1
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Makthal N, Saha S, Huang E, John J, Meena H, Aggarwal S, Högbom M, Kumaraswami M. Manganese uptake by MtsABC contributes to the pathogenesis of human pathogen group A streptococcus by resisting host nutritional immune defenses. Infect Immun 2024; 92:e0007724. [PMID: 38869295 PMCID: PMC11238556 DOI: 10.1128/iai.00077-24] [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: 02/16/2024] [Accepted: 05/22/2024] [Indexed: 06/14/2024] Open
Abstract
The interplay between host nutritional immune mechanisms and bacterial nutrient uptake systems has a major impact on the disease outcome. The host immune factor calprotectin (CP) limits the availability of essential transition metals, such as manganese (Mn) and zinc (Zn), to control the growth of invading pathogens. We previously demonstrated that the competition between CP and the human pathogen group A streptococcus (GAS) for Zn impacts GAS pathogenesis. However, the contribution of Mn sequestration by CP in GAS infection control and the role of GAS Mn acquisition systems in overcoming host-imposed Mn limitation remain unknown. Using a combination of in vitro and in vivo studies, we show that GAS-encoded mtsABC is a Mn uptake system that aids bacterial evasion of CP-imposed Mn scarcity and promotes GAS virulence. Mn deficiency caused by either the inactivation of mtsC or CP also impaired the protective function of GAS-encoded Mn-dependent superoxide dismutase. Our ex vivo studies using human saliva show that saliva is a Mn-scant body fluid, and Mn acquisition by MtsABC is critical for GAS survival in human saliva. Finally, animal infection studies using wild-type (WT) and CP-/- mice showed that MtsABC is critical for GAS virulence in WT mice but dispensable in mice lacking CP, indicating the direct interplay between MtsABC and CP in vivo. Together, our studies elucidate the role of the Mn import system in GAS evasion of host-imposed metal sequestration and underscore the translational potential of MtsABC as a therapeutic or prophylactic target.
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Affiliation(s)
- Nishanth Makthal
- Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, Houston, Texas, USA
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas, USA
| | - Subhasree Saha
- Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, Houston, Texas, USA
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas, USA
| | - Elaine Huang
- Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, Houston, Texas, USA
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas, USA
| | - Juliane John
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Science, Stockholm, Sweden
| | - Himani Meena
- Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, Houston, Texas, USA
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas, USA
| | - Shifu Aggarwal
- Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, Houston, Texas, USA
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas, USA
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Science, Stockholm, Sweden
| | - Muthiah Kumaraswami
- Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, Houston, Texas, USA
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas, USA
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2
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Nithimethachoke T, Boonmak C, Morikawa M. A novel alkane monooxygenase evolved from a broken piece of ribonucleotide reductase in Geobacillus kaustophilus HTA426 isolated from Mariana Trench. Extremophiles 2024; 28:18. [PMID: 38353731 PMCID: PMC10867098 DOI: 10.1007/s00792-024-01332-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Accepted: 12/30/2023] [Indexed: 02/16/2024]
Abstract
We have accidentally found that a thermophilic Geobacillus kaustophilus HTA426 is capable of degrading alkanes although it has no alkane oxygenating enzyme genes. Our experimental results revealed that a putative ribonucleotide reductase small subunit GkR2loxI (GK2771) gene encodes a novel heterodinuclear Mn-Fe alkane monooxygenase/hydroxylase. GkR2loxI protein can perform two-electron oxidations similar to homonuclear diiron bacterial multicomponent soluble methane monooxygenases. This finding not only answers a long-standing question about the substrate of the R2lox protein clade, but also expands our understanding of the vast diversity and new evolutionary lineage of the bacterial alkane monooxygenase/hydroxylase family.
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Affiliation(s)
- Tanasap Nithimethachoke
- Graduate School of Environmental Science, Hokkaido University, Kita-10 Nishi-5, Kita-ku, Sapporo, 060-0810, Japan
| | - Chanita Boonmak
- Department of Microbiology, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Rd., Lat Yao, Chatuchak, Bangkok, 10900, Thailand
| | - Masaaki Morikawa
- Graduate School of Environmental Science, Hokkaido University, Kita-10 Nishi-5, Kita-ku, Sapporo, 060-0810, Japan.
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3
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Lebrette H, Srinivas V, John J, Aurelius O, Kumar R, Lundin D, Brewster AS, Bhowmick A, Sirohiwal A, Kim IS, Gul S, Pham C, Sutherlin KD, Simon P, Butryn A, Aller P, Orville AM, Fuller FD, Alonso-Mori R, Batyuk A, Sauter NK, Yachandra VK, Yano J, Kaila VRI, Sjöberg BM, Kern J, Roos K, Högbom M. Structure of a ribonucleotide reductase R2 protein radical. Science 2023; 382:109-113. [PMID: 37797025 PMCID: PMC7615503 DOI: 10.1126/science.adh8160] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 08/30/2023] [Indexed: 10/07/2023]
Abstract
Aerobic ribonucleotide reductases (RNRs) initiate synthesis of DNA building blocks by generating a free radical within the R2 subunit; the radical is subsequently shuttled to the catalytic R1 subunit through proton-coupled electron transfer (PCET). We present a high-resolution room temperature structure of the class Ie R2 protein radical captured by x-ray free electron laser serial femtosecond crystallography. The structure reveals conformational reorganization to shield the radical and connect it to the translocation path, with structural changes propagating to the surface where the protein interacts with the catalytic R1 subunit. Restructuring of the hydrogen bond network, including a notably short O-O interaction of 2.41 angstroms, likely tunes and gates the radical during PCET. These structural results help explain radical handling and mobilization in RNR and have general implications for radical transfer in proteins.
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Affiliation(s)
- Hugo Lebrette
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, Stockholm, Sweden
- Laboratoire de Microbiologie et Génétique Moléculaires, Centre de Biologie Intégrative, CNRS, Université Toulouse III, Toulouse, France
| | - Vivek Srinivas
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, Stockholm, Sweden
| | - Juliane John
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, Stockholm, Sweden
| | - Oskar Aurelius
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, Stockholm, Sweden
- MAX IV Laboratory, Lund University, Lund, Sweden
| | - Rohit Kumar
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, Stockholm, Sweden
| | - Daniel Lundin
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, Stockholm, Sweden
| | - Aaron S. Brewster
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Asmit Bhowmick
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Abhishek Sirohiwal
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, Stockholm, Sweden
| | - In-Sik Kim
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Sheraz Gul
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Cindy Pham
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Kyle D. Sutherlin
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Philipp Simon
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Agata Butryn
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, United Kingdom
- Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, United Kingdom
| | - Pierre Aller
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, United Kingdom
- Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, United Kingdom
| | - Allen M. Orville
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, United Kingdom
- Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, United Kingdom
| | | | | | | | - Nicholas K. Sauter
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Vittal K. Yachandra
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Junko Yano
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Ville R. I. Kaila
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, Stockholm, Sweden
| | - Britt-Marie Sjöberg
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, Stockholm, Sweden
| | - Jan Kern
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Katarina Roos
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, Stockholm, Sweden
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4
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Yuan F, Su B, Yu Y, Wang J. Study and design of amino acid-based radical enzymes using unnatural amino acids. RSC Chem Biol 2023; 4:431-446. [PMID: 37292061 PMCID: PMC10246556 DOI: 10.1039/d2cb00250g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 05/17/2023] [Indexed: 06/10/2023] Open
Abstract
Radical enzymes harness the power of reactive radical species by placing them in a protein scaffold, and they are capable of catalysing many important reactions. New native radical enzymes, especially those with amino acid-based radicals, in the category of non-heme iron enzymes (including ribonucleotide reductases), heme enzymes, copper enzymes, and FAD-radical enzymes have been discovered and characterized. We discussed recent research efforts to discover new native amino acid-based radical enzymes, and to study the roles of radicals in processes such as enzyme catalysis and electron transfer. Furthermore, design of radical enzymes in a small and simple scaffold not only allows us to study the radical in a well-controlled system and test our understanding of the native enzymes, but also allows us to create powerful enzymes. In the study and design of amino acid-based radical enzymes, the use of unnatural amino acids allows precise control of pKa values and reduction potentials of the residue, as well as probing the location of the radical through spectroscopic methods, making it a powerful research tool. Our understanding of amino acid-based radical enzymes will allow us to tailor them to create powerful catalysts and better therapeutics.
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Affiliation(s)
- Feiyan Yuan
- Institute of Biochemical Engineering, Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, Ministry of Industry and Information Technology, School of Chemistry and Chemical Engineering, Beijing Institute of Technology Beijing 102488 China
| | - Binbin Su
- Institute of Biochemical Engineering, Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, Ministry of Industry and Information Technology, School of Chemistry and Chemical Engineering, Beijing Institute of Technology Beijing 102488 China
| | - Yang Yu
- Institute of Biochemical Engineering, Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, Ministry of Industry and Information Technology, School of Chemistry and Chemical Engineering, Beijing Institute of Technology Beijing 102488 China
| | - Jiangyun Wang
- Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences Beijing 100101 China
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5
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Rennekamp B, Karfusehr C, Kurth M, Ünal A, Monego D, Riedmiller K, Gryn'ova G, Hudson DM, Gräter F. Collagen breaks at weak sacrificial bonds taming its mechanoradicals. Nat Commun 2023; 14:2075. [PMID: 37045839 PMCID: PMC10097693 DOI: 10.1038/s41467-023-37726-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 03/29/2023] [Indexed: 04/14/2023] Open
Abstract
Collagen is a force-bearing, hierarchical structural protein important to all connective tissue. In tendon collagen, high load even below macroscopic failure level creates mechanoradicals by homolytic bond scission, similar to polymers. The location and type of initial rupture sites critically decide on both the mechanical and chemical impact of these micro-ruptures on the tissue, but are yet to be explored. We here use scale-bridging simulations supported by gel electrophoresis and mass spectrometry to determine breakage points in collagen. We find collagen crosslinks, as opposed to the backbone, to harbor the weakest bonds, with one particular bond in trivalent crosslinks as the most dominant rupture site. We identify this bond as sacrificial, rupturing prior to other bonds while maintaining the material's integrity. Also, collagen's weak bonds funnel ruptures such that the potentially harmful mechanoradicals are readily stabilized. Our results suggest this unique failure mode of collagen to be tailored towards combatting an early onset of macroscopic failure and material ageing.
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Affiliation(s)
- Benedikt Rennekamp
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany
- Interdisciplinary Center for Scientific Computing, Heidelberg University, INF 205, 69120, Heidelberg, Germany
- Max Planck School Matter to Life, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Christoph Karfusehr
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany
- Max Planck School Matter to Life, Jahnstrasse 29, 69120, Heidelberg, Germany
- Physics Department and ZNN, Technical University Munich, Coulombwall 4a, 85748, Garching, Germany
| | - Markus Kurth
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany
- Interdisciplinary Center for Scientific Computing, Heidelberg University, INF 205, 69120, Heidelberg, Germany
| | - Aysecan Ünal
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany
- Interdisciplinary Center for Scientific Computing, Heidelberg University, INF 205, 69120, Heidelberg, Germany
- Max Planck School Matter to Life, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Debora Monego
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany
| | - Kai Riedmiller
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany
| | - Ganna Gryn'ova
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany
- Interdisciplinary Center for Scientific Computing, Heidelberg University, INF 205, 69120, Heidelberg, Germany
| | - David M Hudson
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, 98195, USA
| | - Frauke Gräter
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany.
- Interdisciplinary Center for Scientific Computing, Heidelberg University, INF 205, 69120, Heidelberg, Germany.
- Max Planck School Matter to Life, Jahnstrasse 29, 69120, Heidelberg, Germany.
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6
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Zou J, Yang L, Feng W. Mechanism of Radical Initiation and Transfer in Class Id Ribonucleotide Reductase Based on Density Functional Theory. Inorg Chem 2023; 62:2561-2575. [PMID: 36721875 DOI: 10.1021/acs.inorgchem.2c02926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Class Id ribonucleotide reductase (RNR) is a newly discovered enzyme, which employs the dimanganese cofactor in the superoxidized state (MnIII/MnIV) as the radical initiator. The dimanganese cofactor of class Id RNR in the reduced state (inactive) is clearly based on the crystal structure of the Fj-β subunit. However, the state of the dimanganese cofactor of class Id RNR in the oxidized state (active) is not known. The X-band EPR spectra have shown that the activated Fj-β subunit exists in two distinct complexes, 1 and 2. In this work, quantum mechanical/molecular mechanical calculations were carried out to study class Id RNR. First, we have determined that complex 2 contains a MnIII-(μ-oxo)2-MnIV cluster, and complex 1 contains a MnIII-(μ-hydroxo/μ-oxo)-MnIV cluster. Then, based on the determined dimanganese cofactors, the mechanism of radical initiation and transfer in class Id RNR is revealed. The MnIII-(μ-oxo)2-MnIV cluster in complex 2 has not enough reduction potential to initiate radical transfer directly. Instead, it needs to be monoprotonated into MnIII-(μ-hydroxo/μ-oxo)-MnIV (complex 1) before the radical transfer. The protonation state of μ-oxo can be regulated by changing the protein microenvironment, which is induced by the protein aggregation and separation of β subunits with α subunits. The radical transfer between the cluster of MnIII-(μ-hydroxo/μ-oxo)-MnIV and Trp30 in the radical-transfer chain of the Fj-β subunit (MnIII/MnIV ↔ His100 ↔ Asp194 ↔ Trp30 ↔ Arg99) is a water-mediated tri-proton-coupled electron transfer, which transfers proton from the ε-amino group of Lys71 to the carboxyl group of Glu97 via the water molecule Wat551 and the bridging μ-hydroxo ligand through a three-step reaction. This newly discovered proton-coupled electron-transfer mechanism in class Id RNR is different from those reported in the known Ia-Ic RNRs. The ε-amino group of Lys71, which serves as a proton donor, plays an important role in the radical transfer.
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Affiliation(s)
- Jinxin Zou
- Department of Biological Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Lu Yang
- Department of Biological Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Wei Feng
- Department of Biological Engineering, Beijing University of Chemical Technology, Beijing 100029, China
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7
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Čapek J, Večerek B. Why is manganese so valuable to bacterial pathogens? Front Cell Infect Microbiol 2023; 13:943390. [PMID: 36816586 PMCID: PMC9936198 DOI: 10.3389/fcimb.2023.943390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 01/04/2023] [Indexed: 02/05/2023] Open
Abstract
Apart from oxygenic photosynthesis, the extent of manganese utilization in bacteria varies from species to species and also appears to depend on external conditions. This observation is in striking contrast to iron, which is similar to manganese but essential for the vast majority of bacteria. To adequately explain the role of manganese in pathogens, we first present in this review that the accumulation of molecular oxygen in the Earth's atmosphere was a key event that linked manganese utilization to iron utilization and put pressure on the use of manganese in general. We devote a large part of our contribution to explanation of how molecular oxygen interferes with iron so that it enhances oxidative stress in cells, and how bacteria have learned to control the concentration of free iron in the cytosol. The functioning of iron in the presence of molecular oxygen serves as a springboard for a fundamental understanding of why manganese is so valued by bacterial pathogens. The bulk of this review addresses how manganese can replace iron in enzymes. Redox-active enzymes must cope with the higher redox potential of manganese compared to iron. Therefore, specific manganese-dependent isoenzymes have evolved that either lower the redox potential of the bound metal or use a stronger oxidant. In contrast, redox-inactive enzymes can exchange the metal directly within the individual active site, so no isoenzymes are required. It appears that in the physiological context, only redox-inactive mononuclear or dinuclear enzymes are capable of replacing iron with manganese within the same active site. In both cases, cytosolic conditions play an important role in the selection of the metal used. In conclusion, we summarize both well-characterized and less-studied mechanisms of the tug-of-war for manganese between host and pathogen.
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Affiliation(s)
- Jan Čapek
- *Correspondence: Jan Čapek, ; Branislav Večerek,
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8
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Burnim AA, Xu D, Spence MA, Jackson CJ, Ando N. Analysis of insertions and extensions in the functional evolution of the ribonucleotide reductase family. Protein Sci 2022; 31:e4483. [PMID: 36307939 PMCID: PMC9669993 DOI: 10.1002/pro.4483] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 10/22/2022] [Indexed: 12/14/2022]
Abstract
Ribonucleotide reductases (RNRs) are used by all free-living organisms and many viruses to catalyze an essential step in the de novo biosynthesis of DNA precursors. RNRs are remarkably diverse by primary sequence and cofactor requirement, while sharing a conserved fold and radical-based mechanism for nucleotide reduction. In this work, we expand on our recent phylogenetic inference of the entire RNR family and describe the evolutionarily relatedness of insertions and extensions around the structurally homologous catalytic barrel. Using evo-velocity and sequence similarity network (SSN) analyses, we show that the N-terminal regulatory motif known as the ATP-cone domain was likely inherited from an ancestral RNR. By combining SSN analysis with AlphaFold2 predictions, we also show that the C-terminal extensions of class II RNRs can contain folded domains that share homology with an Fe-S cluster assembly protein. Finally, using sequence analysis and AlphaFold2, we show that the sequence motif of a catalytically essential insertion known as the finger loop is tightly coupled to the catalytic mechanism. Based on these results, we propose an evolutionary model for the diversification of the RNR family.
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Affiliation(s)
- Audrey A. Burnim
- Department of Chemistry and Chemical BiologyCornell UniversityIthacaNew YorkUSA
| | - Da Xu
- Department of Chemistry and Chemical BiologyCornell UniversityIthacaNew YorkUSA
| | - Matthew A. Spence
- Research School of ChemistryAustralian National UniversityCanberraAustralian Capital TerritoryAustralia
| | - Colin J. Jackson
- Research School of ChemistryAustralian National UniversityCanberraAustralian Capital TerritoryAustralia,Australian Research Council Centre of Excellence for Innovations in Peptide and Protein ScienceAustralian National UniversityCanberraAustralian Capital TerritoryAustralia,Australian Research Council Centre of Excellence in Synthetic BiologyAustralian National UniversityCanberraAustralian Capital TerritoryAustralia
| | - Nozomi Ando
- Department of Chemistry and Chemical BiologyCornell UniversityIthacaNew YorkUSA
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9
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John J, Aurelius O, Srinivas V, Saura P, Kim IS, Bhowmick A, Simon PS, Dasgupta M, Pham C, Gul S, Sutherlin KD, Aller P, Butryn A, Orville AM, Cheah MH, Owada S, Tono K, Fuller FD, Batyuk A, Brewster AS, Sauter NK, Yachandra VK, Yano J, Kaila VRI, Kern J, Lebrette H, Högbom M. Redox-controlled reorganization and flavin strain within the ribonucleotide reductase R2b-NrdI complex monitored by serial femtosecond crystallography. eLife 2022; 11:79226. [PMID: 36083619 PMCID: PMC9462851 DOI: 10.7554/elife.79226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
Redox reactions are central to biochemistry and are both controlled by and induce protein structural changes. Here, we describe structural rearrangements and crosstalk within the Bacillus cereus ribonucleotide reductase R2b-NrdI complex, a di-metal carboxylate-flavoprotein system, as part of the mechanism generating the essential catalytic free radical of the enzyme. Femtosecond crystallography at an X-ray free electron laser was utilized to obtain structures at room temperature in defined redox states without suffering photoreduction. Together with density functional theory calculations, we show that the flavin is under steric strain in the R2b-NrdI protein complex, likely tuning its redox properties to promote superoxide generation. Moreover, a binding site in close vicinity to the expected flavin O2 interaction site is observed to be controlled by the redox state of the flavin and linked to the channel proposed to funnel the produced superoxide species from NrdI to the di-manganese site in protein R2b. These specific features are coupled to further structural changes around the R2b-NrdI interaction surface. The mechanistic implications for the control of reactive oxygen species and radical generation in protein R2b are discussed.
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Affiliation(s)
- Juliane John
- Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, Stockholm, Sweden
| | - Oskar Aurelius
- Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, Stockholm, Sweden.,MAX IV Laboratory, Lund University, Lund, Sweden
| | - Vivek Srinivas
- Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, Stockholm, Sweden
| | - Patricia Saura
- Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, Stockholm, Sweden
| | - In-Sik Kim
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Asmit Bhowmick
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Philipp S Simon
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Medhanjali Dasgupta
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Cindy Pham
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Sheraz Gul
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Kyle D Sutherlin
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Pierre Aller
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, United Kingdom.,Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, United Kingdom
| | - Agata Butryn
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, United Kingdom.,Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, United Kingdom
| | - Allen M Orville
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, United Kingdom.,Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, United Kingdom
| | - Mun Hon Cheah
- Department of Chemistry - Ångström, Molecular Biomimetics, Uppsala University, Uppsala, Sweden
| | - Shigeki Owada
- Japan Synchrotron Radiation Research Institute, Sayo-gun, Japan.,RIKEN SPring-8 Center, Sayo-gun, Japan
| | - Kensuke Tono
- Japan Synchrotron Radiation Research Institute, Sayo-gun, Japan.,RIKEN SPring-8 Center, Sayo-gun, Japan
| | - Franklin D Fuller
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, United States
| | - Alexander Batyuk
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, United States
| | - Aaron S Brewster
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Nicholas K Sauter
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Vittal K Yachandra
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Junko Yano
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Ville R I Kaila
- Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, Stockholm, Sweden
| | - Jan Kern
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Hugo Lebrette
- Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, Stockholm, Sweden
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, Stockholm, Sweden
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10
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Burnim AA, Spence MA, Xu D, Jackson CJ, Ando N. Comprehensive phylogenetic analysis of the ribonucleotide reductase family reveals an ancestral clade. eLife 2022; 11:79790. [PMID: 36047668 PMCID: PMC9531940 DOI: 10.7554/elife.79790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 08/31/2022] [Indexed: 11/30/2022] Open
Abstract
Ribonucleotide reductases (RNRs) are used by all free-living organisms and many viruses to catalyze an essential step in the de novo biosynthesis of DNA precursors. RNRs are remarkably diverse by primary sequence and cofactor requirement, while sharing a conserved fold and radical-based mechanism for nucleotide reduction. Here, we structurally aligned the diverse RNR family by the conserved catalytic barrel to reconstruct the first large-scale phylogeny consisting of 6779 sequences that unites all extant classes of the RNR family and performed evo-velocity analysis to independently validate our evolutionary model. With a robust phylogeny in-hand, we uncovered a novel, phylogenetically distinct clade that is placed as ancestral to the classes I and II RNRs, which we have termed clade Ø. We employed small-angle X-ray scattering (SAXS), cryogenic-electron microscopy (cryo-EM), and AlphaFold2 to investigate a member of this clade from Synechococcus phage S-CBP4 and report the most minimal RNR architecture to-date. Based on our analyses, we propose an evolutionary model of diversification in the RNR family and delineate how our phylogeny can be used as a roadmap for targeted future study. Billions of years ago, the Earth’s atmosphere had very little oxygen. It was only after some bacteria and early plants evolved to harness energy from sunlight that oxygen began to fill the Earth’s environment. Oxygen is highly reactive and can interfere with enzymes and other molecules that are essential to life. Organisms living at this point in history therefore had to adapt to survive in this new oxygen-rich world. An ancient family of enzymes known as ribonucleotide reductases are used by all free-living organisms and many viruses to repair and replicate their DNA. Because of their essential role in managing DNA, these enzymes have been around on Earth for billions of years. Understanding how they evolved could therefore shed light on how nature adapted to increasing oxygen levels and other environmental changes at the molecular level. One approach to study how proteins evolved is to use computational analysis to construct a phylogenetic tree. This reveals how existing members of a family are related to one another based on the chain of molecules (known as amino acids) that make up each protein. Despite having similar structures and all having the same function, ribonucleotide reductases have remarkably diverse sequences of amino acids. This makes it computationally very demanding to build a phylogenetic tree. To overcome this, Burnim, Spence, Xu et al. created a phylogenetic tree using structural information from a part of the enzyme that is relatively similar in many modern-day ribonucleotide reductases. The final result took seven continuous months on a supercomputer to generate, and includes over 6,000 members of the enzyme family. The phylogenetic tree revealed a new distinct group of ribonucleotide reductases that may explain how one adaptation to increasing levels of oxygen emerged in some family members, while another adaptation emerged in others. The approach used in this work also opens up a new way to study how other highly diverse enzymes and other protein families evolved, potentially revealing new insights about our planet’s past.
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Affiliation(s)
- Audrey A Burnim
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, United States
| | - Matthew A Spence
- Research School of Chemistry, Australian National University, Canberra, Australia
| | - Da Xu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, United States
| | - Colin J Jackson
- Research School of Chemistry, Australian National University, Canberra, Australia
| | - Nozomi Ando
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, United States
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11
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Huff SE, Winter JM, Dealwis CG. Inhibitors of the Cancer Target Ribonucleotide Reductase, Past and Present. Biomolecules 2022; 12:biom12060815. [PMID: 35740940 PMCID: PMC9221315 DOI: 10.3390/biom12060815] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 06/01/2022] [Accepted: 06/07/2022] [Indexed: 01/02/2023] Open
Abstract
Ribonucleotide reductase (RR) is an essential multi-subunit enzyme found in all living organisms; it catalyzes the rate-limiting step in dNTP synthesis, namely, the conversion of ribonucleoside diphosphates to deoxyribonucleoside diphosphates. As expression levels of human RR (hRR) are high during cell replication, hRR has long been considered an attractive drug target for a range of proliferative diseases, including cancer. While there are many excellent reviews regarding the structure, function, and clinical importance of hRR, recent years have seen an increase in novel approaches to inhibiting hRR that merit an updated discussion of the existing inhibitors and strategies to target this enzyme. In this review, we discuss the mechanisms and clinical applications of classic nucleoside analog inhibitors of hRRM1 (large catalytic subunit), including gemcitabine and clofarabine, as well as inhibitors of the hRRM2 (free radical housing small subunit), including triapine and hydroxyurea. Additionally, we discuss novel approaches to targeting RR and the discovery of new classes of hRR inhibitors.
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Affiliation(s)
- Sarah E. Huff
- Department of Pediatrics, University of California, San Diego, CA 92093, USA;
| | - Jordan M. Winter
- Department of Surgery, Division of Surgical Oncology, University Hospitals Cleveland Medical Center, Akron, OH 44106, USA;
| | - Chris G. Dealwis
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106, USA
- Correspondence:
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12
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Abstract
Some oxidoreductase enzymes use redox-active tyrosine, tryptophan, cysteine, and/or glycine residues as one-electron, high-potential redox (radical) cofactors. Amino-acid radical cofactors typically perform one of four tasks-they work in concert with a metallocofactor to carry out a multielectron redox process, serve as storage sites for oxidizing equivalents, activate the substrate molecules, or move oxidizing equivalents over long distances. It is challenging to experimentally resolve the thermodynamic and kinetic redox properties of a single-amino-acid residue. The inherently reactive and highly oxidizing properties of amino-acid radicals increase the experimental barriers further still. This review describes a family of stable and well-structured model proteins that was made specifically to study tyrosine and tryptophan oxidation-reduction. The so-called α3X model protein system was combined with very-high-potential protein film voltammetry, transient absorption spectroscopy, and theoretical methods to gain a comprehensive description of the thermodynamic and kinetic properties of protein tyrosine and tryptophan radicals.
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Affiliation(s)
- Cecilia Tommos
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA;
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13
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Banerjee R, Srinivas V, Lebrette H. Ferritin-Like Proteins: A Conserved Core for a Myriad of Enzyme Complexes. Subcell Biochem 2022; 99:109-153. [PMID: 36151375 DOI: 10.1007/978-3-031-00793-4_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Ferritin-like proteins share a common fold, a four α-helix bundle core, often coordinating a pair of metal ions. Although conserved, the ferritin fold permits a diverse set of reactions, and is central in a multitude of macromolecular enzyme complexes. Here, we emphasize this diversity through three members of the ferritin-like superfamily: the soluble methane monooxygenase, the class I ribonucleotide reductase and the aldehyde deformylating oxygenase. They all rely on dinuclear metal cofactors to catalyze different challenging oxygen-dependent reactions through the formation of multi-protein complexes. Recent studies using cryo-electron microscopy, serial femtosecond crystallography at an X-ray free electron laser source, or single-crystal X-ray diffraction, have reported the structures of the active protein complexes, and revealed unprecedented insights into the molecular mechanisms of these three enzymes.
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Affiliation(s)
- Rahul Banerjee
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Vivek Srinivas
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Hugo Lebrette
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), CNRS, UPS, Université de Toulouse, Toulouse, France.
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14
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Zou J, Chen Y, Feng W. Mechanism of DOPA radical generation and transfer in metal-free class Ie ribonucleotide reductase based on density functional theory. Comput Struct Biotechnol J 2022; 20:1111-1131. [PMID: 35317236 PMCID: PMC8902622 DOI: 10.1016/j.csbj.2022.02.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/25/2022] [Accepted: 02/26/2022] [Indexed: 11/12/2022] Open
Abstract
The mechanism of DOPA radical generation, transfer and regeneration is revealed. The superoxide O2•− should be protonated to HO2• prior to oxidizing Tyr126 to DOPA radical. The protonation of Asp88 is the prerequisite for the DOPA radical generation and radical transfer. Lys213 is a key residue for the transfer of the DOPA radical.
Quantum mechanical/molecular mechanical (QM/MM) calculations were carried out to investigate the mechanisms of the generation, transfer, and regeneration of the DOPA radical for metal-free class Ie ribonucleotide reductase. The crystal structure of MfR2 (Nature, 2018, 563, 416–420) was adopted for the calculations. The QM/MM calculations have revealed several key points that are vital for understanding the mechanisms. The superoxide O2•− provided by the flavoprotein NrdI cannot directly oxidize the residue Tyr126 to the DOPA radical. It should be protonated to HO2•. The calculation results suggest that the covalent modification of Tyr126 and the DOPA radical generation can be carried out with no involvement of metal cofactors. This addresses the concerns of the articles (Nature, 2018, 563, 416–420; PNAS, 2018, 115, 10022–10027). Another concern from the articles is that how the DOPA radical is transferred from the radical trap. The DFT calculations have demonstrated that Lys213 is a key residue for the radical transfer from the DOPA radical. The ε-amino group of Lys213 is used not only as a bridge for the electron transfer but also as a proton donor. It can provide a proton to DOPA126 via a water molecule, and thus the radical transfer from DOPA126 to Trp52 is facilitated. It has also been revealed that the protonation of Asp88 is the prerequisite for the DOPA radical generation and the radical transfer in class Ie. Once the radical is quenched, it can be regenerated via the oxidations by superoxide O2•− and hydroperoxyl radical HO2•.
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15
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Zhao PF, Liu ZQ. Attaching a Dipeptide to Fullerene as an Antioxidant Hybrid against DNA Oxidation. Chem Res Toxicol 2021; 34:2366-2374. [PMID: 34672520 DOI: 10.1021/acs.chemrestox.1c00283] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Emerging evidence has revealed that oxidative damages of DNA correlate with the pathogenesis of some diseases, and numerous investigations have also suggested that supplementation of antioxidants is beneficial for keeping health by rectifying in vivo redox status. Here, we construct antioxidative dipeptides with the Ugi four-component reaction (comprising p-aminobenzyl alcohol, benzaldehyde, or vanillin, a series of antioxidative carboxylic acids and isocyanides as reagents) and then attempt to attach the dipeptides to [60]fullerene by the Bingel reaction. However, this endeavor does not lead to the amelioration of the radical-scavenging property because abilities of fullerenyl dipeptides to trap 2,2'-diphenyl-1-picrylhydrazyl and galvinoxyl radicals are still dependent upon the phenolic hydroxyl group in the dipeptide scaffold rather than upon the fullerenyl group. Alternatively, when the obtained fullerenyl dipeptides are evaluated in a peroxyl radical-induced oxidation of DNA, it is found that introducing a fullerene moiety into dipeptide enables antioxidative effect to be enhanced 20-30% because the fullerene moiety facilitates the corresponding dipeptide to intercalate with DNA strands, and thus, to increase the antioxidative efficacy. Our results suggest that connecting an antioxidative skeleton with the hydrophobic fullerene moiety might lead to a series of novel antioxidant hybrids applied for the inhibition of DNA oxidation.
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Affiliation(s)
- Peng-Fei Zhao
- Department of Organic Chemistry, College of Chemistry, Jilin University, Changchun 130021, People's Republic of China
| | - Zai-Qun Liu
- Department of Organic Chemistry, College of Chemistry, Jilin University, Changchun 130021, People's Republic of China
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16
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Metal utilization in genome-reduced bacteria: Do human mycoplasmas rely on iron? Comput Struct Biotechnol J 2021; 19:5752-5761. [PMID: 34765092 PMCID: PMC8566771 DOI: 10.1016/j.csbj.2021.10.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 10/08/2021] [Accepted: 10/12/2021] [Indexed: 12/04/2022] Open
Abstract
Mycoplasmas are parasitic bacteria with streamlined genomes and complex nutritional requirements. Although iron is vital for almost all organisms, its utilization by mycoplasmas is controversial. Despite its minimalist nature, mycoplasmas can survive and persist within the host, where iron availability is rigorously restricted through nutritional immunity. In this review, we describe the putative iron-enzymes, transporters, and metalloregulators of four relevant human mycoplasmas. This work brings in light critical differences in the mycoplasma-iron interplay. Mycoplasma penetrans, the species with the largest genome (1.36 Mb), shows a more classic repertoire of iron-related proteins, including different enzymes using iron-sulfur clusters as well as iron storage and transport systems. In contrast, the iron requirement is less apparent in the three species with markedly reduced genomes, Mycoplasma genitalium (0.58 Mb), Mycoplasma hominis (0.67 Mb) and Mycoplasma pneumoniae (0.82 Mb), as they exhibit only a few proteins possibly involved in iron homeostasis. The multiple facets of iron metabolism in mycoplasmas illustrate the remarkable evolutive potential of these minimal organisms when facing nutritional immunity and question the dependence of several human-infecting species for iron. Collectively, our data contribute to better understand the unique biology and infective strategies of these successful pathogens.
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Key Words
- ABC, ATP-binding cassette
- ECF transporter
- ECF, energy-coupling factor
- Fur, ferric uptake regulator
- Hrl, histidine-rich lipoprotein
- Iron homeostasis
- Metal acquisition
- Metalloenzyme
- Mge, Mycoplasma genitalium
- Mho, Mycoplasma hominis
- Mollicutes
- Mpe, Mycoplasma penetrans
- Mpn, Mycoplasma pneumonia
- Mycoplasmas
- PDB, protein data bank
- RNR, ribonucleotide reductase
- XRF, X-ray fluorescence
- ZIP, zinc-iron permease
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17
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McLean JT, Benny A, Nolan MD, Swinand G, Scanlan EM. Cysteinyl radicals in chemical synthesis and in nature. Chem Soc Rev 2021; 50:10857-10894. [PMID: 34397045 DOI: 10.1039/d1cs00254f] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Nature harnesses the unique properties of cysteinyl radical intermediates for a diverse range of essential biological transformations including DNA biosynthesis and repair, metabolism, and biological photochemistry. In parallel, the synthetic accessibility and redox chemistry of cysteinyl radicals renders them versatile reactive intermediates for use in a vast array of synthetic applications such as lipidation, glycosylation and fluorescent labelling of proteins, peptide macrocyclization and stapling, desulfurisation of peptides and proteins, and development of novel therapeutics. This review provides the reader with an overview of the role of cysteinyl radical intermediates in both chemical synthesis and biological systems, with a critical focus on mechanistic details. Direct insights from biological systems, where applied to chemical synthesis, are highlighted and potential avenues from nature which are yet to be explored synthetically are presented.
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Affiliation(s)
- Joshua T McLean
- Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, 152-160 Pearse St., Dublin, D02 R590, Ireland.
| | - Alby Benny
- Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, 152-160 Pearse St., Dublin, D02 R590, Ireland.
| | - Mark D Nolan
- Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, 152-160 Pearse St., Dublin, D02 R590, Ireland.
| | - Glenna Swinand
- Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, 152-160 Pearse St., Dublin, D02 R590, Ireland.
| | - Eoin M Scanlan
- Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, 152-160 Pearse St., Dublin, D02 R590, Ireland.
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18
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Abstract
Radicals in biology, once thought to all be bad actors, are now known to play a central role in many enzymatic reactions. Of the known radical-based enzymes, ribonucleotide reductases (RNRs) are pre-eminent as they are essential in the biology of all organisms by providing the building blocks and controlling the fidelity of DNA replication and repair. Intense examination of RNRs has led to the development of new tools and a guiding framework for the study of radicals in biology, pointing the way to future frontiers in radical enzymology.
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Affiliation(s)
- JoAnne Stubbe
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 20139 USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 20139 USA
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138 USA
| | - Daniel G. Nocera
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138 USA
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19
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Ruskoski TB, Boal AK. The periodic table of ribonucleotide reductases. J Biol Chem 2021; 297:101137. [PMID: 34461093 PMCID: PMC8463856 DOI: 10.1016/j.jbc.2021.101137] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 08/20/2021] [Accepted: 08/26/2021] [Indexed: 12/30/2022] Open
Abstract
In most organisms, transition metal ions are necessary cofactors of ribonucleotide reductase (RNR), the enzyme responsible for biosynthesis of the 2'-deoxynucleotide building blocks of DNA. The metal ion generates an oxidant for an active site cysteine (Cys), yielding a thiyl radical that is necessary for initiation of catalysis in all RNRs. Class I enzymes, widespread in eukaryotes and aerobic microbes, share a common requirement for dioxygen in assembly of the active Cys oxidant and a unique quaternary structure, in which the metallo- or radical-cofactor is found in a separate subunit, β, from the catalytic α subunit. The first class I RNRs, the class Ia enzymes, discovered and characterized more than 30 years ago, were found to use a diiron(III)-tyrosyl-radical Cys oxidant. Although class Ia RNRs have historically served as the model for understanding enzyme mechanism and function, more recently, remarkably diverse bioinorganic and radical cofactors have been discovered in class I RNRs from pathogenic microbes. These enzymes use alternative transition metal ions, such as manganese, or posttranslationally installed tyrosyl radicals for initiation of ribonucleotide reduction. Here we summarize the recent progress in discovery and characterization of novel class I RNR radical-initiating cofactors, their mechanisms of assembly, and how they might function in the context of the active class I holoenzyme complex.
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Affiliation(s)
- Terry B Ruskoski
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Amie K Boal
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, USA.
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20
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Watson RA, Offenbacher AR, Barry BA. Detection of Catalytically Linked Conformational Changes in Wild-Type Class Ia Ribonucleotide Reductase Using Reaction-Induced FTIR Spectroscopy. J Phys Chem B 2021; 125:8362-8372. [PMID: 34289692 DOI: 10.1021/acs.jpcb.1c03038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The enzyme, ribonucleotide reductase (RNR), is essential for DNA synthesis in all cells. The class Ia Escherichia coli RNR consists of two dimeric subunits, α2 and β2, which form an active but unstable heterodimer of dimers, α2β2. The structure of the wild-type form of the enzyme has been challenging to study due to the instability of the catalytic complex. A long-range proton-coupled electron-transfer (PCET) pathway facilitates radical migration from the Y122 radical-diiron cofactor in the β subunit to an active site cysteine, C439, in the α subunit to initiate the RNR chemistry. The PCET reactions and active site chemistry are spectroscopically masked by a rate-limiting, conformational gate. Here, we present a reaction-induced Fourier transform infrared (RIFTIR) spectroscopic method to monitor the mechanism of the active, wild-type RNR α2β2 complex. This method is employed to obtain new information about conformational changes accompanying RNR catalysis, including the role of carboxylate interactions, deprotonation, and oxidation of active site cysteines, and a detailed description of reversible secondary structural changes. Labeling of tyrosine revealed a conformationally active tyrosine in the β subunit, assigned to Y356β, which is part of the intersubunit PCET pathway. New insights into the roles of the inhibitors, azidoUDP and dATP, and the sensitivity of RIFTIR spectroscopy to detect subtle conformational motions arising from protein allostery are also presented.
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Affiliation(s)
- Ryan Atlee Watson
- Department of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, United States
| | - Adam R Offenbacher
- Department of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, United States.,Department of Chemistry, East Carolina University, Greenville, North Carolina, United States
| | - Bridgette A Barry
- Department of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, United States
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21
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Nogueira WG, Jaiswal AK, Tiwari S, Ramos RTJ, Ghosh P, Barh D, Azevedo V, Soares SC. Computational identification of putative common genomic drug and vaccine targets in Mycoplasma genitalium. Genomics 2021; 113:2730-2743. [PMID: 34118385 DOI: 10.1016/j.ygeno.2021.06.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 05/17/2021] [Accepted: 06/07/2021] [Indexed: 10/21/2022]
Abstract
Mycoplasma genitalium is an obligate intracellular bacterium that is responsible for several sexually transmitted infections, including non-gonococcal urethritis in men and several inflammatory reproductive tract syndromes in women. Here, we applied subtractive genomics and reverse vaccinology approaches for in silico prediction of potential vaccine and drug targets against five strains of M. genitalium. We identified 403 genes shared by all five strains, from which 104 non-host homologous proteins were selected, comprising of 44 exposed/secreted/membrane proteins and 60 cytoplasmic proteins. Based on the essentiality, functionality, and structure-based binding affinity, we finally predicted 19 (14 novel) putative vaccine and 7 (2 novel) candidate drug targets. The docking analysis showed six molecules from the ZINC database as promising drug candidates against the identified targets. Altogether, both vaccine candidates and drug targets identified here may contribute to the future development of therapeutic strategies to control the spread of M. genitalium worldwide.
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Affiliation(s)
- Wylerson G Nogueira
- Laboratório de Genética Celular e Molecular, Departamento de Genetica, Ecologia e Evolucao, Instituto de Ciências Biológicas,Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Arun Kumar Jaiswal
- Laboratório de Genética Celular e Molecular, Departamento de Genetica, Ecologia e Evolucao, Instituto de Ciências Biológicas,Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.; Department of Immunology, Microbiology and Parasitology, Universidade Federal do Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Sandeep Tiwari
- Laboratório de Genética Celular e Molecular, Departamento de Genetica, Ecologia e Evolucao, Instituto de Ciências Biológicas,Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil..
| | - Rommel T J Ramos
- Laboratory of Genomic and Bioinformatics, Center of Genomics and System Biology, Universidade Federal do Pará, Belém, Pará, Brazil
| | - Preetam Ghosh
- Department of Computer Science, Virginia Commonwealth University, Richmond VA-23284, USA
| | - Debmalya Barh
- Centre for Genomics and Applied Gene Technology, Institute of Integrative Omics and Applied Biotechnology (IIOAB), Nonakuri, Purba Medinipur, West Bengal, India
| | - Vasco Azevedo
- Laboratório de Genética Celular e Molecular, Departamento de Genetica, Ecologia e Evolucao, Instituto de Ciências Biológicas,Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Siomar C Soares
- Department of Immunology, Microbiology and Parasitology, Universidade Federal do Triângulo Mineiro, Uberaba, Minas Gerais, Brazil.
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22
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Liu ZQ. Multicomponent Reactions for Integrating Multiple Functional Groups into an Antioxidant. CHEM REC 2020; 20:1516-1529. [PMID: 33063420 DOI: 10.1002/tcr.202000080] [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: 07/10/2020] [Revised: 09/14/2020] [Accepted: 09/14/2020] [Indexed: 11/07/2022]
Abstract
A large number of convincing evidences has revealed the correlation of the pathogeny of diseases with the oxidative damages of DNA, protein, biomembrane, and other biological species, while supplementation of antioxidants is demonstrated to be a promising way to avoid, at least, rectify the unbalance redox status in vivo. Although many endeavors have focused on synthesis of antioxidants, a main hurdle still hinders the wide usages of synthetic antioxidants because of low bioavailability and potential cytotoxicity. The search for antioxidants with multiple functional groups being recognized by different receptors becomes a much sought by researchers, and multicomponent reactions (MCRs) provide with powerful tools for the construction of multifunctional antioxidants. Presented herein is a personal account on the application of MCRs for the synthesis of multifunctional antioxidants, while radical-induced oxidation of DNA acts as the experimental system for evaluating antioxidative effect. Concretely, the Biginelli three-component reaction (3CR) affords such a dihydropyrimidine scaffold that the tautomerization between C=S and C-SH leads to antioxidative effect. The Povarov 3CR is able to integrate multiple antioxidative groups, i. e., ferrocenyl and -N(CH3 )2 , into a quinoline scaffold, while the Groebke 3CR provides with imidazo[1,2-a]pyridine skeleton for inhibiting DNA oxidation. Additionally, the Knoevenagel-related MCRs also become efficient strategies for achieving radical-scavengers. On the other hand, the Ugi 4CR and Passerini 3CR result in the dipeptide and α-acyloxycarboxamide, respectively, with the benefit for the integration of antioxidative features by aliphatic chains. Therefore, MCRs have emerged as efficient tools for integrating multiple antioxidative features into one molecule in order to meet with complicated requirements from various biological surroundings.
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Affiliation(s)
- Zai-Qun Liu
- Department of Organic Chemistry, College of Chemistry, Jilin University, Changchun, 130021, People's Republic of China
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23
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Martínez-Carranza M, Jonna VR, Lundin D, Sahlin M, Carlson LA, Jemal N, Högbom M, Sjöberg BM, Stenmark P, Hofer A. A ribonucleotide reductase from Clostridium botulinum reveals distinct evolutionary pathways to regulation via the overall activity site. J Biol Chem 2020; 295:15576-15587. [PMID: 32883811 DOI: 10.1074/jbc.ra120.014895] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/02/2020] [Indexed: 01/05/2023] Open
Abstract
Ribonucleotide reductase (RNR) is a central enzyme for the synthesis of DNA building blocks. Most aerobic organisms, including nearly all eukaryotes, have class I RNRs consisting of R1 and R2 subunits. The catalytic R1 subunit contains an overall activity site that can allosterically turn the enzyme on or off by the binding of ATP or dATP, respectively. The mechanism behind the ability to turn the enzyme off via the R1 subunit involves the formation of different types of R1 oligomers in most studied species and R1-R2 octamers in Escherichia coli To better understand the distribution of different oligomerization mechanisms, we characterized the enzyme from Clostridium botulinum, which belongs to a subclass of class I RNRs not studied before. The recombinantly expressed enzyme was analyzed by size-exclusion chromatography, gas-phase electrophoretic mobility macromolecular analysis, EM, X-ray crystallography, and enzyme assays. Interestingly, it shares the ability of the E. coli RNR to form inhibited R1-R2 octamers in the presence of dATP but, unlike the E. coli enzyme, cannot be turned off by combinations of ATP and dGTP/dTTP. A phylogenetic analysis of class I RNRs suggests that activity regulation is not ancestral but was gained after the first subclasses diverged and that RNR subclasses with inhibition mechanisms involving R1 oligomerization belong to a clade separated from the two subclasses forming R1-R2 octamers. These results give further insight into activity regulation in class I RNRs as an evolutionarily dynamic process.
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Affiliation(s)
| | | | - Daniel Lundin
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Margareta Sahlin
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Lars-Anders Carlson
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden; Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Newal Jemal
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Britt-Marie Sjöberg
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Pål Stenmark
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden; Department of Experimental Medical Science, Lund University, Lund, Sweden.
| | - Anders Hofer
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden.
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24
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Greene BL, Kang G, Cui C, Bennati M, Nocera DG, Drennan CL, Stubbe J. Ribonucleotide Reductases: Structure, Chemistry, and Metabolism Suggest New Therapeutic Targets. Annu Rev Biochem 2020; 89:45-75. [PMID: 32569524 PMCID: PMC7316142 DOI: 10.1146/annurev-biochem-013118-111843] [Citation(s) in RCA: 109] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ribonucleotide reductases (RNRs) catalyze the de novo conversion of nucleotides to deoxynucleotides in all organisms, controlling their relative ratios and abundance. In doing so, they play an important role in fidelity of DNA replication and repair. RNRs' central role in nucleic acid metabolism has resulted in five therapeutics that inhibit human RNRs. In this review, we discuss the structural, dynamic, and mechanistic aspects of RNR activity and regulation, primarily for the human and Escherichia coli class Ia enzymes. The unusual radical-based organic chemistry of nucleotide reduction, the inorganic chemistry of the essential metallo-cofactor biosynthesis/maintenance, the transport of a radical over a long distance, and the dynamics of subunit interactions all present distinct entry points toward RNR inhibition that are relevant for drug discovery. We describe the current mechanistic understanding of small molecules that target different elements of RNR function, including downstream pathways that lead to cell cytotoxicity. We conclude by summarizing novel and emergent RNR targeting motifs for cancer and antibiotic therapeutics.
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Affiliation(s)
- Brandon L Greene
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA;
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Gyunghoon Kang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA;
| | - Chang Cui
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA;
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Marina Bennati
- Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
- Department of Chemistry, University of Göttingen, 37073 Göttingen, Germany
| | - Daniel G Nocera
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Catherine L Drennan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA;
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - JoAnne Stubbe
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA;
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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25
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Reichl E, Ertl M, Knör G. Multielectron Redox Catalysis with Efficient Tyrosinase Activity Based on a Visible-Light Controlled Artificial Photoenzyme. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Eva Reichl
- Institute of Inorganic Chemistry; Johannes Kepler University Linz; Altenberger Strasse 69 4040 Linz Austria
| | - Martin Ertl
- Institute of Inorganic Chemistry; Johannes Kepler University Linz; Altenberger Strasse 69 4040 Linz Austria
- Linz School of Education; Altenberger Strasse 69 4040 Linz Austria
| | - Günther Knör
- Institute of Inorganic Chemistry; Johannes Kepler University Linz; Altenberger Strasse 69 4040 Linz Austria
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26
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Zapp C, Obarska-Kosinska A, Rennekamp B, Kurth M, Hudson DM, Mercadante D, Barayeu U, Dick TP, Denysenkov V, Prisner T, Bennati M, Daday C, Kappl R, Gräter F. Mechanoradicals in tensed tendon collagen as a source of oxidative stress. Nat Commun 2020; 11:2315. [PMID: 32385229 PMCID: PMC7210969 DOI: 10.1038/s41467-020-15567-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 03/10/2020] [Indexed: 12/31/2022] Open
Abstract
As established nearly a century ago, mechanoradicals originate from homolytic bond scission in polymers. The existence, nature and biological relevance of mechanoradicals in proteins, instead, are unknown. We here show that mechanical stress on collagen produces radicals and subsequently reactive oxygen species, essential biological signaling molecules. Electron-paramagnetic resonance (EPR) spectroscopy of stretched rat tail tendon, atomistic molecular dynamics simulations and quantum-chemical calculations show that the radicals form by bond scission in the direct vicinity of crosslinks in collagen. Radicals migrate to adjacent clusters of aromatic residues and stabilize on oxidized tyrosyl radicals, giving rise to a distinct EPR spectrum consistent with a stable dihydroxyphenylalanine (DOPA) radical. The protein mechanoradicals, as a yet undiscovered source of oxidative stress, finally convert into hydrogen peroxide. Our study suggests collagen I to have evolved as a radical sponge against mechano-oxidative damage and proposes a mechanism for exercise-induced oxidative stress and redox-mediated pathophysiological processes. The existence, nature and biological relevance of mechanoradicals in proteins are unknown. Here authors show that mechanical stress on collagen produces radicals and subsequently reactive oxygen species and suggest that collagen I evolved as a radical sponge against mechano-oxidative damage.
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Affiliation(s)
- Christopher Zapp
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany.,Institute for Theoretical Physics, Heidelberg University, Philosophenweg 16, 69120, Heidelberg, Germany
| | - Agnieszka Obarska-Kosinska
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany.,Hamburg Unit c/o DESY, European Molecular Biology Laboratory, Notkestrasse 85, 22607, Hamburg, Germany
| | - Benedikt Rennekamp
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany.,Institute for Theoretical Physics, Heidelberg University, Philosophenweg 16, 69120, Heidelberg, Germany
| | - Markus Kurth
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany
| | - David M Hudson
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, 98195, USA
| | - Davide Mercadante
- Biochemical Institute, University of Zuerich, Winterthurerstr. 190, 8057, Zuerich, Switzerland
| | - Uladzimir Barayeu
- Faculty of Biosciences, Heidelberg University, Im Neuenheimer Feld 234, 69120, Heidelberg, Germany.,Division of Redox Regulation, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Tobias P Dick
- Division of Redox Regulation, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Vasyl Denysenkov
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt am Main, Germany
| | - Thomas Prisner
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt am Main, Germany
| | - Marina Bennati
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Csaba Daday
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany.,Interdisciplinary Center for Scientific Computing, Heidelberg University, INF 205, 69120, Heidelberg, Germany
| | - Reinhard Kappl
- Institute for Biophysics, Saarland University Medical Center, CIPMM Geb. 48, 66421, Homburg/Saar, Germany
| | - Frauke Gräter
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany. .,Interdisciplinary Center for Scientific Computing, Heidelberg University, INF 205, 69120, Heidelberg, Germany.
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27
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Grāve K, Griese JJ, Berggren G, Bennett MD, Högbom M. The Bacillus anthracis class Ib ribonucleotide reductase subunit NrdF intrinsically selects manganese over iron. J Biol Inorg Chem 2020; 25:571-582. [PMID: 32296998 PMCID: PMC7239806 DOI: 10.1007/s00775-020-01782-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/22/2020] [Indexed: 01/30/2023]
Abstract
Abstract Correct protein metallation in the complex mixture of the cell is a prerequisite for metalloprotein function. While some metals, such as Cu, are commonly chaperoned, specificity towards metals earlier in the Irving–Williams series is achieved through other means, the determinants of which are poorly understood. The dimetal carboxylate family of proteins provides an intriguing example, as different proteins, while sharing a common fold and the same 4-carboxylate 2-histidine coordination sphere, are known to require either a Fe/Fe, Mn/Fe or Mn/Mn cofactor for function. We previously showed that the R2lox proteins from this family spontaneously assemble the heterodinuclear Mn/Fe cofactor. Here we show that the class Ib ribonucleotide reductase R2 protein from Bacillus anthracis spontaneously assembles a Mn/Mn cofactor in vitro, under both aerobic and anoxic conditions, when the metal-free protein is subjected to incubation with MnII and FeII in equal concentrations. This observation provides an example of a protein scaffold intrinsically predisposed to defy the Irving–Williams series and supports the assumption that the Mn/Mn cofactor is the biologically relevant cofactor in vivo. Substitution of a second coordination sphere residue changes the spontaneous metallation of the protein to predominantly form a heterodinuclear Mn/Fe cofactor under aerobic conditions and a Mn/Mn metal center under anoxic conditions. Together, the results describe the intrinsic metal specificity of class Ib RNR and provide insight into control mechanisms for protein metallation. Graphical Abstract ![]()
Electronic supplementary material The online version of this article (10.1007/s00775-020-01782-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kristīne Grāve
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 10691, Stockholm, Sweden
| | - Julia J Griese
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 10691, Stockholm, Sweden.,Department of Cell and Molecular Biology, Uppsala University, BMC, Box 596, 75124, Uppsala, Sweden
| | - Gustav Berggren
- Department of Chemistry, Ångström Laboratory, Uppsala University, Lägerhyddsvägen 1, 75120, Uppsala, Sweden
| | - Matthew D Bennett
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 10691, Stockholm, Sweden
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 10691, Stockholm, Sweden.
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28
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Ravichandran K, Olshansky L, Nocera DG, Stubbe J. Subunit Interaction Dynamics of Class Ia Ribonucleotide Reductases: In Search of a Robust Assay. Biochemistry 2020; 59:1442-1453. [PMID: 32186371 DOI: 10.1021/acs.biochem.0c00001] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ribonucleotide reductases (RNRs) catalyze the conversion of nucleotides (NDP) to deoxynucleotides (dNDP), in part, by controlling the ratios and quantities of dNTPs available for DNA replication and repair. The active form of Escherichia coli class Ia RNR is an asymmetric α2β2 complex in which α2 contains the active site and β2 contains the stable diferric-tyrosyl radical cofactor responsible for initiating the reduction chemistry. Each dNDP is accompanied by disulfide bond formation. We now report that, under in vitro conditions, β2 can initiate turnover in α2 catalytically under both "one" turnover (no external reductant, though producing two dCDPs) and multiple turnover (with an external reductant) assay conditions. In the absence of reductant, rapid chemical quench analysis of a reaction of α2, substrate, and effector with variable amounts of β2 (1-, 10-, and 100-fold less than α2) yields 3 dCDP/α2 at all ratios of α2:β2 with a rate constant of 8-9 s-1, associated with a rate-limiting conformational change. Stopped-flow fluorescence spectroscopy with a fluorophore-labeled β reveals that the rate constants for subunit association (163 ± 7 μM-1 s-1) and dissociation (75 ± 10 s-1) are fast relative to turnover, consistent with catalytic β2. When assaying in the presence of an external reducing system, the turnover number is dictated by the ratio of α2:β2, their concentrations, and the concentration and nature of the reducing system; the rate-limiting step can change from the conformational gating to a step or steps involving disulfide rereduction, dissociation of the inhibited α4β4 state, or both. The issues encountered with E. coli RNR are likely of importance in all class I RNRs and are central to understanding the development of screening assays for inhibitors of these enzymes.
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Affiliation(s)
- Kanchana Ravichandran
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Lisa Olshansky
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.,Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Daniel G Nocera
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - JoAnne Stubbe
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.,Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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29
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Moore RM, Harrison AO, McAllister SM, Polson SW, Wommack KE. Iroki: automatic customization and visualization of phylogenetic trees. PeerJ 2020; 8:e8584. [PMID: 32149022 PMCID: PMC7049256 DOI: 10.7717/peerj.8584] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 01/17/2020] [Indexed: 12/26/2022] Open
Abstract
Phylogenetic trees are an important analytical tool for evaluating community diversity and evolutionary history. In the case of microorganisms, the decreasing cost of sequencing has enabled researchers to generate ever-larger sequence datasets, which in turn have begun to fill gaps in the evolutionary history of microbial groups. However, phylogenetic analyses of these types of datasets create complex trees that can be challenging to interpret. Scientific inferences made by visual inspection of phylogenetic trees can be simplified and enhanced by customizing various parts of the tree. Yet, manual customization is time-consuming and error prone, and programs designed to assist in batch tree customization often require programming experience or complicated file formats for annotation. Iroki, a user-friendly web interface for tree visualization, addresses these issues by providing automatic customization of large trees based on metadata contained in tab-separated text files. Iroki’s utility for exploring biological and ecological trends in sequencing data was demonstrated through a variety of microbial ecology applications in which trees with hundreds to thousands of leaf nodes were customized according to extensive collections of metadata. The Iroki web application and documentation are available at https://www.iroki.net or through the VIROME portal http://virome.dbi.udel.edu. Iroki’s source code is released under the MIT license and is available at https://github.com/mooreryan/iroki.
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Affiliation(s)
- Ryan M Moore
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, United States of America
| | - Amelia O Harrison
- School of Marine Science and Policy, University of Delaware, Newark, DE, United States of America
| | - Sean M McAllister
- School of Marine Science and Policy, University of Delaware, Newark, DE, United States of America
| | - Shawn W Polson
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, United States of America
| | - K Eric Wommack
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, United States of America
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30
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Liu ZQ. Bridging free radical chemistry with drug discovery: A promising way for finding novel drugs efficiently. Eur J Med Chem 2019; 189:112020. [PMID: 32006794 DOI: 10.1016/j.ejmech.2019.112020] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 12/06/2019] [Accepted: 12/27/2019] [Indexed: 02/07/2023]
Abstract
Many diseases have been regarded to correlate with the in vivo oxidative damages, which are caused by overproduced free radicals from metabolic process or reactive oxygen species (ROS). This background motivates chemists to explore free radical reactions and to design a number of antioxidants, but whether free radical chemistry can be applied to accelerate the efficacy of the drug discovery is still underrepresented. Herein, in light of recent findings as well as kinetics on free radical reaction, the discipline of free radical chemistry is introduced to be a novel tool for finding potential drugs from antioxidant libraries accumulated during the study on free radical chemistry. These antioxidants provide with such abundant types of structural skeleton that might be employed to inhibit oxidations in different biological microenvironments. Although the in vitro characterization on the antioxidative property exerts a potential role of an antioxidant as a prodrug, the in vivo investigation on the property for quenching free radicals will make a final decision for the antioxidant whether it is worthy to be further explored pharmacologically. Therefore, it is reasonable to expect that bridging free radical chemistry with the pharmacological research will provide with a succinct way for finding novel drugs efficiently.
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Affiliation(s)
- Zai-Qun Liu
- Department of Organic Chemistry, College of Chemistry, Jilin University, No.2519 Jiefang Road, Changchun, 130021, People's Republic of China.
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31
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Kutin Y, Kositzki R, Branca RMM, Srinivas V, Lundin D, Haumann M, Högbom M, Cox N, Griese JJ. Chemical flexibility of heterobimetallic Mn/Fe cofactors: R2lox and R2c proteins. J Biol Chem 2019; 294:18372-18386. [PMID: 31591267 DOI: 10.1074/jbc.ra119.010570] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 10/04/2019] [Indexed: 11/06/2022] Open
Abstract
A heterobimetallic Mn/Fe cofactor is present in the R2 subunit of class Ic ribonucleotide reductases (R2c) and in R2-like ligand-binding oxidases (R2lox). Although the protein-derived metal ligands are the same in both groups of proteins, the connectivity of the two metal ions and the chemistry each cofactor performs are different: in R2c, a one-electron oxidant, the Mn/Fe dimer is linked by two oxygen bridges (μ-oxo/μ-hydroxo), whereas in R2lox, a two-electron oxidant, it is linked by a single oxygen bridge (μ-hydroxo) and a fatty acid ligand. Here, we identified a second coordination sphere residue that directs the divergent reactivity of the protein scaffold. We found that the residue that directly precedes the N-terminal carboxylate metal ligand is conserved as a glycine within the R2lox group but not in R2c. Substitution of the glycine with leucine converted the resting-state R2lox cofactor to an R2c-like cofactor, a μ-oxo/μ-hydroxo-bridged MnIII/FeIII dimer. This species has recently been observed as an intermediate of the oxygen activation reaction in WT R2lox, indicating that it is physiologically relevant. Cofactor maturation in R2c and R2lox therefore follows the same pathway, with structural and functional divergence of the two cofactor forms following oxygen activation. We also show that the leucine-substituted variant no longer functions as a two-electron oxidant. Our results reveal that the residue preceding the N-terminal metal ligand directs the cofactor's reactivity toward one- or two-electron redox chemistry, presumably by setting the protonation state of the bridging oxygens and thereby perturbing the redox potential of the Mn ion.
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Affiliation(s)
- Yury Kutin
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Ramona Kositzki
- Institut für Experimentalphysik, Freie Universität Berlin, D-14195 Berlin, Germany
| | - Rui M M Branca
- Cancer Proteomics Mass Spectrometry, Department of Oncology-Pathology, Science for Life Laboratory, Karolinska Institute, Box 1031, SE-171 21 Solna, Sweden
| | - Vivek Srinivas
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Daniel Lundin
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Michael Haumann
- Institut für Experimentalphysik, Freie Universität Berlin, D-14195 Berlin, Germany
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Nicholas Cox
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia.
| | - Julia J Griese
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden; Department of Cell and Molecular Biology, Uppsala University, SE-751 24 Uppsala, Sweden.
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32
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Class Id ribonucleotide reductase utilizes a Mn 2(IV,III) cofactor and undergoes large conformational changes on metal loading. J Biol Inorg Chem 2019; 24:863-877. [PMID: 31414238 PMCID: PMC6754362 DOI: 10.1007/s00775-019-01697-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 08/02/2019] [Indexed: 12/15/2022]
Abstract
Outside of the photosynthetic machinery, high-valent manganese cofactors are rare in biology. It was proposed that a recently discovered subclass of ribonucleotide reductase (RNR), class Id, is dependent on a Mn2(IV,III) cofactor for catalysis. Class I RNRs consist of a substrate-binding component (NrdA) and a metal-containing radical-generating component (NrdB). Herein we utilize a combination of EPR spectroscopy and enzyme assays to underscore the enzymatic relevance of the Mn2(IV,III) cofactor in class Id NrdB from Facklamia ignava. Once formed, the Mn2(IV,III) cofactor confers enzyme activity that correlates well with cofactor quantity. Moreover, we present the X-ray structure of the apo- and aerobically Mn-loaded forms of the homologous class Id NrdB from Leeuwenhoekiella blandensis, revealing a dimanganese centre typical of the subclass, with a tyrosine residue maintained at distance from the metal centre and a lysine residue projected towards the metals. Structural comparison of the apo- and metal-loaded forms of the protein reveals a refolding of the loop containing the conserved lysine and an unusual shift in the orientation of helices within a monomer, leading to the opening of a channel towards the metal site. Such major conformational changes have not been observed in NrdB proteins before. Finally, in vitro reconstitution experiments reveal that the high-valent manganese cofactor is not formed spontaneously from oxygen, but can be generated from at least two different reduced oxygen species, i.e. H2O2 and superoxide (O 2 ·- ). Considering the observed differences in the efficiency of these two activating reagents, we propose that the physiologically relevant mechanism involves superoxide.
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33
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Grāve K, Lambert W, Berggren G, Griese JJ, Bennett MD, Logan DT, Högbom M. Redox-induced structural changes in the di-iron and di-manganese forms of Bacillus anthracis ribonucleotide reductase subunit NrdF suggest a mechanism for gating of radical access. J Biol Inorg Chem 2019; 24:849-861. [PMID: 31410573 PMCID: PMC6754363 DOI: 10.1007/s00775-019-01703-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 08/06/2019] [Indexed: 12/11/2022]
Abstract
Class Ib ribonucleotide reductases (RNR) utilize a di-nuclear manganese or iron cofactor for reduction of superoxide or molecular oxygen, respectively. This generates a stable tyrosyl radical (Y·) in the R2 subunit (NrdF), which is further used for ribonucleotide reduction in the R1 subunit of RNR. Here, we report high-resolution crystal structures of Bacillus anthracis NrdF in the metal-free form (1.51 Å) and in complex with manganese (MnII/MnII, 1.30 Å). We also report three structures of the protein in complex with iron, either prepared anaerobically (FeII/FeII form, 1.32 Å), or prepared aerobically in the photo-reduced FeII/FeII form (1.63 Å) and with the partially oxidized metallo-cofactor (1.46 Å). The structures reveal significant conformational dynamics, likely to be associated with the generation, stabilization, and transfer of the radical to the R1 subunit. Based on observed redox-dependent structural changes, we propose that the passage for the superoxide, linking the FMN cofactor of NrdI and the metal site in NrdF, is closed upon metal oxidation, blocking access to the metal and radical sites. In addition, we describe the structural mechanics likely to be involved in this process.
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Affiliation(s)
- Kristīne Grāve
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 10691, Stockholm, Sweden
| | - Wietske Lambert
- PRA Health Sciences, Amerikaweg 18, 9407 TK, Assen, The Netherlands
| | - Gustav Berggren
- Department of Chemistry, Ångström Laboratory, Uppsala University, Lägerhyddsvägen 1, 75120, Uppsala, Sweden
| | - Julia J Griese
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 10691, Stockholm, Sweden.,Department of Cell and Molecular Biology, Uppsala University. BMC, Box 596, 75124, Uppsala, Sweden
| | - Matthew D Bennett
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 10691, Stockholm, Sweden
| | - Derek T Logan
- Department of Biochemistry and Structural Biology, Lund University, Box 124, 221 00, Lund, Sweden.
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 10691, Stockholm, Sweden.
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34
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Buckel W. Enzymatic Reactions Involving Ketyls: From a Chemical Curiosity to a General Biochemical Mechanism. Biochemistry 2019; 58:5221-5233. [PMID: 30995029 DOI: 10.1021/acs.biochem.9b00171] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Ketyls are radical anions with nucleophilic properties. Ketyls obtained by enzymatic one-electron reduction of thioesters were proposed as intermediates for the dehydration of (R)-2-hydroxyacyl-CoA to (E)-2-enoyl-CoA. This concept was extended to the Birch-like reduction of benzoyl-CoA to 1,5-cyclohexadienecarboxyl-CoA. Nature uses two methods to achieve the therefore required low reduction potentials of less than -600 mV, either by an ATP-driven electron transfer similar to that catalyzed by the iron protein of nitrogenase or by electron bifurcation. Ketyls formed by thiyl radical-initiated oxidation of alcohols followed by deprotonation are involved in coenzyme B12-independent diol dehydratases, other glycyl radical enzymes mediating key reactions in the degradations of choline, taurine, and 4-hydroxyproline, and all three classes of ribonucleotide reductases. A special case is the dehydration of 4-hydroxybutyryl-CoA to crotonyl-CoA, which most likely proceeds via an oxidation to an allylic ketyl but requires neither a strong reductant nor an external radical generator.
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Affiliation(s)
- Wolfgang Buckel
- Fachbereich Biologie , Philipps-Universität , 35032 Marburg , Germany
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35
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Rose HR, Maggiolo AO, McBride MJ, Palowitch GM, Pandelia ME, Davis KM, Yennawar NH, Boal AK. Structures of Class Id Ribonucleotide Reductase Catalytic Subunits Reveal a Minimal Architecture for Deoxynucleotide Biosynthesis. Biochemistry 2019; 58:1845-1860. [PMID: 30855138 PMCID: PMC6456427 DOI: 10.1021/acs.biochem.8b01252] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Class I ribonucleotide reductases (RNRs) share a common mechanism of nucleotide reduction in a catalytic α subunit. All RNRs initiate catalysis with a thiyl radical, generated in class I enzymes by a metallocofactor in a separate β subunit. Class Id RNRs use a simple mechanism of cofactor activation involving oxidation of a MnII2 cluster by free superoxide to yield a metal-based MnIIIMnIV oxidant. This simple cofactor assembly pathway suggests that class Id RNRs may be representative of the evolutionary precursors to more complex class Ia-c enzymes. X-ray crystal structures of two class Id α proteins from Flavobacterium johnsoniae ( Fj) and Actinobacillus ureae ( Au) reveal that this subunit is distinctly small. The enzyme completely lacks common N-terminal ATP-cone allosteric motifs that regulate overall activity, a process that normally occurs by dATP-induced formation of inhibitory quaternary structures to prevent productive β subunit association. Class Id RNR activity is insensitive to dATP in the Fj and Au enzymes evaluated here, as expected. However, the class Id α protein from Fj adopts higher-order structures, detected crystallographically and in solution. The Au enzyme does not exhibit these quaternary forms. Our study reveals structural similarity between bacterial class Id and eukaryotic class Ia α subunits in conservation of an internal auxiliary domain. Our findings with the Fj enzyme illustrate that nucleotide-independent higher-order quaternary structures can form in simple RNRs with truncated or missing allosteric motifs.
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Affiliation(s)
- Hannah R. Rose
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Ailiena O. Maggiolo
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Molly J. McBride
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Gavin M. Palowitch
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
| | | | - Katherine M. Davis
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Neela H. Yennawar
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802
| | - Amie K. Boal
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
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Harrison AO, Moore RM, Polson SW, Wommack KE. Reannotation of the Ribonucleotide Reductase in a Cyanophage Reveals Life History Strategies Within the Virioplankton. Front Microbiol 2019; 10:134. [PMID: 30804913 PMCID: PMC6370689 DOI: 10.3389/fmicb.2019.00134] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 01/21/2019] [Indexed: 01/16/2023] Open
Abstract
Ribonucleotide reductases (RNRs) are ancient enzymes that catalyze the reduction of ribonucleotides to deoxyribonucleotides. They are required for virtually all cellular life and are prominent within viral genomes. RNRs share a common ancestor and must generate a protein radical for direct ribonucleotide reduction. The mechanisms by which RNRs produce radicals are diverse and divide RNRs into three major classes and several subclasses. The diversity of radical generation methods means that cellular organisms and viruses typically contain the RNR best-suited to the environmental conditions surrounding DNA replication. However, such diversity has also fostered high rates of RNR misannotation within subject sequence databases. These misannotations have resulted in incorrect translative presumptions of RNR biochemistry and have diminished the utility of this marker gene for ecological studies of viruses. We discovered a misannotation of the RNR gene within the Prochlorococcus phage P-SSP7 genome, which caused a chain of misannotations within commonly observed RNR genes from marine virioplankton communities. These RNRs are found in marine cyanopodo- and cyanosiphoviruses and are currently misannotated as Class II RNRs, which are O2-independent and require cofactor B12. In fact, these cyanoviral RNRs are Class I enzymes that are O2-dependent and may require a di-metal cofactor made of Fe, Mn, or a combination of the two metals. The discovery of an overlooked Class I β subunit in the P-SSP7 genome, together with phylogenetic analysis of the α and β subunits confirms that the RNR from P-SSP7 is a Class I RNR. Phylogenetic and conserved residue analyses also suggest that the P-SSP7 RNR may constitute a novel Class I subclass. The reannotation of the RNR clade represented by P-SSP7 means that most lytic cyanophage contain Class I RNRs, while their hosts, B12-producing Synechococcus and Prochlorococcus, contain Class II RNRs. By using a Class I RNR, cyanophage avoid a dependence on host-produced B12, a more effective strategy for a lytic virus. The discovery of a novel RNR β subunit within cyanopodoviruses also implies that some unknown viral genes may be familiar cellular genes that are too divergent for homology-based annotation methods to identify.
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Affiliation(s)
- Amelia O. Harrison
- School of Marine Science and Policy, University of Delaware, Newark, DE, United States
| | - Ryan M. Moore
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, United States
| | - Shawn W. Polson
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, United States
| | - K. Eric Wommack
- School of Marine Science and Policy, University of Delaware, Newark, DE, United States
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Griese JJ, Kositzki R, Haumann M, Högbom M. Assembly of a heterodinuclear Mn/Fe cofactor is coupled to tyrosine-valine ether cross-link formation in the R2-like ligand-binding oxidase. J Biol Inorg Chem 2019; 24:211-221. [PMID: 30689052 PMCID: PMC6399176 DOI: 10.1007/s00775-019-01639-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 01/18/2019] [Indexed: 11/28/2022]
Abstract
R2-like ligand-binding oxidases (R2lox) assemble a heterodinuclear Mn/Fe cofactor which performs reductive dioxygen (O2) activation, catalyzes formation of a tyrosine-valine ether cross-link in the protein scaffold, and binds a fatty acid in a putative substrate channel. We have previously shown that the N-terminal metal binding site 1 is unspecific for manganese or iron in the absence of O2, but prefers manganese in the presence of O2, whereas the C-terminal site 2 is specific for iron. Here, we analyze the effects of amino acid exchanges in the cofactor environment on cofactor assembly and metalation specificity using X-ray crystallography, X-ray absorption spectroscopy, and metal quantification. We find that exchange of either the cross-linking tyrosine or the valine, regardless of whether the mutation still allows cross-link formation or not, results in unspecific manganese or iron binding at site 1 both in the absence or presence of O2, while site 2 still prefers iron as in the wild-type. In contrast, a mutation that blocks binding of the fatty acid does not affect the metal specificity of either site under anoxic or aerobic conditions, and cross-link formation is still observed. All variants assemble a dinuclear trivalent metal cofactor in the aerobic resting state, independently of cross-link formation. These findings imply that the cross-link residues are required to achieve the preference for manganese in site 1 in the presence of O2. The metalation specificity, therefore, appears to be established during the redox reactions leading to cross-link formation.
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Affiliation(s)
- Julia J Griese
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden. .,Department of Cell and Molecular Biology, Uppsala University, 751 24, Uppsala, Sweden.
| | - Ramona Kositzki
- Institut für Experimentalphysik, Freie Universität Berlin, 14195, Berlin, Germany
| | - Michael Haumann
- Institut für Experimentalphysik, Freie Universität Berlin, 14195, Berlin, Germany
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University, 106 91, Stockholm, Sweden.
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Stubbe J, Seyedsayamdost MR. Discovery of a New Class I Ribonucleotide Reductase with an Essential DOPA Radical and NO Metal as an Initiator of Long-Range Radical Transfer. Biochemistry 2018; 58:435-437. [PMID: 30586288 DOI: 10.1021/acs.biochem.8b01238] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- JoAnne Stubbe
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Mohammad R Seyedsayamdost
- Department of Chemistry , Princeton University , Frick Laboratory , Princeton , New Jersey 08544 , United States
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