein, we discuss the stepwise synthesis, characterization, and magnetic properties of a Fe(II)/Mn(II) species and related Fe(II)/Fe(II) complexes.
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Affiliation(s)
- Pablo Ríos
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica, Centro de Innovación en Química Avanzada (ORFEO-CINQA), CSIC and Universidad de Sevilla, 41092 Sevilla, Spain
- Department of Chemistry, University of California Berkeley, Berkeley, USA.
| | - Matthew S See
- Department of Chemistry, University of California Berkeley, Berkeley, USA.
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Oscar Gonzalez
- Department of Chemistry, University of California Berkeley, Berkeley, USA.
| | - Rex C Handford
- Department of Chemistry, University of California Berkeley, Berkeley, USA.
| | - Amélie Nicolay
- Department of Chemistry, University of California Berkeley, Berkeley, USA.
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Guodong Rao
- Department of Chemistry, University of California, Davis, Davis, California 95616, USA.
| | - R David Britt
- Department of Chemistry, University of California, Davis, Davis, California 95616, USA.
| | - D Kwabena Bediako
- Department of Chemistry, University of California Berkeley, Berkeley, USA.
| | - T Don Tilley
- Department of Chemistry, University of California Berkeley, Berkeley, USA.
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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2
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Škerlová J, Brynda J, Šobotník J, Zákopčaník M, Novák P, Bourguignon T, Sillam-Dussès D, Řezáčová P. Crystal structure of blue laccase BP76, a unique termite suicidal defense weapon. Structure 2024:S0969-2126(24)00278-8. [PMID: 39151418 DOI: 10.1016/j.str.2024.07.015] [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: 01/12/2024] [Revised: 06/21/2024] [Accepted: 07/22/2024] [Indexed: 08/19/2024]
Abstract
Aging workers of the termite Neocapritermes taracua can defend their colony by sacrificing themselves by body rupture, mixing the externally stored blue laccase BP76 with hydroquinones to produce a sticky liquid rich in toxic benzoquinones. Here, we describe the crystal structure of BP76 isolated from N. taracua in its native form. The structure reveals several stabilization strategies, including compact folding, glycosylation, and flexible loops with disulfide bridges and tight dimer interface. The remarkable stability of BP76 maintains its catalytic activity in solid state during the lifespan of N. taracua workers, providing old workers with an efficient defensive weapon to protect their colony.
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Affiliation(s)
- Jana Škerlová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 160 00 Prague, Czech Republic
| | - Jiří Brynda
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 160 00 Prague, Czech Republic
| | - Jan Šobotník
- Faculty of Tropical AgriSciences, Czech University of Life Sciences, 165 00 Prague, Czech Republic; Institute of Entomology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czech Republic
| | - Marek Zákopčaník
- Institute of Microbiology, Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Petr Novák
- Institute of Microbiology, Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Thomas Bourguignon
- Okinawa Institute of Science and Technology Graduate University, Okinawa 904-0495, Japan
| | - David Sillam-Dussès
- Laboratory of Experimental and Comparative Ethology, UR 4443, Université Sorbonne Paris Nord, 93430 Villetaneuse, France
| | - Pavlína Řezáčová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 160 00 Prague, Czech Republic.
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3
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Lee JL, Biswas S, Ziller JW, Bominaar EL, Hendrich MP, Borovik AS. Accessing a synthetic Fe IIIMn IV core to model biological heterobimetallic active sites. Chem Sci 2024; 15:2817-2826. [PMID: 38404374 PMCID: PMC10882444 DOI: 10.1039/d3sc04900k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 12/22/2023] [Indexed: 02/27/2024] Open
Abstract
Metalloproteins with dinuclear cores are known to bind and activate dioxygen, with a subclass of these proteins having active sites containing FeMn cofactors and activities ranging from long-range proton-coupled electron transfer (PCET) to post-translational peptide modification. While mechanistic studies propose that these metallocofactors access FeIIIMnIV intermediates, there is a dearth of related synthetic analogs. Herein, the first well-characterized synthetic FeIII-(μ-O)-MnIV complex is reported; this complex shows similar spectroscopic features as the catalytically competent FeIIIMnIV intermediate X found in Class Ic ribonucleotide reductase and demonstrates PCET function towards phenolic substrates. This complex is prepared from the oxidation of the isolable FeIII-(μ-O)-MnIII species, whose stepwise assembly is facilitated by a tripodal ligand containing phosphinic amido groups. Structural and spectroscopic studies found proton movement involving the FeIIIMnIII core, whereby the initial bridging hydroxido ligand is converted to an oxido ligand with concomitant protonation of one phosphinic amido group. This series of FeMn complexes allowed us to address factors that may dictate the preference of an active site for a heterobimetallic cofactor over one that is homobimetallic: comparisons of the redox properties of our FeMn complexes with those of the di-Fe analogs suggested that the relative thermodynamic ease of accessing an FeIIIMnIV core can play an important role in determining the metal ion composition when the key catalytic steps do not require an overly potent oxidant. Moreover, these complexes allowed us to demonstrate the effect of the hyperfine interaction from non-Fe nuclei on 57Fe Mössbauer spectra which is relevant to MnFe intermediates in proteins.
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Affiliation(s)
- Justin L Lee
- Department of Chemistry, University of California-Irvine Irvine CA 92697 USA
| | - Saborni Biswas
- Department of Chemistry, Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Joseph W Ziller
- Department of Chemistry, University of California-Irvine Irvine CA 92697 USA
| | - Emile L Bominaar
- Department of Chemistry, Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Michael P Hendrich
- Department of Chemistry, Carnegie Mellon University Pittsburgh PA 15213 USA
| | - A S Borovik
- Department of Chemistry, University of California-Irvine Irvine CA 92697 USA
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4
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Nithimethachoke T, Boonmak C, Morikawa M. A novel alkane monooxygenase evolved from a broken piece of ribonucleotide reductase in Geobacillus kaustophilus HTA426 isolated from Mariana Trench. Extremophiles 2024; 28:18. [PMID: 38353731 PMCID: PMC10867098 DOI: 10.1007/s00792-024-01332-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Accepted: 12/30/2023] [Indexed: 02/16/2024]
Abstract
We have accidentally found that a thermophilic Geobacillus kaustophilus HTA426 is capable of degrading alkanes although it has no alkane oxygenating enzyme genes. Our experimental results revealed that a putative ribonucleotide reductase small subunit GkR2loxI (GK2771) gene encodes a novel heterodinuclear Mn-Fe alkane monooxygenase/hydroxylase. GkR2loxI protein can perform two-electron oxidations similar to homonuclear diiron bacterial multicomponent soluble methane monooxygenases. This finding not only answers a long-standing question about the substrate of the R2lox protein clade, but also expands our understanding of the vast diversity and new evolutionary lineage of the bacterial alkane monooxygenase/hydroxylase family.
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Affiliation(s)
- Tanasap Nithimethachoke
- Graduate School of Environmental Science, Hokkaido University, Kita-10 Nishi-5, Kita-ku, Sapporo, 060-0810, Japan
| | - Chanita Boonmak
- Department of Microbiology, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Rd., Lat Yao, Chatuchak, Bangkok, 10900, Thailand
| | - Masaaki Morikawa
- Graduate School of Environmental Science, Hokkaido University, Kita-10 Nishi-5, Kita-ku, Sapporo, 060-0810, Japan.
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5
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Ibrahim IH. Metalloproteins and metalloproteomics in health and disease. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2024; 141:123-176. [PMID: 38960472 DOI: 10.1016/bs.apcsb.2023.12.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Metalloproteins represents more than one third of human proteome, with huge variation in physiological functions and pathological implications, depending on the metal/metals involved and tissue context. Their functions range from catalysis, bioenergetics, redox, to DNA repair, cell proliferation, signaling, transport of vital elements, and immunity. The human metalloproteomic studies revealed that many families of metalloproteins along with individual metalloproteins are dysregulated under several clinical conditions. Also, several sorts of interaction between redox- active or redox- inert metalloproteins are observed in health and disease. Metalloproteins profiling shows distinct alterations in neurodegenerative diseases, cancer, inflammation, infection, diabetes mellitus, among other diseases. This makes metalloproteins -either individually or as families- a promising target for several therapeutic approaches. Inhibitors and activators of metalloenzymes, metal chelators, along with artificial metalloproteins could be versatile in diagnosis and treatment of several diseases, in addition to other biomedical and industrial applications.
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Affiliation(s)
- Iman Hassan Ibrahim
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy (Girls), Al-Azhar University, Cairo, Egypt.
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6
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Liu C, Powell MM, Rao G, Britt RD, Rittle J. Bioinformatic Discovery of a Cambialistic Monooxygenase. J Am Chem Soc 2024; 146:1783-1788. [PMID: 38198693 PMCID: PMC10811679 DOI: 10.1021/jacs.3c12131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/05/2024] [Accepted: 01/08/2024] [Indexed: 01/12/2024]
Abstract
Dinuclear monooxygenases mediate challenging C-H bond oxidation reactions throughout nature. Many of these enzymes are presumed to exclusively utilize diiron cofactors. Herein we report the bioinformatic discovery of an orphan dinuclear monooxygenase that preferentially utilizes a heterobimetallic manganese-iron (Mn/Fe) cofactor to mediate an O2-dependent C-H bond hydroxylation reaction. Unlike the structurally similar Mn/Fe-dependent monooxygenase AibH2, the diiron form of this enzyme (SfbO) exhibits a nascent enzymatic activity. This behavior raises the possibility that many other dinuclear monooxygenases may be endowed with the capacity to harness cofactors with a variable metal content.
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Affiliation(s)
- Chang Liu
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California 94720, United States
| | - Magan M. Powell
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California 94720, United States
| | - Guodong Rao
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - R. David Britt
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - Jonathan Rittle
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California 94720, United States
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7
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Powell M, Rao G, Britt RD, Rittle J. Enzymatic Hydroxylation of Aliphatic C-H Bonds by a Mn/Fe Cofactor. J Am Chem Soc 2023; 145:16526-16537. [PMID: 37471626 PMCID: PMC10401708 DOI: 10.1021/jacs.3c03419] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Indexed: 07/22/2023]
Abstract
The aerobic oxidation of carbon-hydrogen (C-H) bonds in biology is currently known to be accomplished by a limited set of cofactors that typically include heme, nonheme iron, and copper. While manganese cofactors perform difficult oxidation reactions, including water oxidation within Photosystem II, they are generally not known to be used for C-H bond activation, and those that do catalyze this important reaction display limited intrinsic reactivity. Here we report that the 2-aminoisobutyric acid hydroxylase from Rhodococcus wratislaviensis, AibH1H2, requires manganese to functionalize a strong, aliphatic C-H bond (BDE = 100 kcal/mol). Structural and spectroscopic studies of this enzyme reveal a redox-active, heterobimetallic manganese-iron active site at the locus of O2 activation and substrate coordination. This result expands the known reactivity of biological manganese-iron cofactors, which was previously restricted to single-electron transfer or stoichiometric protein oxidation. Furthermore, the AibH1H2 cofactor is supported by a protein fold distinct from typical bimetallic oxygenases, and bioinformatic analyses identify related proteins abundant in microorganisms. This suggests that many uncharacterized monooxygenases may similarly require manganese to perform oxidative biochemical tasks.
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Affiliation(s)
- Magan
M. Powell
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California 94720, United States
| | - Guodong Rao
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - R. David Britt
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - Jonathan Rittle
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California 94720, United States
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8
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Gaynor RB, McIntyre BN, Lindsey SL, Clavo KA, Shy WE, Mees DE, Mu G, Donnadieu B, Creutz SE. Steric Effects on the Chelation of Mn 2+ and Zn 2+ by Hexadentate Polyimidazole Ligands: Modeling Metal Binding by Calprotectin Site 2. Chemistry 2023; 29:e202300447. [PMID: 37067464 PMCID: PMC10640917 DOI: 10.1002/chem.202300447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/14/2023] [Accepted: 04/17/2023] [Indexed: 04/18/2023]
Abstract
Recently, there has been increasing interest in the design of ligands that bind Mn2+ with high affinity and selectivity, but this remains a difficult challenge. It has been proposed that the cavity size of the binding pocket is a critical factor in most synthetic and biological examples of selective Mn2+ binding. Here, we use a bioinspired approach adapted from the hexahistidine binding site of the manganese-sequestering protein calprotectin to systematically study the effect of cavity size on Mn2+ and Zn2+ binding. We have designed a hexadentate, trisimidazole ligand whose cavity size can be tuned through peripheral modification of the steric bulk of the imidazole substituents. Conformational dynamics and redox potentials of the complexes are dependent on ligand steric bulk. Stability constants are consistent with the hypothesis that larger ligand cavities are relatively favorable for Mn2+ over Zn2+ , but this effect alone may not be sufficient to achieve Mn2+ selectivity.
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Affiliation(s)
- Ryan B Gaynor
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Baylee N McIntyre
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Shelby L Lindsey
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Kaylee A Clavo
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - William E Shy
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - David E Mees
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Ge Mu
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Bruno Donnadieu
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Sidney E Creutz
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762, USA
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9
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Powell MM, Rao G, Britt RD, Rittle J. Enzymatic Hydroxylation of Aliphatic C-H Bonds by a Mn/Fe Cofactor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.10.532131. [PMID: 36945426 PMCID: PMC10029006 DOI: 10.1101/2023.03.10.532131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
Manganese cofactors activate strong chemical bonds in many essential enzymes. Yet very few manganese-dependent enzymes are known to functionalize ubiquitous carbon-hydrogen (C-H) bonds, and those that catalyze this important reaction display limited intrinsic reactivity. Herein, we report that the 2-aminoisobutyric acid hydroxylase from Rhodococcus wratislaviensis requires manganese to functionalize a C-H bond possessing a bond dissociation enthalpy (BDE) exceeding 100 kcal/mol. Structural and spectroscopic studies of this enzyme reveal a redox-active, heterobimetallic manganese-iron active site that utilizes a manganese ion at the locus for O 2 activation and substrate coordination. Accordingly, this enzyme represents the first documented Mn-dependent monooxygenase in biology. Related proteins are widespread in microorganisms suggesting that many uncharacterized monooxygenases may utilize manganese-containing cofactors to accomplish diverse biological tasks.
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10
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Poptic AL, Chen YP, Chang T, Chen YS, Moore CE, Zhang S. Site-Differentiated Mn IIFe II Complex Reproducing the Selective Assembly of Biological Heterobimetallic Mn/Fe Cofactors. J Am Chem Soc 2023; 145:3491-3498. [PMID: 36749207 DOI: 10.1021/jacs.2c11930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Class Ic ribonucleotide reductases (RNRIc) and R2-like ligand-binding oxidases (R2lox) are known to contain heterobimetallic MnIIFeII cofactors. How these enzymes assemble MnIIFeII cofactors has been a long-standing puzzle due to the weaker binding affinity of MnII versus FeII. In addition, the heterobimetallic selectivity of RNRIc and R2lox has yet to be reproduced with coordination complexes, leading to the hypothesis that RNRIc and R2lox overcome the thermodynamic preference for coordination of FeII over MnII with their carefully constructed three-dimensional protein structures. Herein, we report the selective formation of a heterobimetallic MnIIFeII complex accomplished in the absence of a protein scaffold. Treatment of the ligand Py4DMcT (L) with equimolar amounts of FeII and MnII along with two equivalents of acetate (OAc) affords [LMnIIFeII (OAc)2(OTf)]+ (MnIIFeII) in 80% yield, while the diiron complex [LFeIIFeII(OAc)2(OTf)]+ (FeIIFeII) is produced in only 8% yield. The formation of MnIIFeII is favored regardless of the order of addition of FeII and MnII sources. X-ray diffraction (XRD) of single crystals of MnIIFeII reveals an unsymmetrically coordinated carboxylate ligand─a primary coordination sphere feature shared by both RNRIc and R2lox that differentiates the two metal binding sites. Anomalous XRD studies confirm that MnIIFeII exhibits the same site selectivity as R2lox and RNRIc, with the FeII (d6) center preferentially occupying the distorted octahedral site. We conclude that the successful assembly of MnIIFeII originates from (1) Fe-deficient conditions, (2) site differentiation, and (3) the inability of ligand L to house a dimanganese complex.
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Affiliation(s)
- Anna L Poptic
- Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Ying-Pin Chen
- ChemMatCARS, University of Chicago, Argonne, Illinois 60439, United States
| | - Tieyan Chang
- ChemMatCARS, University of Chicago, Argonne, Illinois 60439, United States
| | - Yu-Sheng Chen
- ChemMatCARS, University of Chicago, Argonne, Illinois 60439, United States
| | - Curtis E Moore
- Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Shiyu Zhang
- Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
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11
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Čapek J, Večerek B. Why is manganese so valuable to bacterial pathogens? Front Cell Infect Microbiol 2023; 13:943390. [PMID: 36816586 PMCID: PMC9936198 DOI: 10.3389/fcimb.2023.943390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 01/04/2023] [Indexed: 02/05/2023] Open
Abstract
Apart from oxygenic photosynthesis, the extent of manganese utilization in bacteria varies from species to species and also appears to depend on external conditions. This observation is in striking contrast to iron, which is similar to manganese but essential for the vast majority of bacteria. To adequately explain the role of manganese in pathogens, we first present in this review that the accumulation of molecular oxygen in the Earth's atmosphere was a key event that linked manganese utilization to iron utilization and put pressure on the use of manganese in general. We devote a large part of our contribution to explanation of how molecular oxygen interferes with iron so that it enhances oxidative stress in cells, and how bacteria have learned to control the concentration of free iron in the cytosol. The functioning of iron in the presence of molecular oxygen serves as a springboard for a fundamental understanding of why manganese is so valued by bacterial pathogens. The bulk of this review addresses how manganese can replace iron in enzymes. Redox-active enzymes must cope with the higher redox potential of manganese compared to iron. Therefore, specific manganese-dependent isoenzymes have evolved that either lower the redox potential of the bound metal or use a stronger oxidant. In contrast, redox-inactive enzymes can exchange the metal directly within the individual active site, so no isoenzymes are required. It appears that in the physiological context, only redox-inactive mononuclear or dinuclear enzymes are capable of replacing iron with manganese within the same active site. In both cases, cytosolic conditions play an important role in the selection of the metal used. In conclusion, we summarize both well-characterized and less-studied mechanisms of the tug-of-war for manganese between host and pathogen.
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Affiliation(s)
- Jan Čapek
- *Correspondence: Jan Čapek, ; Branislav Večerek,
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12
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Kisgeropoulos EC, Gan YJ, Greer SM, Hazel JM, Shafaat HS. Pulsed Multifrequency Electron Paramagnetic Resonance Spectroscopy Reveals Key Branch Points for One- vs Two-Electron Reactivity in Mn/Fe Proteins. J Am Chem Soc 2022; 144:11991-12006. [PMID: 35786920 DOI: 10.1021/jacs.1c13738] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Traditionally, the ferritin-like superfamily of proteins was thought to exclusively use a diiron active site in catalyzing a diverse array of oxygen-dependent reactions. In recent years, novel redox-active cofactors featuring heterobimetallic Mn/Fe active sites have been discovered in both the radical-generating R2 subunit of class Ic (R2c) ribonucleotide reductases (RNRs) and the related R2-like ligand-binding oxidases (R2lox). However, the protein-specific factors that differentiate the radical reactivity of R2c from the C-H activation reactions of R2lox remain unknown. In this work, multifrequency pulsed electron paramagnetic resonance (EPR) spectroscopy and ligand hyperfine techniques in conjunction with broken-symmetry density functional theory calculations are used to characterize the molecular and electronic structures of two EPR-active intermediates trapped during aerobic assembly of the R2lox Mn/Fe cofactor. A MnIII(μ-O)(μ-OH)FeIII species is identified as the first EPR-active species and represents a common state between the two classes of redox-active Mn/Fe proteins. The species downstream from the MnIII(μ-O)(μ-OH)FeIII state exhibits unique EPR properties, including unprecedented spectral breadth and isotope-dependent g-tensors, which are attributed to a weakly coupled, hydrogen-bonded MnIII(μ-OH)FeIII species. This final intermediate precedes formation of the MnIII/FeIII resting state and is suggested to be relevant to understanding the endogenous reactivity of R2lox.
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Affiliation(s)
- Effie C Kisgeropoulos
- The Ohio State Biochemistry Program, The Ohio State University, 100 W 18th Avenue, Columbus, Ohio 43210, United States
| | - Yunqiao J Gan
- Department of Chemistry and Biochemistry, The Ohio State University, 100 W 18th Avenue, Columbus, Ohio 43210, United States
| | - Samuel M Greer
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States.,Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Joseph M Hazel
- Department of Chemistry and Biochemistry, The Ohio State University, 100 W 18th Avenue, Columbus, Ohio 43210, United States
| | - Hannah S Shafaat
- The Ohio State Biochemistry Program, The Ohio State University, 100 W 18th Avenue, Columbus, Ohio 43210, United States.,Department of Chemistry and Biochemistry, The Ohio State University, 100 W 18th Avenue, Columbus, Ohio 43210, United States
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13
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Diamanti R, Srinivas V, Johansson A, Nordström A, Griese JJ, Lebrette H, Högbom M. Comparative structural analysis provides new insights into the function of R2-like ligand-binding oxidase. FEBS Lett 2022; 596:1600-1610. [PMID: 35175627 PMCID: PMC9314684 DOI: 10.1002/1873-3468.14319] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 02/10/2022] [Accepted: 02/14/2022] [Indexed: 11/11/2022]
Abstract
R2‐like ligand‐binding oxidase (R2lox) is a ferritin‐like protein that harbours a heterodinuclear manganese–iron active site. Although R2lox function is yet to be established, the enzyme binds a fatty acid ligand coordinating the metal centre and catalyses the formation of a tyrosine–valine ether cross‐link in the protein scaffold upon O2 activation. Here, we characterized the ligands copurified with R2lox by mass spectrometry‐based metabolomics. Moreover, we present the crystal structures of two new homologs of R2lox, from Saccharopolyspora erythraea and Sulfolobus acidocaldarius, at 1.38 Å and 2.26 Å resolution, respectively, providing the highest resolution structure for R2lox, as well as new insights into putative mechanisms regulating the function of the enzyme.
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Affiliation(s)
- Riccardo Diamanti
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Vivek Srinivas
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91, Stockholm, Sweden
| | | | | | - Julia J Griese
- Department of Cell and Molecular Biology, Uppsala University, SE-751 24, Uppsala, Sweden
| | - Hugo Lebrette
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91, Stockholm, Sweden.,Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062, Toulouse, France
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91, Stockholm, Sweden
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14
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Banerjee R, Srinivas V, Lebrette H. Ferritin-Like Proteins: A Conserved Core for a Myriad of Enzyme Complexes. Subcell Biochem 2022; 99:109-153. [PMID: 36151375 DOI: 10.1007/978-3-031-00793-4_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Ferritin-like proteins share a common fold, a four α-helix bundle core, often coordinating a pair of metal ions. Although conserved, the ferritin fold permits a diverse set of reactions, and is central in a multitude of macromolecular enzyme complexes. Here, we emphasize this diversity through three members of the ferritin-like superfamily: the soluble methane monooxygenase, the class I ribonucleotide reductase and the aldehyde deformylating oxygenase. They all rely on dinuclear metal cofactors to catalyze different challenging oxygen-dependent reactions through the formation of multi-protein complexes. Recent studies using cryo-electron microscopy, serial femtosecond crystallography at an X-ray free electron laser source, or single-crystal X-ray diffraction, have reported the structures of the active protein complexes, and revealed unprecedented insights into the molecular mechanisms of these three enzymes.
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Affiliation(s)
- Rahul Banerjee
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Vivek Srinivas
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Hugo Lebrette
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, UPS, Université de Toulouse, Toulouse, France.
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15
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Smethurst DGJ, Shcherbik N. Interchangeable utilization of metals: New perspectives on the impacts of metal ions employed in ancient and extant biomolecules. J Biol Chem 2021; 297:101374. [PMID: 34732319 PMCID: PMC8633580 DOI: 10.1016/j.jbc.2021.101374] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 10/25/2021] [Accepted: 10/28/2021] [Indexed: 02/08/2023] Open
Abstract
Metal ions provide considerable functionality across biological systems, and their utilization within biomolecules has adapted through changes in the chemical environment to maintain the activity they facilitate. While ancient earth's atmosphere was rich in iron and manganese and low in oxygen, periods of atmospheric oxygenation significantly altered the availability of certain metal ions, resulting in ion replacement within biomolecules. This adaptation mechanism has given rise to the phenomenon of metal cofactor interchangeability, whereby contemporary proteins and nucleic acids interact with multiple metal ions interchangeably, with different coordinated metals influencing biological activity, stability, and toxic potential. The ability of extant organisms to adapt to fluctuating metal availability remains relevant in a number of crucial biomolecules, including the superoxide dismutases of the antioxidant defense systems and ribonucleotide reductases. These well-studied and ancient enzymes illustrate the potential for metal interchangeability and adaptive utilization. More recently, the ribosome has also been demonstrated to exhibit interchangeable interactions with metal ions with impacts on function, stability, and stress adaptation. Using these and other examples, here we review the biological significance of interchangeable metal ions from a new angle that combines both biochemical and evolutionary viewpoints. The geochemical pressures and chemical properties that underlie biological metal utilization are discussed in the context of their impact on modern disease states and treatments.
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Affiliation(s)
- Daniel G J Smethurst
- Department for Cell Biology and Neuroscience, School of Osteopathic Medicine, Rowan University, Stratford, New Jersey, USA.
| | - Natalia Shcherbik
- Department for Cell Biology and Neuroscience, School of Osteopathic Medicine, Rowan University, Stratford, New Jersey, USA.
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16
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Jeoung JH, Rünger S, Haumann M, Neumann B, Klemke F, Davis V, Fischer A, Dau H, Wollenberger U, Dobbek H. Bimetallic Mn, Fe, Co, and Ni Sites in a Four-Helix Bundle Protein: Metal Binding, Structure, and Peroxide Activation. Inorg Chem 2021; 60:17498-17508. [PMID: 34757735 DOI: 10.1021/acs.inorgchem.1c01919] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bimetallic active sites in enzymes catalyze small-molecule conversions that are among the top 10 challenges in chemistry. As different metal cofactors are typically incorporated in varying protein scaffolds, it is demanding to disentangle the individual contributions of the metal and the protein matrix to the activity. Here, we compared the structure, properties, and hydrogen peroxide reactivity of four homobimetallic cofactors (Mn(II)2, Fe(II)2, Co(II)2, Ni(II)2) that were reconstituted into a four-helix bundle protein. Reconstituted proteins were studied in solution and in crystals. All metals bind with high affinity and yield similar cofactor structures. Cofactor variants react with H2O2 but differ in their turnover rates, accumulated oxidation states, and trapped peroxide-bound intermediates. Varying the metal composition thus creates opportunities to tune the reactivity of the bimetallic cofactor and to study and functionalize reactive species.
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Affiliation(s)
- Jae-Hun Jeoung
- Department of Biology, Strukturbiologie/Biochemie, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany
| | - Stefan Rünger
- Department of Biology, Strukturbiologie/Biochemie, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany
| | - Michael Haumann
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Bettina Neumann
- Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam, Germany
| | - Friederike Klemke
- Department of Biology, Strukturbiologie/Biochemie, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany
| | - Victoria Davis
- Institute for Inorganic and Analytical Chemistry (IAAC), Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany.,Freiburg Material Research Center (FMF), University of Freiburg, 79104 Freiburg, Germany.,Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79104 Freiburg, Germany.,Cluster of Excellence livMatS@FIT─Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79104 Freiburg, Germany
| | - Anna Fischer
- Institute for Inorganic and Analytical Chemistry (IAAC), Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany.,Freiburg Material Research Center (FMF), University of Freiburg, 79104 Freiburg, Germany.,Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79104 Freiburg, Germany.,Cluster of Excellence livMatS@FIT─Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79104 Freiburg, Germany
| | - Holger Dau
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Ulla Wollenberger
- Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam, Germany
| | - Holger Dobbek
- Department of Biology, Strukturbiologie/Biochemie, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany
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17
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Naughton KJ, Treviño RE, Moore PJ, Wertz AE, Dickson JA, Shafaat HS. In Vivo Assembly of a Genetically Encoded Artificial Metalloenzyme for Hydrogen Production. ACS Synth Biol 2021; 10:2116-2120. [PMID: 34370434 DOI: 10.1021/acssynbio.1c00177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The genetic encoding of artificial enzymes represents a substantial advantage relative to traditional molecular catalyst optimization, as laboratory-based directed evolution coupled with high-throughput screening methods can provide rapid development and functional characterization of enzyme libraries. However, these techniques have been of limited utility in the field of artificial metalloenzymes due to the need for in vitro cofactor metalation. Here, we report the development of methodology for in vivo production of nickel-substituted rubredoxin, an artificial metalloenzyme that is a structural, functional, and mechanistic mimic of the [NiFe] hydrogenases. Direct voltammetry on cell lysate establishes precedent for the development of an electrochemical screen. This technique will be broadly applicable to the in vivo generation of artificial metalloenzymes that require a non-native metal cofactor, offering a route for rapid enzyme optimization and setting the stage for integration of artificial metalloenzymes into biochemical pathways within diverse hosts.
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Affiliation(s)
- Kassandra J. Naughton
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Regina E. Treviño
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Peter J. Moore
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Ashlee E. Wertz
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - J. Alex Dickson
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Hannah S. Shafaat
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
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18
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Enhanced relative stability of heterobimetallic Fe(II), Zn(II), and Mg(II) clusters supported by a µ-phenoxo bridge. Inorganica Chim Acta 2020. [DOI: 10.1016/j.ica.2020.119547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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19
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Grāve K, Griese JJ, Berggren G, Bennett MD, Högbom M. The Bacillus anthracis class Ib ribonucleotide reductase subunit NrdF intrinsically selects manganese over iron. J Biol Inorg Chem 2020; 25:571-582. [PMID: 32296998 PMCID: PMC7239806 DOI: 10.1007/s00775-020-01782-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/22/2020] [Indexed: 01/30/2023]
Abstract
Abstract Correct protein metallation in the complex mixture of the cell is a prerequisite for metalloprotein function. While some metals, such as Cu, are commonly chaperoned, specificity towards metals earlier in the Irving–Williams series is achieved through other means, the determinants of which are poorly understood. The dimetal carboxylate family of proteins provides an intriguing example, as different proteins, while sharing a common fold and the same 4-carboxylate 2-histidine coordination sphere, are known to require either a Fe/Fe, Mn/Fe or Mn/Mn cofactor for function. We previously showed that the R2lox proteins from this family spontaneously assemble the heterodinuclear Mn/Fe cofactor. Here we show that the class Ib ribonucleotide reductase R2 protein from Bacillus anthracis spontaneously assembles a Mn/Mn cofactor in vitro, under both aerobic and anoxic conditions, when the metal-free protein is subjected to incubation with MnII and FeII in equal concentrations. This observation provides an example of a protein scaffold intrinsically predisposed to defy the Irving–Williams series and supports the assumption that the Mn/Mn cofactor is the biologically relevant cofactor in vivo. Substitution of a second coordination sphere residue changes the spontaneous metallation of the protein to predominantly form a heterodinuclear Mn/Fe cofactor under aerobic conditions and a Mn/Mn metal center under anoxic conditions. Together, the results describe the intrinsic metal specificity of class Ib RNR and provide insight into control mechanisms for protein metallation. Graphical Abstract ![]()
Electronic supplementary material The online version of this article (10.1007/s00775-020-01782-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kristīne Grāve
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 10691, Stockholm, Sweden
| | - Julia J Griese
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 10691, Stockholm, Sweden.,Department of Cell and Molecular Biology, Uppsala University, BMC, Box 596, 75124, Uppsala, Sweden
| | - Gustav Berggren
- Department of Chemistry, Ångström Laboratory, Uppsala University, Lägerhyddsvägen 1, 75120, Uppsala, Sweden
| | - Matthew D Bennett
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 10691, Stockholm, Sweden
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 10691, Stockholm, Sweden.
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20
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Kisgeropoulos EC, Griese JJ, Smith ZR, Branca RMM, Schneider CR, Högbom M, Shafaat HS. Key Structural Motifs Balance Metal Binding and Oxidative Reactivity in a Heterobimetallic Mn/Fe Protein. J Am Chem Soc 2020; 142:5338-5354. [PMID: 32062969 DOI: 10.1021/jacs.0c00333] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Heterobimetallic Mn/Fe proteins represent a new cofactor paradigm in bioinorganic chemistry and pose countless outstanding questions. The assembly of the active site defies common chemical convention by contradicting the Irving-Williams series, while the scope of reactivity remains unexplored. In this work, the assembly and C-H bond activation process in the Mn/Fe R2-like ligand-binding oxidase (R2lox) protein is investigated using a suite of biophysical techniques, including time-resolved optical spectroscopy, global kinetic modeling, X-ray crystallography, electron paramagnetic resonance spectroscopy, protein electrochemistry, and mass spectrometry. Selective metal binding is found to be under thermodynamic control, with the binding sites within the apo-protein exhibiting greater MnII affinity than FeII affinity. The comprehensive analysis of structure and reactivity of wild-type R2lox and targeted primary and secondary sphere mutants indicate that the efficiency of C-H bond activation directly correlates with the Mn/Fe cofactor reduction potentials and is inversely related to divalent metal binding affinity. These findings suggest the R2lox active site is precisely tuned for achieving both selective heterobimetallic binding and high levels of reactivity and offer a mechanism to examine the means by which proteins achieve appropriate metal incorporation.
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Affiliation(s)
| | - Julia J Griese
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.,Department of Cell and Molecular Biology, Uppsala University, SE-751 24 Uppsala, Sweden
| | | | - Rui M M Branca
- Department of Oncology-Pathology, Science for Life Laboratory, Karolinska Institutet, SE-171 21 Solna, Sweden
| | | | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
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21
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Mebs S, Srinivas V, Kositzki R, Griese JJ, Högbom M, Haumann M. Fate of oxygen species from O 2 activation at dimetal cofactors in an oxidase enzyme revealed by 57Fe nuclear resonance X-ray scattering and quantum chemistry. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:148060. [PMID: 31394094 DOI: 10.1016/j.bbabio.2019.148060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 07/30/2019] [Accepted: 08/02/2019] [Indexed: 10/26/2022]
Abstract
Oxygen (O2) activation is a central challenge in chemistry and catalyzed at prototypic dimetal cofactors in biological enzymes with diverse functions. Analysis of intermediates is required to elucidate the reaction paths of reductive O2 cleavage. An oxidase protein from the bacterium Geobacillus kaustophilus, R2lox, was used for aerobic in-vitro reconstitution with only 57Fe(II) or Mn(II) plus 57Fe(II) ions to yield [FeFe] or [MnFe] cofactors under various oxygen and solvent isotopic conditions including 16/18O and H/D exchange. 57Fe-specific X-ray scattering techniques were employed to collect nuclear forward scattering (NFS) and nuclear resonance vibrational spectroscopy (NRVS) data of the R2lox proteins. NFS revealed Fe/Mn(III)Fe(III) cofactor states and Mössbauer quadrupole splitting energies. Quantum chemical calculations of NRVS spectra assigned molecular structures, vibrational modes, and protonation patterns of the cofactors, featuring a terminal water (H2O) bound at iron or manganese in site 1 and a metal-bridging hydroxide (μOH-) ligand. A procedure for quantitation and correlation of experimental and computational NRVS difference signals due to isotope labeling was developed. This approach revealed that the protons of the ligands as well as the terminal water at the R2lox cofactors exchange with the bulk solvent whereas 18O from 18O2 cleavage is incorporated in the hydroxide bridge. In R2lox, the two water molecules from four-electron O2 reduction are released in a two-step reaction to the solvent. These results establish combined NRVS and QM/MM for tracking of iron-based oxygen activation in biological and chemical catalysts and clarify the reductive O2 cleavage route in an enzyme.
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Affiliation(s)
- Stefan Mebs
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Vivek Srinivas
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16, 10691 Stockholm, Sweden
| | - Ramona Kositzki
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Julia J Griese
- Department of Cell and Molecular Biology, Structural Biology, Uppsala University, Box 596, 75124 Uppsala, Sweden
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16, 10691 Stockholm, Sweden
| | - Michael Haumann
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
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22
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Kutin Y, Kositzki R, Branca RMM, Srinivas V, Lundin D, Haumann M, Högbom M, Cox N, Griese JJ. Chemical flexibility of heterobimetallic Mn/Fe cofactors: R2lox and R2c proteins. J Biol Chem 2019; 294:18372-18386. [PMID: 31591267 DOI: 10.1074/jbc.ra119.010570] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 10/04/2019] [Indexed: 11/06/2022] Open
Abstract
A heterobimetallic Mn/Fe cofactor is present in the R2 subunit of class Ic ribonucleotide reductases (R2c) and in R2-like ligand-binding oxidases (R2lox). Although the protein-derived metal ligands are the same in both groups of proteins, the connectivity of the two metal ions and the chemistry each cofactor performs are different: in R2c, a one-electron oxidant, the Mn/Fe dimer is linked by two oxygen bridges (μ-oxo/μ-hydroxo), whereas in R2lox, a two-electron oxidant, it is linked by a single oxygen bridge (μ-hydroxo) and a fatty acid ligand. Here, we identified a second coordination sphere residue that directs the divergent reactivity of the protein scaffold. We found that the residue that directly precedes the N-terminal carboxylate metal ligand is conserved as a glycine within the R2lox group but not in R2c. Substitution of the glycine with leucine converted the resting-state R2lox cofactor to an R2c-like cofactor, a μ-oxo/μ-hydroxo-bridged MnIII/FeIII dimer. This species has recently been observed as an intermediate of the oxygen activation reaction in WT R2lox, indicating that it is physiologically relevant. Cofactor maturation in R2c and R2lox therefore follows the same pathway, with structural and functional divergence of the two cofactor forms following oxygen activation. We also show that the leucine-substituted variant no longer functions as a two-electron oxidant. Our results reveal that the residue preceding the N-terminal metal ligand directs the cofactor's reactivity toward one- or two-electron redox chemistry, presumably by setting the protonation state of the bridging oxygens and thereby perturbing the redox potential of the Mn ion.
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Affiliation(s)
- Yury Kutin
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Ramona Kositzki
- Institut für Experimentalphysik, Freie Universität Berlin, D-14195 Berlin, Germany
| | - Rui M M Branca
- Cancer Proteomics Mass Spectrometry, Department of Oncology-Pathology, Science for Life Laboratory, Karolinska Institute, Box 1031, SE-171 21 Solna, Sweden
| | - Vivek Srinivas
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Daniel Lundin
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Michael Haumann
- Institut für Experimentalphysik, Freie Universität Berlin, D-14195 Berlin, Germany
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Nicholas Cox
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia.
| | - Julia J Griese
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden; Department of Cell and Molecular Biology, Uppsala University, SE-751 24 Uppsala, Sweden.
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23
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Xu H, Lebrette H, Clabbers MTB, Zhao J, Griese JJ, Zou X, Högbom M. Solving a new R2lox protein structure by microcrystal electron diffraction. SCIENCE ADVANCES 2019; 5:eaax4621. [PMID: 31457106 PMCID: PMC6685719 DOI: 10.1126/sciadv.aax4621] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 06/27/2019] [Indexed: 05/06/2023]
Abstract
Microcrystal electron diffraction (MicroED) has recently shown potential for structural biology. It enables the study of biomolecules from micrometer-sized 3D crystals that are too small to be studied by conventional x-ray crystallography. However, to date, MicroED has only been applied to redetermine protein structures that had already been solved previously by x-ray diffraction. Here, we present the first new protein structure-an R2lox enzyme-solved using MicroED. The structure was phased by molecular replacement using a search model of 35% sequence identity. The resulting electrostatic scattering potential map at 3.0-Å resolution was of sufficient quality to allow accurate model building and refinement. The dinuclear metal cofactor could be located in the map and was modeled as a heterodinuclear Mn/Fe center based on previous studies. Our results demonstrate that MicroED has the potential to become a widely applicable tool for revealing novel insights into protein structure and function.
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Affiliation(s)
- Hongyi Xu
- Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden
- Corresponding author. (H.X.); (M.H.); (X.Z.)
| | - Hugo Lebrette
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden
| | - Max T. B. Clabbers
- Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden
| | - Jingjing Zhao
- Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden
| | - Julia J. Griese
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden
- Department of Cell and Molecular Biology, Uppsala University, 75124 Uppsala, Sweden
| | - Xiaodong Zou
- Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden
- Corresponding author. (H.X.); (M.H.); (X.Z.)
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden
- Corresponding author. (H.X.); (M.H.); (X.Z.)
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24
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Griese JJ, Högbom M. Location-specific quantification of protein-bound metal ions by X-ray anomalous dispersion: Q-XAD. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2019; 75:764-771. [PMID: 31373575 DOI: 10.1107/s2059798319009926] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 07/10/2019] [Indexed: 12/18/2022]
Abstract
Here, a method is described which exploits X-ray anomalous dispersion (XAD) to quantify mixtures of metal ions in the binding sites of proteins and can be applied to metalloprotein crystals of average quality. This method has successfully been used to study site-specific metal binding in a protein from the R2-like ligand-binding oxidase family which assembles a heterodinuclear Mn/Fe cofactor. While previously only the relative contents of Fe and Mn in each metal-binding site have been assessed, here it is shown that the method can be extended to quantify the relative occupancies of at least three different transition metals, enabling complex competition experiments. The number of different metal ions that can be quantified is only limited by the number of high-quality anomalous data sets that can be obtained from one crystal, as one data set has to be collected for each transition-metal ion that is present (or is suspected to be present) in the protein, ideally at the absorption edge of each metal. A detailed description of the method, Q-XAD, is provided.
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Affiliation(s)
- Julia J Griese
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden
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25
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Bedin M, Agarwala H, Marx J, Schünemann V, Ott S, Thapper A. Synthesis and properties of a heterobimetallic iron-manganese complex and its comparison with homobimetallic analogues. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2019.03.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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26
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Schneider CR, Miller EK, Smith ZR, Shafaat HS. Electrochemical Investigation of R2lox, a Novel Class of Heterobimetallic Mn/Fe Protein. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.lb216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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27
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Griese JJ, Kositzki R, Haumann M, Högbom M. Assembly of a heterodinuclear Mn/Fe cofactor is coupled to tyrosine-valine ether cross-link formation in the R2-like ligand-binding oxidase. J Biol Inorg Chem 2019; 24:211-221. [PMID: 30689052 PMCID: PMC6399176 DOI: 10.1007/s00775-019-01639-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 01/18/2019] [Indexed: 11/28/2022]
Abstract
R2-like ligand-binding oxidases (R2lox) assemble a heterodinuclear Mn/Fe cofactor which performs reductive dioxygen (O2) activation, catalyzes formation of a tyrosine-valine ether cross-link in the protein scaffold, and binds a fatty acid in a putative substrate channel. We have previously shown that the N-terminal metal binding site 1 is unspecific for manganese or iron in the absence of O2, but prefers manganese in the presence of O2, whereas the C-terminal site 2 is specific for iron. Here, we analyze the effects of amino acid exchanges in the cofactor environment on cofactor assembly and metalation specificity using X-ray crystallography, X-ray absorption spectroscopy, and metal quantification. We find that exchange of either the cross-linking tyrosine or the valine, regardless of whether the mutation still allows cross-link formation or not, results in unspecific manganese or iron binding at site 1 both in the absence or presence of O2, while site 2 still prefers iron as in the wild-type. In contrast, a mutation that blocks binding of the fatty acid does not affect the metal specificity of either site under anoxic or aerobic conditions, and cross-link formation is still observed. All variants assemble a dinuclear trivalent metal cofactor in the aerobic resting state, independently of cross-link formation. These findings imply that the cross-link residues are required to achieve the preference for manganese in site 1 in the presence of O2. The metalation specificity, therefore, appears to be established during the redox reactions leading to cross-link formation.
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Affiliation(s)
- Julia J Griese
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden. .,Department of Cell and Molecular Biology, Uppsala University, 751 24, Uppsala, Sweden.
| | - Ramona Kositzki
- Institut für Experimentalphysik, Freie Universität Berlin, 14195, Berlin, Germany
| | - Michael Haumann
- Institut für Experimentalphysik, Freie Universität Berlin, 14195, Berlin, Germany
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden.
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28
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Griese JJ, Branca RMM, Srinivas V, Högbom M. Ether cross-link formation in the R2-like ligand-binding oxidase. J Biol Inorg Chem 2018; 23:879-886. [PMID: 29946980 PMCID: PMC6060897 DOI: 10.1007/s00775-018-1583-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 06/20/2018] [Indexed: 12/27/2022]
Abstract
R2-like ligand-binding oxidases contain a dinuclear metal cofactor which can consist either of two iron ions or one manganese and one iron ion, but the heterodinuclear Mn/Fe cofactor is the preferred assembly in the presence of MnII and FeII in vitro. We have previously shown that both types of cofactor are capable of catalyzing formation of a tyrosine–valine ether cross-link in the protein scaffold. Here we demonstrate that Mn/Fe centers catalyze cross-link formation more efficiently than Fe/Fe centers, indicating that the heterodinuclear cofactor is the biologically relevant one. We further explore the chemical potential of the Mn/Fe cofactor by introducing mutations at the cross-linking valine residue. We find that cross-link formation is possible also to the tertiary beta-carbon in an isoleucine, but not to the secondary beta-carbon or tertiary gamma-carbon in a leucine, nor to the primary beta-carbon of an alanine. These results illustrate that the reactivity of the cofactor is highly specific and directed.
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Affiliation(s)
- Julia J Griese
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden. .,Department of Cell and Molecular Biology, Uppsala University, 751 24, Uppsala, Sweden.
| | - Rui M M Branca
- Cancer Proteomics Mass Spectrometry, Department of Oncology-Pathology, Science for Life Laboratory, Karolinska Institutet, Box 1031, 171 21, Solna, Sweden
| | - Vivek Srinivas
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden.
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29
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Jasniewski AJ, Que L. Dioxygen Activation by Nonheme Diiron Enzymes: Diverse Dioxygen Adducts, High-Valent Intermediates, and Related Model Complexes. Chem Rev 2018; 118:2554-2592. [PMID: 29400961 PMCID: PMC5920527 DOI: 10.1021/acs.chemrev.7b00457] [Citation(s) in RCA: 304] [Impact Index Per Article: 50.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A growing subset of metalloenzymes activates dioxygen with nonheme diiron active sites to effect substrate oxidations that range from the hydroxylation of methane and the desaturation of fatty acids to the deformylation of fatty aldehydes to produce alkanes and the six-electron oxidation of aminoarenes to nitroarenes in the biosynthesis of antibiotics. A common feature of their reaction mechanisms is the formation of O2 adducts that evolve into more reactive derivatives such as diiron(II,III)-superoxo, diiron(III)-peroxo, diiron(III,IV)-oxo, and diiron(IV)-oxo species, which carry out particular substrate oxidation tasks. In this review, we survey the various enzymes belonging to this unique subset and the mechanisms by which substrate oxidation is carried out. We examine the nature of the reactive intermediates, as revealed by X-ray crystallography and the application of various spectroscopic methods and their associated reactivity. We also discuss the structural and electronic properties of the model complexes that have been found to mimic salient aspects of these enzyme active sites. Much has been learned in the past 25 years, but key questions remain to be answered.
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Affiliation(s)
- Andrew J. Jasniewski
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
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30
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Ardini M, Howes BD, Fiorillo A, Falvo E, Sottini S, Rovai D, Lantieri M, Ilari A, Gatteschi D, Spina G, Chiancone E, Stefanini S, Fittipaldi M. Study of manganese binding to the ferroxidase centre of human H-type ferritin. J Inorg Biochem 2018; 182:103-112. [PMID: 29454149 DOI: 10.1016/j.jinorgbio.2018.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/11/2018] [Accepted: 02/04/2018] [Indexed: 01/15/2023]
Abstract
Ferritins are ubiquitous and conserved proteins endowed with enzymatic ferroxidase activity, that oxidize Fe(II) ions at the dimetal ferroxidase centre to form a mineralized Fe(III) oxide core deposited within the apo-protein shell. Herein, the in vitro formation of a heterodimetal cofactor constituted by Fe and Mn ions has been investigated in human H ferritin (hHFt). Namely, Mn and Fe binding at the hHFt ferroxidase centre and its effects on Fe(II) oxidation have been investigated by UV-Vis ferroxidation kinetics, fluorimetric titrations, multifrequency EPR, and preliminary Mössbauer spectroscopy. Our results show that in hHFt, both Fe(II) and Mn(II) bind the ferroxidase centre forming a Fe-Mn cofactor. Moreover, molecular oxygen seems to favour Mn(II) binding and increases the ferroxidation activity of the Mn-loaded protein. The data suggest that Mn influences the Fe binding and the efficiency of the ferroxidation reaction. The higher efficiency of the Mn-Fe heterometallic centre may have a physiological relevance in specific cell types (i.e. glia cells), where the concentration of Mn is the same order of magnitude as iron.
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Affiliation(s)
- Matteo Ardini
- Department of Biochemical Sciences "A. Rossi-Fanelli", Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Barry D Howes
- INSTM, Department of Chemistry "U. Schiff", University of Florence, Via della Lastruccia, 3-13 50019 Sesto Fiorentino, Florence, Italy
| | - Annarita Fiorillo
- Department of Biochemical Sciences "A. Rossi-Fanelli", Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Elisabetta Falvo
- Department of Biochemical Sciences "A. Rossi-Fanelli", Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy; CNR-Institute of Molecular Biology and Pathology, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Silvia Sottini
- INSTM, Department of Chemistry "U. Schiff", University of Florence, Via della Lastruccia, 3-13 50019 Sesto Fiorentino, Florence, Italy
| | - Donella Rovai
- INSTM, Department of Chemistry "U. Schiff", University of Florence, Via della Lastruccia, 3-13 50019 Sesto Fiorentino, Florence, Italy
| | - Marco Lantieri
- ISC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Florence, Italy
| | - Andrea Ilari
- CNR-Institute of Molecular Biology and Pathology, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Dante Gatteschi
- INSTM, Department of Chemistry "U. Schiff", University of Florence, Via della Lastruccia, 3-13 50019 Sesto Fiorentino, Florence, Italy
| | - Gabriele Spina
- INSTM, Department of Physics and Astronomy, University of Florence, Via Sansone 1, 50019 Sesto Fiorentino, Florence, Italy
| | - Emilia Chiancone
- Department of Biochemical Sciences "A. Rossi-Fanelli", Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy; CNR-Institute of Molecular Biology and Pathology, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Simonetta Stefanini
- Department of Biochemical Sciences "A. Rossi-Fanelli", Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.
| | - Maria Fittipaldi
- INSTM, Department of Physics and Astronomy, University of Florence, Via Sansone 1, 50019 Sesto Fiorentino, Florence, Italy.
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31
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Maugeri PT, Griese JJ, Branca RM, Miller EK, Smith ZR, Eirich J, Högbom M, Shafaat HS. Driving Protein Conformational Changes with Light: Photoinduced Structural Rearrangement in a Heterobimetallic Oxidase. J Am Chem Soc 2018; 140:1471-1480. [PMID: 29268610 DOI: 10.1021/jacs.7b11966] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The heterobimetallic R2lox protein binds both manganese and iron ions in a site-selective fashion and activates oxygen, ultimately performing C-H bond oxidation to generate a tyrosine-valine cross-link near the active site. In this work, we demonstrate that, following assembly, R2lox undergoes photoinduced changes to the active site geometry and metal coordination motif. Through spectroscopic, structural, and mass spectrometric characterization, the photoconverted species is found to consist of a tyrosinate-bound iron center following light-induced decarboxylation of a coordinating glutamate residue and cleavage of the tyrosine-valine cross-link. This process occurs with high quantum efficiencies (Φ = 3%) using violet and near-ultraviolet light, suggesting that the photodecarboxylation is initiated via ligand-to-metal charge transfer excitation. Site-directed mutagenesis and structural analysis suggest that the cross-linked tyrosine-162 is the coordinating residue. One primary product is observed following irradiation, indicating potential use of this class of proteins, which contains a putative substrate channel, for controlled photoinduced decarboxylation processes, with relevance for in vivo functionality of R2lox as well as application in environmental remediation.
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Affiliation(s)
- Pearson T Maugeri
- Biophysics Graduate Program, The Ohio State University , Columbus, Ohio 43210, United States
| | - Julia J Griese
- Department of Biochemistry and Biophysics, Stockholm University , SE-106 91 Stockholm, Sweden
| | - Rui M Branca
- Department of Oncology-Pathology, Science for Life Laboratory, Karolinska Institutet , SE-17165 Stockholm, Sweden
| | - Effie K Miller
- Ohio State Biochemistry Program, The Ohio State University , Columbus, Ohio 43210, United States
| | - Zachary R Smith
- Department of Chemistry and Biochemistry, The Ohio State University , Columbus, Ohio 43210, United States
| | - Jürgen Eirich
- Department of Oncology-Pathology, Science for Life Laboratory, Karolinska Institutet , SE-17165 Stockholm, Sweden
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University , SE-106 91 Stockholm, Sweden
| | - Hannah S Shafaat
- Biophysics Graduate Program, The Ohio State University , Columbus, Ohio 43210, United States.,Ohio State Biochemistry Program, The Ohio State University , Columbus, Ohio 43210, United States.,Department of Chemistry and Biochemistry, The Ohio State University , Columbus, Ohio 43210, United States
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32
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Miller EK, Trivelas NE, Maugeri PT, Blaesi EJ, Shafaat HS. Time-Resolved Investigations of Heterobimetallic Cofactor Assembly in R2lox Reveal Distinct Mn/Fe Intermediates. Biochemistry 2017; 56:3369-3379. [PMID: 28574263 DOI: 10.1021/acs.biochem.7b00403] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The assembly mechanism of the Mn/Fe ligand-binding oxidases (R2lox), a family of proteins that are homologous to the nonheme diiron carboxylate enzymes, has been investigated using time-resolved techniques. Multiple heterobimetallic intermediates that exhibit unique spectral features, including visible absorption bands and exceptionally broad electron paramagnetic resonance signatures, are observed through optical and magnetic resonance spectroscopies. On the basis of comparison to known diiron species and model compounds, the spectra have been attributed to (μ-peroxo)-MnIII/FeIII and high-valent Mn/Fe species. Global spectral analysis coupled with isotopic substitution and kinetic modeling reveals elementary rate constants for the assembly of Mn/Fe R2lox under aerobic conditions. A complete reaction mechanism for cofactor maturation that is consistent with experimental data has been developed. These results suggest that the Mn/Fe cofactor can perform direct C-H bond abstraction, demonstrating the potential for potent chemical reactivity that remains unexplored.
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Affiliation(s)
| | | | | | - Elizabeth J Blaesi
- Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
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33
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Kositzki R, Mebs S, Marx J, Griese JJ, Schuth N, Högbom M, Schünemann V, Haumann M. Protonation State of MnFe and FeFe Cofactors in a Ligand-Binding Oxidase Revealed by X-ray Absorption, Emission, and Vibrational Spectroscopy and QM/MM Calculations. Inorg Chem 2016; 55:9869-9885. [PMID: 27610479 DOI: 10.1021/acs.inorgchem.6b01752] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Enzymes with a dimetal-carboxylate cofactor catalyze reactions among the top challenges in chemistry such as methane and dioxygen (O2) activation. Recently described proteins bind a manganese-iron cofactor (MnFe) instead of the classical diiron cofactor (FeFe). Determination of atomic-level differences of homo- versus hetero-bimetallic cofactors is crucial to understand their diverse redox reactions. We studied a ligand-binding oxidase from the bacterium Geobacillus kaustophilus (R2lox) loaded with a FeFe or MnFe cofactor, which catalyzes O2 reduction and an unusual tyrosine-valine ether cross-link formation, as revealed by X-ray crystallography. Advanced X-ray absorption, emission, and vibrational spectroscopy methods and quantum chemical and molecular mechanics calculations provided relative Mn/Fe contents, X-ray photoreduction kinetics, metal-ligand bond lengths, metal-metal distances, metal oxidation states, spin configurations, valence-level degeneracy, molecular orbital composition, nuclear quadrupole splitting energies, and vibrational normal modes for both cofactors. A protonation state with an axial water (H2O) ligand at Mn or Fe in binding site 1 and a metal-bridging hydroxo group (μOH) in a hydrogen-bonded network is assigned. Our comprehensive picture of the molecular, electronic, and dynamic properties of the cofactors highlights reorientation of the unique axis along the Mn-OH2 bond for the Mn1(III) Jahn-Teller ion but along the Fe-μOH bond for the octahedral Fe1(III). This likely corresponds to a more positive redox potential of the Mn(III)Fe(III) cofactor and higher proton affinity of its μOH group. Refined model structures for the Mn(III)Fe(III) and Fe(III)Fe(III) cofactors are presented. Implications of our findings for the site-specific metalation of R2lox and performance of the O2 reduction and cross-link formation reactions are discussed.
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Affiliation(s)
- Ramona Kositzki
- Fachbereich Physik, Freie Universität Berlin , 14195 Berlin, Germany
| | - Stefan Mebs
- Fachbereich Physik, Freie Universität Berlin , 14195 Berlin, Germany
| | - Jennifer Marx
- Fachbereich Physik, Technische Universität Kaiserslautern , 67663 Kaiserslautern, Germany
| | - Julia J Griese
- Department of Biochemistry and Biophysics, Stockholm University , 10691 Stockholm, Sweden
| | - Nils Schuth
- Fachbereich Physik, Freie Universität Berlin , 14195 Berlin, Germany
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University , 10691 Stockholm, Sweden.,Department of Chemistry, Stanford University , Stanford, California 94305, United States
| | - Volker Schünemann
- Fachbereich Physik, Technische Universität Kaiserslautern , 67663 Kaiserslautern, Germany
| | - Michael Haumann
- Fachbereich Physik, Freie Universität Berlin , 14195 Berlin, Germany
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34
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Kutin Y, Srinivas V, Fritz M, Kositzki R, Shafaat HS, Birrell J, Bill E, Haumann M, Lubitz W, Högbom M, Griese JJ, Cox N. Divergent assembly mechanisms of the manganese/iron cofactors in R2lox and R2c proteins. J Inorg Biochem 2016; 162:164-177. [PMID: 27138102 DOI: 10.1016/j.jinorgbio.2016.04.019] [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: 01/25/2016] [Revised: 04/04/2016] [Accepted: 04/12/2016] [Indexed: 01/22/2023]
Abstract
A manganese/iron cofactor which performs multi-electron oxidative chemistry is found in two classes of ferritin-like proteins, the small subunit (R2) of class Ic ribonucleotide reductase (R2c) and the R2-like ligand-binding oxidase (R2lox). It is unclear how a heterodimeric Mn/Fe metallocofactor is assembled in these two related proteins as opposed to a homodimeric Fe/Fe cofactor, especially considering the structural similarity and proximity of the two metal-binding sites in both protein scaffolds and the similar first coordination sphere ligand preferences of MnII and FeII. Using EPR and Mössbauer spectroscopies as well as X-ray anomalous dispersion, we examined metal loading and cofactor activation of both proteins in vitro (in solution). We find divergent cofactor assembly mechanisms for the two systems. In both cases, excess MnII promotes heterobimetallic cofactor assembly. In the absence of FeII, R2c cooperatively binds MnII at both metal sites, whereas R2lox does not readily bind MnII at either site. Heterometallic cofactor assembly is favored at substoichiometric FeII concentrations in R2lox. FeII and MnII likely bind to the protein in a stepwise fashion, with FeII binding to site 2 initiating cofactor assembly. In R2c, however, heterometallic assembly is presumably achieved by the displacement of MnII by FeII at site 2. The divergent metal loading mechanisms are correlated with the putative in vivo functions of R2c and R2lox, and most likely with the intracellular MnII/FeII concentrations in the host organisms from which they were isolated.
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Affiliation(s)
- Yuri Kutin
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Vivek Srinivas
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Matthieu Fritz
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ramona Kositzki
- Institut für Experimentalphysik, Freie Universität Berlin, D-14195 Berlin, Germany
| | - Hannah S Shafaat
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - James Birrell
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Eckhard Bill
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Michael Haumann
- Institut für Experimentalphysik, Freie Universität Berlin, D-14195 Berlin, Germany
| | - Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden; Department of Chemistry, Stanford University, Stanford, CA 94305, United States.
| | - Julia J Griese
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
| | - Nicholas Cox
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany; Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
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35
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Kerber WD, Goheen JT, Perez KA, Siegler MA. Enhanced Stability of the FeII/MnII State in a Synthetic Model of Heterobimetallic Cofactor Assembly. Inorg Chem 2015; 55:848-57. [DOI: 10.1021/acs.inorgchem.5b02322] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- William D. Kerber
- Department
of Chemistry, Bucknell University, Lewisburg, Pennsylvania 17837, United States
| | - Joshua T. Goheen
- Department
of Chemistry, Bucknell University, Lewisburg, Pennsylvania 17837, United States
| | - Kaitlyn A. Perez
- Department
of Chemistry, Bucknell University, Lewisburg, Pennsylvania 17837, United States
| | - Maxime A. Siegler
- Department
of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
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36
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Griese JJ, Kositzki R, Schrapers P, Branca RMM, Nordström A, Lehtiö J, Haumann M, Högbom M. Structural Basis for Oxygen Activation at a Heterodinuclear Manganese/Iron Cofactor. J Biol Chem 2015; 290:25254-72. [PMID: 26324712 PMCID: PMC4646176 DOI: 10.1074/jbc.m115.675223] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Revised: 08/24/2015] [Indexed: 12/31/2022] Open
Abstract
Two recently discovered groups of prokaryotic di-metal carboxylate proteins harbor a heterodinuclear Mn/Fe cofactor. These are the class Ic ribonucleotide reductase R2 proteins and a group of oxidases that are found predominantly in pathogens and extremophiles, called R2-like ligand-binding oxidases (R2lox). We have recently shown that the Mn/Fe cofactor of R2lox self-assembles from Mn(II) and Fe(II) in vitro and catalyzes formation of a tyrosine-valine ether cross-link in the protein scaffold (Griese, J. J., Roos, K., Cox, N., Shafaat, H. S., Branca, R. M., Lehtiö, J., Gräslund, A., Lubitz, W., Siegbahn, P. E., and Högbom, M. (2013) Proc. Natl. Acad. Sci. U.S.A. 110, 17189-17194). Here, we present a detailed structural analysis of R2lox in the nonactivated, reduced, and oxidized resting Mn/Fe- and Fe/Fe-bound states, as well as the nonactivated Mn/Mn-bound state. X-ray crystallography and x-ray absorption spectroscopy demonstrate that the active site ligand configuration of R2lox is essentially the same regardless of cofactor composition. Both the Mn/Fe and the diiron cofactor activate oxygen and catalyze formation of the ether cross-link, whereas the dimanganese cluster does not. The structures delineate likely routes for gated oxygen and substrate access to the active site that are controlled by the redox state of the cofactor. These results suggest that oxygen activation proceeds via similar mechanisms at the Mn/Fe and Fe/Fe center and that R2lox proteins might utilize either cofactor in vivo based on metal availability.
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Affiliation(s)
- Julia J Griese
- From the Stockholm Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ramona Kositzki
- the Institut für Experimentalphysik, Freie Universität Berlin, D-14195 Berlin, Germany
| | - Peer Schrapers
- the Institut für Experimentalphysik, Freie Universität Berlin, D-14195 Berlin, Germany
| | - Rui M M Branca
- the Cancer Proteomics Mass Spectrometry, Department of Oncology-Pathology, Science for Life Laboratory, Karolinska Institutet, Box 1031, SE-171 21 Solna, Sweden, and
| | - Anders Nordström
- the Department of Molecular Biology, Umeå University, SE-90187 Umeå, Sweden
| | - Janne Lehtiö
- the Cancer Proteomics Mass Spectrometry, Department of Oncology-Pathology, Science for Life Laboratory, Karolinska Institutet, Box 1031, SE-171 21 Solna, Sweden, and
| | - Michael Haumann
- the Institut für Experimentalphysik, Freie Universität Berlin, D-14195 Berlin, Germany
| | - Martin Högbom
- From the Stockholm Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden,
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37
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Rapatskiy L, Ames WM, Pérez-Navarro M, Savitsky A, Griese JJ, Weyhermüller T, Shafaat HS, Högbom M, Neese F, Pantazis DA, Cox N. Characterization of Oxygen Bridged Manganese Model Complexes Using Multifrequency 17O-Hyperfine EPR Spectroscopies and Density Functional Theory. J Phys Chem B 2015. [DOI: 10.1021/acs.jpcb.5b04614] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Leonid Rapatskiy
- Max-Planck Institute for Chemical Energy, Stiftstr. 34-36, Mülheim an der Ruhr, DE-45470 Germany
| | - William M. Ames
- Max-Planck Institute for Chemical Energy, Stiftstr. 34-36, Mülheim an der Ruhr, DE-45470 Germany
| | - Montserrat Pérez-Navarro
- Max-Planck Institute for Chemical Energy, Stiftstr. 34-36, Mülheim an der Ruhr, DE-45470 Germany
| | - Anton Savitsky
- Max-Planck Institute for Chemical Energy, Stiftstr. 34-36, Mülheim an der Ruhr, DE-45470 Germany
| | - Julia J. Griese
- Department
of Biochemistry and Biophysics, Stockholm University, Stockholm SE-106 91, Sweden
| | - Thomas Weyhermüller
- Max-Planck Institute for Chemical Energy, Stiftstr. 34-36, Mülheim an der Ruhr, DE-45470 Germany
| | - Hannah S. Shafaat
- Max-Planck Institute for Chemical Energy, Stiftstr. 34-36, Mülheim an der Ruhr, DE-45470 Germany
| | - Martin Högbom
- Department
of Biochemistry and Biophysics, Stockholm University, Stockholm SE-106 91, Sweden
| | - Frank Neese
- Max-Planck Institute for Chemical Energy, Stiftstr. 34-36, Mülheim an der Ruhr, DE-45470 Germany
| | - Dimitrios A. Pantazis
- Max-Planck Institute for Chemical Energy, Stiftstr. 34-36, Mülheim an der Ruhr, DE-45470 Germany
| | - Nicholas Cox
- Max-Planck Institute for Chemical Energy, Stiftstr. 34-36, Mülheim an der Ruhr, DE-45470 Germany
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38
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Evolutionary expansion of the amidohydrolase superfamily in bacteria in response to the synthetic compounds molinate and diuron. Appl Environ Microbiol 2015; 81:2612-24. [PMID: 25636851 DOI: 10.1128/aem.04016-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The amidohydrolase superfamily has remarkable functional diversity, with considerable structural and functional annotation of known sequences. In microbes, the recent evolution of several members of this family to catalyze the breakdown of environmental xenobiotics is not well understood. An evolutionary transition from binuclear to mononuclear metal ion coordination at the active sites of these enzymes could produce large functional changes such as those observed in nature, but there are few clear examples available to support this hypothesis. To investigate the role of binuclear-mononuclear active-site transitions in the evolution of new function in this superfamily, we have characterized two recently evolved enzymes that catalyze the hydrolysis of the synthetic herbicides molinate (MolA) and phenylurea (PuhB). In this work, the crystal structures, mutagenesis, metal ion analysis, and enzyme kinetics of both MolA and PuhB establish that these enzymes utilize a mononuclear active site. However, bioinformatics and structural comparisons reveal that the closest putative ancestor of these enzymes had a binuclear active site, indicating that a binuclear-mononuclear transition has occurred. These proteins may represent examples of evolution modifying the characteristics of existing catalysts to satisfy new requirements, specifically, metal ion rearrangement leading to large leaps in activity that would not otherwise be possible.
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39
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Shafaat HS, Griese JJ, Pantazis DA, Roos K, Andersson CS, Popović-Bijelić A, Gräslund A, Siegbahn PEM, Neese F, Lubitz W, Högbom M, Cox N. Electronic structural flexibility of heterobimetallic Mn/Fe cofactors: R2lox and R2c proteins. J Am Chem Soc 2014; 136:13399-409. [PMID: 25153930 DOI: 10.1021/ja507435t] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The electronic structure of the Mn/Fe cofactor identified in a new class of oxidases (R2lox) described by Andersson and Högbom [Proc. Natl. Acad. Sci. U.S.A. 2009, 106, 5633] is reported. The R2lox protein is homologous to the small subunit of class Ic ribonucleotide reductase (R2c) but has a completely different in vivo function. Using multifrequency EPR and related pulse techniques, it is shown that the cofactor of R2lox represents an antiferromagnetically coupled Mn(III)/Fe(III) dimer linked by a μ-hydroxo/bis-μ-carboxylato bridging network. The Mn(III) ion is coordinated by a single water ligand. The R2lox cofactor is photoactive, converting into a second form (R2loxPhoto) upon visible illumination at cryogenic temperatures (77 K) that completely decays upon warming. This second, unstable form of the cofactor more closely resembles the Mn(III)/Fe(III) cofactor seen in R2c. It is shown that the two forms of the R2lox cofactor differ primarily in terms of the local site geometry and electronic state of the Mn(III) ion, as best evidenced by a reorientation of its unique (55)Mn hyperfine axis. Analysis of the metal hyperfine tensors in combination with density functional theory (DFT) calculations suggests that this change is triggered by deprotonation of the μ-hydroxo bridge. These results have important consequences for the mixed-metal R2c cofactor and the divergent chemistry R2lox and R2c perform.
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Affiliation(s)
- Hannah S Shafaat
- Max-Planck-Institut für Chemische Energiekonversion , Stiftstrasse 34-36, Mülheim an der Ruhr D-45470, Germany
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Griese JJ, Srinivas V, Högbom M. Assembly of nonheme Mn/Fe active sites in heterodinuclear metalloproteins. J Biol Inorg Chem 2014; 19:759-74. [PMID: 24771036 PMCID: PMC4118035 DOI: 10.1007/s00775-014-1140-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 04/14/2014] [Indexed: 11/23/2022]
Abstract
The ferritin superfamily contains several protein groups that share a common fold and metal coordinating ligands. The different groups utilize different dinuclear cofactors to perform a diverse set of reactions. Several groups use an oxygen-activating di-iron cluster, while others use di-manganese or heterodinuclear Mn/Fe cofactors. Given the similar primary ligand preferences of Mn and Fe as well as the similarities between the binding sites, the basis for metal specificity in these systems remains enigmatic. Recent data for the heterodinuclear cluster show that the protein scaffold per se is capable of discriminating between Mn and Fe and can assemble the Mn/Fe center in the absence of any potential assembly machineries or metal chaperones. Here we review the current understanding of the assembly of the heterodinuclear cofactor in the two different protein groups in which it has been identified, ribonucleotide reductase R2c proteins and R2-like ligand-binding oxidases. Interestingly, although the two groups form the same metal cluster they appear to employ partly different mechanisms to assemble it. In addition, it seems that both the thermodynamics of metal binding and the kinetics of oxygen activation play a role in achieving metal specificity.
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Affiliation(s)
- Julia J. Griese
- Arrhenius Laboratories for Natural Sciences A4, Department of Biochemistry and Biophysics, Stockholm Center for Biomembrane Research, Stockholm University, 10691 Stockholm, Sweden
| | - Vivek Srinivas
- Arrhenius Laboratories for Natural Sciences A4, Department of Biochemistry and Biophysics, Stockholm Center for Biomembrane Research, Stockholm University, 10691 Stockholm, Sweden
| | - Martin Högbom
- Arrhenius Laboratories for Natural Sciences A4, Department of Biochemistry and Biophysics, Stockholm Center for Biomembrane Research, Stockholm University, 10691 Stockholm, Sweden
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