1
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Li RN, Chen SL. Mechanistic Insights into the N-Hydroxylations Catalyzed by the Binuclear Iron Domain of SznF Enzyme: Key Piece in the Synthesis of Streptozotocin. Chemistry 2024; 30:e202303845. [PMID: 38212866 DOI: 10.1002/chem.202303845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 01/13/2024]
Abstract
SznF, a member of the emerging family of heme-oxygenase-like (HO-like) di-iron oxidases and oxygenases, employs two distinct domains to catalyze the conversion of Nω-methyl-L-arginine (L-NMA) into N-nitroso-containing product, which can subsequently be transformed into streptozotocin. Using unrestricted density functional theory (UDFT) with the hybrid functional B3LYP, we have mechanistically investigated the two sequential hydroxylations of L-NMA catalyzed by SznF's binuclear iron central domain. Mechanism B primarily involves the O-O bond dissociation, forming Fe(IV)=O, induced by the H+/e- introduction to the FeA side of μ-1,2-peroxo-Fe2(III/III), the substrate hydrogen abstraction by Fe(IV)=O, and the hydroxyl rebound to the substrate N radical. The stochastic addition of H+/e- to the FeB side (mechanism C) can transition to mechanism B, thereby preventing enzyme deactivation. Two other competing mechanisms, involving the direct O-O bond dissociation (mechanism A) and the addition of H2O as a co-substrate (mechanism D), have been ruled out.
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Affiliation(s)
- Rui-Ning Li
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Shi-Lu Chen
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China
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2
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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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3
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Smethurst DGJ, Shcherbik N. Interchangeable utilization of metals: New perspectives on the impacts of metal ions employed in ancient and extant biomolecules. J Biol Chem 2021; 297:101374. [PMID: 34732319 PMCID: PMC8633580 DOI: 10.1016/j.jbc.2021.101374] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 10/25/2021] [Accepted: 10/28/2021] [Indexed: 02/08/2023] Open
Abstract
Metal ions provide considerable functionality across biological systems, and their utilization within biomolecules has adapted through changes in the chemical environment to maintain the activity they facilitate. While ancient earth's atmosphere was rich in iron and manganese and low in oxygen, periods of atmospheric oxygenation significantly altered the availability of certain metal ions, resulting in ion replacement within biomolecules. This adaptation mechanism has given rise to the phenomenon of metal cofactor interchangeability, whereby contemporary proteins and nucleic acids interact with multiple metal ions interchangeably, with different coordinated metals influencing biological activity, stability, and toxic potential. The ability of extant organisms to adapt to fluctuating metal availability remains relevant in a number of crucial biomolecules, including the superoxide dismutases of the antioxidant defense systems and ribonucleotide reductases. These well-studied and ancient enzymes illustrate the potential for metal interchangeability and adaptive utilization. More recently, the ribosome has also been demonstrated to exhibit interchangeable interactions with metal ions with impacts on function, stability, and stress adaptation. Using these and other examples, here we review the biological significance of interchangeable metal ions from a new angle that combines both biochemical and evolutionary viewpoints. The geochemical pressures and chemical properties that underlie biological metal utilization are discussed in the context of their impact on modern disease states and treatments.
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Affiliation(s)
- Daniel G J Smethurst
- Department for Cell Biology and Neuroscience, School of Osteopathic Medicine, Rowan University, Stratford, New Jersey, USA.
| | - Natalia Shcherbik
- Department for Cell Biology and Neuroscience, School of Osteopathic Medicine, Rowan University, Stratford, New Jersey, USA.
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4
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Resa S, Millán A, Fuentes N, Crovetto L, Luisa Marcos M, Lezama L, Choquesillo-Lazarte D, Blanco V, Campaña AG, Cárdenas DJ, Cuerva JM. O–H and (CO)N–H bond weakening by coordination to Fe(ii). Dalton Trans 2019; 48:2179-2189. [DOI: 10.1039/c8dt04689a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Coordination of hydroxyl/amide groups to Fe(ii) diminishes BDFEs of O–H and (CO)N–H bonds down to 76.0 and 80.5 kcal mol−1 respectively.
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5
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Wei W, Siegbahn PEM, Liao R. Mechanism of the Dinuclear Iron Enzymep‐Aminobenzoate N‐oxygenase from Density Functional Calculations. ChemCatChem 2018. [DOI: 10.1002/cctc.201801072] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Wen‐Jie Wei
- Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of Education Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica Hubei Key Laboratory of Materials Chemistry and Service Failure School of Chemistry and Chemical EngineeringHuazhong University of Science and Technology Wuhan 430074 P. R. China
| | - Per E. M. Siegbahn
- Department of Organic Chemistry, Arrhenius LaboratoryStockholm University Stockholm SE-10691 Sweden
| | - Rong‐Zhen Liao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of Education Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica Hubei Key Laboratory of Materials Chemistry and Service Failure School of Chemistry and Chemical EngineeringHuazhong University of Science and Technology Wuhan 430074 P. R. China
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6
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Wei WJ, Siegbahn PEM, Liao RZ. Theoretical Study of the Mechanism of the Nonheme Iron Enzyme EgtB. Inorg Chem 2017; 56:3589-3599. [PMID: 28277674 DOI: 10.1021/acs.inorgchem.6b03177] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
EgtB is a nonheme iron enzyme catalyzing the C-S bond formation between γ-glutamyl cysteine (γGC) and N-α-trimethyl histidine (TMH) in the ergothioneine biosynthesis. Density functional calculations were performed to elucidate and delineate the reaction mechanism of this enzyme. Two different mechanisms were considered, depending on whether the sulfoxidation or the S-C bond formation takes place first. The calculations suggest that the S-O bond formation occurs first between the thiolate and the ferric superoxide, followed by homolytic O-O bond cleavage, very similar to the case of cysteine dioxygenase. Subsequently, proton transfer from a second-shell residue Tyr377 to the newly generated iron-oxo moiety takes place, which is followed by proton transfer from the TMH imidazole to Tyr377, facilitated by two crystallographically observed water molecules. Next, the S-C bond is formed between γGC and TMH, followed by proton transfer from the imidazole CH moiety to Tyr377, which was calculated to be the rate-limiting step for the whole reaction, with a barrier of 17.9 kcal/mol in the quintet state. The calculated barrier for the rate-limiting step agrees quite well with experimental kinetic data. Finally, this proton is transferred back to the imidazole nitrogen to form the product. The alternative thiyl radical attack mechanism has a very high barrier, being 25.8 kcal/mol, ruling out this possibility.
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Affiliation(s)
- Wen-Jie Wei
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology , Wuhan 430074, China
| | - Per E M Siegbahn
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University , SE-10691 Stockholm, Sweden
| | - Rong-Zhen Liao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology , Wuhan 430074, China
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7
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Sproviero EM. Geometrical properties of the manganese(iv)/iron(iii) cofactor of Chlamydia trachomatis ribonucleotide reductase unveiled by simulations of XAS spectra. Dalton Trans 2017; 46:4724-4736. [DOI: 10.1039/c6dt03893j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A combination of EXAFS simulations and DFT calculations, including a novel protocol to evaluate Debye–Waller factors, provide insights into the structure of the Mn(iv)/Fe(iii) cofactor ofCtR2.
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Affiliation(s)
- Eduardo M. Sproviero
- Department of Chemistry and Biochemistry
- University of the Sciences in Philadelphia
- Philadelphia
- USA
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8
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Kositzki R, Mebs S, Marx J, Griese JJ, Schuth N, Högbom M, Schünemann V, Haumann M. Protonation State of MnFe and FeFe Cofactors in a Ligand-Binding Oxidase Revealed by X-ray Absorption, Emission, and Vibrational Spectroscopy and QM/MM Calculations. Inorg Chem 2016; 55:9869-9885. [PMID: 27610479 DOI: 10.1021/acs.inorgchem.6b01752] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Enzymes with a dimetal-carboxylate cofactor catalyze reactions among the top challenges in chemistry such as methane and dioxygen (O2) activation. Recently described proteins bind a manganese-iron cofactor (MnFe) instead of the classical diiron cofactor (FeFe). Determination of atomic-level differences of homo- versus hetero-bimetallic cofactors is crucial to understand their diverse redox reactions. We studied a ligand-binding oxidase from the bacterium Geobacillus kaustophilus (R2lox) loaded with a FeFe or MnFe cofactor, which catalyzes O2 reduction and an unusual tyrosine-valine ether cross-link formation, as revealed by X-ray crystallography. Advanced X-ray absorption, emission, and vibrational spectroscopy methods and quantum chemical and molecular mechanics calculations provided relative Mn/Fe contents, X-ray photoreduction kinetics, metal-ligand bond lengths, metal-metal distances, metal oxidation states, spin configurations, valence-level degeneracy, molecular orbital composition, nuclear quadrupole splitting energies, and vibrational normal modes for both cofactors. A protonation state with an axial water (H2O) ligand at Mn or Fe in binding site 1 and a metal-bridging hydroxo group (μOH) in a hydrogen-bonded network is assigned. Our comprehensive picture of the molecular, electronic, and dynamic properties of the cofactors highlights reorientation of the unique axis along the Mn-OH2 bond for the Mn1(III) Jahn-Teller ion but along the Fe-μOH bond for the octahedral Fe1(III). This likely corresponds to a more positive redox potential of the Mn(III)Fe(III) cofactor and higher proton affinity of its μOH group. Refined model structures for the Mn(III)Fe(III) and Fe(III)Fe(III) cofactors are presented. Implications of our findings for the site-specific metalation of R2lox and performance of the O2 reduction and cross-link formation reactions are discussed.
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Affiliation(s)
- Ramona Kositzki
- Fachbereich Physik, Freie Universität Berlin , 14195 Berlin, Germany
| | - Stefan Mebs
- Fachbereich Physik, Freie Universität Berlin , 14195 Berlin, Germany
| | - Jennifer Marx
- Fachbereich Physik, Technische Universität Kaiserslautern , 67663 Kaiserslautern, Germany
| | - Julia J Griese
- Department of Biochemistry and Biophysics, Stockholm University , 10691 Stockholm, Sweden
| | - Nils Schuth
- Fachbereich Physik, Freie Universität Berlin , 14195 Berlin, Germany
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Stockholm University , 10691 Stockholm, Sweden.,Department of Chemistry, Stanford University , Stanford, California 94305, United States
| | - Volker Schünemann
- Fachbereich Physik, Technische Universität Kaiserslautern , 67663 Kaiserslautern, Germany
| | - Michael Haumann
- Fachbereich Physik, Freie Universität Berlin , 14195 Berlin, Germany
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9
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Liao RZ, Siegbahn PEM. Mechanism and selectivity of the dinuclear iron benzoyl-coenzyme A epoxidase BoxB. Chem Sci 2015; 6:2754-2764. [PMID: 28706665 PMCID: PMC5489048 DOI: 10.1039/c5sc00313j] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 03/02/2015] [Indexed: 12/22/2022] Open
Abstract
DFT calculations are used to elucidate the reaction mechanism and selectivity of BoxB catalyzed benzoyl-CoA epoxidation.
Benzoyl-CoA epoxidase is a dinuclear iron enzyme that catalyzes the epoxidation reaction of the aromatic ring of benzoyl-CoA with chemo-, regio- and stereo-selectivity. It has been suggested that this enzyme may also catalyze the deoxygenation reaction of epoxide, suggesting a unique bifunctionality among the diiron enzymes. We report a density functional theory study of this enzyme aimed at elucidating its mechanism and the various selectivities. The epoxidation is suggested to start with the binding of the O2 molecule to the diferrous center to generate a diferric peroxide complex, followed by concerted O–O bond cleavage and epoxide formation. Two different pathways have been located, leading to (2S,3R)-epoxy and (2R,3S)-epoxy products, with barriers of 17.6 and 20.4 kcal mol–1, respectively. The barrier difference is 2.8 kcal mol–1, corresponding to a diastereomeric excess of about 99 : 1. Further isomerization from epoxide to phenol is found to have quite a high barrier, which cannot compete with the product release step. After product release into solution, fast epoxide–oxepin isomerization and racemization can take place easily, leading to a racemic mixture of (2S,3R) and (2R,3S) products. The deoxygenation of epoxide to regenerate benzoyl-CoA by a diferrous form of the enzyme proceeds via a stepwise mechanism. The C2–O bond cleavage happens first, coupled with one electron transfer from one iron center to the substrate, to form a radical intermediate, which is followed by the second C3–O bond cleavage. The first step is rate-limiting with a barrier of only 10.8 kcal mol–1. Further experimental studies are encouraged to verify our results.
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Affiliation(s)
- Rong-Zhen Liao
- Key Laboratory for Large-Format Battery Materials and System , Ministry of Education , School of Chemistry and Chemical Engineering , Huazhong University of Science and Technology , Wuhan 430074 , China .
| | - Per E M Siegbahn
- Department of Organic Chemistry , Arrhenius Laboratory , Stockholm University , SE-10691 Stockholm , Sweden .
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10
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Shafaat HS, Griese JJ, Pantazis DA, Roos K, Andersson CS, Popović-Bijelić A, Gräslund A, Siegbahn PEM, Neese F, Lubitz W, Högbom M, Cox N. Electronic structural flexibility of heterobimetallic Mn/Fe cofactors: R2lox and R2c proteins. J Am Chem Soc 2014; 136:13399-409. [PMID: 25153930 DOI: 10.1021/ja507435t] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The electronic structure of the Mn/Fe cofactor identified in a new class of oxidases (R2lox) described by Andersson and Högbom [Proc. Natl. Acad. Sci. U.S.A. 2009, 106, 5633] is reported. The R2lox protein is homologous to the small subunit of class Ic ribonucleotide reductase (R2c) but has a completely different in vivo function. Using multifrequency EPR and related pulse techniques, it is shown that the cofactor of R2lox represents an antiferromagnetically coupled Mn(III)/Fe(III) dimer linked by a μ-hydroxo/bis-μ-carboxylato bridging network. The Mn(III) ion is coordinated by a single water ligand. The R2lox cofactor is photoactive, converting into a second form (R2loxPhoto) upon visible illumination at cryogenic temperatures (77 K) that completely decays upon warming. This second, unstable form of the cofactor more closely resembles the Mn(III)/Fe(III) cofactor seen in R2c. It is shown that the two forms of the R2lox cofactor differ primarily in terms of the local site geometry and electronic state of the Mn(III) ion, as best evidenced by a reorientation of its unique (55)Mn hyperfine axis. Analysis of the metal hyperfine tensors in combination with density functional theory (DFT) calculations suggests that this change is triggered by deprotonation of the μ-hydroxo bridge. These results have important consequences for the mixed-metal R2c cofactor and the divergent chemistry R2lox and R2c perform.
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Affiliation(s)
- Hannah S Shafaat
- Max-Planck-Institut für Chemische Energiekonversion , Stiftstrasse 34-36, Mülheim an der Ruhr D-45470, Germany
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11
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Griese JJ, Srinivas V, Högbom M. Assembly of nonheme Mn/Fe active sites in heterodinuclear metalloproteins. J Biol Inorg Chem 2014; 19:759-74. [PMID: 24771036 PMCID: PMC4118035 DOI: 10.1007/s00775-014-1140-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 04/14/2014] [Indexed: 11/23/2022]
Abstract
The ferritin superfamily contains several protein groups that share a common fold and metal coordinating ligands. The different groups utilize different dinuclear cofactors to perform a diverse set of reactions. Several groups use an oxygen-activating di-iron cluster, while others use di-manganese or heterodinuclear Mn/Fe cofactors. Given the similar primary ligand preferences of Mn and Fe as well as the similarities between the binding sites, the basis for metal specificity in these systems remains enigmatic. Recent data for the heterodinuclear cluster show that the protein scaffold per se is capable of discriminating between Mn and Fe and can assemble the Mn/Fe center in the absence of any potential assembly machineries or metal chaperones. Here we review the current understanding of the assembly of the heterodinuclear cofactor in the two different protein groups in which it has been identified, ribonucleotide reductase R2c proteins and R2-like ligand-binding oxidases. Interestingly, although the two groups form the same metal cluster they appear to employ partly different mechanisms to assemble it. In addition, it seems that both the thermodynamics of metal binding and the kinetics of oxygen activation play a role in achieving metal specificity.
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Affiliation(s)
- Julia J. Griese
- Arrhenius Laboratories for Natural Sciences A4, Department of Biochemistry and Biophysics, Stockholm Center for Biomembrane Research, Stockholm University, 10691 Stockholm, Sweden
| | - Vivek Srinivas
- Arrhenius Laboratories for Natural Sciences A4, Department of Biochemistry and Biophysics, Stockholm Center for Biomembrane Research, Stockholm University, 10691 Stockholm, Sweden
| | - Martin Högbom
- Arrhenius Laboratories for Natural Sciences A4, Department of Biochemistry and Biophysics, Stockholm Center for Biomembrane Research, Stockholm University, 10691 Stockholm, Sweden
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12
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Luber S, Leung S, Herrmann C, Du WH, Noodleman L, Batista VS. EXAFS simulation refinement based on broken-symmetry DFT geometries for the Mn(IV)-Fe(III) center of class I RNR from Chlamydia trachomatis. Dalton Trans 2014; 43:576-83. [PMID: 24129440 PMCID: PMC3855085 DOI: 10.1039/c3dt51563j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ribonucleotide reductases (RNRs) catalyze the reduction of ribonucleotides into deoxyribonucleotides necessary for DNA biosynthesis. Unlike the conventional class Ia RNRs which use a diiron cofactor in their subunit R2, the active site of the RNR-R2 from Chlamydia trachomatis (Ct) contains a Mn/Fe cofactor. The detailed structure of the Mn/Fe core has yet to be established. In this paper we evaluate six different structural models of the Ct RNR active site in the Mn(iv)/Fe(iii) state by using Mössbauer parameter calculations and simulations of Mn/Fe extended X-ray absorption fine structure (EXAFS) spectroscopy, and we identify a structure similar to a previously proposed DFT-optimized model that shows quantitative agreement with both EXAFS and Mössbauer spectroscopic data.
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Affiliation(s)
- Sandra Luber
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520, USA
| | - Sophie Leung
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520, USA
| | - Carmen Herrmann
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520, USA
| | - Wenge Han Du
- Department of Integrative Structural and Computational Biology, TPC15, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Louis Noodleman
- Department of Integrative Structural and Computational Biology, TPC15, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Victor S. Batista
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520, USA
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13
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Blomberg MRA, Borowski T, Himo F, Liao RZ, Siegbahn PEM. Quantum chemical studies of mechanisms for metalloenzymes. Chem Rev 2014; 114:3601-58. [PMID: 24410477 DOI: 10.1021/cr400388t] [Citation(s) in RCA: 436] [Impact Index Per Article: 43.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Margareta R A Blomberg
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University , SE-106 91 Stockholm, Sweden
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14
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Campaña AG, Buñuel E, Cuerva JM, Cárdenas DJ. The role of water-based hydrogen atom wires in long-range electron-transfer reactions in aqueous media for the FeII-FeIII self-exchange and related systems. Chemistry 2013; 19:16187-91. [PMID: 24249687 DOI: 10.1002/chem.201301971] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Indexed: 12/17/2022]
Abstract
Extended reach: A calculated mechanism for long-range proton-coupled electron transfer (PCET, see picture) through an array of structured water molecules between Fe(III)-Fe(III) complexes accounts for the reaction enthalpy and kinetic isotope effect previously measured for this reaction. This mechanism may be general and occur for other hydroxo-metal complexes.
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Affiliation(s)
- Araceli G Campaña
- Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Granada, Campus de Fuentenueva, 18071 Granada (Spain)
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15
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Kwak Y, Jiang W, Dassama LMK, Park K, Bell CB, Liu LV, Wong SD, Saito M, Kobayashi Y, Kitao S, Seto M, Yoda Y, Alp EE, Zhao J, Bollinger JM, Krebs C, Solomon EI. Geometric and electronic structure of the Mn(IV)Fe(III) cofactor in class Ic ribonucleotide reductase: correlation to the class Ia binuclear non-heme iron enzyme. J Am Chem Soc 2013; 135:17573-84. [PMID: 24131208 DOI: 10.1021/ja409510d] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The class Ic ribonucleotide reductase (RNR) from Chlamydia trachomatis (Ct) utilizes a Mn/Fe heterobinuclear cofactor, rather than the Fe/Fe cofactor found in the β (R2) subunit of the class Ia enzymes, to react with O2. This reaction produces a stable Mn(IV)Fe(III) cofactor that initiates a radical, which transfers to the adjacent α (R1) subunit and reacts with the substrate. We have studied the Mn(IV)Fe(III) cofactor using nuclear resonance vibrational spectroscopy (NRVS) and absorption (Abs)/circular dichroism (CD)/magnetic CD (MCD)/variable temperature, variable field (VTVH) MCD spectroscopies to obtain detailed insight into its geometric/electronic structure and to correlate structure with reactivity; NRVS focuses on the Fe(III), whereas MCD reflects the spin-allowed transitions mostly on the Mn(IV). We have evaluated 18 systematically varied structures. Comparison of the simulated NRVS spectra to the experimental data shows that the cofactor has one carboxylate bridge, with Mn(IV) at the site proximal to Phe127. Abs/CD/MCD/VTVH MCD data exhibit 12 transitions that are assigned as d-d and oxo and OH(-) to metal charge-transfer (CT) transitions. Assignments are based on MCD/Abs intensity ratios, transition energies, polarizations, and derivative-shaped pseudo-A term CT transitions. Correlating these results with TD-DFT calculations defines the Mn(IV)Fe(III) cofactor as having a μ-oxo, μ-hydroxo core and a terminal hydroxo ligand on the Mn(IV). From DFT calculations, the Mn(IV) at site 1 is necessary to tune the redox potential to a value similar to that of the tyrosine radical in class Ia RNR, and the OH(-) terminal ligand on this Mn(IV) provides a high proton affinity that could gate radical translocation to the α (R1) subunit.
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Affiliation(s)
- Yeonju Kwak
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
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16
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Tereniak SJ, Carlson RK, Clouston LJ, Young VG, Bill E, Maurice R, Chen YS, Kim HJ, Gagliardi L, Lu CC. Role of the Metal in the Bonding and Properties of Bimetallic Complexes Involving Manganese, Iron, and Cobalt. J Am Chem Soc 2013; 136:1842-55. [DOI: 10.1021/ja409016w] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Stephen J. Tereniak
- Department
of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
| | - Rebecca K. Carlson
- Department
of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
- Supercomputing
Institute and Chemical Theory Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Laura J. Clouston
- Department
of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
| | - Victor G. Young
- Department
of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
| | - Eckhard Bill
- Max Planck Institut für Chemische Energiekonversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Rémi Maurice
- Department
of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
- Supercomputing
Institute and Chemical Theory Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Yu-Sheng Chen
- ChemMatCARS, University of Chicago, Argonne, Illinois 60439, United States
| | - Hyun Jung Kim
- Department
of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
- Supercomputing
Institute and Chemical Theory Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Laura Gagliardi
- Department
of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
- Supercomputing
Institute and Chemical Theory Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Connie C. Lu
- Department
of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
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17
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Roos K, Siegbahn PEM. Activation of Dimanganese Class Ib Ribonucleotide Reductase by Hydrogen Peroxide: Mechanistic Insights from Density Functional Theory. Inorg Chem 2013; 52:4173-84. [DOI: 10.1021/ic3008427] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Katarina Roos
- Department of Physics, Stockholm University, SE-106 91 Stockholm,
Sweden
| | - Per E. M. Siegbahn
- Department of Physics, Stockholm University, SE-106 91 Stockholm,
Sweden
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18
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Sigfridsson KGV, Chernev P, Leidel N, Popović-Bijelić A, Gräslund A, Haumann M. Rapid X-ray photoreduction of dimetal-oxygen cofactors in ribonucleotide reductase. J Biol Chem 2013; 288:9648-9661. [PMID: 23400774 DOI: 10.1074/jbc.m112.438796] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Prototypic dinuclear metal cofactors with varying metallation constitute a class of O2-activating catalysts in numerous enzymes such as ribonucleotide reductase. Reliable structures are required to unravel the reaction mechanisms. However, protein crystallography data may be compromised by x-ray photoreduction (XRP). We studied XPR of Fe(III)Fe(III) and Mn(III)Fe(III) sites in the R2 subunit of Chlamydia trachomatis ribonucleotide reductase using x-ray absorption spectroscopy. Rapid and biphasic x-ray photoreduction kinetics at 20 and 80 K for both cofactor types suggested sequential formation of (III,II) and (II,II) species and similar redox potentials of iron and manganese sites. Comparing with typical x-ray doses in crystallography implies that (II,II) states are reached in <1 s in such studies. First-sphere metal coordination and metal-metal distances differed after chemical reduction at room temperature and after XPR at cryogenic temperatures, as corroborated by model structures from density functional theory calculations. The inter-metal distances in the XPR-induced (II,II) states, however, are similar to R2 crystal structures. Therefore, crystal data of initially oxidized R2-type proteins mostly contain photoreduced (II,II) cofactors, which deviate from the native structures functional in O2 activation, explaining observed variable metal ligation motifs. This situation may be remedied by novel femtosecond free electron-laser protein crystallography techniques.
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Affiliation(s)
| | - Petko Chernev
- Free University Berlin, Institute of Experimental Physics, 14195 Berlin, Germany
| | - Nils Leidel
- Free University Berlin, Institute of Experimental Physics, 14195 Berlin, Germany
| | - Ana Popović-Bijelić
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden
| | - Astrid Gräslund
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden
| | - Michael Haumann
- Free University Berlin, Institute of Experimental Physics, 14195 Berlin, Germany.
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19
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Dassama LMK, Jiang W, Varano PT, Pandelia ME, Conner DA, Xie J, Bollinger JM, Krebs C. Radical-translocation intermediates and hurdling of pathway defects in "super-oxidized" (Mn(IV)/Fe(IV)) Chlamydia trachomatis ribonucleotide reductase. J Am Chem Soc 2012; 134:20498-506. [PMID: 23157728 PMCID: PMC3931446 DOI: 10.1021/ja309468s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A class I ribonucleotide reductase (RNR) uses either a tyrosyl radical (Y(•)) or a Mn(IV)/Fe(III) cluster in its β subunit to oxidize a cysteine residue ∼35 Å away in its α subunit, generating a thiyl radical that abstracts hydrogen (H(•)) from the substrate. With either oxidant, the inter-subunit "hole-transfer" or "radical-translocation" (RT) process is thought to occur by a "hopping" mechanism involving multiple tyrosyl (and perhaps one tryptophanyl) radical intermediates along a specific pathway. The hopping intermediates have never been directly detected in a Mn/Fe-dependent (class Ic) RNR nor in any wild-type (wt) RNR. The Mn(IV)/Fe(III) cofactor of Chlamydia trachomatis RNR assembles via a Mn(IV)/Fe(IV) intermediate. Here we show that this cofactor-assembly intermediate can propagate a hole into the RT pathway when α is present, accumulating radicals with EPR spectra characteristic of Y(•)'s. The dependence of Y(•) accumulation on the presence of substrate suggests that RT within this "super-oxidized" enzyme form is gated by the protein, and the failure of a β variant having the subunit-interfacial pathway Y substituted by phenylalanine to support radical accumulation implies that the Y(•)(s) in the wt enzyme reside(s) within the RT pathway. Remarkably, two variant β proteins having pathway substitutions rendering them inactive in their Mn(IV)/Fe(III) states can generate the pathway Y(•)'s in their Mn(IV)/Fe(IV) states and also effect nucleotide reduction. Thus, the use of the more oxidized cofactor permits the accumulation of hopping intermediates and the "hurdling" of engineered defects in the RT pathway.
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Affiliation(s)
- Laura M. K. Dassama
- Departments of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
| | - Wei Jiang
- Departments of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Paul T. Varano
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Maria-Eirini Pandelia
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Denise A. Conner
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Jiajia Xie
- Departments of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
| | - J. Martin Bollinger
- Departments of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Carsten Krebs
- Departments of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
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20
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Cotruvo JA, Stubbe J. Metallation and mismetallation of iron and manganese proteins in vitro and in vivo: the class I ribonucleotide reductases as a case study. Metallomics 2012; 4:1020-36. [PMID: 22991063 PMCID: PMC3488304 DOI: 10.1039/c2mt20142a] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
How cells ensure correct metallation of a given protein and whether a degree of promiscuity in metal binding has evolved are largely unanswered questions. In a classic case, iron- and manganese-dependent superoxide dismutases (SODs) catalyze the disproportionation of superoxide using highly similar protein scaffolds and nearly identical active sites. However, most of these enzymes are active with only one metal, although both metals can bind in vitro and in vivo. Iron(ii) and manganese(ii) bind weakly to most proteins and possess similar coordination preferences. Their distinct redox properties suggest that they are unlikely to be interchangeable in biological systems except when they function in Lewis acid catalytic roles, yet recent work suggests this is not always the case. This review summarizes the diversity of ways in which iron and manganese are substituted in similar or identical protein frameworks. As models, we discuss (1) enzymes, such as epimerases, thought to use Fe(II) as a Lewis acid under normal growth conditions but which switch to Mn(II) under oxidative stress; (2) extradiol dioxygenases, which have been found to use both Fe(II) and Mn(II), the redox role of which in catalysis remains to be elucidated; (3) SODs, which use redox chemistry and are generally metal-specific; and (4) the class I ribonucleotide reductases (RNRs), which have evolved unique biosynthetic pathways to control metallation. The primary focus is the class Ib RNRs, which can catalyze formation of a stable radical on a tyrosine residue in their β2 subunits using either a di-iron or a recently characterized dimanganese cofactor. The physiological roles of enzymes that can switch between iron and manganese cofactors are discussed, as are insights obtained from the studies of many groups regarding iron and manganese homeostasis and the divergent and convergent strategies organisms use for control of protein metallation. We propose that, in many of the systems discussed, "discrimination" between metals is not performed by the protein itself, but it is instead determined by the environment in which the protein is expressed.
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Affiliation(s)
- Joseph A. Cotruvo
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA.; Fax: +1 617 324-0505; Tel: +1 617 253-1814
| | - JoAnne Stubbe
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA.; Fax: +1 617 324-0505; Tel: +1 617 253-1814
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA
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21
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Dassama LMK, Boal AK, Krebs C, Rosenzweig AC, Bollinger JM. Evidence that the β subunit of Chlamydia trachomatis ribonucleotide reductase is active with the manganese ion of its manganese(IV)/iron(III) cofactor in site 1. J Am Chem Soc 2012; 134:2520-3. [PMID: 22242660 DOI: 10.1021/ja211314p] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The reaction of a class I ribonucleotide reductase (RNR) begins when a cofactor in the β subunit oxidizes a cysteine residue ~35 Å away in the α subunit, generating a thiyl radical. In the class Ic enzyme from Chlamydia trachomatis (Ct), the cysteine oxidant is the Mn(IV) ion of a Mn(IV)/Fe(III) cluster, which assembles in a reaction between O(2) and the Mn(II)/Fe(II) complex of β. The heterodinuclear nature of the cofactor raises the question of which site, 1 or 2, contains the Mn(IV) ion. Because site 1 is closer to the conserved location of the cysteine-oxidizing tyrosyl radical of class Ia and Ib RNRs, we suggested that the Mn(IV) ion most likely resides in this site (i.e., (1)Mn(IV)/(2)Fe(III)), but a subsequent computational study favored its occupation of site 2 ((1)Fe(III)/(2)Mn(IV)). In this work, we have sought to resolve the location of the Mn(IV) ion in Ct RNR-β by correlating X-ray crystallographic anomalous scattering intensities with catalytic activity for samples of the protein reconstituted in vitro by two different procedures. In samples containing primarily Mn(IV)/Fe(III) clusters, Mn preferentially occupies site 1, but some anomalous scattering from site 2 is observed, implying that both (1)Mn(II)/(2)Fe(II) and (1)Fe(II)/(2)Mn(II) complexes are competent to react with O(2) to produce the corresponding oxidized states. However, with diminished Mn(II) loading in the reconstitution, there is no evidence for Mn occupancy of site 2, and the greater activity of these "low-Mn" samples on a per-Mn basis implies that the (1)Mn(IV)/(2)Fe(III)-β is at least the more active of the two oxidized forms and may be the only active form.
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Affiliation(s)
- Laura M K Dassama
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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22
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Leidel N, Popović-Bijelić A, Havelius KGV, Chernev P, Voevodskaya N, Gräslund A, Haumann M. High-valent [MnFe] and [FeFe] cofactors in ribonucleotide reductases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:430-44. [PMID: 22222354 DOI: 10.1016/j.bbabio.2011.12.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 12/13/2011] [Accepted: 12/16/2011] [Indexed: 11/30/2022]
Abstract
Ribonucleotide reductases (RNRs) are essential for DNA synthesis in most organisms. In class-Ic RNR from Chlamydia trachomatis (Ct), a MnFe cofactor in subunit R2 forms the site required for enzyme activity, instead of an FeFe cofactor plus a redox-active tyrosine in class-Ia RNRs, for example in mouse (Mus musculus, Mm). For R2 proteins from Ct and Mm, either grown in the presence of, or reconstituted with Mn and Fe ions, structural and electronic properties of higher valence MnFe and FeFe sites were determined by X-ray absorption spectroscopy and complementary techniques, in combination with bond-valence-sum and density functional theory calculations. At least ten different cofactor species could be tentatively distinguished. In Ct R2, two different Mn(IV)Fe(III) site configurations were assigned either L(4)Mn(IV)(μO)(2)Fe(III)L(4) (metal-metal distance of ~2.75Å, L = ligand) prevailing in metal-grown R2, or L(4)Mn(IV)(μO)(μOH)Fe(III)L(4) (~2.90Å) dominating in metal-reconstituted R2. Specific spectroscopic features were attributed to an Fe(IV)Fe(III) site (~2.55Å) with a L(4)Fe(IV)(μO)(2)Fe(III)L(3) core structure. Several Mn,Fe(III)Fe(III) (~2.9-3.1Å) and Mn,Fe(III)Fe(II) species (~3.3-3.4Å) likely showed 5-coordinated Mn(III) or Fe(III). Rapid X-ray photoreduction of iron and shorter metal-metal distances in the high-valent states suggested radiation-induced modifications in most crystal structures of R2. The actual configuration of the MnFe and FeFe cofactors seems to depend on assembly sequences, bound metal type, valence state, and previous catalytic activity involving subunit R1. In Ct R2, the protonation of a bridging oxide in the Mn(IV)(μO)(μOH)Fe(III) core may be important for preventing premature site reduction and initiation of the radical chemistry in R1.
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Affiliation(s)
- Nils Leidel
- Institut für Experimentalphysik, Freie Universität Berlin, 14195 Berlin, Germany
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23
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Roos K, Siegbahn PEM. A comparison of two-electron chemistry performed by the manganese and iron heterodimer and homodimers. J Biol Inorg Chem 2011; 17:363-73. [DOI: 10.1007/s00775-011-0858-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Accepted: 11/02/2011] [Indexed: 10/15/2022]
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24
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Han WG, Sandala GM, Giammona DA, Bashford D, Noodleman L. Mössbauer properties of the diferric cluster and the differential iron(II)-binding affinity of the iron sites in protein R2 of class Ia Escherichia coli ribonucleotide reductase: a DFT/electrostatics study. Dalton Trans 2011; 40:11164-75. [PMID: 21837345 PMCID: PMC3604995 DOI: 10.1039/c1dt10950b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The R2 subunit of class-Ia ribonucleotide reductase (RNR) from Escherichia coli (E. coli) contains a diiron active site. Starting from the apo-protein and Fe(II) in solution at low Fe(II)/apoR2 ratios, mononuclear Fe(II) binding is observed indicating possible different Fe(II) binding affinities for the two alternative sites. Further, based on their Mössbauer spectroscopy and two-iron-isotope reaction experiments, Bollinger et al. (J. Am. Chem. Soc., 1997, 119, 5976-5977) proposed that the site Fe1, which bonds to Asp84, should be associated with the higher observed (57)Fe Mössbauer quadrupole splitting (2.41 mm s(-1)) and lower isomer shift (0.45 mm s(-1)) in the Fe(III)Fe(III) state, site Fe2, which is further from Tyr122, should have a greater affinity for Fe(II) binding than site Fe1, and Fe(IV) in the intermediate X state should reside at site Fe2. In this paper, using density functional theory (DFT) incorporated with the conductor-like screening (COSMO) solvation model and with the finite-difference Poisson-Boltzmann self-consistent reaction field (PB-SCRF) methodologies, we have demonstrated that the observed large quadrupole splitting for the diferric state R2 does come from site Fe1(III) and it is mainly caused by the binding position of the carboxylate group of the Asp84 sidechain. Further, a series of active site clusters with mononuclear Fe(II) binding at either site Fe1 or Fe2 have been studied, which show that with a single dielectric medium outside the active site quantum region, there is no energetic preference for Fe(II) binding at one site over another. However, when including the explicit extended protein environment in the PB-SCRF model, the reaction field favors the Fe(II) binding at site Fe2 rather than at site Fe1 by ~9 kcal mol(-1). Therefore our calculations support the proposal of the previous Mössbauer spectroscopy and two-iron-isotope reaction experiments by Bollinger et al.
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Affiliation(s)
- Wen-Ge Han
- Department of Molecular Biology, TPC15, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
| | - Gregory M. Sandala
- Department of Molecular Biology, TPC15, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
| | - Debra Ann Giammona
- Structural Biology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105
| | - Donald Bashford
- Structural Biology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105
| | - Louis Noodleman
- Department of Molecular Biology, TPC15, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
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25
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Cotruvo JA, Stubbe J. Class I ribonucleotide reductases: metallocofactor assembly and repair in vitro and in vivo. Annu Rev Biochem 2011; 80:733-67. [PMID: 21456967 DOI: 10.1146/annurev-biochem-061408-095817] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Incorporation of metallocofactors essential for the activity of many enyzmes is a major mechanism of posttranslational modification. The cellular machinery required for these processes in the case of mono- and dinuclear nonheme iron and manganese cofactors has remained largely elusive. In addition, many metallocofactors can be converted to inactive forms, and pathways for their repair have recently come to light. The class I ribonucleotide reductases (RNRs) catalyze the conversion of nucleotides to deoxynucleotides and require dinuclear metal clusters for activity: an Fe(III)Fe(III)-tyrosyl radical (Y•) cofactor (class Ia), a Mn(III)Mn(III)-Y• cofactor (class Ib), and a Mn(IV)Fe(III) cofactor (class Ic). The class Ia, Ib, and Ic RNRs are structurally homologous and contain almost identical metal coordination sites. Recent progress in our understanding of the mechanisms by which the cofactor of each of these RNRs is generated in vitro and in vivo and by which the damaged cofactors are repaired is providing insight into how nature prevents mismetallation and orchestrates active cluster formation in high yields.
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Affiliation(s)
- Joseph A Cotruvo
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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26
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Öhrström M, Popović-Bijelić A, Luo J, Stenmark P, Högbom M, Gräslund A. Inhibition of chlamydial class Ic ribonucleotide reductase by C-terminal peptides from protein R2. J Pept Sci 2011; 17:756-62. [DOI: 10.1002/psc.1399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 06/16/2011] [Accepted: 06/27/2011] [Indexed: 12/14/2022]
Affiliation(s)
- Maria Öhrström
- Department of Biochemistry and Biophysics; Stockholm University; SE-10691 ; Stockholm; Sweden
| | - Ana Popović-Bijelić
- Department of Biochemistry and Biophysics; Stockholm University; SE-10691 ; Stockholm; Sweden
| | - Jinghui Luo
- Department of Biochemistry and Biophysics; Stockholm University; SE-10691 ; Stockholm; Sweden
| | - Pål Stenmark
- Department of Biochemistry and Biophysics; Stockholm University; SE-10691 ; Stockholm; Sweden
| | - Martin Högbom
- Department of Biochemistry and Biophysics; Stockholm University; SE-10691 ; Stockholm; Sweden
| | - Astrid Gräslund
- Department of Biochemistry and Biophysics; Stockholm University; SE-10691 ; Stockholm; Sweden
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27
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Cárdenas DJ, Cuerva JM, Alías M, Buñuel E, Campaña AG. Water-based hydrogen-atom wires as mediators in long-range proton-coupled electron transfer in enzymes: a new twist on water reactivity. Chemistry 2011; 17:8318-23. [PMID: 21671300 DOI: 10.1002/chem.201100964] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 04/27/2011] [Indexed: 12/31/2022]
Affiliation(s)
- Diego J Cárdenas
- Departamento de Química Orgánica, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049-Madrid, Spain.
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28
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Krebs C, Bollinger JM, Booker SJ. Cyanobacterial alkane biosynthesis further expands the catalytic repertoire of the ferritin-like 'di-iron-carboxylate' proteins. Curr Opin Chem Biol 2011; 15:291-303. [PMID: 21440485 PMCID: PMC3113506 DOI: 10.1016/j.cbpa.2011.02.019] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 02/01/2011] [Accepted: 02/21/2011] [Indexed: 01/19/2023]
Abstract
Enzymes that activate dioxygen at carboxylate-bridged non-heme diiron clusters residing within ferritin-like, four-helix-bundle protein architectures have crucial roles in, among other processes, the global carbon cycle (e.g. soluble methane monooxygenase), fatty acid biosynthesis [plant fatty acyl-acyl carrier protein (ACP) desaturases], DNA biosynthesis [the R2 or β2 subunits of class Ia ribonucleotide reductases (RNRs)], and cellular iron trafficking (ferritins). Classic studies on class Ia RNRs showed long ago how this obligatorily oxidative di-iron/O2 chemistry can be used to activate an enzyme for even a reduction reaction, and more recent investigations of class Ib and Ic RNRs, coupled with earlier studies on dimanganese catalases, have shown that members of this protein family can also incorporate either one or two Mn ions and use them in place of iron for redox catalysis. These two strategies--oxidative activation for non-oxidative reactions and use of alternative metal ions--expand the catalytic repertoire of the family, probably to include activities that remain to be discovered. Indeed, a recent study has suggested that fatty aldehyde decarbonylases (ADs) from cyanobacteria, purported to catalyze a redox-neutral cleavage of a Cn aldehyde to the Cn-1 alkane (or alkene) and CO, also belong to this enzyme family and are most similar in structure to two other members with heterodinuclear (Mn-Fe) cofactors. Here, we first briefly review both the chemical principles underlying the O2-dependent oxidative chemistry of the 'classical' di-iron-carboxylate proteins and the two aforementioned strategies that have expanded their functional range, and then consider what metal ion(s) and what chemical mechanism(s) might be employed by the newly discovered cyanobacterial ADs.
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Affiliation(s)
- Carsten Krebs
- Department of Chemistry and Department of Biochemistry and Molecular Biology, Penn State University, 332 Chemistry Building, University Park, PA, 16802, USA
| | - J. Martin Bollinger
- Department of Chemistry and Department of Biochemistry and Molecular Biology, Penn State University, 336 Chemistry Building, University Park, PA, 16802, USA
| | - Squire J. Booker
- Department of Chemistry and Department of Biochemistry and Molecular Biology, Penn State University, 302 Chemistry Building, University Park, PA, 16802, USA
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29
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Liao RZ, Yu JG, Himo F. Quantum Chemical Modeling of Enzymatic Reactions: The Case of Decarboxylation. J Chem Theory Comput 2011; 7:1494-501. [PMID: 26610140 DOI: 10.1021/ct200031t] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We present a systematic study of the decarboxylation step of the enzyme aspartate decarboxylase with the purpose of assessing the quantum chemical cluster approach for modeling this important class of decarboxylase enzymes. Active site models ranging in size from 27 to 220 atoms are designed, and the barrier and reaction energy of this step are evaluated. To model the enzyme surrounding, homogeneous polarizable medium techniques are used with several dielectric constants. The main conclusion is that when the active site model reaches a certain size, the solvation effects from the surroundings saturate. Similar results have previously been obtained from systematic studies of other classes of enzymes, suggesting that they are of a quite general nature.
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Affiliation(s)
- Rong-Zhen Liao
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.,College of Chemistry, Beijing Normal University, Beijing, 100875, People's Republic of China
| | - Jian-Guo Yu
- College of Chemistry, Beijing Normal University, Beijing, 100875, People's Republic of China
| | - Fahmi Himo
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden
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30
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Siegbahn PE, Himo F. The quantum chemical cluster approach for modeling enzyme reactions. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2011. [DOI: 10.1002/wcms.13] [Citation(s) in RCA: 166] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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31
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Högbom M. Metal use in ribonucleotide reductase R2, di-iron, di-manganese and heterodinuclear—an intricate bioinorganic workaround to use different metals for the same reaction. Metallomics 2011; 3:110-20. [DOI: 10.1039/c0mt00095g] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Busch M, Ahlberg E, Panas I. Hydroxide oxidation and peroxide formation at embedded binuclear transition metal sites; TM = Cr, Mn, Fe, Co. Phys Chem Chem Phys 2011; 13:15062-8. [DOI: 10.1039/c1cp20487d] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Han WG, Giammona DA, Bashford D, Noodleman L. Density functional theory analysis of structure, energetics, and spectroscopy for the Mn-Fe active site of Chlamydia trachomatis ribonucleotide reductase in four oxidation states. Inorg Chem 2010; 49:7266-81. [PMID: 20604534 PMCID: PMC2919573 DOI: 10.1021/ic902051t] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Models for the Mn-Fe active site structure of ribonucleotide reductase (RNR) from pathogenic bacteria Chlamydia trachomatis (Ct) in different oxidation states have been studied in this paper, using broken-symmetry density functional theory (DFT) incorporated with the conductor like screening (COSMO) solvation model and also with finite-difference Poisson-Boltzmann self-consistent reaction field (PB-SCRF) calculations. The detailed structures for the reduced Mn(II)-Fe(II), the met Mn(III)-Fe(III), the oxidized Mn(IV)-Fe(III) and the superoxidized Mn(IV)-Fe(IV) states are predicted. The calculated properties, including geometries, (57)Fe Mossbauer isomer shifts and quadrupole splittings, and (57)Fe and (55)Mn electron nuclear double resonance (ENDOR) hyperfine coupling constants, are compared with the available experimental data. The Mössbauer and energetic calculations show that the (mu-oxo, mu-hydroxo) models better represent the structure of the Mn(IV)-Fe(III) state than the di-mu-oxo models. The predicted Mn(IV)-Fe(III) distances (2.95 and 2.98 A) in the (mu-oxo, mu-hydroxo) models are in agreement with the extended X-ray absorption fine structure (EXAFS) experimental value of 2.92 A (Younker et al. J. Am. Chem. Soc. 2008, 130, 15022-15027). The effect of the protein and solvent environment on the assignment of the Mn metal position is examined by comparing the relative energies of alternative mono-Mn(II) active site structures. It is proposed that if the Mn(II)-Fe(II) protein is prepared with prior addition of Mn(II) or with Mn(II) richer than Fe(II), Mn is likely positioned at metal site 2, which is further from Phe127.
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Affiliation(s)
- Wen-Ge Han
- Department of Molecular Biology, TPC15, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
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Jiang W, Xie J, Varano PT, Krebs C, Bollinger JM. Two distinct mechanisms of inactivation of the class Ic ribonucleotide reductase from Chlamydia trachomatis by hydroxyurea: implications for the protein gating of intersubunit electron transfer. Biochemistry 2010; 49:5340-9. [PMID: 20462199 DOI: 10.1021/bi100037b] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Catalysis by a class I ribonucleotide reductase (RNR) begins when a cysteine (C) residue in the alpha(2) subunit is oxidized to a thiyl radical (C(*)) by a cofactor approximately 35 A away in the beta(2) subunit. In a class Ia or Ib RNR, a stable tyrosyl radical (Y(*)) is the C oxidant, whereas a Mn(IV)/Fe(III) cluster serves this function in the class Ic enzyme from Chlamydia trachomatis (Ct). It is thought that, in either case, a chain of Y residues spanning the two subunits mediates C oxidation by forming transient "pathway" Y(*)s in a multistep electron transfer (ET) process that is "gated" by the protein so that it occurs only in the ready holoenzyme complex. The drug hydroxyurea (HU) inactivates both Ia/b and Ic beta(2) subunits by reducing their C oxidants. Reduction of the stable cofactor Y(*) (Y122(*)) in Escherichia coli class Ia beta(2) is faster in the presence of alpha(2) and a substrate (CDP), leading to speculation that HU might intercept a transient ET pathway Y(*) under these turnover conditions. Here we show that this mechanism is one of two that are operant in HU inactivation of the Ct enzyme. HU reacts with the Mn(IV)/Fe(III) cofactor to give two distinct products: the previously described homogeneous Mn(III)/Fe(III)-beta(2) complex, which forms only under turnover conditions (in the presence of alpha(2) and the substrate), and a distinct, diamagnetic Mn/Fe cluster, which forms approximately 900-fold less rapidly as a second phase in the reaction under turnover conditions and as the sole outcome in the reaction of Mn(IV)/Fe(III)-beta(2) only. Formation of Mn(III)/Fe(III)-beta(2) also requires (i) either Y338, the subunit-interfacial ET pathway residue of beta(2), or Y222, the surface residue that relays the "extra electron" to the Mn(IV)/Fe(IV) intermediate during activation of beta(2) but is not part of the catalytic ET pathway, and (ii) W51, the cofactor-proximal residue required for efficient ET between either Y222 or Y338 and the cofactor. The combined requirements for the catalytic subunit, the substrate, and, most importantly, a functional surface-to-cofactor electron relay system imply that HU effects the Mn(IV)/Fe(III) --> Mn(III)/Fe(III) reduction by intercepting a Y(*) that forms when the ready holoenzyme complex is assembled, the ET gate is opened, and the Mn(IV) oxidizes either Y222 or Y338.
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Affiliation(s)
- Wei Jiang
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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The manganese/iron-carboxylate proteins: what is what, where are they, and what can the sequences tell us? J Biol Inorg Chem 2009; 15:339-49. [DOI: 10.1007/s00775-009-0606-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Popović-Bijelić A, Voevodskaya N, Domkin V, Thelander L, Gräslund A. Metal Binding and Activity of Ribonucleotide Reductase Protein R2 Mutants: Conditions for Formation of the Mixed Manganese−Iron Cofactor. Biochemistry 2009; 48:6532-9. [DOI: 10.1021/bi900693s] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ana Popović-Bijelić
- Department of Biochemistry and Biophysics, Stockholm University, S-10691 Stockholm, Sweden
| | - Nina Voevodskaya
- Department of Biochemistry and Biophysics, Stockholm University, S-10691 Stockholm, Sweden
| | - Vladimir Domkin
- Department of Medical Biochemistry and Biophysics, Umeå University, S-90187 Umeå, Sweden
| | - Lars Thelander
- Department of Medical Biochemistry and Biophysics, Umeå University, S-90187 Umeå, Sweden
| | - Astrid Gräslund
- Department of Biochemistry and Biophysics, Stockholm University, S-10691 Stockholm, Sweden
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