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Li RN, Chen SL. Mechanistic Insights into the N-Hydroxylations Catalyzed by the Binuclear Iron Domain of SznF Enzyme: Key Piece in the Synthesis of Streptozotocin. Chemistry 2024; 30:e202303845. [PMID: 38212866 DOI: 10.1002/chem.202303845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 01/13/2024]
Abstract
SznF, a member of the emerging family of heme-oxygenase-like (HO-like) di-iron oxidases and oxygenases, employs two distinct domains to catalyze the conversion of Nω-methyl-L-arginine (L-NMA) into N-nitroso-containing product, which can subsequently be transformed into streptozotocin. Using unrestricted density functional theory (UDFT) with the hybrid functional B3LYP, we have mechanistically investigated the two sequential hydroxylations of L-NMA catalyzed by SznF's binuclear iron central domain. Mechanism B primarily involves the O-O bond dissociation, forming Fe(IV)=O, induced by the H+/e- introduction to the FeA side of μ-1,2-peroxo-Fe2(III/III), the substrate hydrogen abstraction by Fe(IV)=O, and the hydroxyl rebound to the substrate N radical. The stochastic addition of H+/e- to the FeB side (mechanism C) can transition to mechanism B, thereby preventing enzyme deactivation. Two other competing mechanisms, involving the direct O-O bond dissociation (mechanism A) and the addition of H2O as a co-substrate (mechanism D), have been ruled out.
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Affiliation(s)
- Rui-Ning Li
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Shi-Lu Chen
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China
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2
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Wang W, Wang Y, Xi H, Song Z, Zhang W, Xie L, Ma D, Qin N, Wang H. Extension Peptide of Plant Ferritin from Setaria italica Presents a Novel Fold. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:934-943. [PMID: 36576327 DOI: 10.1021/acs.jafc.2c07595] [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: 06/17/2023]
Abstract
The extension peptide (EP) is the most distinctive feature of mature plant ferritin. Some EPs have exhibited serine-like protease activity, which is associated with iron uptake and release. EP forms a helix and a long loop, followed by a conserved core helical bundle. However, whether the EP adopts a stable or uniform folding pattern in all plants remains unclear. To clarify this, we investigated the crystal structure of ferritin-1 from Setaria italica (SiFer1), a type of monocotyledon. In our structure of SiFer1, the EP is different from other EPs in other solved structures of plant ferritins and consisted of a pair of β-sheets, a shorter helix, and two loops, which masks two hydrophobic pockets on the outer surface of every subunit. Furthermore, sequence analysis and structure comparison suggest that the EPs in ferritins from monocotyledons may adopt a novel fold pattern, and the conformations of EPs in ferritins are alterable among different plant species. Furthermore, additional eight iron atoms were first founded binding in the fourfold channels, demonstrating the vital function of fourfold channels in iron diffusion. In all, our structure provides new clues for understanding plant ferritins and the functions of the EP.
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Affiliation(s)
- Wenming Wang
- Institute of Molecular Science, Shanxi University, Taiyuan 030006, China
| | - Yuan Wang
- Institute of Molecular Science, Shanxi University, Taiyuan 030006, China
| | - Hongfang Xi
- Institute of Molecular Science, Shanxi University, Taiyuan 030006, China
| | - Zidan Song
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071, China
| | - Wenlong Zhang
- College of Chinese Medicine and Food Engineering, Experimental Management Center, Shanxi University of Chinese Medicine, Jinzhong 030619, China
| | - Leilei Xie
- College of Chinese Medicine and Food Engineering, Experimental Management Center, Shanxi University of Chinese Medicine, Jinzhong 030619, China
| | - Danyang Ma
- Institute of Molecular Science, Shanxi University, Taiyuan 030006, China
| | - Nan Qin
- College of Chinese Medicine and Food Engineering, Experimental Management Center, Shanxi University of Chinese Medicine, Jinzhong 030619, China
| | - Hongfei Wang
- Institute of Molecular Science, Shanxi University, Taiyuan 030006, China
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3
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Distinct structural characteristics define a new subfamily of Mycoplasma ferritin. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2022.03.119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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4
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Song X, Liu J, Wang B. Emergence of Function from Nonheme Diiron Oxygenases: A Quantum Mechanical/Molecular Mechanical Study of Oxygen Activation and Organophosphonate Catabolism Mechanisms by PhnZ. ACS Catal 2022. [DOI: 10.1021/acscatal.1c05116] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Xitong Song
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| | - Jia Liu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
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5
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Jiang Z, Wang C, Wu Z, Chen K, Yang W, Deng H, Song H, Zhou X. Enzymatic deamination of the epigenetic nucleoside N6-methyladenosine regulates gene expression. Nucleic Acids Res 2021; 49:12048-12068. [PMID: 34850126 PMCID: PMC8643624 DOI: 10.1093/nar/gkab1124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 10/20/2021] [Accepted: 11/16/2021] [Indexed: 12/26/2022] Open
Abstract
N6-methyladenosine (m6A) modification is the most extensively studied epigenetic modification due to its crucial role in regulating an array of biological processes. Herein, Bsu06560, formerly annotated as an adenine deaminase derived from Bacillus subtilis 168, was recognized as the first enzyme capable of metabolizing the epigenetic nucleoside N6-methyladenosine. A model of Bsu06560 was constructed, and several critical residues were putatively identified via mutational screening. Two mutants, F91L and Q150W, provided a superiorly enhanced conversion ratio of adenosine and N6-methyladenosine. The CRISPR-Cas9 system generated Bsu06560-knockout, F91L, and Q150W mutations from the B. subtilis 168 genome. Transcriptional profiling revealed a higher global gene expression level in BS-F91L and BS-Q150W strains with enhanced N6-methyladenosine deaminase activity. The differentially expressed genes were categorized using GO, COG, KEGG and verified through RT-qPCR. This study assessed the crucial roles of Bsu06560 in regulating adenosine and N6-methyladenosine metabolism, which influence a myriad of biological processes. This is the first systematic research to identify and functionally annotate an enzyme capable of metabolizing N6-methyladenosine and highlight its significant roles in regulation of bacterial metabolism. Besides, this study provides a novel method for controlling gene expression through the mutations of critical residues.
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Affiliation(s)
- Zhuoran Jiang
- The Institute of Advanced Studies, and Key Laboratory of Biomedical Polymers-Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, 40072 Wuhan, P.R. China
| | - Chao Wang
- The Institute of Advanced Studies, and Key Laboratory of Biomedical Polymers-Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, 40072 Wuhan, P.R. China
| | - Zixin Wu
- The Institute of Advanced Studies, and Key Laboratory of Biomedical Polymers-Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, 40072 Wuhan, P.R. China
| | - Kun Chen
- The Institute of Advanced Studies, and Key Laboratory of Biomedical Polymers-Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, 40072 Wuhan, P.R. China
| | - Wei Yang
- The Institute of Advanced Studies, and Key Laboratory of Biomedical Polymers-Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, 40072 Wuhan, P.R. China
| | - Hexiang Deng
- The Institute of Advanced Studies, and Key Laboratory of Biomedical Polymers-Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, 40072 Wuhan, P.R. China
| | - Heng Song
- The Institute of Advanced Studies, and Key Laboratory of Biomedical Polymers-Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, 40072 Wuhan, P.R. China
| | - Xiang Zhou
- The Institute of Advanced Studies, and Key Laboratory of Biomedical Polymers-Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, 40072 Wuhan, P.R. China
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6
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Miller KR, Biswas S, Jasniewski A, Follmer AH, Biswas A, Albert T, Sabuncu S, Bominaar EL, Hendrich MP, Moënne-Loccoz P, Borovik AS. Artificial Metalloproteins with Dinuclear Iron-Hydroxido Centers. J Am Chem Soc 2021; 143:2384-2393. [PMID: 33528256 DOI: 10.1021/jacs.0c12564] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Dinuclear iron centers with a bridging hydroxido or oxido ligand form active sites within a variety of metalloproteins. A key feature of these sites is the ability of the protein to control the structures around the Fe centers, which leads to entatic states that are essential for function. To simulate this controlled environment, artificial proteins have been engineered using biotin-streptavidin (Sav) technology in which Fe complexes from adjacent subunits can assemble to form [FeIII-(μ-OH)-FeIII] cores. The assembly process is promoted by the site-specific localization of the Fe complexes within a subunit through the designed mutation of a tyrosinate side chain to coordinate the Fe centers. An important outcome is that the Sav host can regulate the Fe···Fe separation, which is known to be important for function in natural metalloproteins. Spectroscopic and structural studies from X-ray diffraction methods revealed uncommonly long Fe···Fe separations that change by less than 0.3 Å upon the binding of additional bridging ligands. The structural constraints imposed by the protein host on the di-Fe cores are unique and create examples of active sites having entatic states within engineered artificial metalloproteins.
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Affiliation(s)
- Kelsey R Miller
- Department of Chemistry, 1102 Natural Sciences II, University of California, Irvine, California 92697, United States
| | - Saborni Biswas
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Andrew Jasniewski
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697, United States
| | - Alec H Follmer
- Department of Chemistry, 1102 Natural Sciences II, University of California, Irvine, California 92697, United States
| | - Ankita Biswas
- Department of Chemistry, 1102 Natural Sciences II, University of California, Irvine, California 92697, United States
| | - Therese Albert
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Mail Code HRC3, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Sinan Sabuncu
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Mail Code HRC3, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Emile L Bominaar
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Michael P Hendrich
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Pierre Moënne-Loccoz
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Mail Code HRC3, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - A S Borovik
- Department of Chemistry, 1102 Natural Sciences II, University of California, Irvine, California 92697, United States
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7
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Melman A, Bou-Abdallah F. Iron mineralization and core dissociation in mammalian homopolymeric H-ferritin: Current understanding and future perspectives. Biochim Biophys Acta Gen Subj 2020; 1864:129700. [DOI: 10.1016/j.bbagen.2020.129700] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 07/30/2020] [Accepted: 07/31/2020] [Indexed: 01/13/2023]
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8
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Biochemistry of mammalian ferritins in the regulation of cellular iron homeostasis and oxidative responses. SCIENCE CHINA. LIFE SCIENCES 2020; 64:352-362. [PMID: 32974854 DOI: 10.1007/s11427-020-1795-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/11/2020] [Indexed: 02/08/2023]
Abstract
Ferritin, an iron-storage protein, regulates cellular iron metabolism and oxidative stress. The ferritin structure is characterized as a spherical cage, inside which large amounts of iron are deposited in a safe, compact and bioavailable form. All ferritins readily catalyze Fe(II) oxidation by peroxides at the ferroxidase center to prevent free Fe(II) from participating in oxygen free radical formation via Fenton chemistry. Thus, ferritin is generally recognized as a cytoprotective stratagem against intracellular oxidative damage The expression of cytosolic ferritins is usually regulated by iron status and oxidative stress at both the transcriptional and post-transcriptional levels. The mechanism of ferritin-mediated iron recycling is far from clarified, though nuclear receptor co-activator 4 (NCOA4) was recently identified as a cargo receptor for ferritin-based lysosomal degradation. Cytosolic ferritins are heteropolymers assembled by H- and L-chains in different proportions. The mitochondrial ferritins are homopolymers and distributed in restricted tissues. They play protective roles in mitochondria where heme- and Fe/S-enzymes are synthesized and high levels of ROS are produced. Genetic ferritin disorders are mainly related to the L-chain mutations, which generally cause severe movement diseases. This review is focused on the biochemistry and function of mammalian intracellular ferritin as the major iron-storage and anti-oxidation protein.
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9
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Narayanan S, Shahbazian-Yassar R, Shokuhfar T. In Situ Visualization of Ferritin Biomineralization via Graphene Liquid Cell-Transmission Electron Microscopy. ACS Biomater Sci Eng 2020; 6:3208-3216. [PMID: 33463263 DOI: 10.1021/acsbiomaterials.9b01889] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ferritin biomineralization is essential to regulate the toxic Fe2+ iron ions in the human body. Unravelling the mechanism of biomineralization in ferritin facilitates our understanding of the causes underlying many iron disorder-related diseases. Until now, no report of in situ visualization of ferritin biomineralization events at nanoscale exists due to the requirement for high-resolution imaging of nanometer-sized ferritin proteins in their hydrated states. Herein, for the first time, we show that the biomineralization processes within individual ferritin proteins can be visualized by means of graphene liquid cell-transmission electron microscopy (GLC-TEM). The increase in the ratio of Fe3+/Fe2+ ions over time monitored via electron energy loss spectroscopy (EELS) reveals the change in oxidation state of iron oxide phases with time. This study lays a foundation for future investigations on iron regulation mechanisms in healthy and dysfunctional ferritins.
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Affiliation(s)
- Surya Narayanan
- Department of Bioengineering, University of Illinois at Chicago, 851 South Morgan Street, Chicago, Illinois 60607, United States
| | - Reza Shahbazian-Yassar
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, 842 West Taylor Street, Chicago, Illinois 60607, United States
| | - Tolou Shokuhfar
- Department of Bioengineering, University of Illinois at Chicago, 851 South Morgan Street, Chicago, Illinois 60607, United States
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10
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Narayanan S, Firlar E, Rasul MG, Foroozan T, Farajpour N, Covnot L, Shahbazian-Yassar R, Shokuhfar T. On the structure and chemistry of iron oxide cores in human heart and human spleen ferritins using graphene liquid cell electron microscopy. NANOSCALE 2019; 11:16868-16878. [PMID: 31482911 DOI: 10.1039/c9nr01541h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ferritin is a protein that regulates the iron ions in humans by storing them in the form of iron oxides. Despite extensive efforts to understand the ferritin iron oxide structures, it is still not clear how ferritin proteins with a distinct light (L) and heavy (H) chain subunit ratio impact the biomineralization process. In situ graphene liquid cell-transmission electron microscopy (GLC-TEM) provides an indispensable platform to study the atomic structure of ferritin mineral cores in their native liquid environment. In this study, we report differences in the iron oxide formation in human spleen ferritins (HSFs) and human heart ferritins (HHFs) using in situ GLC-TEM. Scanning transmission electron microscopy (STEM) along with selected area electron diffraction (SAED) of the mineral core and electron energy loss spectroscopy (EELS) analyses enabled the visualization of morphologies, crystal structures and the chemistry of iron oxide cores in HSFs and HHFs. Our study revealed the presence of metastable ferrihydrite (5Fe2O3·9H2O) as a dominant phase in hydrated HSFs and HHFs, while a stable hematite (α-Fe2O3) phase predominated in non-hydrated HSFs and HHFs. In addition, a higher Fe3+/Fe2+ ratio was found in HHFs in comparison with HSFs. This study provides new understanding on iron-oxide phases that exist in hydrated ferritin proteins from different human organs. Such new insights are needed to map ferritin biomineralization pathways and possible correlations with various iron-related disorders in humans.
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Affiliation(s)
- Surya Narayanan
- University of Illinois at Chicago, Department of Bioengineering, Chicago, IL 60607, USA.
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11
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Ide Y, Tominaka S, Yoneno Y, Komaguchi K, Takei T, Nishida H, Tsunoji N, Machida A, Sano T. Condensed ferric dimers for green photocatalytic synthesis of nylon precursors. Chem Sci 2019; 10:6604-6611. [PMID: 31367311 PMCID: PMC6625416 DOI: 10.1039/c9sc01253b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 05/07/2019] [Indexed: 11/29/2022] Open
Abstract
Although iron oxides have been extensively studied as photocatalysts because of their abundance and environmental compatibility, their performance is notoriously low due to factors such as low photoinduced charge-separation efficiency. Iron oxides, thus, must be modified with expensive and/or toxic materials to attain higher performances, which devalues their appeal as sustainable materials. Here, we design an iron oxide exhibiting an unprecedentedly high photocatalytic performance unrealized by previous photocatalysts such as TiO2 for reactions including the selective oxidation of cyclohexane to industrial nylon precursors. The iron oxide photocatalyst consists of ferric dimers, otherwise extremely unstable, formed via etching of Fe and O sites from ferric oxide nanoparticles immobilized within porous silica. We demonstrate a remarkably high photoinduced charge-separation efficiency (long lifetime of active species) of the ferric dimers due to their electronic structure and the potential of this supported photocatalyst for many more reactions.
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Affiliation(s)
- Yusuke Ide
- International Center for Materials Nanoarchitectonics (MANA) , National Institute for Materials Science , 1-1 Namiki , Tsukuba , Ibaraki 305-0044 , Japan . ;
| | - Satoshi Tominaka
- International Center for Materials Nanoarchitectonics (MANA) , National Institute for Materials Science , 1-1 Namiki , Tsukuba , Ibaraki 305-0044 , Japan . ;
| | - Yumi Yoneno
- Department of Earth Sciences , Waseda University , 1-6-1 Nishiwaseda, Shinjuku-ku , Tokyo 165-8050 , Japan
| | - Kenji Komaguchi
- Graduate School of Engineering , Department of Applied Chemistry , Hiroshima University , 1-4-1 Kagamiyama , Higashi-Hiroshima 739-8527 , Japan
| | - Toshiaki Takei
- International Center for Materials Nanoarchitectonics (MANA) , National Institute for Materials Science , 1-1 Namiki , Tsukuba , Ibaraki 305-0044 , Japan . ;
| | - Hidechika Nishida
- Graduate School of Engineering , Department of Applied Chemistry , Hiroshima University , 1-4-1 Kagamiyama , Higashi-Hiroshima 739-8527 , Japan
| | - Nao Tsunoji
- Graduate School of Engineering , Department of Applied Chemistry , Hiroshima University , 1-4-1 Kagamiyama , Higashi-Hiroshima 739-8527 , Japan
| | - Akihiko Machida
- Synchrotron Radiation Research Center , National Institutes for Quantum and Radiological Science and Technology , 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 , Japan
| | - Tsuneji Sano
- Graduate School of Engineering , Department of Applied Chemistry , Hiroshima University , 1-4-1 Kagamiyama , Higashi-Hiroshima 739-8527 , Japan
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12
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Wei W, Siegbahn PEM, Liao R. Mechanism of the Dinuclear Iron Enzymep‐Aminobenzoate N‐oxygenase from Density Functional Calculations. ChemCatChem 2018. [DOI: 10.1002/cctc.201801072] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Wen‐Jie Wei
- Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of Education Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica Hubei Key Laboratory of Materials Chemistry and Service Failure School of Chemistry and Chemical EngineeringHuazhong University of Science and Technology Wuhan 430074 P. R. China
| | - Per E. M. Siegbahn
- Department of Organic Chemistry, Arrhenius LaboratoryStockholm University Stockholm SE-10691 Sweden
| | - Rong‐Zhen Liao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of Education Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica Hubei Key Laboratory of Materials Chemistry and Service Failure School of Chemistry and Chemical EngineeringHuazhong University of Science and Technology Wuhan 430074 P. R. China
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13
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Cutsail GE, Banerjee R, Zhou A, Que L, Lipscomb JD, DeBeer S. High-Resolution Extended X-ray Absorption Fine Structure Analysis Provides Evidence for a Longer Fe···Fe Distance in the Q Intermediate of Methane Monooxygenase. J Am Chem Soc 2018; 140:16807-16820. [PMID: 30398343 DOI: 10.1021/jacs.8b10313] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Despite decades of intense research, the core structure of the methane C-H bond breaking diiron(IV) intermediate, Q, of soluble methane monooxygenase remains controversial, with conflicting reports supporting either a "diamond" diiron core structure or an open core structure. Early extended X-ray absorption fine structure (EXAFS) data assigned a short 2.46 Å Fe-Fe distance to Q (Shu et al. Science 1997, 275, 515 ) that is inconsistent with several theoretical studies and in conflict with our recent high-resolution Fe K-edge X-ray absorption spectroscopy (XAS) studies (Castillo et al. J. Am. Chem. Soc. 2017, 139, 18024 ). Herein, we revisit the EXAFS of Q using high-energy resolution fluorescence-detected extended X-ray absorption fine structure (HERFD-EXAFS) studies. The present data show no evidence for a short Fe-Fe distance, but rather a long 3.4 Å diiron distance, as observed in open core synthetic model complexes. The previously reported 2.46 Å feature plausibly arises from a background metallic iron contribution from the experimental setup, which is eliminated in HERFD-EXAFS due to the increased selectivity. Herein, we explore the origin of the short diiron feature in partial-fluorescent yield EXAFS measurements and discuss the diagnostic features of background metallic scattering contribution to the EXAFS of dilute biological samples. Lastly, differences in sample preparation and resultant sample inhomogeneity in rapid-freeze quenched samples for EXAFS analysis are discussed. The presented approaches have broad implications for EXAFS studies of all dilute iron-containing samples.
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Affiliation(s)
- George E Cutsail
- Max Planck Institute for Chemical Energy Conversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr , Germany
| | - Rahul Banerjee
- Department of Biochemistry, Molecular Biology and Biophysics , University of Minnesota , 321 Church Street SE , Minneapolis , Minnesota 55455 , United States.,Center for Metals in Biocatalysis , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Ang Zhou
- Center for Metals in Biocatalysis , University of Minnesota , Minneapolis , Minnesota 55455 , United States.,Department of Chemistry , University of Minnesota , 207 Pleasant Street SE , Minneapolis , Minnesota 55455 , United States
| | - Lawrence Que
- Center for Metals in Biocatalysis , University of Minnesota , Minneapolis , Minnesota 55455 , United States.,Department of Chemistry , University of Minnesota , 207 Pleasant Street SE , Minneapolis , Minnesota 55455 , United States
| | - John D Lipscomb
- Department of Biochemistry, Molecular Biology and Biophysics , University of Minnesota , 321 Church Street SE , Minneapolis , Minnesota 55455 , United States.,Center for Metals in Biocatalysis , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr , Germany
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14
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Hagen WR, Hagedoorn PL, Honarmand Ebrahimi K. The workings of ferritin: a crossroad of opinions. Metallomics 2018; 9:595-605. [PMID: 28573266 DOI: 10.1039/c7mt00124j] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Biochemistry of the essential element iron is complicated by radical chemistry associated with Fe(ii) ions and by the extremely low solubility of the Fe(iii) ion in near-neutral water. To mitigate these problems cells from all domains of life synthesize the protein ferritin to take up and oxidize Fe(ii) and to form a soluble storage of Fe(iii) from which iron can be made available for physiology. A long history of studies on ferritin has not yet resulted in a generally accepted mechanism of action of this enzyme. In fact strong disagreement exists between extant ideas on several key steps in the workings of ferritin. The scope of this review is to explain the experimental background of these controversies and to indicate directions towards their possible resolution.
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Affiliation(s)
- Wilfred R Hagen
- Delft University of Technology, Department of Biotechnology, van der Maasweg 9, 2629 HZ Delft, The Netherlands.
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15
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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: 316] [Impact Index Per Article: 52.7] [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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16
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Jasniewski AJ, Komor AJ, Lipscomb JD, Que L. Unprecedented (μ-1,1-Peroxo)diferric Structure for the Ambiphilic Orange Peroxo Intermediate of the Nonheme N-Oxygenase CmlI. J Am Chem Soc 2017; 139:10472-10485. [PMID: 28673082 PMCID: PMC5568637 DOI: 10.1021/jacs.7b05389] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The final step in the biosynthesis of the antibiotic chloramphenicol is the oxidation of an aryl-amine substrate to an aryl-nitro product catalyzed by the N-oxygenase CmlI in three two-electron steps. The CmlI active site contains a diiron cluster ligated by three histidine and four glutamate residues and activates dioxygen to perform its role in the biosynthetic pathway. It was previously shown that the active oxidant used by CmlI to facilitate this chemistry is a peroxo-diferric intermediate (CmlIP). Spectroscopic characterization demonstrated that the peroxo binding geometry of CmlIP is not consistent with the μ-1,2 mode commonly observed in nonheme diiron systems. Its geometry was tentatively assigned as μ-η2:η1 based on comparison with resonance Raman (rR) features of mixed-metal model complexes in the absence of appropriate diiron models. Here, X-ray absorption spectroscopy (XAS) and rR studies have been used to establish a refined structure for the diferric cluster of CmlIP. The rR experiments carried out with isotopically labeled water identified the symmetric and asymmetric vibrations of an Fe-O-Fe unit in the active site at 485 and 780 cm-1, respectively, which was confirmed by the 1.83 Å Fe-O bond observed by XAS. In addition, a unique Fe···O scatterer at 2.82 Å observed from XAS analysis is assigned as arising from the distal O atom of a μ-1,1-peroxo ligand that is bound symmetrically between the irons. The (μ-oxo)(μ-1,1-peroxo)diferric core structure associated with CmlIP is unprecedented among diiron cluster-containing enzymes and corresponding biomimetic complexes. Importantly, it allows the peroxo-diferric intermediate to be ambiphilic, acting as an electrophilic oxidant in the initial N-hydroxylation of an arylamine and then becoming a nucleophilic oxidant in the final oxidation of an aryl-nitroso intermediate to the aryl-nitro product.
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Affiliation(s)
- Andrew J. Jasniewski
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455
- Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455
| | - Anna J. Komor
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455
- Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455
| | - John D. Lipscomb
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455
- Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455
| | - Lawrence Que
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455
- Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455
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17
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Ebrahimi KH, Bill E, Hagedoorn PL, Hagen WR. Spectroscopic evidence for the role of a site of the di-iron catalytic center of ferritins in tuning the kinetics of Fe(ii) oxidation. MOLECULAR BIOSYSTEMS 2017; 12:3576-3588. [PMID: 27722502 DOI: 10.1039/c6mb00235h] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Ferritin is a nanocage protein made of 24 subunits. Its major role is to manage intracellular concentrations of free Fe(ii) and Fe(iii) ions, which is pivotal for iron homeostasis across all domains of life. This function of the protein is regulated by a conserved di-iron catalytic center and has been the subject of extensive studies over the past 50 years. Yet, it has not been fully understood how Fe(ii) is oxidized in the di-iron catalytic center and it is not known why eukaryotic and microbial ferritins oxidize Fe(ii) with different kinetics. In an attempt to obtain a new insight into the mechanism of Fe(ii) oxidation and understand the origin of the observed differences in the catalysis of Fe(ii) oxidation among ferritins we studied and compared the mechanism of Fe(ii) oxidation in the eukaryotic human H-type ferritin (HuHF) and the archaeal ferritin from Pyrococcus furiosus (PfFtn). The results show that the spectroscopic characteristics of the intermediate of Fe(ii) oxidation and the Fe(iii)-products are the same in these two ferritins supporting the proposal of unity in the mechanism of Fe(ii) oxidation among eukaryotic and microbial ferritins. Moreover, we observed that a site in the di-iron catalytic center controls the distribution of Fe(ii) among subunits of HuHF and PfFtn differently. This observation explains the reported differences between HuHF and PfFtn in the kinetics of Fe(ii) oxidation and the amount of O2 consumed per Fe(ii) oxidized. These results provide a fresh understanding of the mechanism of Fe(ii) oxidation by ferritins.
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Affiliation(s)
- Kourosh Honarmand Ebrahimi
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Eckhard Bill
- Max Planck Institute for Chemical Energy Conversion (MPI-CEC), Stiftstrasse 34-36, D-45470 Mülheim, Germany
| | - Peter-Leon Hagedoorn
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Wilfred R Hagen
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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18
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Honarmand Ebrahimi K, Bill E, Hagedoorn P, Hagen WR. Spectroscopic evidence for the presence of a high-valent Fe(IV) species in the ferroxidase reaction of an archaeal ferritin. FEBS Lett 2017; 591:1712-1719. [PMID: 28542723 PMCID: PMC5519934 DOI: 10.1002/1873-3468.12697] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/10/2017] [Accepted: 05/21/2017] [Indexed: 12/20/2022]
Abstract
A high‐valent Fe(IV) species is proposed to be generated from the decay of a peroxodiferric intermediate in the catalytic cycle at the di‐iron cofactor center of dioxygen‐activating enzymes such as methane monooxygenase. However, it is believed that this intermediate is not formed in the di‐iron substrate site of ferritin, where oxidation of Fe(II) substrate to Fe(III) (the ferroxidase reaction) occurs also via a peroxodiferric intermediate. In opposition to this generally accepted view, here we present evidence for the occurrence of a high‐valent Fe(IV) in the ferroxidase reaction of an archaeal ferritin, which is based on trapped intermediates obtained with the freeze‐quench technique and combination of spectroscopic characterization. We hypothesize that a Fe(IV) intermediate catalyzes oxidation of excess Fe(II) nearby the ferroxidase center.
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Affiliation(s)
| | - Eckhard Bill
- Max Planck Institute for Chemical Energy Conversion (MPI‐CEC)MülheimGermany
| | | | - Wilfred R. Hagen
- Department of BiotechnologyDelft University of TechnologyThe Netherlands
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19
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Diversity of Fe 2+ entry and oxidation in ferritins. Curr Opin Chem Biol 2017; 37:122-128. [DOI: 10.1016/j.cbpa.2017.02.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 02/27/2017] [Accepted: 02/28/2017] [Indexed: 01/08/2023]
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20
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Turishchev SY, Antipov SS, Novolokina NV, Chuvenkova OA, Melekhov VV, Ovsyannikov R, Senkovskii BV, Timchenko AA, Ozoline ON, Domashevskaya EP. A soft X-ray synchrotron study of the charge state of iron ions in the ferrihydrite core of the ferritin Dps protein in Escherichia coli. Biophysics (Nagoya-shi) 2016. [DOI: 10.1134/s0006350916050286] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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21
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Kim S, Lee JH, Seok JH, Park YH, Jung SW, Cho AE, Lee C, Chung MS, Kim KH. Structural Basis of Novel Iron-Uptake Route and Reaction Intermediates in Ferritins from Gram-Negative Bacteria. J Mol Biol 2016; 428:5007-5018. [PMID: 27777002 DOI: 10.1016/j.jmb.2016.10.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 10/17/2016] [Accepted: 10/18/2016] [Indexed: 10/20/2022]
Abstract
Iron and oxygen chemistry is mediated by iron proteins for many biological functions. Carboxylate-bridged diiron enzymes including ferritin have the common mechanism of oxygen activation via peroxodiferric intermediates. However, the route for iron uptake and the structural identification of intermediates still remain incomplete. The 4-fold symmetry channel of Helicobacter pylori ferritin was previously proposed as the iron-uptake route in eubacteria, but the amino acid residues at the 4-fold channel are not highly conserved. Here, we show evidence for a short path for iron uptake from His93 on the surface to the ferroxidase center in H. pylori ferritin and Escherichia coli ferritin. The amino acid residues along this path are highly conserved in Gram-negative bacteria and some archaea, and the mutants containing S20A and H93L showed significantly decreased iron oxidation. Surprisingly, the E. coli ferritin S20A crystal structure showed oxygen binding and side-on, symmetric μ-η2:η2 peroxodiferric and oxodiferric intermediates. The results provide the structural basis for understanding the chemical nature of intermediates in iron oxidation in bacteria and some of archaea.
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Affiliation(s)
- Sella Kim
- Department of Biotechnology & Bioinformatics, Korea University, Sejong 339-700, Korea
| | - Ji-Hye Lee
- Department of Biotechnology & Bioinformatics, Korea University, Sejong 339-700, Korea
| | - Jong Hyeon Seok
- Department of Biotechnology & Bioinformatics, Korea University, Sejong 339-700, Korea
| | - Yi-Ho Park
- Department of Biotechnology & Bioinformatics, Korea University, Sejong 339-700, Korea
| | - Sang Won Jung
- Department of Biotechnology & Bioinformatics, Korea University, Sejong 339-700, Korea
| | - Art E Cho
- Department of Biotechnology & Bioinformatics, Korea University, Sejong 339-700, Korea
| | - Cheolju Lee
- Functional Proteomics Center, Korea Institute of Science and Technology, Seoul 136-791, Korea
| | - Mi Sook Chung
- Department of Food and Nutrition, Duksung Women's University, Seoul 132-714, Korea
| | - Kyung Hyun Kim
- Department of Biotechnology & Bioinformatics, Korea University, Sejong 339-700, Korea.
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22
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Jasniewski AJ, Knoot CJ, Lipscomb JD, Que L. A Carboxylate Shift Regulates Dioxygen Activation by the Diiron Nonheme β-Hydroxylase CmlA upon Binding of a Substrate-Loaded Nonribosomal Peptide Synthetase. Biochemistry 2016; 55:5818-5831. [PMID: 27668828 PMCID: PMC5258830 DOI: 10.1021/acs.biochem.6b00834] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The first step in the nonribosomal peptide synthetase (NRPS)-based biosynthesis of chloramphenicol is the β-hydroxylation of the precursor l-p-aminophenylalanine (l-PAPA) catalyzed by the monooxygenase CmlA. The active site of CmlA contains a dinuclear iron cluster that is reduced to the diferrous state (WTR) to initiate O2 activation. However, rapid O2 activation occurs only when WTR is bound to CmlP, the NRPS to which l-PAPA is covalently attached. Here the X-ray crystal structure of WTR is reported, which is very similar to that of the as-isolated diferric enzyme in which the irons are coordinately saturated. X-ray absorption spectroscopy is used to investigate the WTR cluster ligand structure as well as the structures of WTR in complex with a functional CmlP variant (CmlPAT) with and without l-PAPA attached. It is found that formation of the active WTR:CmlPAT-l-PAPA complex converts at least one iron of the cluster from six- to five-coordinate by changing a bidentately bound amino acid carboxylate to monodentate on Fe1. The only bidentate carboxylate in the structure of WTR is E377. The crystal structure of the CmlA variant E377D shows only monodentate carboxylate coordination. Reduced E377D reacts rapidly with O2 in the presence or absence of CmlPAT-l-PAPA, showing loss of regulation. However, this variant fails to catalyze hydroxylation, suggesting that E377 has the dual role of coupling regulation of O2 reactivity with juxtaposition of the substrate and the reactive oxygen species. The carboxylate shift in response to substrate binding represents a novel regulatory strategy for oxygen activation in diiron oxygenases.
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Affiliation(s)
- Andrew J. Jasniewski
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455
- Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455
| | - Cory J. Knoot
- Department of Biochemistry Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455
- Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455
| | - John D. Lipscomb
- Department of Biochemistry Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455
- Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455
| | - Lawrence Que
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455
- Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455
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23
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Chandramouli B, Bernacchioni C, Di Maio D, Turano P, Brancato G. Electrostatic and Structural Bases of Fe2+ Translocation through Ferritin Channels. J Biol Chem 2016; 291:25617-25628. [PMID: 27756844 DOI: 10.1074/jbc.m116.748046] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 10/03/2016] [Indexed: 01/14/2023] Open
Abstract
Ferritin molecular cages are marvelous 24-mer supramolecular architectures that enable massive iron storage (>2000 iron atoms) within their inner cavity. This cavity is connected to the outer environment by two channels at C3 and C4 symmetry axes of the assembly. Ferritins can also be exploited as carriers for in vivo imaging and therapeutic applications, owing to their capability to effectively protect synthetic non-endogenous agents within the cage cavity and deliver them to targeted tissue cells without stimulating adverse immune responses. Recently, X-ray crystal structures of Fe2+-loaded ferritins provided important information on the pathways followed by iron ions toward the ferritin cavity and the catalytic centers within the protein. However, the specific mechanisms enabling Fe2+ uptake through wild-type and mutant ferritin channels is largely unknown. To shed light on this question, we report extensive molecular dynamics simulations, site-directed mutagenesis, and kinetic measurements that characterize the transport properties and translocation mechanism of Fe2+ through the two ferritin channels, using the wild-type bullfrog Rana catesbeiana H' protein and some of its variants as case studies. We describe the structural features that determine Fe2+ translocation with atomistic detail, and we propose a putative mechanism for Fe2+ transport through the channel at the C3 symmetry axis, which is the only iron-permeable channel in vertebrate ferritins. Our findings have important implications for understanding how ion permeation occurs, and further how it may be controlled via purposely engineered channels for novel biomedical applications based on ferritin.
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Affiliation(s)
- Balasubramanian Chandramouli
- From the Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, .,the Istituto Nazionale di Fisica Nucleare (INFN) Sezione di Pisa, Largo Bruno Pontecorvo 3, 56127 Pisa, and
| | - Caterina Bernacchioni
- the Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Danilo Di Maio
- From the Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa.,the Istituto Nazionale di Fisica Nucleare (INFN) Sezione di Pisa, Largo Bruno Pontecorvo 3, 56127 Pisa, and
| | - Paola Turano
- the Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Giuseppe Brancato
- From the Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, .,the Istituto Nazionale di Fisica Nucleare (INFN) Sezione di Pisa, Largo Bruno Pontecorvo 3, 56127 Pisa, and
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24
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Jasniewski AJ, Engstrom LM, Vu VV, Park MH, Que L. X-ray absorption spectroscopic characterization of the diferric-peroxo intermediate of human deoxyhypusine hydroxylase in the presence of its substrate eIF5a. J Biol Inorg Chem 2016; 21:605-18. [PMID: 27380180 PMCID: PMC4990465 DOI: 10.1007/s00775-016-1373-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 06/16/2016] [Indexed: 11/29/2022]
Abstract
Human deoxyhypusine hydroxylase (hDOHH) is an enzyme that is involved in the critical post-translational modification of the eukaryotic translation initiation factor 5A (eIF5A). Following the conversion of a lysine residue on eIF5A to deoxyhypusine (Dhp) by deoxyhypusine synthase, hDOHH hydroxylates Dhp to yield the unusual amino acid residue hypusine (Hpu), a modification that is essential for eIF5A to promote peptide synthesis at the ribosome, among other functions. Purification of hDOHH overexpressed in E. coli affords enzyme that is blue in color, a feature that has been associated with the presence of a peroxo-bridged diiron(III) active site. To gain further insight into the nature of the diiron site and how it may change as hDOHH goes through the catalytic cycle, we have conducted X-ray absorption spectroscopic studies of hDOHH on five samples that represent different species along its reaction pathway. Structural analysis of each species has been carried out, starting with the reduced diferrous state, proceeding through its O2 adduct, and ending with a diferric decay product. Our results show that the Fe⋯Fe distances found for the five samples fall within a narrow range of 3.4-3.5 Å, suggesting that hDOHH has a fairly constrained active site. This pattern differs significantly from what has been associated with canonical dioxygen activating nonheme diiron enzymes, such as soluble methane monooxygenase and Class 1A ribonucleotide reductases, for which the Fe⋯Fe distance can change by as much as 1 Å during the redox cycle. These results suggest that the O2 activation mechanism for hDOHH deviates somewhat from that associated with the canonical nonheme diiron enzymes, opening the door to new mechanistic possibilities for this intriguing family of enzymes.
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Affiliation(s)
- Andrew J Jasniewski
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN, 55455, USA
| | - Lisa M Engstrom
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN, 55455, USA
| | - Van V Vu
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN, 55455, USA
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, 298-300A Nguyen Tat Thanh Street, Ward 13, District 4, Ho Chi Minh City, Vietnam
| | - Myung Hee Park
- National Institute of Dental and Craniofacial Research, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN, 55455, USA.
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25
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Theil EC, Tosha T, Behera RK. Solving Biology's Iron Chemistry Problem with Ferritin Protein Nanocages. Acc Chem Res 2016; 49:784-91. [PMID: 27136423 DOI: 10.1021/ar500469e] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Ferritins reversibly synthesize iron-oxy(ferrihydrite) biominerals inside large, hollow protein nanocages (10-12 nm, ∼480 000 g/mol); the iron biominerals are metabolic iron concentrates for iron protein biosyntheses. Protein cages of 12- or 24-folded ferritin subunits (4-α-helix polypeptide bundles) self-assemble, experimentally. Ferritin biomineral structures differ among animals and plants or bacteria. The basic ferritin mineral structure is ferrihydrite (Fe2O3·H2O) with either low phosphate in the highly ordered animal ferritin biominerals, Fe/PO4 ∼ 8:1, or Fe/PO4 ∼ 1:1 in the more amorphous ferritin biominerals of plants and bacteria. While different ferritin environments, plant bacterial-like plastid organelles and animal cytoplasm, might explain ferritin biomineral differences, investigation is required. Currently, the physiological significance of plant-specific and animal-specific ferritin iron minerals is unknown. The iron content of ferritin in living tissues ranges from zero in "apoferritin" to as high as ∼4500 iron atoms. Ferritin biomineralization begins with the reaction of Fe(2+) with O2 at ferritin enzyme (Fe(2+)/O oxidoreductase) sites. The product of ferritin enzyme activity, diferric oxy complexes, is also the precursor of ferritin biomineral. Concentrations of Fe(3+) equivalent to 2.0 × 10(-1) M are maintained in ferritin solutions, contrasting with the Fe(3+) Ks ∼ 10(-18) M. Iron ions move into, through, and out of ferritin protein cages in structural subdomains containing conserved amino acids. Cage subdomains include (1) ion channels for Fe(2+) entry/exit, (2) enzyme (oxidoreductase) site for coupling Fe(2+) and O yielding diferric oxy biomineral precursors, and (3) ferric oxy nucleation channels, where diferric oxy products from up to three enzyme sites interact while moving toward the central, biomineral growth cavity (12 nm diameter) where ferric oxy species, now 48-mers, grow in ferric oxy biomineral. High ferritin protein cage symmetry (3-fold and 4-fold axes) and amino acid conservation coincide with function, shown by amino acid substitution effects. 3-Fold symmetry axes control Fe(2+) entry (enzyme catalysis of Fe(2+)/O2 oxidoreduction) and Fe(2+) exit (reductive ferritin mineral dissolution); 3-fold symmetry axes influence Fe(2+)exit from dissolved mineral; bacterial ferritins diverge slightly in Fe/O2 reaction mechanisms and intracage paths of iron-oxy complexes. Biosynthesis rates of ferritin protein change with Fe(2+) and O2 concentrations, dependent on DNA-binding, and heme binding protein, Bach 1. Increased cellular O2 indirectly stabilizes ferritin DNA/Bach 1 interactions. Heme, Fe-protoporphyrin IX, decreases ferritin DNA-Bach 1 binding, causing increased ferritin mRNA biosynthesis (transcription). Direct Fe(2+) binding to ferritin mRNA decreases binding of an inhibitory protein, IRP, causing increased ferritin mRNA translation (protein biosynthesis). Newly synthesized ferritin protein consumes Fe(2+) in biomineral, decreasing Fe(2)(+) and creating a regulatory feedback loop. Ferritin without iron is "apoferritin". Iron removal from ferritin, experimentally, uses biological reductants, for example, NADH + FMN, or chemical reductants, for example, thioglycolic acid, with Fe(2+) chelators; physiological mechanism(s) are murky. Clear, however, is the necessity of ferritin for terrestrial life by conferring oxidant protection (plants, animals, and bacteria), virulence (bacteria), and embryonic survival (mammals). Future studies of ferritin structure/function and Fe(2+)/O2 chemistry will lead to new ferritin uses in medicine, nutrition, and nanochemistry.
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Affiliation(s)
- Elizabeth C. Theil
- Children’s Hospital Oakland Research Institute, Oakland, California 94609, United States
- Department of Structural
and Molecular Biochemistry, North Carolina State University, Raleigh, North Carolina 27695-7313, United States
| | - Takehiko Tosha
- Children’s Hospital Oakland Research Institute, Oakland, California 94609, United States
- Department of Structural
and Molecular Biochemistry, North Carolina State University, Raleigh, North Carolina 27695-7313, United States
| | - Rabindra K. Behera
- Children’s Hospital Oakland Research Institute, Oakland, California 94609, United States
- Department of Structural
and Molecular Biochemistry, North Carolina State University, Raleigh, North Carolina 27695-7313, United States
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26
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Nami F, Gast P, Groenen EJJ. Rapid Freeze-Quench EPR Spectroscopy: Improved Collection of Frozen Particles. APPLIED MAGNETIC RESONANCE 2016; 47:643-653. [PMID: 27340337 PMCID: PMC4875044 DOI: 10.1007/s00723-016-0783-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 04/18/2016] [Indexed: 05/22/2023]
Abstract
Rapid freeze-quench (RFQ) in combination with electron paramagnetic resonance (EPR) spectroscopy at X-band is a proven technique to trap and characterize paramagnetic intermediates of biochemical reactions. Preparation of suitable samples is still cumbersome, despite many attempts to remedy this problem, and limits the wide applicability of RFQ EPR. We present a method, which improves the collection of freeze-quench particles from isopentane and their packing in an EPR tube. The method is based on sucking the particle suspension into an EPR tube with a filter at the bottom. This procedure results in a significant reduction of the required volume of reactants, which allows the economical use of valuable reactants such as proteins. The approach also enables the successful collection of smaller frozen particles, which are generated at higher flow rates. The method provides for a reproducible, efficient and fast collection of the freeze-quench particles and can be easily adapted to RFQ EPR at higher microwave frequencies than X-band.
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Affiliation(s)
- Faezeh Nami
- Huygens-Kamerlingh Onnes Laboratory, Department of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - Peter Gast
- Huygens-Kamerlingh Onnes Laboratory, Department of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - Edgar J. J. Groenen
- Huygens-Kamerlingh Onnes Laboratory, Department of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
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27
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Bernacchioni C, Ghini V, Theil EC, Turano P. Modulating the permeability of ferritin channels. RSC Adv 2016. [DOI: 10.1039/c5ra25056k] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Electric field gradients across the C3 and C4 ferritin channels controls the directional Fe2+fluxes towards the catalytic ferroxidase center.
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Affiliation(s)
- C. Bernacchioni
- CERM
- University of Florence
- 50019 Sesto Fiorentino
- Italy
- Department of Chemistry
| | - V. Ghini
- CERM
- University of Florence
- 50019 Sesto Fiorentino
- Italy
- Department of Chemistry
| | - E. C. Theil
- Children's Hospital Oakland Research Institute
- Oakland
- USA
- Department of Molecular and Structural Biochemistry
- North Carolina State University
| | - P. Turano
- CERM
- University of Florence
- 50019 Sesto Fiorentino
- Italy
- Department of Chemistry
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28
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Kwak Y, Schwartz JK, Huang VW, Boice E, Kurtz DM, Solomon EI. CD/MCD/VTVH-MCD Studies of Escherichia coli Bacterioferritin Support a Binuclear Iron Cofactor Site. Biochemistry 2015; 54:7010-8. [PMID: 26551523 DOI: 10.1021/acs.biochem.5b01033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ferritins and bacterioferritins (Bfrs) utilize a binuclear non-heme iron binding site to catalyze oxidation of Fe(II), leading to formation of an iron mineral core within a protein shell. Unlike ferritins, in which the diiron site binds Fe(II) as a substrate, which then autoxidizes and migrates to the mineral core, the diiron site in Bfr has a 2-His/4-carboxylate ligand set that is commonly found in diiron cofactor enzymes. Bfrs could, therefore, utilize the diiron site as a cofactor rather than for substrate iron binding. In this study, we applied circular dichroism (CD), magnetic CD (MCD), and variable-temperature, variable-field MCD (VTVH-MCD) spectroscopies to define the geometric and electronic structures of the biferrous active site in Escherichia coli Bfr. For these studies, we used an engineered M52L variant, which is known to eliminate binding of a heme cofactor but to have very minor effects on either iron oxidation or mineral core formation. We also examined an H46A/D50A/M52L Bfr variant, which additionally disrupts a previously observed mononuclear non-heme iron binding site inside the protein shell. The spectral analyses define a binuclear and an additional mononuclear ferrous site. The biferrous site shows two different five-coordinate centers. After O2 oxidation and re-reduction, only the mononuclear ferrous signal is eliminated. The retention of the biferrous but not the mononuclear ferrous site upon O2 cycling supports a mechanism in which the binuclear site acts as a cofactor for the O2 reaction, while the mononuclear site binds the substrate Fe(II) that, after its oxidation to Fe(III), migrates to the mineral core.
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Affiliation(s)
- Yeonju Kwak
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
| | - Jennifer K Schwartz
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
| | - Victor W Huang
- Department of Chemistry, University of Texas at San Antonio , One UTSA Circle, San Antonio, Texas 78249, United States
| | - Emily Boice
- Department of Chemistry, University of Texas at San Antonio , One UTSA Circle, San Antonio, Texas 78249, United States
| | - Donald M Kurtz
- Department of Chemistry, University of Texas at San Antonio , One UTSA Circle, San Antonio, Texas 78249, United States
| | - Edward I Solomon
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
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29
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Pozzi C, Di Pisa F, Bernacchioni C, Ciambellotti S, Turano P, Mangani S. Iron binding to human heavy-chain ferritin. ACTA ACUST UNITED AC 2015; 71:1909-20. [PMID: 26327381 DOI: 10.1107/s1399004715013073] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 07/07/2015] [Indexed: 11/10/2022]
Abstract
Maxi-ferritins are ubiquitous iron-storage proteins with a common cage architecture made up of 24 identical subunits of five α-helices that drive iron biomineralization through catalytic iron(II) oxidation occurring at oxidoreductase sites (OS). Structures of iron-bound human H ferritin were solved at high resolution by freezing ferritin crystals at different time intervals after exposure to a ferrous salt. Multiple binding sites were identified that define the iron path from the entry ion channels to the oxidoreductase sites. Similar data are available for another vertebrate ferritin: the M protein from Rana catesbeiana. A comparative analysis of the iron sites in the two proteins identifies new reaction intermediates and underlines clear differences in the pattern of ligands that define the additional iron sites that precede the oxidoreductase binding sites along this path. Stopped-flow kinetics assays revealed that human H ferritin has different levels of activity compared with its R. catesbeiana counterpart. The role of the different pattern of transient iron-binding sites in the OS is discussed with respect to the observed differences in activity across the species.
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Affiliation(s)
- Cecilia Pozzi
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Flavio Di Pisa
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Caterina Bernacchioni
- Dipartimento di Chimica, Università di Firenze, Via Della Lastruccia 3, Sesto Fiorentino, 50019 Firenze, Italy
| | - Silvia Ciambellotti
- Dipartimento di Chimica, Università di Firenze, Via Della Lastruccia 3, Sesto Fiorentino, 50019 Firenze, Italy
| | - Paola Turano
- Dipartimento di Chimica, Università di Firenze, Via Della Lastruccia 3, Sesto Fiorentino, 50019 Firenze, Italy
| | - Stefano Mangani
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Via Aldo Moro 2, 53100 Siena, Italy
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30
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Behera RK, Torres R, Tosha T, Bradley JM, Goulding CW, Theil EC. Fe(2+) substrate transport through ferritin protein cage ion channels influences enzyme activity and biomineralization. J Biol Inorg Chem 2015. [PMID: 26202907 DOI: 10.1007/s00775-015-1279-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Ferritins, complex protein nanocages, form internal iron-oxy minerals (Fe2O3·H2O), by moving cytoplasmic Fe(2+) through intracage ion channels to cage-embedded enzyme (2Fe(2+)/O2 oxidoreductase) sites where ferritin biomineralization is initiated. The products of ferritin enzyme activity are diferric oxy complexes that are mineral precursors. Conserved, carboxylate amino acid side chains of D127 from each of three cage subunits project into ferritin ion channels near the interior ion channel exits and, thus, could direct Fe(2+) movement to the internal enzyme sites. Ferritin D127E was designed and analyzed to probe properties of ion channel size and carboxylate crowding near the internal ion channel opening. Glu side chains are chemically equivalent to, but longer by one -CH2 than Asp, side chains. Ferritin D127E assembled into normal protein cages, but diferric peroxo formation (enzyme activity) was not observed, when measured at 650 nm (DFP λ max). The caged biomineral formation, measured at 350 nm in the middle of the broad, nonspecific Fe(3+)-O absorption band, was slower. Structural differences (protein X-ray crystallography), between ion channels in wild type and ferritin D127E, which correlate with the inhibition of ferritin D127E enzyme activity include: (1) narrower interior ion channel openings/pores; (2) increased numbers of ion channel protein-metal binding sites, and (3) a change in ion channel electrostatics due to carboxylate crowding. The contributions of ion channel size and structure to ferritin activity reflect metal ion transport in ion channels are precisely regulated both in ferritin protein nanocages and membranes of living cells.
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Affiliation(s)
- Rabindra K Behera
- Children's Hospital Oakland Research Institute (CHORI), 5700 Martin Luther King Jr. Way, Oakland, CA, 94609, USA
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31
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Pozzi C, Di Pisa F, Lalli D, Rosa C, Theil E, Turano P, Mangani S. Time-lapse anomalous X-ray diffraction shows how Fe(2+) substrate ions move through ferritin protein nanocages to oxidoreductase sites. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2015; 71:941-53. [PMID: 25849404 PMCID: PMC4388269 DOI: 10.1107/s1399004715002333] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Accepted: 02/03/2015] [Indexed: 11/10/2022]
Abstract
Ferritin superfamily protein cages reversibly synthesize internal biominerals, Fe2O3·H2O. Fe(2+) and O2 (or H2O2) substrates bind at oxidoreductase sites in the cage, initiating biomineral synthesis to concentrate iron and prevent potentially toxic reactions products from Fe(2+)and O2 or H2O2 chemistry. By freezing ferritin crystals of Rana catesbeiana ferritin M (RcMf) at different time intervals after exposure to a ferrous salt, a series of high-resolution anomalous X-ray diffraction data sets were obtained that led to crystal structures that allowed the direct observation of ferrous ions entering, moving along and binding at enzyme sites in the protein cages. The ensemble of crystal structures from both aerobic and anaerobic conditions provides snapshots of the iron substrate bound at different cage locations that vary with time. The observed differential occupation of the two iron sites in the enzyme oxidoreductase centre (with Glu23 and Glu58, and with Glu58, His61 and Glu103 as ligands, respectively) and other iron-binding sites (with Glu53, His54, Glu57, Glu136 and Asp140 as ligands) reflects the approach of the Fe(2+) substrate and its progression before the enzymatic cycle 2Fe(2+) + O2 → Fe(3+)-O-O-Fe(3+) → Fe(3+)-O(H)-Fe(3+) and turnover. The crystal structures also revealed different Fe(2+) coordination compounds bound to the ion channels located at the threefold and fourfold symmetry axes of the cage.
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Affiliation(s)
- Cecilia Pozzi
- Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Flavio Di Pisa
- Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Daniela Lalli
- Dipartimento di Chimica and CERM, University of Florence, Via Della Lastruccia 3, Sesto Fiorentino, 50019 Firenze, Italy
| | - Camilla Rosa
- Dipartimento di Chimica and CERM, University of Florence, Via Della Lastruccia 3, Sesto Fiorentino, 50019 Firenze, Italy
| | - Elizabeth Theil
- Children’s Hospital, Oakland Research Institute, 5700 Martin Luther King Jr Way, Oakland, CA 94609, USA
| | - Paola Turano
- Dipartimento di Chimica and CERM, University of Florence, Via Della Lastruccia 3, Sesto Fiorentino, 50019 Firenze, Italy
| | - Stefano Mangani
- Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
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32
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Bernacchioni C, Ciambellotti S, Theil EC, Turano P. Is His54 a gating residue for the ferritin ferroxidase site? BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1118-22. [PMID: 25727028 DOI: 10.1016/j.bbapap.2015.02.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 02/17/2015] [Accepted: 02/18/2015] [Indexed: 10/23/2022]
Abstract
Ferritin is a ubiquitous iron concentrating nanocage protein that functions through the enzymatic oxidation of ferrous iron and the reversible synthesis of a caged ferric-oxo biomineral. Among vertebrate ferritins, the bullfrog M homopolymer ferritin is a frequent model for analyzing the role of specific amino acids in the enzymatic reaction and translocation of iron species within the protein cage. X-ray crystal structures of ferritin in the presence of metal ions have revealed His54 binding to iron(II) and other divalent cations, with its imidazole ring proposed as "gate" that influences iron movement to/from the active site. To investigate its role, His54 was mutated to Ala. The H54A ferritin variant was expressed and its reactivity studied via UV-vis stopped-flow kinetics. The H54A variant exhibited a 20% increase in the initial reaction rate of formation of ferric products with 2 or 4 Fe²⁺/subunit and higher than 200% with 20 Fe²⁺/subunit. The possible meaning of the increased efficiency of the ferritin reaction induced by this mutation is proposed taking advantage of the comparative sequence analysis of other ferritins. The data here reported are consistent with a role for His54 as a metal ion trap that maintains the correct levels of access of iron to the active site. This article is part of a Special Issue entitled: Cofactor-dependent proteins: evolution, chemical diversity and bio-applications.
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Affiliation(s)
- Caterina Bernacchioni
- Magnetic Resonance Center CERM, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy; Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Florence, Italy
| | - Silvia Ciambellotti
- Magnetic Resonance Center CERM, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy; Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Florence, Italy
| | - Elizabeth C Theil
- Children's Hospital Oakland Research Institute, 5700 Martin Luther King, Jr. Way, Oakland, CA 94609, USA; Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 29695-7622, USA
| | - Paola Turano
- Magnetic Resonance Center CERM, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy; Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Florence, Italy.
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33
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Makris TM, Vu VV, Meier KK, Komor AJ, Rivard BS, Münck E, Que L, Lipscomb JD. An unusual peroxo intermediate of the arylamine oxygenase of the chloramphenicol biosynthetic pathway. J Am Chem Soc 2015; 137:1608-17. [PMID: 25564306 PMCID: PMC4318726 DOI: 10.1021/ja511649n] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Streptomyces venezuelae CmlI catalyzes the six-electron oxygenation of the arylamine precursor of chloramphenicol in a nonribosomal peptide synthetase (NRPS)-based pathway to yield the nitroaryl group of the antibiotic. Optical, EPR, and Mössbauer studies show that the enzyme contains a nonheme dinuclear iron cluster. Addition of O(2) to the diferrous state of the cluster results in an exceptionally long-lived intermediate (t(1/2) = 3 h at 4 °C) that is assigned as a peroxodiferric species (CmlI-peroxo) based upon the observation of an (18)O(2)-sensitive resonance Raman (rR) vibration. CmlI-peroxo is spectroscopically distinct from the well characterized and commonly observed cis-μ-1,2-peroxo (μ-η(1):η(1)) intermediates of nonheme diiron enzymes. Specifically, it exhibits a blue-shifted broad absorption band around 500 nm and a rR spectrum with a ν(O-O) that is at least 60 cm(-1) lower in energy. Mössbauer studies of the peroxo state reveal a diferric cluster having iron sites with small quadrupole splittings and distinct isomer shifts (0.54 and 0.62 mm/s). Taken together, the spectroscopic comparisons clearly indicate that CmlI-peroxo does not have a μ-η(1):η(1)-peroxo ligand; we propose that a μ-η(1):η(2)-peroxo ligand accounts for its distinct spectroscopic properties. CmlI-peroxo reacts with a range of arylamine substrates by an apparent second-order process, indicating that CmlI-peroxo is the reactive species of the catalytic cycle. Efficient production of chloramphenicol from the free arylamine precursor suggests that CmlI catalyzes the ultimate step in the biosynthetic pathway and that the precursor is not bound to the NRPS during this step.
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Affiliation(s)
- Thomas M. Makris
- Department of Biochemistry, Molecular Biology, and
Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Center for Metals in Biocatalysis, University of
Minnesota, Minneapolis, MN 55455
| | - Van V. Vu
- Center for Metals in Biocatalysis, University of
Minnesota, Minneapolis, MN 55455
- Department of Chemistry, University of Minnesota, Minneapolis,
Minnesota 55455, United States
| | - Katlyn K. Meier
- Department of Chemistry, Carnegie Mellon University,
Pittsburgh, PA 15213, United States
| | - Anna J. Komor
- Center for Metals in Biocatalysis, University of
Minnesota, Minneapolis, MN 55455
- Department of Chemistry, University of Minnesota, Minneapolis,
Minnesota 55455, United States
| | - Brent S. Rivard
- Department of Biochemistry, Molecular Biology, and
Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Center for Metals in Biocatalysis, University of
Minnesota, Minneapolis, MN 55455
| | - Eckard Münck
- Department of Chemistry, Carnegie Mellon University,
Pittsburgh, PA 15213, United States
| | - Lawrence Que
- Center for Metals in Biocatalysis, University of
Minnesota, Minneapolis, MN 55455
- Department of Chemistry, University of Minnesota, Minneapolis,
Minnesota 55455, United States
| | - John D. Lipscomb
- Department of Biochemistry, Molecular Biology, and
Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Center for Metals in Biocatalysis, University of
Minnesota, Minneapolis, MN 55455
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34
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Piccioli M, Turano P. Transient iron coordination sites in proteins: Exploiting the dual nature of paramagnetic NMR. Coord Chem Rev 2015. [DOI: 10.1016/j.ccr.2014.05.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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35
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Honarmand Ebrahimi K, Hagedoorn PL, Hagen WR. Unity in the Biochemistry of the Iron-Storage Proteins Ferritin and Bacterioferritin. Chem Rev 2014; 115:295-326. [DOI: 10.1021/cr5004908] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Kourosh Honarmand Ebrahimi
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628
BC Delft, The Netherlands
| | - Peter-Leon Hagedoorn
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628
BC Delft, The Netherlands
| | - Wilfred R. Hagen
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628
BC Delft, The Netherlands
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36
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Arenas-Salinas M, Townsend PD, Brito C, Marquez V, Marabolli V, Gonzalez-Nilo F, Matias C, Watt RK, López-Castro JD, Domínguez-Vera J, Pohl E, Yévenes A. The crystal structure of ferritin from Chlorobium tepidum reveals a new conformation of the 4-fold channel for this protein family. Biochimie 2014; 106:39-47. [PMID: 25079050 DOI: 10.1016/j.biochi.2014.07.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 07/18/2014] [Indexed: 12/19/2022]
Abstract
Ferritins are ubiquitous iron-storage proteins found in all kingdoms of life. They share a common architecture made of 24 subunits of five α-helices. The recombinant Chlorobium tepidum ferritin (rCtFtn) is a structurally interesting protein since sequence alignments with other ferritins show that this protein has a significantly extended C-terminus, which possesses 12 histidine residues as well as several aspartate and glutamic acid residues that are potential metal ion binding residues. We show that the macromolecular assembly of rCtFtn exhibits a cage-like hollow shell consisting of 24 monomers that are related by 4-3-2 symmetry; similar to the assembly of other ferritins. In all ferritins of known structure the short fifth α-helix adopts an acute angle with respect to the four-helix bundle. However, the crystal structure of the rCtFtn presented here shows that this helix adopts a new conformation defining a new assembly of the 4-fold channel of rCtFtn. This conformation allows the arrangement of the C-terminal region into the inner cavity of the protein shell. Furthermore, two Fe(III) ions were found in each ferroxidase center of rCtFtn, with an average FeA-FeB distance of 3 Å; corresponding to a diferric μ-oxo/hydroxo species. This is the first ferritin crystal structure with an isolated di-iron center in an iron-storage ferritin. The crystal structure of rCtFtn and the biochemical results presented here, suggests that rCtFtn presents similar biochemical properties reported for other members of this protein family albeit with distinct structural plasticity.
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Affiliation(s)
- Mauricio Arenas-Salinas
- Centro de Bioinformática y Simulación Molecular, Facultad de Ingeniería, Universidad de Talca, Talca, Chile
| | - Philip D Townsend
- Department of Chemistry & School of Biological and Biomedical Sciences, Durham University, Durham DH1 3LE, UK
| | - Christian Brito
- Centro de Bioinformática y Biología Integrativa, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile
| | - Valeria Marquez
- Centro de Bioinformática y Biología Integrativa, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile
| | - Vanessa Marabolli
- Centro de Bioinformática y Biología Integrativa, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile
| | - Fernando Gonzalez-Nilo
- Centro de Bioinformática y Biología Integrativa, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile
| | - Cata Matias
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - Richard K Watt
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - Juan D López-Castro
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - José Domínguez-Vera
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Ehmke Pohl
- Department of Chemistry & School of Biological and Biomedical Sciences, Durham University, Durham DH1 3LE, UK
| | - Alejandro Yévenes
- Departamento de Química Física, Facultad de Química, Pontificia Universidad Católica de Chile, Santiago, Chile.
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37
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Kwak Y, Schwartz JK, Haldar S, Behera RK, Tosha T, Theil EC, Solomon EI. Spectroscopic studies of single and double variants of M ferritin: lack of conversion of a biferrous substrate site into a cofactor site for O2 activation. Biochemistry 2014; 53:473-82. [PMID: 24397299 PMCID: PMC3985457 DOI: 10.1021/bi4013726] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Ferritin has a binuclear non-heme
iron active site that functions
to oxidize iron as a substrate for formation of an iron mineral core.
Other enzymes of this class have tightly bound diiron cofactor sites
that activate O2 to react with substrate. Ferritin has
an active site ligand set with 1-His/4-carboxylate/1-Gln rather than
the 2-His/4-carboxylate set of the cofactor site. This ligand variation
has been thought to make a major contribution to this biferrous substrate
rather than cofactor site reactivity. However, the Q137E/D140H double
variant of M ferritin, has a ligand set that is equivalent to most
of the diiron cofactor sites, yet did not rapidly react with O2 or generate the peroxy intermediate observed in the cofactor
sites. Therefore, in this study, a combined spectroscopic methodology
of circular dichroism (CD)/magnetic CD (MCD)/variable temperature,
variable field (VTVH) MCD has been applied to evaluate the factors
required for the rapid O2 activation observed in cofactor
sites. This methodology defines the coordination environment of each
iron and the bridging ligation of the biferrous active sites in the
double and corresponding single variants of frog M ferritin. Based
on spectral changes, the D140H single variant has the new His ligand
binding, and the Q137E variant has the new carboxylate forming a μ-1,3
bridge. The spectra for the Q137E/D140H double variant, which has
the cofactor ligand set, however, reflects a site that is more coordinately
saturated than the cofactor sites in other enzymes including ribonucleotide
reductase, indicating the presence of additional water ligation. Correlation
of this double variant and the cofactor sites to their O2 reactivities indicates that electrostatic and steric changes in
the active site and, in particular, the hydrophobic nature of a cofactor
site associated with its second sphere protein environment, make important
contributions to the activation of O2 by the binuclear
non-heme iron enzymes.
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Affiliation(s)
- Yeonju Kwak
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
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38
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Lalli D, Turano P. Solution and solid state NMR approaches to draw iron pathways in the ferritin nanocage. Acc Chem Res 2013; 46:2676-85. [PMID: 24000809 DOI: 10.1021/ar4000983] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Ferritins are intracellular proteins that can store thousands of iron(III) ions as a solid mineral. These structures autoassemble from four-helix bundle subunits to form a hollow sphere and are a prototypical example of protein nanocages. The protein acts as a reservoir, encapsulating iron as ferric oxide in its central cavity in a nontoxic and bioavailable form. Scientists have long known the structural details of the protein shell, owing to very high resolution X-ray structures of the apoform. However, the atomic level mechanism governing the multistep biomineralization process remained largely elusive. Through analysis of the chemical behavior of ferritin mutants, chemists have found the role of some residues in key reaction steps. Using Mössbauer and XAS, they have identified some di-iron intermediates of the catalytic reaction trapped by rapid freeze quench. However, structural information about the iron interaction sites remains scarce. The entire process is governed by a number of specific, but weak, interactions between the protein shell and the iron species moving across the cage. While this situation may constitute a major problem for crystallography, NMR spectroscopy represents an optimal tool to detect and characterize transient species involving soluble proteins. Regardless, NMR analysis of the 480 kDa ferritin represents a real challenge. Our interest in ferritin chemistry inspired us to use an original combination of solution and solid state approaches. While the highly symmetric structure of the homo-24-mer frog ferritin greatly simplifies the spectra, the large protein size hinders the efficient coherence transfer in solution, thus preventing the sequence specific assignments. In contrast, extensive (13)C-spin diffusion makes the solution (13)C-(13)C NOESY experiment our gold standard to monitor protein side chains both in the apoprotein alone and in its interaction with paramagnetic iron species, inducing line broadening on the resonances of nearby residues. We could retrieve the structural information embedded in the (13)C-(13)C NOESY due to a partial sequence specific assignment of protein backbone and side chains we obtained from solid state MAS NMR of ferritin microcrystals. We used the 59 assigned amino acids (∼33% of the total) as probes to locate paramagnetic ferric species in the protein cage. Through this approach, we could identify ferric dimers at the ferroxidase site and on their pathway towards the nanocage. Comparison with existing data on bacterioferritins and bacterial ferritins, as well as with eukaryotic ferritins loaded with various nonfunctional divalent ions, allowed us to reinterpret the available information. The resulting picture of the ferroxidase site is slightly different with various ferritins but is designed to provide multiple and generally weak iron ligands. The latter assist binding of two incoming iron(II) ions in two proximal positions to facilitate coupling with oxygen. Subsequent oxidation is accompanied by a decrease in the metal-metal distance (consistent with XAS/Mössbauer) and in the number of protein residues involved in metal coordination, facilitating the release of products as di-iron clusters under the effect of new incoming iron(II) ions.
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Affiliation(s)
- Daniela Lalli
- CERM and Department of Chemistry, University of Florence, via Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy
| | - Paola Turano
- CERM and Department of Chemistry, University of Florence, via Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy
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39
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Pievo R, Angerstein B, Fielding AJ, Koch C, Feussner I, Bennati M. A rapid freeze-quench setup for multi-frequency EPR spectroscopy of enzymatic reactions. Chemphyschem 2013; 14:4094-101. [PMID: 24323853 DOI: 10.1002/cphc.201300714] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 10/22/2013] [Indexed: 11/11/2022]
Abstract
Electron paramagnetic resonance (EPR) spectroscopy in combination with the rapid freeze-quench (RFQ) technique is a well-established method to trap and characterize intermediates in chemical or enzymatic reactions at the millisecond or even shorter time scales. The method is particularly powerful for mechanistic studies of enzymatic reactions when combined with high-frequency EPR (ν≥90 GHz), which permits the identification of substrate or protein radical intermediates by their electronic g values. In this work, we describe a new custom-designed micro-mix rapid freeze-quench apparatus, for which reagent volumes for biological samples as small as 20 μL are required. The apparatus was implemented with homemade sample collectors appropriate for 9, 34, and 94 GHz EPR capillaries (4, 2, and 0.87 mm outer diameter, respectively) and the performance was evaluated. We demonstrate the application potential of the RFQ apparatus by following the enzymatic reaction of PpoA, a fungal dioxygenase producing hydro(pero)xylated fatty acids. The larger spectral resolution at 94 GHz allows the discernment of structural changes in the EPR spectra, which are not detectable in the same samples at the standard 9 GHz frequency.
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Affiliation(s)
- Roberta Pievo
- Max Planck Institute for Biophysical Chemistry, Am Faßberg 11, 37077 Göttingen (Germany).
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40
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Abstract
At the center of iron and oxidant metabolism is the ferritin superfamily: protein cages with Fe(2+) ion channels and two catalytic Fe/O redox centers that initiate the formation of caged Fe2O3·H2O. Ferritin nanominerals, initiated within the protein cage, grow inside the cage cavity (5 or 8 nm in diameter). Ferritins contribute to normal iron flow, maintenance of iron concentrates for iron cofactor syntheses, sequestration of iron from invading pathogens, oxidant protection, oxidative stress recovery, and, in diseases where iron accumulates excessively, iron chelation strategies. In eukaryotic ferritins, biomineral order/crystallinity is influenced by nucleation channels between active sites and the mineral growth cavity. Animal ferritin cages contain, uniquely, mixtures of catalytically active (H) and inactive (L) polypeptide subunits with varied rates of Fe(2+)/O2 catalysis and mineral crystallinity. The relatively low mineral order in liver ferritin, for example, coincides with a high percentage of L subunits and, thus, a low percentage of catalytic sites and nucleation channels. Low mineral order facilitates rapid iron turnover and the physiological role of liver ferritin as a general iron source for other tissues. Here, current concepts of ferritin structure/function/genetic regulation are discussed and related to possible therapeutic targets such as mini-ferritin/Dps protein active sites (selective pathogen inhibition in infection), nanocage pores (iron chelation in therapeutic hypertransfusion), mRNA noncoding, IRE riboregulator (normalizing the ferritin iron content after therapeutic hypertransfusion), and protein nanovessels to deliver medicinal or sensor cargo.
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Affiliation(s)
- Elizabeth C Theil
- Children's Hospital Oakland Research Institute (CHORI) , 5700 Martin Luther King Jr. Way, Oakland, California 94609, United States , and Department of Molecular and Structural Biochemistry, North Carolina State University , Raleigh, North Carolina 2765-7622, United States
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41
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Dassama LMK, Silakov A, Krest CM, Calixto JC, Krebs C, Bollinger JM, Green MT. A 2.8 Å Fe-Fe separation in the Fe2(III/IV) intermediate, X, from Escherichia coli ribonucleotide reductase. J Am Chem Soc 2013; 135:16758-61. [PMID: 24094084 DOI: 10.1021/ja407438p] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A class Ia ribonucleotide reductase (RNR) employs a μ-oxo-Fe2(III/III)/tyrosyl radical cofactor in its β subunit to oxidize a cysteine residue ~35 Å away in its α subunit; the resultant cysteine radical initiates substrate reduction. During self-assembly of the Escherichia coli RNR-β cofactor, reaction of the protein's Fe2(II/II) complex with O2 results in accumulation of an Fe2(III/IV) cluster, termed X, which oxidizes the adjacent tyrosine (Y122) to the radical (Y122(•)) as the cluster is converted to the μ-oxo-Fe2(III/III) product. As the first high-valent non-heme-iron enzyme complex to be identified and the key activating intermediate of class Ia RNRs, X has been the focus of intensive efforts to determine its structure. Initial characterization by extended X-ray absorption fine structure (EXAFS) spectroscopy yielded a Fe-Fe separation (d(Fe-Fe)) of 2.5 Å, which was interpreted to imply the presence of three single-atom bridges (O(2-), HO(-), and/or μ-1,1-carboxylates). This short distance has been irreconcilable with computational and synthetic models, which all have d(Fe-Fe) ≥ 2.7 Å. To resolve this conundrum, we revisited the EXAFS characterization of X. Assuming that samples containing increased concentrations of the intermediate would yield EXAFS data of improved quality, we applied our recently developed method of generating O2 in situ from chlorite using the enzyme chlorite dismutase to prepare X at ~2.0 mM, more than 2.5 times the concentration realized in the previous EXAFS study. The measured d(Fe-Fe) = 2.78 Å is fully consistent with computational models containing a (μ-oxo)2-Fe2(III/IV) core. Correction of the d(Fe-Fe) brings the experimental data and computational models into full conformity and informs analysis of the mechanism by which X generates Y122(•).
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Affiliation(s)
- Laura M K Dassama
- Departments of †Chemistry and ‡Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
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Carmona F, Palacios Ò, Gálvez N, Cuesta R, Atrian S, Capdevila M, Domínguez-Vera JM. Ferritin iron uptake and release in the presence of metals and metalloproteins: Chemical implications in the brain. Coord Chem Rev 2013. [DOI: 10.1016/j.ccr.2013.03.034] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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43
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Crans DC, Woll KA, Prusinskas K, Johnson MD, Norkus E. Metal speciation in health and medicine represented by iron and vanadium. Inorg Chem 2013; 52:12262-75. [PMID: 24041403 DOI: 10.1021/ic4007873] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The influence of metals in biology has become more and more apparent within the past century. Metal ions perform essential roles as critical scaffolds for structure and as catalysts in reactions. Speciation is a key concept that assists researchers in investigating processes that involve metal ions. However, translation of the essential area across scientific fields has been plagued by language discrepancies. To rectify this, the IUPAC Commission provided a framework in which speciation is defined as the distribution of species. Despite these attempts, contributions from inorganic chemists to the area of speciation have not fully materialized in part because the past decade's contributions focused on technological advances, which are not yet to the stage of measuring speciation distribution in biological solutions. In the following, we describe how speciation influences the area of metals in medicine and how speciation distribution has been characterized so far. We provide two case studies as an illustration, namely, vanadium and iron. Vanadium both has therapeutic importance and is known as a cofactor for metalloenzymes. In addition to being a cation, vanadium(V) has analogy with phosphorus and as such is a potent inhibitor for phosphorylases. Because speciation can change the metal's existence in cationic or anionic forms, speciation has profound effects on biological systems. We also highlight how speciation impacts iron metabolism, focusing on the rather low abundance of biologically relevant iron cation that actually exists in biological fluids. fluids. Furthermore, we point to recent investigations into the mechanism of Fenton chemistry, and that the emerging results show pH dependence. The studies suggest formation of Fe(IV)-intermediates and that the generally accepted mechanism may only apply at low pH. With broader recognition toward biological speciation, we are confident that future investigations on metal-based systems will progress faster and with significant results. Studying metal complexes to explore the properties of a potential "active species" and further uncovering the details associated with their specific composition and geometry are likely to be important to the action.
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Affiliation(s)
- Debbie C Crans
- Department of Chemistry, Colorado State University , Fort Collins, Colorado 80523, United States
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44
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Pap JS, Cranswick MA, Balogh-Hergovich E, Baráth G, Giorgi M, Rohde GT, Kaizer J, Speier G, Que L. An Iron(II)(1,3-bis(2'-pyridylimino)isoindoline) Complex as a Catalyst for Substrate Oxidation with H 2O 2. Evidence for a Transient Peroxodiiron(III) Species. Eur J Inorg Chem 2013; 2013:3858-3866. [PMID: 24587695 PMCID: PMC3935335 DOI: 10.1002/ejic.201300162] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Indexed: 11/06/2022]
Abstract
The complex [Fe(indH)(solvent)3](ClO4)2 (1) has been isolated from the reaction of equimolar amounts of 1,3-bis(2'-pyridylimino)isoindoline (indH) and Fe(ClO4)2 in acetonitrile and characterized by X-ray crystallography and several spectroscopic techniques. It is a suitable catalyst for the oxidation of thioanisoles and benzyl alcohols with H2O2 as the oxidant. Hammett correlations and kinetic isotope effect experiments support the involvement of an electrophilic metal-based oxidant. A metastable green species (2) is observed when 1 is reacted with H2O2 at -40 °C, which has been characterized to have a FeIII(μ-O)(μ-O2)FeIII core on the basis of UV-Vis, electron paramagnetic resonance, resonance Raman, and X-ray absorption spectroscopic data.
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Affiliation(s)
- József S Pap
- Department of Chemistry, University of Pannonia, 8201 Veszprém, Wartha Vince u. 1., Hungary
| | - Matthew A Cranswick
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN 55455, USA
| | - E Balogh-Hergovich
- Department of Chemistry, University of Pannonia, 8201 Veszprém, Wartha Vince u. 1., Hungary
| | - Gábor Baráth
- Department of Chemistry, University of Pannonia, 8201 Veszprém, Wartha Vince u. 1., Hungary
| | - Michel Giorgi
- Aix-Marseille Université, FR1739, Spectropole, Campus St. Jérôme, Avenue Escadrille Normandie-Niemen, 13397 Marseille cedex 20, France
| | - Gregory T Rohde
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN 55455, USA
| | - József Kaizer
- Department of Chemistry, University of Pannonia, 8201 Veszprém, Wartha Vince u. 1., Hungary
| | - Gábor Speier
- Department of Chemistry, University of Pannonia, 8201 Veszprém, Wartha Vince u. 1., Hungary
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN 55455, USA
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Harris TV, Morokuma K. QM/MM Structural and Spectroscopic Analysis of the Di-iron(II) and Di-iron(III) Ferroxidase Site in M Ferritin. Inorg Chem 2013; 52:8551-63. [DOI: 10.1021/ic4006168] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Travis V. Harris
- Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan
| | - Keiji Morokuma
- Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan
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46
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Ebrahimi KH, Hagedoorn PL, Hagen WR. A Conserved Tyrosine in Ferritin Is a Molecular Capacitor. Chembiochem 2013; 14:1123-33. [DOI: 10.1002/cbic.201300149] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Indexed: 11/06/2022]
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Pfaffen S, Abdulqadir R, Le Brun NE, Murphy MEP. Mechanism of ferrous iron binding and oxidation by ferritin from a pennate diatom. J Biol Chem 2013; 288:14917-25. [PMID: 23548912 PMCID: PMC3663513 DOI: 10.1074/jbc.m113.454496] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
A novel ferritin was recently found in Pseudo-nitzschia multiseries (PmFTN), a marine pennate diatom that plays a major role in global primary production and carbon sequestration into the deep ocean. Crystals of recombinant PmFTN were soaked in iron and zinc solutions, and the structures were solved to 1.65–2.2-Å resolution. Three distinct iron binding sites were identified as determined from anomalous dispersion data from aerobically grown ferrous soaked crystals. Sites A and B comprise the conserved ferroxidase active site, and site C forms a pathway leading toward the central cavity where iron storage occurs. In contrast, crystal structures derived from anaerobically grown and ferrous soaked crystals revealed only one ferrous iron in the active site occupying site A. In the presence of dioxygen, zinc is observed bound to all three sites. Iron oxidation experiments using stopped-flow absorbance spectroscopy revealed an extremely rapid phase corresponding to Fe(II) oxidation at the ferroxidase site, which is saturated after adding 48 ferrous iron to apo-PmFTN (two ferrous iron per subunit), and a much slower phase due to iron core formation. These results suggest an ordered stepwise binding of ferrous iron and dioxygen to the ferroxidase site in preparation for catalysis and a partial mobilization of iron from the site following oxidation.
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Affiliation(s)
- Stephanie Pfaffen
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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48
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Watt RK. A Unified Model for Ferritin Iron Loading by the Catalytic Center: Implications for Controlling “Free Iron” during Oxidative Stress. Chembiochem 2013; 14:415-9. [DOI: 10.1002/cbic.201200783] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Indexed: 11/07/2022]
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Abstract
Ferritins, highly symmetrical protein nanocages, are reactors for Fe2+ and dioxygen or hydrogen peroxide that are found in all kingdoms of life and in many different cells of multicellular organisms. They synthesize iron concentrates required for cells to make cofactors of iron proteins (heme, FeS, mono and diiron). The caged ferritin biominerals, Fe2O3•H2O are also antioxidants, acting as sinks for iron and oxidants scavenged from damaged proteins; genetic regulation of ferritin biosynthesis is sensitive to both iron and oxidants. Here, the emphasis here is ferritin oxidoreductase chemistry, ferritin ion channels for Fe 2+ transit into and out of the protein cage and Fe 3+ O mineral nucleation, and uses of ferritin cages in nanocatalysis and nanomaterial synthesis. The Fe2+ and O ferritin protein reactors, likely critical in the transition from anaerobic to aerobic life on earth, play central, contemporary roles that balance iron and oxygen chemistry in biology and have emerging roles in nanotechnology.
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Affiliation(s)
- Elizabeth C. Theil
- Children’s Hospital Oakland Research Institute, University of California, Berkeley
- Department of Nutritional Science and Toxicology, University of California, Berkeley
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50
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Cranswick MA, Meier KK, Shan X, Stubna A, Kaizer J, Mehn MP, Münck E, Que L. Protonation of a peroxodiiron(III) complex and conversion to a diiron(III/IV) intermediate: implications for proton-assisted O-O bond cleavage in nonheme diiron enzymes. Inorg Chem 2012; 51:10417-26. [PMID: 22971084 PMCID: PMC3462276 DOI: 10.1021/ic301642w] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Oxygenation of a diiron(II) complex, [Fe(II)(2)(μ-OH)(2)(BnBQA)(2)(NCMe)(2)](2+) [2, where BnBQA is N-benzyl-N,N-bis(2-quinolinylmethyl)amine], results in the formation of a metastable peroxodiferric intermediate, 3. The treatment of 3 with strong acid affords its conjugate acid, 4, in which the (μ-oxo)(μ-1,2-peroxo)diiron(III) core of 3 is protonated at the oxo bridge. The core structures of 3 and 4 are characterized in detail by UV-vis, Mössbauer, resonance Raman, and X-ray absorption spectroscopies. Complex 4 is shorter-lived than 3 and decays to generate in ~20% yield of a diiron(III/IV) species 5, which can be identified by electron paramagnetic resonance and Mössbauer spectroscopies. This reaction sequence demonstrates for the first time that protonation of the oxo bridge of a (μ-oxo)(μ-1,2-peroxo)diiron(III) complex leads to cleavage of the peroxo O-O bond and formation of a high-valent diiron complex, thereby mimicking the steps involved in the formation of intermediate X in the activation cycle of ribonucleotide reductase.
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Affiliation(s)
- Matthew A. Cranswick
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455
| | - Katlyn K. Meier
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Xiaopeng Shan
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455
| | - Audria Stubna
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Jószef Kaizer
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455
| | - Mark P. Mehn
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455
| | - Eckard Münck
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455
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