1
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Wang Z, Wang M, Zhao Z, Zheng P. Quantification of carboxylate-bridged di-zinc site stability in protein due ferri by single-molecule force spectroscopy. Protein Sci 2023; 32:e4583. [PMID: 36718829 PMCID: PMC9926469 DOI: 10.1002/pro.4583] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 01/16/2023] [Accepted: 01/27/2023] [Indexed: 02/01/2023]
Abstract
Carboxylate-bridged diiron proteins belong to a protein family involved in different physiological processes. These proteins share the conservative EXXH motif, which provides the carboxylate bridge and is critical for metal binding. Here, we choose de novo-designed single-chain due ferri protein (DFsc), a four-helical protein with two EXXH motifs as a model protein, to study the stability of the carboxylate-bridged di-metal binding site. The mechanical and kinetic properties of the di-Zn site in DFsc were obtained by atomic force microscopy-based single-molecule force spectroscopy. Zn-DFsc showed a considerable rupture force of ~200 pN, while the apo-protein is mechanically labile. In addition, multiple rupture pathways were observed with different probabilities, indicating the importance of the EXXH-based carboxylate-bridged metal site. These results demonstrate carboxylate-bridged di-metal site is mechanically stable and improve our understanding of this important type of metalloprotein.
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Affiliation(s)
- Zhiyi Wang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical EngineeringNanjing UniversityNanjingPeople's Republic of China
| | - Mengdie Wang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical EngineeringNanjing UniversityNanjingPeople's Republic of China
| | - Zhongxin Zhao
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical EngineeringNanjing UniversityNanjingPeople's Republic of China
| | - Peng Zheng
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical EngineeringNanjing UniversityNanjingPeople's Republic of China
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2
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Moubarak S, Rippers Y, Elghobashi-Meinhardt N, Mroginski MA. Structural and electronic properties of the active site of [ZnFe] SulE. Front Mol Biosci 2022; 9:945415. [DOI: 10.3389/fmolb.2022.945415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 09/12/2022] [Indexed: 11/13/2022] Open
Abstract
The function of the recently isolated sulerythrin (SulE) has been investigated using a combination of structural and electronic analyses based on quantum mechanical calculations. In the SulE structure of Fushinobu et al. (2003), isolated from a strictly aerobic archaeon, Sulfolobus tokadaii, a dioxygen-containing species was tentatively included at the active site during crystallographic refinement although the substrate specificity of SulE remains unclear. Studies have suggested that a structurally related enzyme, rubrerythrin, functions as a hydrogen peroxide reductase. Since SulE is a truncated version of rubrerythrin, the enzymes are hypothesized to function similarly. Hence, using available X-ray crystallography data (1.7 Å), we constructed various models of SulE containing a ZnII–Fe active site, differing in the nature of the substrate specificity (O2, H2O2), the oxidation level and the spin state of the iron ion, and the protonation states of the coordinating glutamate residues. Also, the substrate H2O2 is modeled in two possible configurations, differing in the orientation of the hydrogen atoms. Overall, the optimized geometries with an O2 substrate do not show good agreement with the experimentally resolved geometry. In contrast, excellent agreement between crystal structure arrangement and optimized geometries is achieved considering a H2O2 substrate and FeII in both spin states, when Glu92 is protonated. These results suggest that the dioxo species detected at the [ZnFe] active site of sulerythrin is H2O2, rather than an O2 molecule in agreement with experimental data indicating that only the diferrous oxidation state of the dimetal site in rubrerythrin reacts rapidly with H2O2. Based on our computations, we proposed a possible reaction pathway for substrate binding at the ZnFeII site of SulE with a H2O2 substrate. In this reaction pathway, Fe or another electron donor, such as NAD(P)H, catalyzes the reduction of H2O2 to water at the zinc–iron site.
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3
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Lennartz F, Jeoung JH, Ruenger S, Dobbek H, Weiss MS. Determining the oxidation state of elements by X-ray crystallography. ACTA CRYSTALLOGRAPHICA SECTION D STRUCTURAL BIOLOGY 2022; 78:238-247. [PMID: 35102889 PMCID: PMC8805299 DOI: 10.1107/s2059798321013048] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 12/08/2021] [Indexed: 11/10/2022]
Abstract
Protein-mediated redox reactions play a critical role in many biological processes and often occur at centres that contain metal ions as cofactors. In order to understand the exact mechanisms behind these reactions it is important to not only characterize the three-dimensional structures of these proteins and their cofactors, but also to identify the oxidation states of the cofactors involved and to correlate this knowledge with structural information. The only suitable approach for this based on crystallographic measurements is spatially resolved anomalous dispersion (SpReAD) refinement, a method that has been used previously to determine the redox states of metals in iron–sulfur cluster-containing proteins. In this article, the feasibility of this approach for small, non-iron–sulfur redox centres is demonstrated by employing SpReAD analysis to characterize Sulfolobus tokodaii sulerythrin, a ruberythrin-like protein that contains a binuclear metal centre. Differences in oxidation states between the individual iron ions of the binuclear metal centre are revealed in sulerythrin crystals treated with H2O2. Furthermore, data collection at high X-ray doses leads to photoreduction of this metal centre, showing that careful control of the total absorbed dose is a prerequisite for successfully determining the oxidation state through SpReAD analysis.
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4
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Jeoung JH, Rünger S, Haumann M, Neumann B, Klemke F, Davis V, Fischer A, Dau H, Wollenberger U, Dobbek H. Bimetallic Mn, Fe, Co, and Ni Sites in a Four-Helix Bundle Protein: Metal Binding, Structure, and Peroxide Activation. Inorg Chem 2021; 60:17498-17508. [PMID: 34757735 DOI: 10.1021/acs.inorgchem.1c01919] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bimetallic active sites in enzymes catalyze small-molecule conversions that are among the top 10 challenges in chemistry. As different metal cofactors are typically incorporated in varying protein scaffolds, it is demanding to disentangle the individual contributions of the metal and the protein matrix to the activity. Here, we compared the structure, properties, and hydrogen peroxide reactivity of four homobimetallic cofactors (Mn(II)2, Fe(II)2, Co(II)2, Ni(II)2) that were reconstituted into a four-helix bundle protein. Reconstituted proteins were studied in solution and in crystals. All metals bind with high affinity and yield similar cofactor structures. Cofactor variants react with H2O2 but differ in their turnover rates, accumulated oxidation states, and trapped peroxide-bound intermediates. Varying the metal composition thus creates opportunities to tune the reactivity of the bimetallic cofactor and to study and functionalize reactive species.
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Affiliation(s)
- Jae-Hun Jeoung
- Department of Biology, Strukturbiologie/Biochemie, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany
| | - Stefan Rünger
- Department of Biology, Strukturbiologie/Biochemie, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany
| | - Michael Haumann
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Bettina Neumann
- Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam, Germany
| | - Friederike Klemke
- Department of Biology, Strukturbiologie/Biochemie, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany
| | - Victoria Davis
- Institute for Inorganic and Analytical Chemistry (IAAC), Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany.,Freiburg Material Research Center (FMF), University of Freiburg, 79104 Freiburg, Germany.,Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79104 Freiburg, Germany.,Cluster of Excellence livMatS@FIT─Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79104 Freiburg, Germany
| | - Anna Fischer
- Institute for Inorganic and Analytical Chemistry (IAAC), Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany.,Freiburg Material Research Center (FMF), University of Freiburg, 79104 Freiburg, Germany.,Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79104 Freiburg, Germany.,Cluster of Excellence livMatS@FIT─Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79104 Freiburg, Germany
| | - Holger Dau
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Ulla Wollenberger
- Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam, Germany
| | - Holger Dobbek
- Department of Biology, Strukturbiologie/Biochemie, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany
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5
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Bonjack-Shterengartz M, Avnir D. The enigma of the near-symmetry of proteins: Domain swapping. PLoS One 2017; 12:e0180030. [PMID: 28708874 PMCID: PMC5510828 DOI: 10.1371/journal.pone.0180030] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 06/08/2017] [Indexed: 01/25/2023] Open
Abstract
The majority of proteins form oligomers which have rotational symmetry. Literature has suggested many functional advantages that the symmetric packing offers. Yet, despite these advantages, the vast majority of protein oligomers are only nearly symmetric. A key question in the field of proteins structure is therefore, if symmetry is so advantageous, why do oligomers settle for aggregates that do not maximize that structural property? The answer to that question is apparently multi-parametric, and involves distortions at the interaction zones of the monomer units of the oligomer in order to minimize the free energy, the dynamics of the protein, the effects of surroundings parameters, and the mechanism of oligomerization. The study of this problem is in its infancy: Only the first parameter has been explored so far. Here we focus on the last parameter-the mechanism of formation. To test this effect we have selected to focus on the domain swapping mechanism of oligomerization, by which oligomers form in a mechanism that swaps identical portions of monomeric units, resulting in an interwoven oligomer. We are using continuous symmetry measures to analyze in detail the oligomer formed by this mechanism, and found, that without exception, in all analyzed cases, perfect symmetry is given away, and we are able to identify that the main burden of distortion lies in the hinge regions that connect the swapped portions. We show that the continuous symmetry analysis method clearly identifies the hinge region of swapped domain proteins-considered to be a non-trivial task. We corroborate our conclusion about the central role of the hinge region in affecting the symmetry of the oligomers, by a special probability analysis developed particularly for that purpose.
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Affiliation(s)
- Maayan Bonjack-Shterengartz
- Institute of Chemistry and the Lise Meitner Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - David Avnir
- Institute of Chemistry and the Lise Meitner Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
- * E-mail:
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6
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Yagi S, Akanuma S, Yamagishi A. Addition of negatively charged residues can reverse the decrease in the solubility of an acidic protein caused by an artificially introduced non-polar surface patch. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:553-60. [DOI: 10.1016/j.bbapap.2013.12.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 12/09/2013] [Accepted: 12/18/2013] [Indexed: 12/12/2022]
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7
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Mary Rajathei D, Selvaraj S. Analysis of sequence repeats of proteins in the PDB. Comput Biol Chem 2013; 47:156-66. [PMID: 24121644 DOI: 10.1016/j.compbiolchem.2013.09.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 08/27/2013] [Accepted: 09/05/2013] [Indexed: 10/26/2022]
Abstract
Internal repeats in protein sequences play a significant role in the evolution of protein structure and function. Applications of different bioinformatics tools help in the identification and characterization of these repeats. In the present study, we analyzed sequence repeats in a non-redundant set of proteins available in the Protein Data Bank (PDB). We used RADAR for detecting internal repeats in a protein, PDBeFOLD for assessing structural similarity, PDBsum for finding functional involvement and Pfam for domain assignment of the repeats in a protein. Through the analysis of sequence repeats, we found that identity of the sequence repeats falls in the range of 20-40% and, the superimposed structures of the most of the sequence repeats maintain similar overall folding. Analysis sequence repeats at the functional level reveals that most of the sequence repeats are involved in the function of the protein through functionally involved residues in the repeat regions. We also found that sequence repeats in single and two domain proteins often contained conserved sequence motifs for the function of the domain.
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Affiliation(s)
- David Mary Rajathei
- Department of Bioinformatics, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620024, Tamilnadu, India
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8
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Sato Y, Kameya M, Fushinobu S, Wakagi T, Arai H, Ishii M, Igarashi Y. A novel enzymatic system against oxidative stress in the thermophilic hydrogen-oxidizing bacterium Hydrogenobacter thermophilus. PLoS One 2012; 7:e34825. [PMID: 22485188 PMCID: PMC3317640 DOI: 10.1371/journal.pone.0034825] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 03/06/2012] [Indexed: 11/19/2022] Open
Abstract
Rubrerythrin (Rbr) is a non-heme iron protein composed of two distinctive domains and functions as a peroxidase in anaerobic organisms. A novel Rbr-like protein, ferriperoxin (Fpx), was identified in Hydrogenobacter thermophilus and was found not to possess the rubredoxin-like domain that is present in typical Rbrs. Although this protein is widely distributed among aerobic organisms, its function remains unknown. In this study, Fpx exhibited ferredoxin:NADPH oxidoreductase (FNR)-dependent peroxidase activity and reduced both hydrogen peroxide (H(2)O(2)) and organic hydroperoxide in the presence of NADPH and FNR as electron donors. The calculated K(m) and V(max) values of Fpx for organic hydroperoxides were comparable to that for H(2)O(2), demonstrating a multiple reactivity of Fpx towards hydroperoxides. An fpx gene disruptant was unable to grow under aerobic conditions, whereas its growth profiles were comparable to those of the wild-type strain under anaerobic and microaerobic conditions, clearly indicating the indispensability of Fpx as an antioxidant of H. thermophilus in aerobic environments. Structural analysis suggested that domain-swapping occurs in Fpx, and this domain-swapped structure is well conserved among thermophiles, implying the importance of structural stability of domain-swapped conformation for thermal environments. In addition, Fpx was located on a deep branch of the phylogenetic tree of Rbr and Rbr-like proteins. This finding, taken together with the wide distribution of Fpx among Bacteria and Archaea, suggests that Fpx is an ancestral type of Rbr homolog that functions as an essential antioxidant and may be part of an ancestral peroxide-detoxification system.
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Affiliation(s)
- Yuya Sato
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Masafumi Kameya
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Shinya Fushinobu
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Takayoshi Wakagi
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Hiroyuki Arai
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Masaharu Ishii
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- * E-mail:
| | - Yasuo Igarashi
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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9
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Thermofluor-based optimization strategy for the stabilization and crystallization of Campylobacter jejuni desulforubrerythrin. Protein Expr Purif 2012; 81:193-200. [DOI: 10.1016/j.pep.2011.10.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 09/30/2011] [Accepted: 10/03/2011] [Indexed: 11/19/2022]
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10
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Dillard BD, Demick JM, Adams MWW, Lanzilotta WN. A cryo-crystallographic time course for peroxide reduction by rubrerythrin from Pyrococcus furiosus. J Biol Inorg Chem 2011; 16:949-59. [PMID: 21647777 DOI: 10.1007/s00775-011-0795-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Accepted: 05/16/2011] [Indexed: 11/28/2022]
Abstract
High-resolution crystal structures of Pyrococcus furiosus rubrerythrin (PfRbr) in the resting (all-ferrous) state and at time points following exposure of the crystals to hydrogen peroxide are reported. This approach was possible because of the relativity slow turnover of PfRbr at room temperature. To this end, we were able to perform time-dependent peroxide treatment of the fully reduced enzyme, under strictly anaerobic conditions, in the crystalline state. In this work we demonstrate, for the first time, that turnover of a thermophilic rubrerythrin results in approximately 2-Å movement of one iron atom in the diiron site from a histidine to a carboxylate ligand. These results confirm that, despite the domain-swapped architecture, the hyperthermophilic rubrerythrins also utilize the classic combination of iron sites together with redox-dependent iron toggling to selectively reduce hydrogen peroxide over dioxygen. In addition, we have identified previously unobserved intermediates in the reaction cycle and observed structural changes that may explain the enzyme precipitation observed for the all-iron form of PfRbr upon oxidation to the all-ferric state.
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Affiliation(s)
- Bret D Dillard
- Department of Biochemistry and Molecular Biology, The Center for Metalloenzyme Studies, University of Georgia, Athens, GA 30602, USA
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11
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Pinto AF, Todorovic S, Hildebrandt P, Yamazaki M, Amano F, Igimi S, Romão CV, Teixeira M. Desulforubrerythrin from Campylobacter jejuni, a novel multidomain protein. J Biol Inorg Chem 2010; 16:501-10. [PMID: 21170562 DOI: 10.1007/s00775-010-0749-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 12/01/2010] [Indexed: 10/18/2022]
Abstract
A novel multidomain metalloprotein from Campylobacter jejuni was overexpressed in Escherichia coli, purified, and extensively characterized. This protein is isolated as a homotetramer of 24-kDa monomers. According to the amino acid sequence, each monomer was predicted to contain three structural domains: an N-terminal desulforedoxin-like domain, followed by a four-helix bundle domain harboring a non-sulfur μ-oxo diiron center, and a rubredoxin-like domain at the C-terminus. The three predicted iron sites were shown to be present and were studied by a combination of UV-vis, EPR, and resonance Raman spectroscopies, which allowed the determination of the electronic and redox properties of each site. The protein contains two FeCys(4) centers with reduction potentials of +240 mV (desulforedoxin-like center) and +185 mV (rubredoxin-like center). These centers are in the high-spin configuration in the as-isolated ferric form. The protein further accommodates a μ-oxo-bridged diiron site with reduction potentials of +270 and +235 mV for the two sequential redox transitions. The protein is rapidly reoxidized by hydrogen peroxide and has a significant NADH-linked hydrogen peroxide reductase activity of 1.8 μmol H(2)O(2) min(-1) mg(-1). Owing to its building blocks and its homology to the rubrerythrin family, the protein is named desulforubrerythrin. It represents a novel example of the large diversity of the organization of domains exhibited by this enzyme family.
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Affiliation(s)
- Ana F Pinto
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República (EAN), 2780-157, Oeiras, Portugal
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12
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Andrews SC. The Ferritin-like superfamily: Evolution of the biological iron storeman from a rubrerythrin-like ancestor. Biochim Biophys Acta Gen Subj 2010; 1800:691-705. [DOI: 10.1016/j.bbagen.2010.05.010] [Citation(s) in RCA: 228] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 05/20/2010] [Accepted: 05/21/2010] [Indexed: 11/25/2022]
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13
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Carrondo MA, Bento I, Matias PM, Lindley PF. Crystallographic evidence for dioxygen interactions with iron proteins. J Biol Inorg Chem 2007; 12:429-42. [PMID: 17318598 DOI: 10.1007/s00775-007-0213-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Accepted: 01/29/2007] [Indexed: 10/23/2022]
Abstract
The interaction of dioxygen with iron plays a key role in many important biological processes, such as dioxygen transport in the bloodstream and the reduction of dioxygen by iron in respiration. However, the catalytic mechanisms employed, for example in ligand oxidation, are not fully understood at the current time despite intensive biochemical, spectroscopic and structural studies. This review outlines the structural evidence obtained by X-ray crystallographic methods for the nature of the interactions between dioxygen and the metal in iron-containing proteins. Proteins involved in iron transport or electron transfer are not included.
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Affiliation(s)
- M Arménia Carrondo
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2781-901, Oeiras, Portugal.
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14
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Guy JE, Abreu IA, Moche M, Lindqvist Y, Whittle E, Shanklin J. A single mutation in the castor Delta9-18:0-desaturase changes reaction partitioning from desaturation to oxidase chemistry. Proc Natl Acad Sci U S A 2006; 103:17220-4. [PMID: 17088542 PMCID: PMC1859913 DOI: 10.1073/pnas.0607165103] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2006] [Indexed: 11/18/2022] Open
Abstract
Sequence analysis of the diiron cluster-containing soluble desaturases suggests they are unrelated to other diiron enzymes; however, structural alignment of the core four-helix bundle of desaturases to other diiron enzymes reveals a conserved iron binding motif with similar spacing in all enzymes of this structural class, implying a common evolutionary ancestry. Detailed structural comparison of the castor desaturase with that of a peroxidase, rubrerythrin, shows remarkable conservation of both identity and geometry of residues surrounding the diiron center, with the exception of residue 199. Position 199 is occupied by a threonine in the castor desaturase, but the equivalent position in rubrerythrin contains a glutamic acid. We previously hypothesized that a carboxylate in this location facilitates oxidase chemistry in rubrerythrin by the close apposition of a residue capable of facilitating proton transfer to the activated oxygen (in a hydrophobic cavity adjacent to the diiron center based on the crystal structure of the oxygen-binding mimic azide). Here we report that desaturase mutant T199D binds substrate but its desaturase activity decreases by approximately 2 x 10(3)-fold. However, it shows a >31-fold increase in peroxide-dependent oxidase activity with respect to WT desaturase, as monitored by single-turnover stopped-flow spectrometry. A 2.65-A crystal structure of T199D reveals active-site geometry remarkably similar to that of rubrerythrin, consistent with its enhanced function as an oxidase enzyme. That a single amino acid substitution can switch reactivity from desaturation to oxidation provides experimental support for the hypothesis that the desaturase evolved from an ancestral oxidase enzyme.
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Affiliation(s)
- Jodie E. Guy
- *Department of Medical Biochemistry and Biophysics, Division of Molecular Structural Biology, Karolinska Institutet, Tomtebodavägen 6, S-171 77 Stockholm, Sweden
| | - Isabel A. Abreu
- Department of Biology, Brookhaven National Laboratory, Upton, NY 11973; and
| | - Martin Moche
- Department of Medical Biochemistry and Biophysics and Structural Genomics Consortium, Karolinska Institutet, S-171 77 Stockholm, Sweden
| | - Ylva Lindqvist
- *Department of Medical Biochemistry and Biophysics, Division of Molecular Structural Biology, Karolinska Institutet, Tomtebodavägen 6, S-171 77 Stockholm, Sweden
| | - Edward Whittle
- Department of Biology, Brookhaven National Laboratory, Upton, NY 11973; and
| | - John Shanklin
- Department of Biology, Brookhaven National Laboratory, Upton, NY 11973; and
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15
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Hindupur A, Liu D, Zhao Y, Bellamy HD, White MA, Fox RO. The crystal structure of the E. coli stress protein YciF. Protein Sci 2006; 15:2605-11. [PMID: 17001035 PMCID: PMC2242421 DOI: 10.1110/ps.062307706] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
YciF is a protein that is up-regulated when bacteria experience stress conditions, and is highly conserved in a range of bacterial species. YciF has no known structure or biochemical function. To learn more about its potential molecular function and its role in the bacterial stress response, we solved the crystal structure of YciF at 2.0 Angstrom resolution by the multiple wavelength anomalous diffraction (MAD) technique. YciF is a dimer in solution, and forms a homodimer in the crystal asymmetric unit. The two monomers form a dimer with a molecular twofold axis, with a significant burial of solvent-accessible surface area. The protein is an all-alpha protein composed of five helices: a four-helix bundle, and a short additional helix at the dimer interface. The protein is structurally similar to portions of the diiron-containing proteins, rubrerythrin and the Bacillus anthracis Dlp-2.
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Affiliation(s)
- Aditya Hindupur
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Texas 77555-0647, USA
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16
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McMullan D, Canaves JM, Quijano K, Abdubek P, Nigoghossian E, Haugen J, Klock HE, Vincent J, Hale J, Paulsen J, Lesley SA. High-throughput protein production for X-ray crystallography and use of size exclusion chromatography to validate or refute computational biological unit predictions. ACTA ACUST UNITED AC 2006; 6:135-41. [PMID: 16211510 DOI: 10.1007/s10969-005-2898-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2004] [Accepted: 02/15/2005] [Indexed: 11/29/2022]
Abstract
The production of large numbers of highly purified proteins for X-ray crystallography is a significant bottleneck in structural genomics. At the Joint Center for Structural Genomics (JCSG; http://www.jcsg.org), specific automated protein expression, purification, and analytical methods are being utilized to study the proteome of Thermotoga maritima. Anion exchange and size exclusion chromatography (SEC), intended for the production of highly purified proteins, have been automated and the procedures are described here in detail. Analytical SEC has been included as a standard quality control test. A biological unit (BU) is the macromolecule that has been proven or is presumed to be functional. Correct assignment of BUs from protein structures can be difficult. BU predictions obtained via the Protein Quaternary Structure file server (PQS; http://pqs.ebi.ac.uk/) were compared to SEC data for 16 representative T. maritima proteins whose structures were solved at the JCSG, revealing an inconsistency in five cases. Herein, we report that SEC can be used to validate or disprove PQS-derived oligomeric models. A substantial amount of associated SEC and structural data should enable us to use certain PQS parameters to gauge the accuracy of these computational models and to generally improve their predictions.
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Affiliation(s)
- Daniel McMullan
- Joint Center for Structural Genomics, Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121-1127, USA
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Tempel W, Liu ZJ, Schubot FD, Shah A, Weinberg MV, Jenney FE, Arendall WB, Adams MWW, Richardson JS, Richardson DC, Rose JP, Wang BC. Structural genomics of Pyrococcus furiosus: X-ray crystallography reveals 3D domain swapping in rubrerythrin. Proteins 2006; 57:878-82. [PMID: 15468318 DOI: 10.1002/prot.20280] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Wolfram Tempel
- Southeast Collaboratory for Structural Genomics, Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, USA
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18
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Iyer RB, Silaghi-Dumitrescu R, Kurtz DM, Lanzilotta WN. High-resolution crystal structures of Desulfovibrio vulgaris (Hildenborough) nigerythrin: facile, redox-dependent iron movement, domain interface variability, and peroxidase activity in the rubrerythrins. J Biol Inorg Chem 2005; 10:407-16. [PMID: 15895271 DOI: 10.1007/s00775-005-0650-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2005] [Accepted: 04/13/2005] [Indexed: 10/25/2022]
Abstract
High-resolution crystal structures of Desulfovibrio vulgaris nigerythrin (DvNgr), a member of the rubrerythrin (Rbr) family, demonstrate an approximately 2-A movement of one iron (Fe1) of the diiron site from a carboxylate to a histidine ligand upon conversion of the mixed-valent ([Fe2(II),Fe1(III)]) to diferrous states, even at cryogenic temperatures. This Glu<-->His ligand "toggling" of one iron, which also occurs in DvRbr, thus, appears to be a characteristic feature of Rbr-type diiron sites. Unique features of DvNgr revealed by these structures include redox-induced flipping of a peptide carbonyl that reversibly forms a hydrogen bond to the histidine ligand to Fe1 of the diiron site, an intra-subunit proximal orientation of the rubredoxin-(Rub)-like and diiron domains, and an electron transfer pathway consisting of six covalent and two hydrogen bonds connecting the Rub-like iron with Fe2 of the diiron site. This pathway can account for DvNgr's relatively rapid peroxidase turnover. The characteristic combination of iron sites together with the redox-dependent iron toggling between protein ligands can account for the selectivity of Rbrs for hydrogen peroxide over dioxygen.
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Affiliation(s)
- Ramesh B Iyer
- Department of Chemistry, University of Georgia, Athens, GA 30602, USA
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