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Zuo Z, Zhou Z, Chang Y, Liu Y, Shen Y, Li Q, Zhang L. Ribonucleotide reductase M2 (RRM2): Regulation, function and targeting strategy in human cancer. Genes Dis 2024; 11:218-233. [PMID: 37588202 PMCID: PMC10425756 DOI: 10.1016/j.gendis.2022.11.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 10/26/2022] [Accepted: 11/14/2022] [Indexed: 12/29/2022] Open
Abstract
Ribonucleotide reductase M2 (RRM2) is a small subunit in ribonucleotide reductases, which participate in nucleotide metabolism and catalyze the conversion of nucleotides to deoxynucleotides, maintaining the dNTP pools for DNA biosynthesis, repair, and replication. RRM2 performs a critical role in the malignant biological behaviors of cancers. The structure, regulation, and function of RRM2 and its inhibitors were discussed. RRM2 gene can produce two transcripts encoding the same ORF. RRM2 expression is regulated at multiple levels during the processes from transcription to translation. Moreover, this gene is associated with resistance, regulated cell death, and tumor immunity. In order to develop and design inhibitors of RRM2, appropriate strategies can be adopted based on different mechanisms. Thus, a greater appreciation of the characteristics of RRM2 is a benefit for understanding tumorigenesis, resistance in cancer, and tumor microenvironment. Moreover, RRM2-targeted therapy will be more attention in future therapeutic approaches for enhancement of treatment effects and amelioration of the dismal prognosis.
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Affiliation(s)
- Zanwen Zuo
- Innovative Drug R&D Center, College of Life Sciences, Huaibei Normal University, Huaibei, Anhui 235000, China
- National “111” Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Key Laboratory of Industrial Microbiology, Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), and School of Food and Biological Engineering, Hubei University of Technology, Wuhan, Hubei 430068, China
| | - Zerong Zhou
- Innovative Drug R&D Center, College of Life Sciences, Huaibei Normal University, Huaibei, Anhui 235000, China
- National “111” Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Key Laboratory of Industrial Microbiology, Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), and School of Food and Biological Engineering, Hubei University of Technology, Wuhan, Hubei 430068, China
| | - Yuzhou Chang
- Department of Biomedical Informatics, The Ohio State University, Columbus, OH 43210, USA
| | - Yan Liu
- School of Agriculture and Biology, and Engineering Research Center of Cell & Therapeutic Antibody, Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yuping Shen
- College of Chemistry and Bioengineering, Hunan University of Science and Engineering, Yongzhou, Hunan 425199, China
| | - Qizhang Li
- Innovative Drug R&D Center, College of Life Sciences, Huaibei Normal University, Huaibei, Anhui 235000, China
- National “111” Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Key Laboratory of Industrial Microbiology, Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), and School of Food and Biological Engineering, Hubei University of Technology, Wuhan, Hubei 430068, China
| | - Lei Zhang
- Innovative Drug R&D Center, College of Life Sciences, Huaibei Normal University, Huaibei, Anhui 235000, China
- Department of Pharmaceutical Botany, School of Pharmacy, Naval Medical University, Shanghai 200433, China
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Battistella B, Lohmiller T, Cula B, Hildebrandt P, Kuhlmann U, Dau H, Mebs S, Ray K. A New Thiolate-Bound Dimanganese Cluster as a Structural and Functional Model for Class Ib Ribonucleotide Reductases. Angew Chem Int Ed Engl 2023; 62:e202217076. [PMID: 36583430 DOI: 10.1002/anie.202217076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 12/24/2022] [Accepted: 12/29/2022] [Indexed: 12/31/2022]
Abstract
In class Ib ribonucleotide reductases (RNRs) a dimanganese(II) cluster activates superoxide (O2 ⋅- ) rather than dioxygen (O2 ), to access a high valent MnIII -O2 -MnIV species, responsible for the oxidation of tyrosine to tyrosyl radical. In a biomimetic approach, we report the synthesis of a thiolate-bound dimanganese complex [MnII 2 (BPMT)(OAc)2 ](ClO)4 (BPMT=(2,6-bis{[bis(2-pyridylmethyl)amino]methyl}-4-methylthiophenolate) (1) and its reaction with O2 ⋅- to form a [(BPMT)MnO2 Mn]2+ complex 2. Resonance Raman investigation revealed the presence of an O-O bond in 2, while EPR analysis displayed a 16-line St =1/2 signal at g=2 typically associated with a MnIII MnIV core, as detected in class Ib RNRs. Unlike all other previously reported Mn-O2 -Mn complexes, generated by O2 ⋅- activation at Mn2 centers, 2 proved to be a capable electrophilic oxidant in aldehyde deformylation and phenol oxidation reactions, rendering it one of the best structural and functional models for class Ib RNRs.
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Affiliation(s)
- Beatrice Battistella
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Thomas Lohmiller
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany.,EPR4Energy Joint Lab, Department Spins in Energy Conversion and Quantum Information Science, Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 16, 12489, Berlin, Germany
| | - Beatrice Cula
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Peter Hildebrandt
- Institut für Chemie, Fakultät II, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Uwe Kuhlmann
- Institut für Chemie, Fakultät II, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Holger Dau
- Institut für Physik, Freie Universität zu Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Stefan Mebs
- Institut für Physik, Freie Universität zu Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Kallol Ray
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
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The “Infernaccio” Gorges: Microbial Diversity of Black Deposits and Isolation of Manganese-Solubilizing Bacteria. BIOLOGY 2022; 11:biology11081204. [PMID: 36009831 PMCID: PMC9404752 DOI: 10.3390/biology11081204] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/02/2022] [Accepted: 08/10/2022] [Indexed: 11/17/2022]
Abstract
Simple Summary “Infernaccio” gorges are one of the Earth’s hidden habitats in Central Italy. Beyond the deep incisions and high slopes, these gorges are characterized by black deposits in gorge walls and covering rock surfaces. Several geological events have shaped these unique geological formations and their microbiota. This study investigated microbial contribution to black deposit formation and isolating Mn-oxide-solubilizing bacteria. Our results provided evidence of the putative role of Bacteria and Archaea in forming manganese oxide deposits. Findings also showed that these deposits are a source of valuable strains with manganese oxide bioleaching properties, essential for bioremediation and metal recovery. Abstract The present study explored the microbial diversity of black deposits found in the “Infernaccio” gorge. X-ray Powdered Diffraction (XRPD) was used to investigate the crystallinity of the samples and to identify the minerals. Scanning electron microscope and energy-dispersive X-ray spectroscopy (SEM-EDS) were used to detect the bacterial imprints, analyze microbe–mineral interactions, and highlight the chemical element distribution in the black deposits. 16S rRNA gene metabarcoding allowed the study of Archaea and Bacteria communities. Mn-oxide-solubilizing isolates were also obtained and characterized by culturable and molecular approaches. The multidisciplinary approach showed the occurrence of deposits composed of birnessite, diopside, halloysite, and leucite. Numerous bacterial imprints confirmed the role of microorganisms in forming these deposits. The Bacteria and Archaea communities associated with these deposits and runoff waters are dynamic and shaped by seasonal changes. The uncultured and unknown taxa are the most common and abundant. These amplicon sequence variants (ASVs) were mainly assigned to Proteobacteria and Bacteroidetes phyla. Six isolates showed interesting Mn solubilization abilities under microaerophilic conditions. Molecular characterization associated isolates to Brevibacterium, Bacillus, Neobacillus, and Rhodococcus genera. The findings enriched our knowledge of geomicrobiological aspects of one of the Earth’s hidden habitats. The study also unveiled the potential of this environment as an isolation source of biotechnologically relevant bacteria.
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A new phenolato-bridged dinuclear manganese(II) complex as a turn-on fluorosensor for Zn2+ ions via Mn2+ ion replacement. Polyhedron 2021. [DOI: 10.1016/j.poly.2021.115226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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A rare flattened tetrahedral Mn(II) salen type complex: Synthesis, crystal structure, biomimetic catalysis and DFT study. Inorganica Chim Acta 2020. [DOI: 10.1016/j.ica.2019.119176] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Balamurugan M, Saravanan N, Ha H, Lee YH, Nam KT. Involvement of high-valent manganese-oxo intermediates in oxidation reactions: realisation in nature, nano and molecular systems. NANO CONVERGENCE 2018; 5:18. [PMID: 30101051 PMCID: PMC6061251 DOI: 10.1186/s40580-018-0150-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 06/19/2018] [Indexed: 05/12/2023]
Abstract
Manganese plays multiple role in many biological redox reactions in which it exists in different oxidation states from Mn(II) to Mn(IV). Among them the high-valent manganese-oxo intermediate plays important role in the activity of certain enzymes and lessons from the natural system provide inspiration for new developments of artificial systems for a sustainable energy supply and various organic conversions. This review describes recent advances and key lessons learned from the nature on high-valent Mn-oxo intermediates. Also we focus on the elemental science developed from the natural system, how the novel strategies are realised in nano particles and molecular sites at heterogeneous and homogeneous reaction conditions respectively. Finally, perspectives on the utilisation of the high-valent manganese-oxo species towards other organic reactions are proposed.
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Affiliation(s)
- Mani Balamurugan
- Department of Materials Science and Engineering, Seoul National University, Seoul, 151-744 South Korea
| | - Natarajan Saravanan
- Department of Materials Science and Engineering, Seoul National University, Seoul, 151-744 South Korea
| | - Heonjin Ha
- Department of Materials Science and Engineering, Seoul National University, Seoul, 151-744 South Korea
| | - Yoon Ho Lee
- Department of Materials Science and Engineering, Seoul National University, Seoul, 151-744 South Korea
| | - Ki Tae Nam
- Department of Materials Science and Engineering, Seoul National University, Seoul, 151-744 South Korea
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7
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Synthesis and magnetic properties of a dinuclear manganese(II) complex with two manganese(II) ions of C2-twisted octahedral geometry. Polyhedron 2016. [DOI: 10.1016/j.poly.2016.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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8
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Bagherzadeh M, Ghanbarpour A, Khavasi HR. Highly efficient aerobic epoxidation of cyclic olefins in mild conditions by a novel binuclear manganese(II) complex containing N-(4-nitrophenyl)picolinamide ligand. CATAL COMMUN 2015. [DOI: 10.1016/j.catcom.2015.02.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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9
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Huang M, Parker MJ, Stubbe J. Choosing the right metal: case studies of class I ribonucleotide reductases. J Biol Chem 2014; 289:28104-11. [PMID: 25160629 DOI: 10.1074/jbc.r114.596684] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Over one-third of all proteins require metallation for function (Waldron, K. J., Rutherford, J. C., Ford, D., and Robinson, N.J. (2009) Nature 460, 823-830). As biochemical studies of most proteins depend on their isolation subsequent to recombinant expression (i.e. they are seldom purified from their host organism), there is no gold standard to assess faithful metallocofactor assembly and associated function. The biosynthetic machinery for metallocofactor formation in the recombinant expression system may be absent, inadequately expressed, or incompatible with a heterologously expressed protein. A combination of biochemical and genetic studies has led to the identification of key proteins involved in biosynthesis and likely repair of the metallocofactor of ribonucleotide reductases in both bacteria and the budding yeast. In this minireview, we will discuss the recent progress in understanding controlled delivery of metal, oxidants, and reducing equivalents for cofactor assembly in ribonucleotide reductases and highlight issues associated with controlling Fe/Mn metallation and avoidance of mismetallation.
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Affiliation(s)
- Mingxia Huang
- From the Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045 and
| | | | - JoAnne Stubbe
- the Departments of Chemistry and Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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10
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Blomberg MRA, Borowski T, Himo F, Liao RZ, Siegbahn PEM. Quantum chemical studies of mechanisms for metalloenzymes. Chem Rev 2014; 114:3601-58. [PMID: 24410477 DOI: 10.1021/cr400388t] [Citation(s) in RCA: 436] [Impact Index Per Article: 43.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Margareta R A Blomberg
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University , SE-106 91 Stockholm, Sweden
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11
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ZHANG C, LIU G, HUANG M. Ribonucleotide reductase metallocofactor: assembly, maintenance and inhibition. FRONTIERS IN BIOLOGY 2014; 9:104-113. [PMID: 24899886 PMCID: PMC4041730 DOI: 10.1007/s11515-014-1302-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Ribonucleotide reductase (RNR) supplies cellular deoxyribonucleotide triphosphates (dNTP) pools by converting ribonucleotides to the corresponding deoxy forms using radical-based chemistry. Eukaryotic RNR comprises α and β subunits: α contains the catalytic and allosteric sites; β houses a diferric-tyrosyl radical cofactor (FeIII2-Y•) that is required to initiates nucleotide reduction in α. Cells have evolved multi-layered mechanisms to regulate RNR level and activity in order to maintain the adequate sizes and ratios of their dNTP pools to ensure high-fidelity DNA replication and repair. The central role of RNR in nucleotide metabolism also makes it a proven target of chemotherapeutics. In this review, we discuss recent progress in understanding the function and regulation of eukaryotic RNRs, with a focus on studies revealing the cellular machineries involved in RNR metallocofactor biosynthesis and its implication in RNR-targeting therapeutics.
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Affiliation(s)
- Caiguo ZHANG
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Guoqi LIU
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Mingxia HUANG
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA
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12
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Sujith PP, Mourya BS, Krishnamurthi S, Meena RM, Loka Bharathi PA. Mobilization of manganese by basalt associated Mn(II)-oxidizing bacteria from the Indian Ridge System. CHEMOSPHERE 2014; 95:486-495. [PMID: 24183631 DOI: 10.1016/j.chemosphere.2013.09.103] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 09/18/2013] [Accepted: 09/26/2013] [Indexed: 06/02/2023]
Abstract
The Indian Ridge System basalt bearing Mn-oxide coatings had todorokite as the major and birnesite as the minor mineral. We posit that microorganisms associated with these basalts participate in the oxidation of Mn and contribute to mineral deposition. We also hypothesized that, the Mn-oxidizing microbes may respond reversibly to pulses of fresh organic carbon introduced into the water column by mobilizing the Mn in Mn-oxides. To test these two hypotheses, we enumerated the number of Mn-oxidizers and -reducers and carried out studies on the mobilization of Mn by microbial communities associated with basalt. In medium containing 100 μM Mn(2+), 10(3) colony forming units (CFU) were recovered with undetectable number of reducers on Mn-oxide amended medium, suggesting that the community was more oxidative. Experiments were then conducted with basalt fragments at 4±2 °C in the presence 'G(+)' and absence 'G(-)' of glucose (0.1%). Controls included set-ups, some of which were poisoned with 15 mM azide and the others of which were heat-killed. The mobilization of Mn in the presence of glucose was 1.76 μg g(-1) d(-1) and in the absence, it was 0.17 μg g(-1) d(-1) after 150 d. Mn mobilization with and without added glucose was 13 and 4 times greater than the corresponding azide treated controls. However, rates in 'G(+)' were 16 times and 'G(-)' 24 times more than the respective heat killed controls. The corresponding total counts in the presence of added glucose increased from 1.63×10(6) to 6.71×10(7) cells g(-1) and from 1.41×10(7) to 3.52×10(7) cells g(-1) in its absence. Thus, the addition of glucose as a proxy for organic carbon changed the community's response from Mn(II)-oxidizing to Mn(IV)-reducing activity. The results confirm the participation of Mn oxidizing bacteria in the mobilization of Mn. Identification of culturable bacteria by 16S rRNA gene analysis showed taxonomic affiliations to Bacillus, Exiguobacterium, Staphylococcus, Brevibacterium and Alcanivorax sp.
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Affiliation(s)
- P P Sujith
- Microbiology Laboratory, National Institute of Oceanography, Council of Scientific and Industrial Research, Dona Paula 403 004, Goa, India
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13
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Crystal structure, infrared and EPR spectra and anticancer activity in vitro of the novel manganese(II) complexes of indolecarboxylic acids. Polyhedron 2014. [DOI: 10.1016/j.poly.2013.10.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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14
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Roos K, Siegbahn PEM. Activation of Dimanganese Class Ib Ribonucleotide Reductase by Hydrogen Peroxide: Mechanistic Insights from Density Functional Theory. Inorg Chem 2013; 52:4173-84. [DOI: 10.1021/ic3008427] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Katarina Roos
- Department of Physics, Stockholm University, SE-106 91 Stockholm,
Sweden
| | - Per E. M. Siegbahn
- Department of Physics, Stockholm University, SE-106 91 Stockholm,
Sweden
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15
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Tomter AB, Zoppellaro G, Andersen NH, Hersleth HP, Hammerstad M, Røhr ÅK, Sandvik GK, Strand KR, Nilsson GE, Bell CB, Barra AL, Blasco E, Le Pape L, Solomon EI, Andersson KK. Ribonucleotide reductase class I with different radical generating clusters. Coord Chem Rev 2013. [DOI: 10.1016/j.ccr.2012.05.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Cotruvo JA, Stubbe J. Metallation and mismetallation of iron and manganese proteins in vitro and in vivo: the class I ribonucleotide reductases as a case study. Metallomics 2012; 4:1020-36. [PMID: 22991063 PMCID: PMC3488304 DOI: 10.1039/c2mt20142a] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
How cells ensure correct metallation of a given protein and whether a degree of promiscuity in metal binding has evolved are largely unanswered questions. In a classic case, iron- and manganese-dependent superoxide dismutases (SODs) catalyze the disproportionation of superoxide using highly similar protein scaffolds and nearly identical active sites. However, most of these enzymes are active with only one metal, although both metals can bind in vitro and in vivo. Iron(ii) and manganese(ii) bind weakly to most proteins and possess similar coordination preferences. Their distinct redox properties suggest that they are unlikely to be interchangeable in biological systems except when they function in Lewis acid catalytic roles, yet recent work suggests this is not always the case. This review summarizes the diversity of ways in which iron and manganese are substituted in similar or identical protein frameworks. As models, we discuss (1) enzymes, such as epimerases, thought to use Fe(II) as a Lewis acid under normal growth conditions but which switch to Mn(II) under oxidative stress; (2) extradiol dioxygenases, which have been found to use both Fe(II) and Mn(II), the redox role of which in catalysis remains to be elucidated; (3) SODs, which use redox chemistry and are generally metal-specific; and (4) the class I ribonucleotide reductases (RNRs), which have evolved unique biosynthetic pathways to control metallation. The primary focus is the class Ib RNRs, which can catalyze formation of a stable radical on a tyrosine residue in their β2 subunits using either a di-iron or a recently characterized dimanganese cofactor. The physiological roles of enzymes that can switch between iron and manganese cofactors are discussed, as are insights obtained from the studies of many groups regarding iron and manganese homeostasis and the divergent and convergent strategies organisms use for control of protein metallation. We propose that, in many of the systems discussed, "discrimination" between metals is not performed by the protein itself, but it is instead determined by the environment in which the protein is expressed.
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Affiliation(s)
- Joseph A. Cotruvo
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA.; Fax: +1 617 324-0505; Tel: +1 617 253-1814
| | - JoAnne Stubbe
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA.; Fax: +1 617 324-0505; Tel: +1 617 253-1814
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA
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Gustafsson TN, Sahlin M, Lu J, Sjöberg BM, Holmgren A. Bacillus anthracis thioredoxin systems, characterization and role as electron donors for ribonucleotide reductase. J Biol Chem 2012; 287:39686-97. [PMID: 23012357 DOI: 10.1074/jbc.m112.413427] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Bacillus anthracis is the causative agent of anthrax, which is associated with a high mortality rate. Like several medically important bacteria, B. anthracis lacks glutathione but encodes many genes annotated as thioredoxins, thioredoxin reductases, and glutaredoxin-like proteins. We have cloned, expressed, and characterized three potential thioredoxins, two potential thioredoxin reductases, and three glutaredoxin-like proteins. Of these, thioredoxin 1 (Trx1) and NrdH reduced insulin, 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB), and the manganese-containing type Ib ribonucleotide reductase (RNR) from B. anthracis in the presence of NADPH and thioredoxin reductase 1 (TR1), whereas thioredoxin 2 (Trx2) could only reduce DTNB. Potential TR2 was verified as an FAD-containing protein reducible by dithiothreitol but not by NAD(P)H. The recently discovered monothiol bacillithiol did not work as a reductant for RNR, either directly or via any of the redoxins. The catalytic efficiency of Trx1 was 3 and 20 times higher than that of Trx2 and NrdH, respectively, as substrates for TR1. Additionally, the catalytic efficiency of Trx1 as an electron donor for RNR was 7-fold higher than that of NrdH. In extracts of B. anthracis, Trx1 was responsible for almost all of the disulfide reductase activity, whereas Western blots showed that the level of Trx1 was 15 and 60 times higher than that of Trx2 and NrdH, respectively. Our findings demonstrate that the most important general disulfide reductase system in B. anthracis is TR1/Trx1 and that Trx1 is the physiologically relevant electron donor for RNR. This information may provide a basis for the development of novel antimicrobial therapies targeting this severe pathogen.
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Affiliation(s)
- Tomas N Gustafsson
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet SE-17177 Stockholm, Sweden
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Sutradhar M, Carrella LM, Rentschler E. Mononuclear Mn(III) and dinuclear Mn(III,III) Schiff base complexes: Influence of π–π stacking on magnetic properties. Polyhedron 2012. [DOI: 10.1016/j.poly.2012.03.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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19
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Spectroscopic studies of the iron and manganese reconstituted tyrosyl radical in Bacillus cereus ribonucleotide reductase R2 protein. PLoS One 2012; 7:e33436. [PMID: 22432022 PMCID: PMC3303829 DOI: 10.1371/journal.pone.0033436] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 02/08/2012] [Indexed: 11/24/2022] Open
Abstract
Ribonucleotide reductase (RNR) catalyzes the rate limiting step in DNA synthesis where ribonucleotides are reduced to the corresponding deoxyribonucleotides. Class Ib RNRs consist of two homodimeric subunits: R1E, which houses the active site; and R2F, which contains a metallo cofactor and a tyrosyl radical that initiates the ribonucleotide reduction reaction. We studied the R2F subunit of B. cereus reconstituted with iron or alternatively with manganese ions, then subsequently reacted with molecular oxygen to generate two tyrosyl-radicals. The two similar X-band EPR spectra did not change significantly over 4 to 50 K. From the 285 GHz EPR spectrum of the iron form, a g1-value of 2.0090 for the tyrosyl radical was extracted. This g1-value is similar to that observed in class Ia E. coli R2 and class Ib R2Fs with iron-oxygen cluster, suggesting the absence of hydrogen bond to the phenoxyl group. This was confirmed by resonance Raman spectroscopy, where the stretching vibration associated to the radical (C-O, ν7a = 1500 cm−1) was found to be insensitive to deuterium-oxide exchange. Additionally, the 18O-sensitive Fe-O-Fe symmetric stretching (483 cm−1) of the metallo-cofactor was also insensitive to deuterium-oxide exchange indicating no hydrogen bonding to the di-iron-oxygen cluster, and thus, different from mouse R2 with a hydrogen bonded cluster. The HF-EPR spectrum of the manganese reconstituted RNR R2F gave a g1-value of ∼2.0094. The tyrosyl radical microwave power saturation behavior of the iron-oxygen cluster form was as observed in class Ia R2, with diamagnetic di-ferric cluster ground state, while the properties of the manganese reconstituted form indicated a magnetic ground state of the manganese-cluster. The recent activity measurements (Crona et al., (2011) J Biol Chem 286: 33053–33060) indicates that both the manganese and iron reconstituted RNR R2F could be functional. The manganese form might be very important, as it has 8 times higher activity.
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Roos K, Siegbahn PEM. A comparison of two-electron chemistry performed by the manganese and iron heterodimer and homodimers. J Biol Inorg Chem 2011; 17:363-73. [DOI: 10.1007/s00775-011-0858-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Accepted: 11/02/2011] [Indexed: 10/15/2022]
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Han WG, Sandala GM, Giammona DA, Bashford D, Noodleman L. Mössbauer properties of the diferric cluster and the differential iron(II)-binding affinity of the iron sites in protein R2 of class Ia Escherichia coli ribonucleotide reductase: a DFT/electrostatics study. Dalton Trans 2011; 40:11164-75. [PMID: 21837345 PMCID: PMC3604995 DOI: 10.1039/c1dt10950b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The R2 subunit of class-Ia ribonucleotide reductase (RNR) from Escherichia coli (E. coli) contains a diiron active site. Starting from the apo-protein and Fe(II) in solution at low Fe(II)/apoR2 ratios, mononuclear Fe(II) binding is observed indicating possible different Fe(II) binding affinities for the two alternative sites. Further, based on their Mössbauer spectroscopy and two-iron-isotope reaction experiments, Bollinger et al. (J. Am. Chem. Soc., 1997, 119, 5976-5977) proposed that the site Fe1, which bonds to Asp84, should be associated with the higher observed (57)Fe Mössbauer quadrupole splitting (2.41 mm s(-1)) and lower isomer shift (0.45 mm s(-1)) in the Fe(III)Fe(III) state, site Fe2, which is further from Tyr122, should have a greater affinity for Fe(II) binding than site Fe1, and Fe(IV) in the intermediate X state should reside at site Fe2. In this paper, using density functional theory (DFT) incorporated with the conductor-like screening (COSMO) solvation model and with the finite-difference Poisson-Boltzmann self-consistent reaction field (PB-SCRF) methodologies, we have demonstrated that the observed large quadrupole splitting for the diferric state R2 does come from site Fe1(III) and it is mainly caused by the binding position of the carboxylate group of the Asp84 sidechain. Further, a series of active site clusters with mononuclear Fe(II) binding at either site Fe1 or Fe2 have been studied, which show that with a single dielectric medium outside the active site quantum region, there is no energetic preference for Fe(II) binding at one site over another. However, when including the explicit extended protein environment in the PB-SCRF model, the reaction field favors the Fe(II) binding at site Fe2 rather than at site Fe1 by ~9 kcal mol(-1). Therefore our calculations support the proposal of the previous Mössbauer spectroscopy and two-iron-isotope reaction experiments by Bollinger et al.
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Affiliation(s)
- Wen-Ge Han
- Department of Molecular Biology, TPC15, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
| | - Gregory M. Sandala
- Department of Molecular Biology, TPC15, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
| | - Debra Ann Giammona
- Structural Biology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105
| | - Donald Bashford
- Structural Biology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105
| | - Louis Noodleman
- Department of Molecular Biology, TPC15, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
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Cotruvo JA, Stubbe J. Class I ribonucleotide reductases: metallocofactor assembly and repair in vitro and in vivo. Annu Rev Biochem 2011; 80:733-67. [PMID: 21456967 DOI: 10.1146/annurev-biochem-061408-095817] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Incorporation of metallocofactors essential for the activity of many enyzmes is a major mechanism of posttranslational modification. The cellular machinery required for these processes in the case of mono- and dinuclear nonheme iron and manganese cofactors has remained largely elusive. In addition, many metallocofactors can be converted to inactive forms, and pathways for their repair have recently come to light. The class I ribonucleotide reductases (RNRs) catalyze the conversion of nucleotides to deoxynucleotides and require dinuclear metal clusters for activity: an Fe(III)Fe(III)-tyrosyl radical (Y•) cofactor (class Ia), a Mn(III)Mn(III)-Y• cofactor (class Ib), and a Mn(IV)Fe(III) cofactor (class Ic). The class Ia, Ib, and Ic RNRs are structurally homologous and contain almost identical metal coordination sites. Recent progress in our understanding of the mechanisms by which the cofactor of each of these RNRs is generated in vitro and in vivo and by which the damaged cofactors are repaired is providing insight into how nature prevents mismetallation and orchestrates active cluster formation in high yields.
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Affiliation(s)
- Joseph A Cotruvo
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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Zhang Y, Stubbe J. Bacillus subtilis class Ib ribonucleotide reductase is a dimanganese(III)-tyrosyl radical enzyme. Biochemistry 2011; 50:5615-23. [PMID: 21561096 DOI: 10.1021/bi200348q] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bacillus subtilis class Ib ribonucleotide reductase (RNR) catalyzes the conversion of nucleotides to deoxynucleotides, providing the building blocks for DNA replication and repair. It is composed of two proteins: α (NrdE) and β (NrdF). β contains the metallo-cofactor, essential for the initiation of the reduction process. The RNR genes are organized within the nrdI-nrdE-nrdF-ymaB operon. Each protein has been cloned, expressed, and purified from Escherichia coli. As isolated, recombinant NrdF (rNrdF) contained a diferric-tyrosyl radical [Fe(III)(2)-Y(•)] cofactor. Alternatively, this cluster could be self-assembled from apo-rNrdF, Fe(II), and O(2). Apo-rNrdF loaded using 4 Mn(II)/β(2), O(2), and reduced NrdI (a flavodoxin) can form a dimanganese(III)-Y(•) [Mn(III)(2)-Y(•)] cofactor. In the presence of rNrdE, ATP, and CDP, Mn(III)(2)-Y(•) and Fe(III)(2)-Y(•) rNrdF generate dCDP at rates of 132 and 10 nmol min(-1) mg(-1), respectively (both normalized for 1 Y(•)/β(2)). To determine the endogenous cofactor of NrdF in B. subtilis, the entire operon was placed behind a Pspank(hy) promoter and integrated into the B. subtilis genome at the amyE site. All four genes were induced in cells grown in Luria-Bertani medium, with levels of NrdE and NrdF elevated 35-fold relative to that of the wild-type strain. NrdE and NrdF were copurified in a 1:1 ratio from this engineered B. subtilis. The visible, EPR, and atomic absorption spectra of the purified NrdENrdF complex (eNrdF) exhibited characteristics of a Mn(III)(2)-Y(•) center with 2 Mn/β(2) and 0.5 Y(•)/β(2) and an activity of 318-363 nmol min(-1) mg(-1) (normalized for 1 Y(•)/β(2)). These data strongly suggest that the B. subtilis class Ib RNR is a Mn(III)(2)-Y(•) enzyme.
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Affiliation(s)
- Yan Zhang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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24
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Krebs C, Bollinger JM, Booker SJ. Cyanobacterial alkane biosynthesis further expands the catalytic repertoire of the ferritin-like 'di-iron-carboxylate' proteins. Curr Opin Chem Biol 2011; 15:291-303. [PMID: 21440485 PMCID: PMC3113506 DOI: 10.1016/j.cbpa.2011.02.019] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 02/01/2011] [Accepted: 02/21/2011] [Indexed: 01/19/2023]
Abstract
Enzymes that activate dioxygen at carboxylate-bridged non-heme diiron clusters residing within ferritin-like, four-helix-bundle protein architectures have crucial roles in, among other processes, the global carbon cycle (e.g. soluble methane monooxygenase), fatty acid biosynthesis [plant fatty acyl-acyl carrier protein (ACP) desaturases], DNA biosynthesis [the R2 or β2 subunits of class Ia ribonucleotide reductases (RNRs)], and cellular iron trafficking (ferritins). Classic studies on class Ia RNRs showed long ago how this obligatorily oxidative di-iron/O2 chemistry can be used to activate an enzyme for even a reduction reaction, and more recent investigations of class Ib and Ic RNRs, coupled with earlier studies on dimanganese catalases, have shown that members of this protein family can also incorporate either one or two Mn ions and use them in place of iron for redox catalysis. These two strategies--oxidative activation for non-oxidative reactions and use of alternative metal ions--expand the catalytic repertoire of the family, probably to include activities that remain to be discovered. Indeed, a recent study has suggested that fatty aldehyde decarbonylases (ADs) from cyanobacteria, purported to catalyze a redox-neutral cleavage of a Cn aldehyde to the Cn-1 alkane (or alkene) and CO, also belong to this enzyme family and are most similar in structure to two other members with heterodinuclear (Mn-Fe) cofactors. Here, we first briefly review both the chemical principles underlying the O2-dependent oxidative chemistry of the 'classical' di-iron-carboxylate proteins and the two aforementioned strategies that have expanded their functional range, and then consider what metal ion(s) and what chemical mechanism(s) might be employed by the newly discovered cyanobacterial ADs.
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Affiliation(s)
- Carsten Krebs
- Department of Chemistry and Department of Biochemistry and Molecular Biology, Penn State University, 332 Chemistry Building, University Park, PA, 16802, USA
| | - J. Martin Bollinger
- Department of Chemistry and Department of Biochemistry and Molecular Biology, Penn State University, 336 Chemistry Building, University Park, PA, 16802, USA
| | - Squire J. Booker
- Department of Chemistry and Department of Biochemistry and Molecular Biology, Penn State University, 302 Chemistry Building, University Park, PA, 16802, USA
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Cotruvo JA, Stubbe J. Escherichia coli class Ib ribonucleotide reductase contains a dimanganese(III)-tyrosyl radical cofactor in vivo. Biochemistry 2011; 50:1672-81. [PMID: 21250660 DOI: 10.1021/bi101881d] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Escherichia coli class Ib ribonucleotide reductase (RNR) converts nucleoside 5'-diphosphates to deoxynucleoside 5'-diphosphates in iron-limited and oxidative stress conditions. We have recently demonstrated in vitro that this RNR is active with both diferric-tyrosyl radical (Fe(III)(2)-Y(•)) and dimanganese(III)-Y(•) (Mn(III)(2)-Y(•)) cofactors in the β2 subunit, NrdF [Cotruvo, J. A., Jr., and Stubbe, J. (2010) Biochemistry 49, 1297-1309]. Here we demonstrate, by purification of this protein from its endogenous levels in an E. coli strain deficient in its five known iron uptake pathways and grown under iron-limited conditions, that the Mn(III)(2)-Y(•) cofactor is assembled in vivo. This is the first definitive determination of the active cofactor of a class Ib RNR purified from its native organism without overexpression. From 88 g of cell paste, 150 μg of NrdF was isolated with ∼95% purity, with 0.2 Y(•)/β2, 0.9 Mn/β2, and a specific activity of 720 nmol min(-1) mg(-1). Under these conditions, the class Ib RNR is the primary active RNR in the cell. Our results strongly suggest that E. coli NrdF is an obligate manganese protein in vivo and that the Mn(III)(2)-Y(•) cofactor assembly pathway we have identified in vitro involving the flavodoxin-like protein NrdI, present inside the cell at catalytic levels, is operative in vivo.
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Affiliation(s)
- Joseph A Cotruvo
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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Stubbe J, Cotruvo JA. Control of metallation and active cofactor assembly in the class Ia and Ib ribonucleotide reductases: diiron or dimanganese? Curr Opin Chem Biol 2011; 15:284-90. [PMID: 21216656 DOI: 10.1016/j.cbpa.2010.12.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 11/27/2010] [Accepted: 12/01/2010] [Indexed: 12/28/2022]
Abstract
Ribonucleotide reductases (RNRs) convert nucleotides to deoxynucleotides in all organisms. Activity of the class Ia and Ib RNRs requires a stable tyrosyl radical (Yⁱ), which can be generated by the reaction of O2 with a diferrous cluster on the β subunit to form active diferric-Yⁱ cofactor. Recent experiments have demonstrated, however, that in vivo the class Ib RNR contains an active dimanganese(III)-Yⁱ cofactor. The similar metal binding sites of the class Ia and Ib RNRs, their ability to bind both MnII and FeII, and the activity of the class Ib RNR with both diferric-Yⁱ and dimanganese(III)-Y cofactors raise the intriguing question of how the cell prevents mismetallation of these essential enzymes. The presence of the class Ib RNR in numerous pathogenic bacteria also highlights the importance of manganese for these organisms' growth and virulence.
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Affiliation(s)
- JoAnne Stubbe
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
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27
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Geiger RA, Chattopadhyay S, Day VW, Jackson TA. Nucleophilic reactivity of a series of peroxomanganese(iii) complexes supported by tetradentate aminopyridyl ligands. Dalton Trans 2011; 40:1707-15. [PMID: 21264424 DOI: 10.1039/c0dt01570a] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Robert A Geiger
- Department of Chemistry, University of Kansas, 1251 Wescoe Hall Drive, Lawrence, KS 66045, USA
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28
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Högbom M. Metal use in ribonucleotide reductase R2, di-iron, di-manganese and heterodinuclear—an intricate bioinorganic workaround to use different metals for the same reaction. Metallomics 2011; 3:110-20. [DOI: 10.1039/c0mt00095g] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Stolle P, Barckhausen O, Oehlmann W, Knobbe N, Vogt C, Pierik AJ, Cox N, Schmidt PP, Reijerse EJ, Lubitz W, Auling G. Homologous expression of the nrdF gene of Corynebacterium ammoniagenes strain ATCC 6872 generates a manganese-metallocofactor (R2F) and a stable tyrosyl radical (Y˙) involved in ribonucleotide reduction. FEBS J 2010; 277:4849-62. [PMID: 20977673 DOI: 10.1111/j.1742-4658.2010.07885.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ribonucleotide reduction, the unique step in the pathway to DNA synthesis, is catalyzed by enzymes via radical-dependent redox chemistry involving an array of diverse metallocofactors. The nucleotide reduction gene (nrdF) encoding the metallocofactor containing small subunit (R2F) of the Corynebacterium ammoniagenes ribonucleotide reductase was reintroduced into strain C. ammoniagenes ATCC 6872. Efficient homologous expression from plasmid pOCA2 using the tac-promotor enabled purification of R2F to homogeneity. The chromatographic protocol provided native R2F with a high ratio of manganese to iron (30:1), high activity (69 μmol 2'-deoxyribonucleotide·mg⁻¹ ·min⁻¹) and distinct absorption at 408 nm, characteristic of a tyrosyl radical (Y˙), which is sensitive to the radical scavenger hydroxyurea. A novel enzyme assay revealed the direct involvement of Y˙ in ribonucleotide reduction because 0.2 nmol 2'-deoxyribonucleotide was formed, driven by 0.4 nmol Y˙ located on R2F. X-band electron paramagnetic resonance spectroscopy demonstrated a tyrosyl radical at an effective g-value of 2.004. Temperature dependent X/Q-band EPR studies revealed that this radical is coupled to a metallocofactor. Similarities of the native C. ammoniagenes ribonucleotide reductase to the in vitro activated Escherichia coli class Ib enzyme containing a dimanganese(III)-tyrosyl metallocofactor are discussed.
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Affiliation(s)
- Patrick Stolle
- Institut für Mikrobiologie, Leibniz Universität Hannover, Germany
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31
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Affiliation(s)
- Britt-Marie Sjöberg
- Department of Molecular Biology and Functional Genomics, Stockholm University, SE-10691 Stockholm, Sweden.
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32
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Johansson R, Torrents E, Lundin D, Sprenger J, Sahlin M, Sjöberg BM, Logan DT. High-resolution crystal structures of the flavoprotein NrdI in oxidized and reduced states--an unusual flavodoxin. Structural biology. FEBS J 2010; 277:4265-77. [PMID: 20831589 DOI: 10.1111/j.1742-4658.2010.07815.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The small flavoprotein NrdI is an essential component of the class Ib ribonucleotide reductase system in many bacteria. NrdI interacts with the class Ib radical generating protein NrdF. It is suggested to be involved in the rescue of inactivated diferric centres or generation of active dimanganese centres in NrdF. Although NrdI bears a superficial resemblance to flavodoxin, its redox properties have been demonstrated to be strikingly different. In particular, NrdI is capable of two-electron reduction, whereas flavodoxins are exclusively one-electron reductants. This has been suggested to depend on a lesser destabilization of the negatively-charged hydroquinone state than in flavodoxins. We have determined the crystal structures of NrdI from Bacillus anthracis, the causative agent of anthrax, in the oxidized and semiquinone forms, at resolutions of 0.96 and 1.4 Å, respectively. These structures, coupled with analysis of all curated NrdI sequences, suggest that NrdI defines a new structural family within the flavodoxin superfamily. The conformational behaviour of NrdI in response to FMN reduction is very similar to that of flavodoxins, involving a peptide flip in a loop near the N5 atom of the flavin ring. However, NrdI is much less negatively charged than flavodoxins, which is expected to affect its redox properties significantly. Indeed, sequence analysis shows a remarkable spread in the predicted isoelectric points of NrdIs, from approximately pH 4-10. The implications of these observations for class Ib ribonucleotide reductase function are discussed.
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Affiliation(s)
- Renzo Johansson
- Department of Biochemistry and Structural Biology, Lund University, Sweden
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34
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Highly Chemical and Regio-selective Catalytic Oxidation with a Novel Manganese Catalyst. CHINESE J CHEM 2010. [DOI: 10.1002/cjoc.20030210723] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Boal AK, Cotruvo JA, Stubbe J, Rosenzweig AC. Structural basis for activation of class Ib ribonucleotide reductase. Science 2010; 329:1526-30. [PMID: 20688982 DOI: 10.1126/science.1190187] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The class Ib ribonucleotide reductase of Escherichia coli can initiate reduction of nucleotides to deoxynucleotides with either a Mn(III)2-tyrosyl radical (Y•) or a Fe(III)2-Y• cofactor in the NrdF subunit. Whereas Fe(III)2-Y• can self-assemble from Fe(II)2-NrdF and O2, activation of Mn(II)2-NrdF requires a reduced flavoprotein, NrdI, proposed to form the oxidant for cofactor assembly by reduction of O2. The crystal structures reported here of E. coli Mn(II)2-NrdF and Fe(II)2-NrdF reveal different coordination environments, suggesting distinct initial binding sites for the oxidants during cofactor activation. In the structures of Mn(II)2-NrdF in complex with reduced and oxidized NrdI, a continuous channel connects the NrdI flavin cofactor to the NrdF Mn(II)2 active site. Crystallographic detection of a putative peroxide in this channel supports the proposed mechanism of Mn(III)2-Y• cofactor assembly.
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Affiliation(s)
- Amie K Boal
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, IL 60208, USA
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36
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Cox N, Ogata H, Stolle P, Reijerse E, Auling G, Lubitz W. A Tyrosyl−Dimanganese Coupled Spin System is the Native Metalloradical Cofactor of the R2F Subunit of the Ribonucleotide Reductase of Corynebacterium ammoniagenes. J Am Chem Soc 2010; 132:11197-213. [DOI: 10.1021/ja1036995] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nicholas Cox
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim (Ruhr), Germany, and Institut für Mikrobiologie, Leibniz Universität Hannover, Schneiderberg 50, D-30167 Hannover, Germany
| | - Hideaki Ogata
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim (Ruhr), Germany, and Institut für Mikrobiologie, Leibniz Universität Hannover, Schneiderberg 50, D-30167 Hannover, Germany
| | - Patrick Stolle
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim (Ruhr), Germany, and Institut für Mikrobiologie, Leibniz Universität Hannover, Schneiderberg 50, D-30167 Hannover, Germany
| | - Edward Reijerse
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim (Ruhr), Germany, and Institut für Mikrobiologie, Leibniz Universität Hannover, Schneiderberg 50, D-30167 Hannover, Germany
| | - Georg Auling
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim (Ruhr), Germany, and Institut für Mikrobiologie, Leibniz Universität Hannover, Schneiderberg 50, D-30167 Hannover, Germany
| | - Wolfgang Lubitz
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim (Ruhr), Germany, and Institut für Mikrobiologie, Leibniz Universität Hannover, Schneiderberg 50, D-30167 Hannover, Germany
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37
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Jiang W, Xie J, Varano PT, Krebs C, Bollinger JM. Two distinct mechanisms of inactivation of the class Ic ribonucleotide reductase from Chlamydia trachomatis by hydroxyurea: implications for the protein gating of intersubunit electron transfer. Biochemistry 2010; 49:5340-9. [PMID: 20462199 DOI: 10.1021/bi100037b] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Catalysis by a class I ribonucleotide reductase (RNR) begins when a cysteine (C) residue in the alpha(2) subunit is oxidized to a thiyl radical (C(*)) by a cofactor approximately 35 A away in the beta(2) subunit. In a class Ia or Ib RNR, a stable tyrosyl radical (Y(*)) is the C oxidant, whereas a Mn(IV)/Fe(III) cluster serves this function in the class Ic enzyme from Chlamydia trachomatis (Ct). It is thought that, in either case, a chain of Y residues spanning the two subunits mediates C oxidation by forming transient "pathway" Y(*)s in a multistep electron transfer (ET) process that is "gated" by the protein so that it occurs only in the ready holoenzyme complex. The drug hydroxyurea (HU) inactivates both Ia/b and Ic beta(2) subunits by reducing their C oxidants. Reduction of the stable cofactor Y(*) (Y122(*)) in Escherichia coli class Ia beta(2) is faster in the presence of alpha(2) and a substrate (CDP), leading to speculation that HU might intercept a transient ET pathway Y(*) under these turnover conditions. Here we show that this mechanism is one of two that are operant in HU inactivation of the Ct enzyme. HU reacts with the Mn(IV)/Fe(III) cofactor to give two distinct products: the previously described homogeneous Mn(III)/Fe(III)-beta(2) complex, which forms only under turnover conditions (in the presence of alpha(2) and the substrate), and a distinct, diamagnetic Mn/Fe cluster, which forms approximately 900-fold less rapidly as a second phase in the reaction under turnover conditions and as the sole outcome in the reaction of Mn(IV)/Fe(III)-beta(2) only. Formation of Mn(III)/Fe(III)-beta(2) also requires (i) either Y338, the subunit-interfacial ET pathway residue of beta(2), or Y222, the surface residue that relays the "extra electron" to the Mn(IV)/Fe(IV) intermediate during activation of beta(2) but is not part of the catalytic ET pathway, and (ii) W51, the cofactor-proximal residue required for efficient ET between either Y222 or Y338 and the cofactor. The combined requirements for the catalytic subunit, the substrate, and, most importantly, a functional surface-to-cofactor electron relay system imply that HU effects the Mn(IV)/Fe(III) --> Mn(III)/Fe(III) reduction by intercepting a Y(*) that forms when the ready holoenzyme complex is assembled, the ET gate is opened, and the Mn(IV) oxidizes either Y222 or Y338.
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Affiliation(s)
- Wei Jiang
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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38
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Gangopadhyay S, Masunov AE, Poalelungi E, Leuenberger MN. Weak antiferromagnetic coupling in molecular ring is predicted correctly by density functional theory plus Hubbard U. J Chem Phys 2010; 132:244104. [DOI: 10.1063/1.3421645] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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39
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Cotruvo JA, Stubbe J. An active dimanganese(III)-tyrosyl radical cofactor in Escherichia coli class Ib ribonucleotide reductase. Biochemistry 2010; 49:1297-309. [PMID: 20070127 DOI: 10.1021/bi902106n] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Escherichia coli class Ib ribonucleotide reductase (RNR) converts nucleoside 5'-diphosphates to deoxynucleoside 5'-diphosphates and is expressed under iron-limited and oxidative stress conditions. This RNR is composed of two homodimeric subunits: alpha2 (NrdE), where nucleotide reduction occurs, and beta2 (NrdF), which contains an unidentified metallocofactor that initiates nucleotide reduction. nrdE and nrdF are found in an operon with nrdI, which encodes an unusual flavodoxin proposed to be involved in metallocofactor biosynthesis and/or maintenance. Ni affinity chromatography of a mixture of E. coli (His)(6)-NrdI and NrdF demonstrated tight association between these proteins. To explore the function of NrdI and identify the metallocofactor, apoNrdF was loaded with Mn(II) and incubated with fully reduced NrdI (NrdI(hq)) and O(2). Active RNR was rapidly produced with 0.25 +/- 0.03 tyrosyl radical (Y*) per beta2 and a specific activity of 600 units/mg. EPR and biochemical studies of the reconstituted cofactor suggest it is Mn(III)(2)-Y*, which we propose is generated by Mn(II)(2)-NrdF reacting with two equivalents of HO(2)(-), produced by reduction of O(2) by NrdF-bound NrdI(hq). In the absence of NrdI(hq), with a variety of oxidants, no active RNR was generated. By contrast, a similar experiment with apoNrdF loaded with Fe(II) and incubated with O(2) in the presence or absence of NrdI(hq) gave 0.2 and 0.7 Y*/beta2 with specific activities of 80 and 300 units/mg, respectively. Thus NrdI(hq) hinders Fe(III)(2)-Y* cofactor assembly in vitro. We propose that NrdI is an essential player in E. coli class Ib RNR cluster assembly and that the Mn(III)(2)-Y* cofactor, not the diferric-Y* one, is the active metallocofactor in vivo.
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Affiliation(s)
- Joseph A Cotruvo
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Abbouni B, Oehlmann W, Stolle P, Pierik AJ, Auling G. Electron paramagnetic resonance (EPR) spectroscopy of the stable-free radical in the native metallo-cofactor of the manganese-ribonucleotide reductase (Mn-RNR) ofCorynebacterium glutamicum. Free Radic Res 2009; 43:943-50. [DOI: 10.1080/10715760903140568] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Ogata H, Stolle P, Stehr M, Auling G, Lubitz W. Crystallization and preliminary X-ray analysis of the small subunit (R2F) of native ribonucleotide reductase from Corynebacterium ammoniagenes. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:878-80. [PMID: 19724122 PMCID: PMC2795590 DOI: 10.1107/s1744309109028978] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 07/22/2009] [Indexed: 11/10/2022]
Abstract
Ribonucleotide reduction, the unique step in DNA-precursor biosynthesis, involves radical-dependent redox chemistry and diverse metallo-cofactors. The metallo-cofactor (R2F) encoded by the nrdF (nucleotide reduction) gene in Corynebacterium ammoniagenes ATCC 6872 was isolated after homologous expression and a new crystal form of ribonucleotide reductase R2F was obtained. R2F was crystallized at 277 K using the vapour-diffusion method with PEG as the precipitating agent. A data set was collected to 1.36 A resolution from a single crystal at 100 K using synchrotron radiation. The crystal belonged to space group C2, with unit-cell parameters a = 96.21, b = 87.68, c = 83.25 A, beta = 99.29 degrees. The crystal contained two molecules per asymmetric unit, with a Matthews coefficient (V(M)) of 2.69 A(3) Da(-1); the solvent content was estimated to be 54.3%. X-ray fluorescence spectroscopy and MAD diffraction data indicated the presence of manganese in the molecule and the absence of iron.
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Affiliation(s)
- Hideaki Ogata
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Patrick Stolle
- Institut für Mikrobiologie, Leibniz Universität Hannover, Schneiderberg 50, D-30167 Hannover, Germany
| | - Matthias Stehr
- Institut für Mikrobiologie, Leibniz Universität Hannover, Schneiderberg 50, D-30167 Hannover, Germany
| | - Georg Auling
- Institut für Mikrobiologie, Leibniz Universität Hannover, Schneiderberg 50, D-30167 Hannover, Germany
| | - Wolfgang Lubitz
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
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Khavasi HR, Sasan K, Pirouzmand M, Ebrahimi SN. Highly Efficient Isobutyraldehyde-Mediated Epoxidation of Cyclic Alkenes with Dioxygen Catalyzed by a Novel Dimeric Manganese(II) Complex Containing an Easy-to-Prepare Flexible Carboxamide Ligand. Inorg Chem 2009; 48:5593-5. [DOI: 10.1021/ic900334w] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | - Samad Nejad Ebrahimi
- Department of Phytochemistry, Medicinal Plants and Drug Research Institute, Shahid Beheshti University, G.C., Evin, Tehran 1983963113, Iran
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Jiang W, Yun D, Saleh L, Bollinger JM, Krebs C. Formation and function of the Manganese(IV)/Iron(III) cofactor in Chlamydia trachomatis ribonucleotide reductase. Biochemistry 2009; 47:13736-44. [PMID: 19061340 DOI: 10.1021/bi8017625] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The beta(2) subunit of a class Ia or Ib ribonucleotide reductase (RNR) is activated when its carboxylate-bridged Fe(2)(II/II) cluster reacts with O(2) to oxidize a nearby tyrosine (Y) residue to a stable radical (Y(*)). During turnover, the Y(*) in beta(2) is thought to reversibly oxidize a cysteine (C) in the alpha(2) subunit to a thiyl radical (C(*)) by a long-distance ( approximately 35 A) proton-coupled electron-transfer (PCET) step. The C(*) in alpha(2) then initiates reduction of the 2' position of the ribonucleoside 5'-diphosphate substrate by abstracting the hydrogen atom from C3'. The class I RNR from Chlamydia trachomatis (Ct) is the prototype of a newly recognized subclass (Ic), which is characterized by the presence of a phenylalanine (F) residue at the site of beta(2) where the essential radical-harboring Y is normally found. We recently demonstrated that Ct RNR employs a heterobinuclear Mn(IV)/Fe(III) cluster for radical initiation. In essence, the Mn(IV) ion of the cluster functionally replaces the Y(*) of the conventional class I RNR. The Ct beta(2) protein also autoactivates by reaction of its reduced (Mn(II)/Fe(II)) metal cluster with O(2). In this reaction, an unprecedented Mn(IV)/Fe(IV) intermediate accumulates almost stoichiometrically and decays by one-electron reduction of the Fe(IV) site. This reduction is mediated by the near-surface residue, Y222, a residue with no functional counterpart in the well-studied conventional class I RNRs. In this review, we recount the discovery of the novel Mn/Fe redox cofactor in Ct RNR and summarize our current understanding of how it assembles and initiates nucleotide reduction.
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Affiliation(s)
- Wei Jiang
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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Modi CK, Patel IA, Thaker BT. Manganese(III) Schiff-base complexes involving heterocyclic β-diketone and diethylene triamine. J COORD CHEM 2008. [DOI: 10.1080/00958970802007688] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- C. K. Modi
- a Department of Chemistry , Sardar Patel University , Vallabh Vidyanagar–388 120, Gujarat, India
| | - I. A. Patel
- b Department of Chemistry , Veer Narmad South Gujarat University , Surat–395 007, Gujarat, India
| | - B. T. Thaker
- b Department of Chemistry , Veer Narmad South Gujarat University , Surat–395 007, Gujarat, India
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NrdI, a flavodoxin involved in maintenance of the diferric-tyrosyl radical cofactor in Escherichia coli class Ib ribonucleotide reductase. Proc Natl Acad Sci U S A 2008; 105:14383-8. [PMID: 18799738 DOI: 10.1073/pnas.0807348105] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ribonucleotide reductase (RNR) catalyzes the conversion of nucleotides to deoxynucleotides and is essential in all organisms. Class I RNRs consist of two homodimeric subunits: alpha2 and beta2. The alpha subunit contains the site of nucleotide reduction, and the beta subunit contains the essential diferric-tyrosyl radical (Y*) cofactor. Escherichia coli contains genes encoding two class I RNRs (Ia and Ib) and a class III RNR, which is active only under anaerobic conditions. Its class Ia RNR, composed of NrdA (alpha) and NrdB (beta), is expressed under normal aerobic growth conditions. The class Ib RNR, composed of NrdE (alpha) and NrdF (beta), is expressed under oxidative stress and iron-limited growth conditions. Our laboratory is interested in pathways of cofactor biosynthesis and maintenance in class I RNRs and modulation of Y* levels as a means of regulating RNR activity. Our recent studies have implicated a [2Fe2S]-ferredoxin, YfaE, in the NrdB diferric-Y* maintenance pathway and possibly in the biosynthetic and regulatory pathways. Here, we report that NrdI is a flavodoxin counterpart to YfaE for the class Ib RNR. It possesses redox properties unprecedented for a flavodoxin (E(ox/sq) = -264 +/- 17 mV and E(sq/hq) = -255 +/- 17 mV) that allow it to mediate a two-electron reduction of the diferric cluster of NrdF via two successive one-electron transfers. Data presented support the presence of a distinct maintenance pathway for NrdEF, orthogonal to that for NrdAB involving YfaE.
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Zocher G, Winkler R, Hertweck C, Schulz GE. Structure and Action of the N-oxygenase AurF from Streptomyces thioluteus. J Mol Biol 2007; 373:65-74. [PMID: 17765264 DOI: 10.1016/j.jmb.2007.06.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Revised: 06/05/2007] [Accepted: 06/06/2007] [Indexed: 11/16/2022]
Abstract
Nitro groups are found in a number of bioactive compounds. Most of them arise by a stepwise mono-oxygenation of amino groups. One of the involved enzymes is AurF participating in the biosynthesis of aureothin. Its structure was established at 2.1 A resolution showing a homodimer with a binuclear manganese cluster. The enzyme preparation, which yielded the analyzed crystals, showed activity using in vitro and in vivo assays. Chain fold and cluster are homologous with ribonucleotide reductase subunit R2 and related enzymes. The two manganese ions and an iron content of about 15% were established by anomalous X-ray diffraction. A comparison of the cluster with more common di-iron clusters suggested an additional histidine in the coordination sphere to cause the preference for manganese over iron. There is no oxo-bridge. The substrate p-amino-benzoate was modeled into the active center. The model is supported by mutant activity measurements. It shows the geometry of the reaction and explains the established substrate spectrum.
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Affiliation(s)
- Georg Zocher
- Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität, Albertstrasse 21, 79104 Freiburg im Breisgau, Germany
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Cañadillas-Delgado L, Fabelo O, Pásan J, Delgado FS, Lloret F, Julve M, Ruiz-Pérez C. Unusual (μ-aqua)bis(μ-carboxylate) Bridge in Homometallic M(II) (M = Mn, Co and Ni) Two-Dimensional Compounds Based on the 1,2,3,4-Butanetetracarboxylic Acid: Synthesis, Structure, and Magnetic Properties. Inorg Chem 2007; 46:7458-65. [PMID: 17691768 DOI: 10.1021/ic7006765] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The first coordination compounds of 1,2,3,4-butanetetracarboxylate anion (butca4-) of the formula [M2(butca)(H2O)5]n.2nH2O [M=Mn(II) (1), Co(II) (2), and Ni(II) (3)] were prepared and their X-ray crystal structures and magnetic properties investigated. The three complexes have a very similar two-dimensional structure which consists of (4,4) networks, 1 and 2 being isostructural. The tetracarboxylate ligand acts as a 4-fold connector leading to two-dimensional (4,4) networks of metal atoms, this topology being possible because of its planar conformation. The nodes of these networks are formed by dinuclear motifs which exhibit the unusual (mu-aqua)bis(mu-carboxylate) bridging unit which is analogous to that observed in some molecules of biological interest. The variable-temperature magnetic susceptibility measurements of 1-3 show that 1 and 2 are antiferromagnetically coupled systems whereas 3 exhibits a ferromagnetic behavior. The analysis of the magnetic data of 1-3 through a simple dinuclear model allowed the determination of the values of the magnetic coupling (J) -3.6 (1), -1.2 (2), and +1.47 cm(-1) (3) with the Hamiltonian being defined as H=-JSA.SB. The countercomplementarity between the two bridges (aqua and syn-syn carboxylate) accounts for the trend exhibited by the values of the magnetic coupling in this family.
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Affiliation(s)
- Laura Cañadillas-Delgado
- Laboratorio de Rayos X y Materiales Moleculares, Departamento de Física Fundamental II, Facultad de Física, Universidad de La Laguna, Av. Astrofísico Francisco SAnchez s/n, 38206 La Laguna (Tenerife), Spain
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Que L, True AE. Dinuclear Iron- and Manganese-Oxo Sites in Biology. PROGRESS IN INORGANIC CHEMISTRY 2007. [DOI: 10.1002/9780470166390.ch3] [Citation(s) in RCA: 213] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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